summary refs log tree commit diff
path: root/malloc/malloc.c
blob: 6b4fc72b200a6432b7b4ceb145b2f8bc9011fa1c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
/* Malloc implementation for multiple threads without lock contention.
   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>
   and Doug Lea <dl@cs.oswego.edu>, 1996.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

/* V2.6.4-pt3 Thu Feb 20 1997

  This work is mainly derived from malloc-2.6.4 by Doug Lea
  <dl@cs.oswego.edu>, which is available from:

                 ftp://g.oswego.edu/pub/misc/malloc.c

  Most of the original comments are reproduced in the code below.

* Why use this malloc?

  This is not the fastest, most space-conserving, most portable, or
  most tunable malloc ever written. However it is among the fastest
  while also being among the most space-conserving, portable and tunable.
  Consistent balance across these factors results in a good general-purpose
  allocator. For a high-level description, see
     http://g.oswego.edu/dl/html/malloc.html

  On many systems, the standard malloc implementation is by itself not
  thread-safe, and therefore wrapped with a single global lock around
  all malloc-related functions.  In some applications, especially with
  multiple available processors, this can lead to contention problems
  and bad performance.  This malloc version was designed with the goal
  to avoid waiting for locks as much as possible.  Statistics indicate
  that this goal is achieved in many cases.

* Synopsis of public routines

  (Much fuller descriptions are contained in the program documentation below.)

  ptmalloc_init();
     Initialize global configuration.  When compiled for multiple threads,
     this function must be called once before any other function in the
     package.  It is not required otherwise.  It is called automatically
     in the Linux/GNU C libray or when compiling with MALLOC_HOOKS.
  malloc(size_t n);
     Return a pointer to a newly allocated chunk of at least n bytes, or null
     if no space is available.
  free(Void_t* p);
     Release the chunk of memory pointed to by p, or no effect if p is null.
  realloc(Void_t* p, size_t n);
     Return a pointer to a chunk of size n that contains the same data
     as does chunk p up to the minimum of (n, p's size) bytes, or null
     if no space is available. The returned pointer may or may not be
     the same as p. If p is null, equivalent to malloc.  Unless the
     #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
     size argument of zero (re)allocates a minimum-sized chunk.
  memalign(size_t alignment, size_t n);
     Return a pointer to a newly allocated chunk of n bytes, aligned
     in accord with the alignment argument, which must be a power of
     two.
  valloc(size_t n);
     Equivalent to memalign(pagesize, n), where pagesize is the page
     size of the system (or as near to this as can be figured out from
     all the includes/defines below.)
  pvalloc(size_t n);
     Equivalent to valloc(minimum-page-that-holds(n)), that is,
     round up n to nearest pagesize.
  calloc(size_t unit, size_t quantity);
     Returns a pointer to quantity * unit bytes, with all locations
     set to zero.
  cfree(Void_t* p);
     Equivalent to free(p).
  malloc_trim(size_t pad);
     Release all but pad bytes of freed top-most memory back
     to the system. Return 1 if successful, else 0.
  malloc_usable_size(Void_t* p);
     Report the number usable allocated bytes associated with allocated
     chunk p. This may or may not report more bytes than were requested,
     due to alignment and minimum size constraints.
  malloc_stats();
     Prints brief summary statistics on stderr.
  mallinfo()
     Returns (by copy) a struct containing various summary statistics.
  mallopt(int parameter_number, int parameter_value)
     Changes one of the tunable parameters described below. Returns
     1 if successful in changing the parameter, else 0.

* Vital statistics:

  Alignment:                            8-byte
       8 byte alignment is currently hardwired into the design.  This
       seems to suffice for all current machines and C compilers.

  Assumed pointer representation:       4 or 8 bytes
       Code for 8-byte pointers is untested by me but has worked
       reliably by Wolfram Gloger, who contributed most of the
       changes supporting this.

  Assumed size_t  representation:       4 or 8 bytes
       Note that size_t is allowed to be 4 bytes even if pointers are 8.

  Minimum overhead per allocated chunk: 4 or 8 bytes
       Each malloced chunk has a hidden overhead of 4 bytes holding size
       and status information.

  Minimum allocated size: 4-byte ptrs:  16 bytes    (including 4 overhead)
                          8-byte ptrs:  24/32 bytes (including, 4/8 overhead)

       When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
       ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
       needed; 4 (8) for a trailing size field
       and 8 (16) bytes for free list pointers. Thus, the minimum
       allocatable size is 16/24/32 bytes.

       Even a request for zero bytes (i.e., malloc(0)) returns a
       pointer to something of the minimum allocatable size.

  Maximum allocated size: 4-byte size_t: 2^31 -  8 bytes
                          8-byte size_t: 2^63 - 16 bytes

       It is assumed that (possibly signed) size_t bit values suffice to
       represent chunk sizes. `Possibly signed' is due to the fact
       that `size_t' may be defined on a system as either a signed or
       an unsigned type. To be conservative, values that would appear
       as negative numbers are avoided.
       Requests for sizes with a negative sign bit will return a
       minimum-sized chunk.

  Maximum overhead wastage per allocated chunk: normally 15 bytes

       Alignment demands, plus the minimum allocatable size restriction
       make the normal worst-case wastage 15 bytes (i.e., up to 15
       more bytes will be allocated than were requested in malloc), with
       two exceptions:
         1. Because requests for zero bytes allocate non-zero space,
            the worst case wastage for a request of zero bytes is 24 bytes.
         2. For requests >= mmap_threshold that are serviced via
            mmap(), the worst case wastage is 8 bytes plus the remainder
            from a system page (the minimal mmap unit); typically 4096 bytes.

* Limitations

    Here are some features that are NOT currently supported

    * No automated mechanism for fully checking that all accesses
      to malloced memory stay within their bounds.
    * No support for compaction.

* Synopsis of compile-time options:

    People have reported using previous versions of this malloc on all
    versions of Unix, sometimes by tweaking some of the defines
    below. It has been tested most extensively on Solaris and
    Linux. People have also reported adapting this malloc for use in
    stand-alone embedded systems.

    The implementation is in straight, hand-tuned ANSI C.  Among other
    consequences, it uses a lot of macros.  Because of this, to be at
    all usable, this code should be compiled using an optimizing compiler
    (for example gcc -O2) that can simplify expressions and control
    paths.

  __STD_C                  (default: derived from C compiler defines)
     Nonzero if using ANSI-standard C compiler, a C++ compiler, or
     a C compiler sufficiently close to ANSI to get away with it.
  MALLOC_DEBUG             (default: NOT defined)
     Define to enable debugging. Adds fairly extensive assertion-based
     checking to help track down memory errors, but noticeably slows down
     execution.
  MALLOC_HOOKS             (default: NOT defined)
     Define to enable support run-time replacement of the allocation
     functions through user-defined `hooks'.
  REALLOC_ZERO_BYTES_FREES (default: NOT defined)
     Define this if you think that realloc(p, 0) should be equivalent
     to free(p). Otherwise, since malloc returns a unique pointer for
     malloc(0), so does realloc(p, 0).
  HAVE_MEMCPY               (default: defined)
     Define if you are not otherwise using ANSI STD C, but still
     have memcpy and memset in your C library and want to use them.
     Otherwise, simple internal versions are supplied.
  USE_MEMCPY               (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
     Define as 1 if you want the C library versions of memset and
     memcpy called in realloc and calloc (otherwise macro versions are used).
     At least on some platforms, the simple macro versions usually
     outperform libc versions.
  HAVE_MMAP                 (default: defined as 1)
     Define to non-zero to optionally make malloc() use mmap() to
     allocate very large blocks.
  HAVE_MREMAP                 (default: defined as 0 unless Linux libc set)
     Define to non-zero to optionally make realloc() use mremap() to
     reallocate very large blocks.
  malloc_getpagesize        (default: derived from system #includes)
     Either a constant or routine call returning the system page size.
  HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
     Optionally define if you are on a system with a /usr/include/malloc.h
     that declares struct mallinfo. It is not at all necessary to
     define this even if you do, but will ensure consistency.
  INTERNAL_SIZE_T           (default: size_t)
     Define to a 32-bit type (probably `unsigned int') if you are on a
     64-bit machine, yet do not want or need to allow malloc requests of
     greater than 2^31 to be handled. This saves space, especially for
     very small chunks.
  _LIBC                     (default: NOT defined)
     Defined only when compiled as part of the Linux libc/glibc.
     Also note that there is some odd internal name-mangling via defines
     (for example, internally, `malloc' is named `mALLOc') needed
     when compiling in this case. These look funny but don't otherwise
     affect anything.
  LACKS_UNISTD_H            (default: undefined)
     Define this if your system does not have a <unistd.h>.
  MORECORE                  (default: sbrk)
     The name of the routine to call to obtain more memory from the system.
  MORECORE_FAILURE          (default: -1)
     The value returned upon failure of MORECORE.
  MORECORE_CLEARS           (default 1)
     True (1) if the routine mapped to MORECORE zeroes out memory (which
     holds for sbrk).
  DEFAULT_TRIM_THRESHOLD
  DEFAULT_TOP_PAD
  DEFAULT_MMAP_THRESHOLD
  DEFAULT_MMAP_MAX
     Default values of tunable parameters (described in detail below)
     controlling interaction with host system routines (sbrk, mmap, etc).
     These values may also be changed dynamically via mallopt(). The
     preset defaults are those that give best performance for typical
     programs/systems.
  DEFAULT_CHECK_ACTION
     When the standard debugging hooks are in place, and a pointer is
     detected as corrupt, do nothing (0), print an error message (1),
     or call abort() (2).


*/

/*

* Compile-time options for multiple threads:

  USE_PTHREADS, USE_THR, USE_SPROC
     Define one of these as 1 to select the thread interface:
     POSIX threads, Solaris threads or SGI sproc's, respectively.
     If none of these is defined as non-zero, you get a `normal'
     malloc implementation which is not thread-safe.  Support for
     multiple threads requires HAVE_MMAP=1.  As an exception, when
     compiling for GNU libc, i.e. when _LIBC is defined, then none of
     the USE_... symbols have to be defined.

  HEAP_MIN_SIZE
  HEAP_MAX_SIZE
     When thread support is enabled, additional `heap's are created
     with mmap calls.  These are limited in size; HEAP_MIN_SIZE should
     be a multiple of the page size, while HEAP_MAX_SIZE must be a power
     of two for alignment reasons.  HEAP_MAX_SIZE should be at least
     twice as large as the mmap threshold.
  THREAD_STATS
     When this is defined as non-zero, some statistics on mutex locking
     are computed.

*/




/* Preliminaries */

#ifndef __STD_C
#if defined (__STDC__)
#define __STD_C     1
#else
#if __cplusplus
#define __STD_C     1
#else
#define __STD_C     0
#endif /*__cplusplus*/
#endif /*__STDC__*/
#endif /*__STD_C*/

#ifndef Void_t
#if __STD_C
#define Void_t      void
#else
#define Void_t      char
#endif
#endif /*Void_t*/

#if __STD_C
# include <stddef.h>   /* for size_t */
# if defined(_LIBC) || defined(MALLOC_HOOKS)
#  include <stdlib.h>  /* for getenv(), abort() */
# endif
#else
# include <sys/types.h>
#endif

/* Macros for handling mutexes and thread-specific data.  This is
   included early, because some thread-related header files (such as
   pthread.h) should be included before any others. */
#include "thread-m.h"

#ifdef __cplusplus
extern "C" {
#endif

#include <stdio.h>    /* needed for malloc_stats */


/*
  Compile-time options
*/


/*
    Debugging:

    Because freed chunks may be overwritten with link fields, this
    malloc will often die when freed memory is overwritten by user
    programs.  This can be very effective (albeit in an annoying way)
    in helping track down dangling pointers.

    If you compile with -DMALLOC_DEBUG, a number of assertion checks are
    enabled that will catch more memory errors. You probably won't be
    able to make much sense of the actual assertion errors, but they
    should help you locate incorrectly overwritten memory.  The
    checking is fairly extensive, and will slow down execution
    noticeably. Calling malloc_stats or mallinfo with MALLOC_DEBUG set will
    attempt to check every non-mmapped allocated and free chunk in the
    course of computing the summaries. (By nature, mmapped regions
    cannot be checked very much automatically.)

    Setting MALLOC_DEBUG may also be helpful if you are trying to modify
    this code. The assertions in the check routines spell out in more
    detail the assumptions and invariants underlying the algorithms.

*/

#if MALLOC_DEBUG
#include <assert.h>
#else
#define assert(x) ((void)0)
#endif


/*
  INTERNAL_SIZE_T is the word-size used for internal bookkeeping
  of chunk sizes. On a 64-bit machine, you can reduce malloc
  overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int'
  at the expense of not being able to handle requests greater than
  2^31. This limitation is hardly ever a concern; you are encouraged
  to set this. However, the default version is the same as size_t.
*/

#ifndef INTERNAL_SIZE_T
#define INTERNAL_SIZE_T size_t
#endif

/*
  REALLOC_ZERO_BYTES_FREES should be set if a call to
  realloc with zero bytes should be the same as a call to free.
  Some people think it should. Otherwise, since this malloc
  returns a unique pointer for malloc(0), so does realloc(p, 0).
*/


/*   #define REALLOC_ZERO_BYTES_FREES */


/*
  HAVE_MEMCPY should be defined if you are not otherwise using
  ANSI STD C, but still have memcpy and memset in your C library
  and want to use them in calloc and realloc. Otherwise simple
  macro versions are defined here.

  USE_MEMCPY should be defined as 1 if you actually want to
  have memset and memcpy called. People report that the macro
  versions are often enough faster than libc versions on many
  systems that it is better to use them.

*/

#define HAVE_MEMCPY 1

#ifndef USE_MEMCPY
#ifdef HAVE_MEMCPY
#define USE_MEMCPY 1
#else
#define USE_MEMCPY 0
#endif
#endif

#if (__STD_C || defined(HAVE_MEMCPY))

#if __STD_C
void* memset(void*, int, size_t);
void* memcpy(void*, const void*, size_t);
#else
Void_t* memset();
Void_t* memcpy();
#endif
#endif

#if USE_MEMCPY

/* The following macros are only invoked with (2n+1)-multiples of
   INTERNAL_SIZE_T units, with a positive integer n. This is exploited
   for fast inline execution when n is small. */

#define MALLOC_ZERO(charp, nbytes)                                            \
do {                                                                          \
  INTERNAL_SIZE_T mzsz = (nbytes);                                            \
  if(mzsz <= 9*sizeof(mzsz)) {                                                \
    INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp);                         \
    if(mzsz >= 5*sizeof(mzsz)) {     *mz++ = 0;                               \
                                     *mz++ = 0;                               \
      if(mzsz >= 7*sizeof(mzsz)) {   *mz++ = 0;                               \
                                     *mz++ = 0;                               \
        if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0;                               \
                                     *mz++ = 0; }}}                           \
                                     *mz++ = 0;                               \
                                     *mz++ = 0;                               \
                                     *mz   = 0;                               \
  } else memset((charp), 0, mzsz);                                            \
} while(0)

#define MALLOC_COPY(dest,src,nbytes)                                          \
do {                                                                          \
  INTERNAL_SIZE_T mcsz = (nbytes);                                            \
  if(mcsz <= 9*sizeof(mcsz)) {                                                \
    INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src);                        \
    INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest);                       \
    if(mcsz >= 5*sizeof(mcsz)) {     *mcdst++ = *mcsrc++;                     \
                                     *mcdst++ = *mcsrc++;                     \
      if(mcsz >= 7*sizeof(mcsz)) {   *mcdst++ = *mcsrc++;                     \
                                     *mcdst++ = *mcsrc++;                     \
        if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++;                     \
                                     *mcdst++ = *mcsrc++; }}}                 \
                                     *mcdst++ = *mcsrc++;                     \
                                     *mcdst++ = *mcsrc++;                     \
                                     *mcdst   = *mcsrc  ;                     \
  } else memcpy(dest, src, mcsz);                                             \
} while(0)

#else /* !USE_MEMCPY */

/* Use Duff's device for good zeroing/copying performance. */

#define MALLOC_ZERO(charp, nbytes)                                            \
do {                                                                          \
  INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp);                           \
  long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
  if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
  switch (mctmp) {                                                            \
    case 0: for(;;) { *mzp++ = 0;                                             \
    case 7:           *mzp++ = 0;                                             \
    case 6:           *mzp++ = 0;                                             \
    case 5:           *mzp++ = 0;                                             \
    case 4:           *mzp++ = 0;                                             \
    case 3:           *mzp++ = 0;                                             \
    case 2:           *mzp++ = 0;                                             \
    case 1:           *mzp++ = 0; if(mcn <= 0) break; mcn--; }                \
  }                                                                           \
} while(0)

#define MALLOC_COPY(dest,src,nbytes)                                          \
do {                                                                          \
  INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src;                            \
  INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest;                           \
  long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
  if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
  switch (mctmp) {                                                            \
    case 0: for(;;) { *mcdst++ = *mcsrc++;                                    \
    case 7:           *mcdst++ = *mcsrc++;                                    \
    case 6:           *mcdst++ = *mcsrc++;                                    \
    case 5:           *mcdst++ = *mcsrc++;                                    \
    case 4:           *mcdst++ = *mcsrc++;                                    \
    case 3:           *mcdst++ = *mcsrc++;                                    \
    case 2:           *mcdst++ = *mcsrc++;                                    \
    case 1:           *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; }       \
  }                                                                           \
} while(0)

#endif


/*
  Define HAVE_MMAP to optionally make malloc() use mmap() to
  allocate very large blocks.  These will be returned to the
  operating system immediately after a free().
*/

#ifndef HAVE_MMAP
#define HAVE_MMAP 1
#endif

/*
  Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
  large blocks.  This is currently only possible on Linux with
  kernel versions newer than 1.3.77.
*/

#ifndef HAVE_MREMAP
#define HAVE_MREMAP defined(__linux__)
#endif

#if HAVE_MMAP

#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>

#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
#define MAP_ANONYMOUS MAP_ANON
#endif

#endif /* HAVE_MMAP */

/*
  Access to system page size. To the extent possible, this malloc
  manages memory from the system in page-size units.

  The following mechanics for getpagesize were adapted from
  bsd/gnu getpagesize.h
*/

#ifndef LACKS_UNISTD_H
#  include <unistd.h>
#endif

#ifndef malloc_getpagesize
#  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
#    ifndef _SC_PAGE_SIZE
#      define _SC_PAGE_SIZE _SC_PAGESIZE
#    endif
#  endif
#  ifdef _SC_PAGE_SIZE
#    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
#  else
#    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
       extern size_t getpagesize();
#      define malloc_getpagesize getpagesize()
#    else
#      include <sys/param.h>
#      ifdef EXEC_PAGESIZE
#        define malloc_getpagesize EXEC_PAGESIZE
#      else
#        ifdef NBPG
#          ifndef CLSIZE
#            define malloc_getpagesize NBPG
#          else
#            define malloc_getpagesize (NBPG * CLSIZE)
#          endif
#        else
#          ifdef NBPC
#            define malloc_getpagesize NBPC
#          else
#            ifdef PAGESIZE
#              define malloc_getpagesize PAGESIZE
#            else
#              define malloc_getpagesize (4096) /* just guess */
#            endif
#          endif
#        endif
#      endif
#    endif
#  endif
#endif



/*

  This version of malloc supports the standard SVID/XPG mallinfo
  routine that returns a struct containing the same kind of
  information you can get from malloc_stats. It should work on
  any SVID/XPG compliant system that has a /usr/include/malloc.h
  defining struct mallinfo. (If you'd like to install such a thing
  yourself, cut out the preliminary declarations as described above
  and below and save them in a malloc.h file. But there's no
  compelling reason to bother to do this.)

  The main declaration needed is the mallinfo struct that is returned
  (by-copy) by mallinfo().  The SVID/XPG malloinfo struct contains a
  bunch of fields, most of which are not even meaningful in this
  version of malloc. Some of these fields are are instead filled by
  mallinfo() with other numbers that might possibly be of interest.

  HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
  /usr/include/malloc.h file that includes a declaration of struct
  mallinfo.  If so, it is included; else an SVID2/XPG2 compliant
  version is declared below.  These must be precisely the same for
  mallinfo() to work.

*/

/* #define HAVE_USR_INCLUDE_MALLOC_H */

#if HAVE_USR_INCLUDE_MALLOC_H
# include "/usr/include/malloc.h"
#else
# ifdef _LIBC
#  include "malloc.h"
# else
#  include "ptmalloc.h"
# endif
#endif



#ifndef DEFAULT_TRIM_THRESHOLD
#define DEFAULT_TRIM_THRESHOLD (128 * 1024)
#endif

/*
    M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
      to keep before releasing via malloc_trim in free().

      Automatic trimming is mainly useful in long-lived programs.
      Because trimming via sbrk can be slow on some systems, and can
      sometimes be wasteful (in cases where programs immediately
      afterward allocate more large chunks) the value should be high
      enough so that your overall system performance would improve by
      releasing.

      The trim threshold and the mmap control parameters (see below)
      can be traded off with one another. Trimming and mmapping are
      two different ways of releasing unused memory back to the
      system. Between these two, it is often possible to keep
      system-level demands of a long-lived program down to a bare
      minimum. For example, in one test suite of sessions measuring
      the XF86 X server on Linux, using a trim threshold of 128K and a
      mmap threshold of 192K led to near-minimal long term resource
      consumption.

      If you are using this malloc in a long-lived program, it should
      pay to experiment with these values.  As a rough guide, you
      might set to a value close to the average size of a process
      (program) running on your system.  Releasing this much memory
      would allow such a process to run in memory.  Generally, it's
      worth it to tune for trimming rather than memory mapping when a
      program undergoes phases where several large chunks are
      allocated and released in ways that can reuse each other's
      storage, perhaps mixed with phases where there are no such
      chunks at all.  And in well-behaved long-lived programs,
      controlling release of large blocks via trimming versus mapping
      is usually faster.

      However, in most programs, these parameters serve mainly as
      protection against the system-level effects of carrying around
      massive amounts of unneeded memory. Since frequent calls to
      sbrk, mmap, and munmap otherwise degrade performance, the default
      parameters are set to relatively high values that serve only as
      safeguards.

      The default trim value is high enough to cause trimming only in
      fairly extreme (by current memory consumption standards) cases.
      It must be greater than page size to have any useful effect.  To
      disable trimming completely, you can set to (unsigned long)(-1);


*/


#ifndef DEFAULT_TOP_PAD
#define DEFAULT_TOP_PAD        (0)
#endif

/*
    M_TOP_PAD is the amount of extra `padding' space to allocate or
      retain whenever sbrk is called. It is used in two ways internally:

      * When sbrk is called to extend the top of the arena to satisfy
        a new malloc request, this much padding is added to the sbrk
        request.

      * When malloc_trim is called automatically from free(),
        it is used as the `pad' argument.

      In both cases, the actual amount of padding is rounded
      so that the end of the arena is always a system page boundary.

      The main reason for using padding is to avoid calling sbrk so
      often. Having even a small pad greatly reduces the likelihood
      that nearly every malloc request during program start-up (or
      after trimming) will invoke sbrk, which needlessly wastes
      time.

      Automatic rounding-up to page-size units is normally sufficient
      to avoid measurable overhead, so the default is 0.  However, in
      systems where sbrk is relatively slow, it can pay to increase
      this value, at the expense of carrying around more memory than
      the program needs.

*/


#ifndef DEFAULT_MMAP_THRESHOLD
#define DEFAULT_MMAP_THRESHOLD (128 * 1024)
#endif

/*

    M_MMAP_THRESHOLD is the request size threshold for using mmap()
      to service a request. Requests of at least this size that cannot
      be allocated using already-existing space will be serviced via mmap.
      (If enough normal freed space already exists it is used instead.)

      Using mmap segregates relatively large chunks of memory so that
      they can be individually obtained and released from the host
      system. A request serviced through mmap is never reused by any
      other request (at least not directly; the system may just so
      happen to remap successive requests to the same locations).

      Segregating space in this way has the benefit that mmapped space
      can ALWAYS be individually released back to the system, which
      helps keep the system level memory demands of a long-lived
      program low. Mapped memory can never become `locked' between
      other chunks, as can happen with normally allocated chunks, which
      menas that even trimming via malloc_trim would not release them.

      However, it has the disadvantages that:

         1. The space cannot be reclaimed, consolidated, and then
            used to service later requests, as happens with normal chunks.
         2. It can lead to more wastage because of mmap page alignment
            requirements
         3. It causes malloc performance to be more dependent on host
            system memory management support routines which may vary in
            implementation quality and may impose arbitrary
            limitations. Generally, servicing a request via normal
            malloc steps is faster than going through a system's mmap.

      All together, these considerations should lead you to use mmap
      only for relatively large requests.


*/



#ifndef DEFAULT_MMAP_MAX
#if HAVE_MMAP
#define DEFAULT_MMAP_MAX       (1024)
#else
#define DEFAULT_MMAP_MAX       (0)
#endif
#endif

/*
    M_MMAP_MAX is the maximum number of requests to simultaneously
      service using mmap. This parameter exists because:

         1. Some systems have a limited number of internal tables for
            use by mmap.
         2. In most systems, overreliance on mmap can degrade overall
            performance.
         3. If a program allocates many large regions, it is probably
            better off using normal sbrk-based allocation routines that
            can reclaim and reallocate normal heap memory. Using a
            small value allows transition into this mode after the
            first few allocations.

      Setting to 0 disables all use of mmap.  If HAVE_MMAP is not set,
      the default value is 0, and attempts to set it to non-zero values
      in mallopt will fail.
*/



#ifndef DEFAULT_CHECK_ACTION
#define DEFAULT_CHECK_ACTION 1
#endif

/* What to do if the standard debugging hooks are in place and a
   corrupt pointer is detected: do nothing (0), print an error message
   (1), or call abort() (2). */



#define HEAP_MIN_SIZE (32*1024)
#define HEAP_MAX_SIZE (1024*1024) /* must be a power of two */

/* HEAP_MIN_SIZE and HEAP_MAX_SIZE limit the size of mmap()ed heaps
      that are dynamically created for multi-threaded programs.  The
      maximum size must be a power of two, for fast determination of
      which heap belongs to a chunk.  It should be much larger than
      the mmap threshold, so that requests with a size just below that
      threshold can be fulfilled without creating too many heaps.
*/



#ifndef THREAD_STATS
#define THREAD_STATS 0
#endif

/* If THREAD_STATS is non-zero, some statistics on mutex locking are
   computed. */


/*

  Special defines for the Linux/GNU C library.

*/


#ifdef _LIBC

#if __STD_C

Void_t * __default_morecore (ptrdiff_t);
Void_t *(*__morecore)(ptrdiff_t) = __default_morecore;

#else

Void_t * __default_morecore ();
Void_t *(*__morecore)() = __default_morecore;

#endif

#define MORECORE (*__morecore)
#define MORECORE_FAILURE 0
#define MORECORE_CLEARS 1
#define mmap    __mmap
#define munmap  __munmap
#define mremap  __mremap
#undef malloc_getpagesize
#define malloc_getpagesize __getpagesize()

#else /* _LIBC */

#if __STD_C
extern Void_t*     sbrk(ptrdiff_t);
#else
extern Void_t*     sbrk();
#endif

#ifndef MORECORE
#define MORECORE sbrk
#endif

#ifndef MORECORE_FAILURE
#define MORECORE_FAILURE -1
#endif

#ifndef MORECORE_CLEARS
#define MORECORE_CLEARS 1
#endif

#endif /* _LIBC */

#ifdef _LIBC

#define cALLOc          __libc_calloc
#define fREe            __libc_free
#define mALLOc          __libc_malloc
#define mEMALIGn        __libc_memalign
#define rEALLOc         __libc_realloc
#define vALLOc          __libc_valloc
#define pvALLOc         __libc_pvalloc
#define mALLINFo        __libc_mallinfo
#define mALLOPt         __libc_mallopt
#define mALLOC_STATs    __malloc_stats
#define mALLOC_USABLE_SIZe __malloc_usable_size
#define mALLOC_TRIm     __malloc_trim
#define mALLOC_GET_STATe __malloc_get_state
#define mALLOC_SET_STATe __malloc_set_state

#else

#define cALLOc          calloc
#define fREe            free
#define mALLOc          malloc
#define mEMALIGn        memalign
#define rEALLOc         realloc
#define vALLOc          valloc
#define pvALLOc         pvalloc
#define mALLINFo        mallinfo
#define mALLOPt         mallopt
#define mALLOC_STATs    malloc_stats
#define mALLOC_USABLE_SIZe malloc_usable_size
#define mALLOC_TRIm     malloc_trim
#define mALLOC_GET_STATe malloc_get_state
#define mALLOC_SET_STATe malloc_set_state

#endif

/* Public routines */

#if __STD_C

#ifndef _LIBC
void    ptmalloc_init(void);
#endif
Void_t* mALLOc(size_t);
void    fREe(Void_t*);
Void_t* rEALLOc(Void_t*, size_t);
Void_t* mEMALIGn(size_t, size_t);
Void_t* vALLOc(size_t);
Void_t* pvALLOc(size_t);
Void_t* cALLOc(size_t, size_t);
void    cfree(Void_t*);
int     mALLOC_TRIm(size_t);
size_t  mALLOC_USABLE_SIZe(Void_t*);
void    mALLOC_STATs(void);
int     mALLOPt(int, int);
struct mallinfo mALLINFo(void);
Void_t* mALLOC_GET_STATe(void);
int     mALLOC_SET_STATe(Void_t*);

#else /* !__STD_C */

#ifndef _LIBC
void    ptmalloc_init();
#endif
Void_t* mALLOc();
void    fREe();
Void_t* rEALLOc();
Void_t* mEMALIGn();
Void_t* vALLOc();
Void_t* pvALLOc();
Void_t* cALLOc();
void    cfree();
int     mALLOC_TRIm();
size_t  mALLOC_USABLE_SIZe();
void    mALLOC_STATs();
int     mALLOPt();
struct mallinfo mALLINFo();
Void_t* mALLOC_GET_STATe();
int     mALLOC_SET_STATe();

#endif /* __STD_C */


#ifdef __cplusplus
};  /* end of extern "C" */
#endif

#if !defined(NO_THREADS) && !HAVE_MMAP
"Can't have threads support without mmap"
#endif


/*
  Type declarations
*/


struct malloc_chunk
{
  INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */
  INTERNAL_SIZE_T size;      /* Size in bytes, including overhead. */
  struct malloc_chunk* fd;   /* double links -- used only if free. */
  struct malloc_chunk* bk;
};

typedef struct malloc_chunk* mchunkptr;

/*

   malloc_chunk details:

    (The following includes lightly edited explanations by Colin Plumb.)

    Chunks of memory are maintained using a `boundary tag' method as
    described in e.g., Knuth or Standish.  (See the paper by Paul
    Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
    survey of such techniques.)  Sizes of free chunks are stored both
    in the front of each chunk and at the end.  This makes
    consolidating fragmented chunks into bigger chunks very fast.  The
    size fields also hold bits representing whether chunks are free or
    in use.

    An allocated chunk looks like this:


    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Size of previous chunk, if allocated            | |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Size of chunk, in bytes                         |P|
      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             User data starts here...                          .
            .                                                               .
            .             (malloc_usable_space() bytes)                     .
            .                                                               |
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Size of chunk                                     |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


    Where "chunk" is the front of the chunk for the purpose of most of
    the malloc code, but "mem" is the pointer that is returned to the
    user.  "Nextchunk" is the beginning of the next contiguous chunk.

    Chunks always begin on even word boundaries, so the mem portion
    (which is returned to the user) is also on an even word boundary, and
    thus double-word aligned.

    Free chunks are stored in circular doubly-linked lists, and look like this:

    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Size of previous chunk                            |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    `head:' |             Size of chunk, in bytes                         |P|
      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Forward pointer to next chunk in list             |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Back pointer to previous chunk in list            |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Unused space (may be 0 bytes long)                .
            .                                                               .
            .                                                               |
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    `foot:' |             Size of chunk, in bytes                           |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    The P (PREV_INUSE) bit, stored in the unused low-order bit of the
    chunk size (which is always a multiple of two words), is an in-use
    bit for the *previous* chunk.  If that bit is *clear*, then the
    word before the current chunk size contains the previous chunk
    size, and can be used to find the front of the previous chunk.
    (The very first chunk allocated always has this bit set,
    preventing access to non-existent (or non-owned) memory.)

    Note that the `foot' of the current chunk is actually represented
    as the prev_size of the NEXT chunk. (This makes it easier to
    deal with alignments etc).

    The two exceptions to all this are

     1. The special chunk `top', which doesn't bother using the
        trailing size field since there is no
        next contiguous chunk that would have to index off it. (After
        initialization, `top' is forced to always exist.  If it would
        become less than MINSIZE bytes long, it is replenished via
        malloc_extend_top.)

     2. Chunks allocated via mmap, which have the second-lowest-order
        bit (IS_MMAPPED) set in their size fields.  Because they are
        never merged or traversed from any other chunk, they have no
        foot size or inuse information.

    Available chunks are kept in any of several places (all declared below):

    * `av': An array of chunks serving as bin headers for consolidated
       chunks. Each bin is doubly linked.  The bins are approximately
       proportionally (log) spaced.  There are a lot of these bins
       (128). This may look excessive, but works very well in
       practice.  All procedures maintain the invariant that no
       consolidated chunk physically borders another one. Chunks in
       bins are kept in size order, with ties going to the
       approximately least recently used chunk.

       The chunks in each bin are maintained in decreasing sorted order by
       size.  This is irrelevant for the small bins, which all contain
       the same-sized chunks, but facilitates best-fit allocation for
       larger chunks. (These lists are just sequential. Keeping them in
       order almost never requires enough traversal to warrant using
       fancier ordered data structures.)  Chunks of the same size are
       linked with the most recently freed at the front, and allocations
       are taken from the back.  This results in LRU or FIFO allocation
       order, which tends to give each chunk an equal opportunity to be
       consolidated with adjacent freed chunks, resulting in larger free
       chunks and less fragmentation.

    * `top': The top-most available chunk (i.e., the one bordering the
       end of available memory) is treated specially. It is never
       included in any bin, is used only if no other chunk is
       available, and is released back to the system if it is very
       large (see M_TRIM_THRESHOLD).

    * `last_remainder': A bin holding only the remainder of the
       most recently split (non-top) chunk. This bin is checked
       before other non-fitting chunks, so as to provide better
       locality for runs of sequentially allocated chunks.

    *  Implicitly, through the host system's memory mapping tables.
       If supported, requests greater than a threshold are usually
       serviced via calls to mmap, and then later released via munmap.

*/

/*
   Bins

    The bins are an array of pairs of pointers serving as the
    heads of (initially empty) doubly-linked lists of chunks, laid out
    in a way so that each pair can be treated as if it were in a
    malloc_chunk. (This way, the fd/bk offsets for linking bin heads
    and chunks are the same).

    Bins for sizes < 512 bytes contain chunks of all the same size, spaced
    8 bytes apart. Larger bins are approximately logarithmically
    spaced. (See the table below.)

    Bin layout:

    64 bins of size       8
    32 bins of size      64
    16 bins of size     512
     8 bins of size    4096
     4 bins of size   32768
     2 bins of size  262144
     1 bin  of size what's left

    There is actually a little bit of slop in the numbers in bin_index
    for the sake of speed. This makes no difference elsewhere.

    The special chunks `top' and `last_remainder' get their own bins,
    (this is implemented via yet more trickery with the av array),
    although `top' is never properly linked to its bin since it is
    always handled specially.

*/

#define NAV             128   /* number of bins */

typedef struct malloc_chunk* mbinptr;

/* An arena is a configuration of malloc_chunks together with an array
   of bins.  With multiple threads, it must be locked via a mutex
   before changing its data structures.  One or more `heaps' are
   associated with each arena, except for the main_arena, which is
   associated only with the `main heap', i.e.  the conventional free
   store obtained with calls to MORECORE() (usually sbrk).  The `av'
   array is never mentioned directly in the code, but instead used via
   bin access macros. */

typedef struct _arena {
  mbinptr av[2*NAV + 2];
  struct _arena *next;
  size_t size;
#if THREAD_STATS
  long stat_lock_direct, stat_lock_loop, stat_lock_wait;
#endif
  mutex_t mutex;
} arena;


/* A heap is a single contiguous memory region holding (coalesceable)
   malloc_chunks.  It is allocated with mmap() and always starts at an
   address aligned to HEAP_MAX_SIZE.  Not used unless compiling for
   multiple threads. */

typedef struct _heap_info {
  arena *ar_ptr; /* Arena for this heap. */
  struct _heap_info *prev; /* Previous heap. */
  size_t size;   /* Current size in bytes. */
  size_t pad;    /* Make sure the following data is properly aligned. */
} heap_info;


/*
  Static functions (forward declarations)
*/

#if __STD_C

static void      chunk_free(arena *ar_ptr, mchunkptr p);
static mchunkptr chunk_alloc(arena *ar_ptr, INTERNAL_SIZE_T size);
static mchunkptr chunk_realloc(arena *ar_ptr, mchunkptr oldp,
                               INTERNAL_SIZE_T oldsize, INTERNAL_SIZE_T nb);
static mchunkptr chunk_align(arena *ar_ptr, INTERNAL_SIZE_T nb,
                             size_t alignment);
static int       main_trim(size_t pad);
#ifndef NO_THREADS
static int       heap_trim(heap_info *heap, size_t pad);
#endif
#if defined(_LIBC) || defined(MALLOC_HOOKS)
static Void_t*   malloc_check(size_t sz);
static void      free_check(Void_t* mem);
static Void_t*   realloc_check(Void_t* oldmem, size_t bytes);
static Void_t*   memalign_check(size_t alignment, size_t bytes);
static Void_t*   malloc_starter(size_t sz);
static void      free_starter(Void_t* mem);
#endif

#else

static void      chunk_free();
static mchunkptr chunk_alloc();
static mchunkptr chunk_realloc();
static mchunkptr chunk_align();
static int       main_trim();
#ifndef NO_THREADS
static int       heap_trim();
#endif
#if defined(_LIBC) || defined(MALLOC_HOOKS)
static Void_t*   malloc_check();
static void      free_check();
static Void_t*   realloc_check();
static Void_t*   memalign_check();
static Void_t*   malloc_starter();
static void      free_starter();
#endif

#endif



/* sizes, alignments */

#define SIZE_SZ                (sizeof(INTERNAL_SIZE_T))
#define MALLOC_ALIGNMENT       (SIZE_SZ + SIZE_SZ)
#define MALLOC_ALIGN_MASK      (MALLOC_ALIGNMENT - 1)
#define MINSIZE                (sizeof(struct malloc_chunk))

/* conversion from malloc headers to user pointers, and back */

#define chunk2mem(p)   ((Void_t*)((char*)(p) + 2*SIZE_SZ))
#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))

/* pad request bytes into a usable size */

#define request2size(req) \
 (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
  (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
   (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))

/* Check if m has acceptable alignment */

#define aligned_OK(m)    (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)




/*
  Physical chunk operations
*/


/* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */

#define PREV_INUSE 0x1

/* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */

#define IS_MMAPPED 0x2

/* Bits to mask off when extracting size */

#define SIZE_BITS (PREV_INUSE|IS_MMAPPED)


/* Ptr to next physical malloc_chunk. */

#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) ))

/* Ptr to previous physical malloc_chunk */

#define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))


/* Treat space at ptr + offset as a chunk */

#define chunk_at_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))




/*
  Dealing with use bits
*/

/* extract p's inuse bit */

#define inuse(p) \
 ((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)

/* extract inuse bit of previous chunk */

#define prev_inuse(p)  ((p)->size & PREV_INUSE)

/* check for mmap()'ed chunk */

#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)

/* set/clear chunk as in use without otherwise disturbing */

#define set_inuse(p) \
 ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE

#define clear_inuse(p) \
 ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)

/* check/set/clear inuse bits in known places */

#define inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)

#define set_inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)

#define clear_inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))




/*
  Dealing with size fields
*/

/* Get size, ignoring use bits */

#define chunksize(p)          ((p)->size & ~(SIZE_BITS))

/* Set size at head, without disturbing its use bit */

#define set_head_size(p, s)   ((p)->size = (((p)->size & PREV_INUSE) | (s)))

/* Set size/use ignoring previous bits in header */

#define set_head(p, s)        ((p)->size = (s))

/* Set size at footer (only when chunk is not in use) */

#define set_foot(p, s)   (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))





/* access macros */

#define bin_at(a, i)   ((mbinptr)((char*)&(((a)->av)[2*(i) + 2]) - 2*SIZE_SZ))
#define init_bin(a, i) ((a)->av[2*i+2] = (a)->av[2*i+3] = bin_at((a), i))
#define next_bin(b)    ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr)))
#define prev_bin(b)    ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr)))

/*
   The first 2 bins are never indexed. The corresponding av cells are instead
   used for bookkeeping. This is not to save space, but to simplify
   indexing, maintain locality, and avoid some initialization tests.
*/

#define binblocks(a)      (bin_at(a,0)->size)/* bitvector of nonempty blocks */
#define top(a)            (bin_at(a,0)->fd)  /* The topmost chunk */
#define last_remainder(a) (bin_at(a,1))      /* remainder from last split */

/*
   Because top initially points to its own bin with initial
   zero size, thus forcing extension on the first malloc request,
   we avoid having any special code in malloc to check whether
   it even exists yet. But we still need to in malloc_extend_top.
*/

#define initial_top(a)    ((mchunkptr)bin_at(a, 0))



/* field-extraction macros */

#define first(b) ((b)->fd)
#define last(b)  ((b)->bk)

/*
  Indexing into bins
*/

#define bin_index(sz)                                                          \
(((((unsigned long)(sz)) >> 9) ==    0) ?       (((unsigned long)(sz)) >>  3): \
 ((((unsigned long)(sz)) >> 9) <=    4) ?  56 + (((unsigned long)(sz)) >>  6): \
 ((((unsigned long)(sz)) >> 9) <=   20) ?  91 + (((unsigned long)(sz)) >>  9): \
 ((((unsigned long)(sz)) >> 9) <=   84) ? 110 + (((unsigned long)(sz)) >> 12): \
 ((((unsigned long)(sz)) >> 9) <=  340) ? 119 + (((unsigned long)(sz)) >> 15): \
 ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \
                                          126)
/*
  bins for chunks < 512 are all spaced 8 bytes apart, and hold
  identically sized chunks. This is exploited in malloc.
*/

#define MAX_SMALLBIN         63
#define MAX_SMALLBIN_SIZE   512
#define SMALLBIN_WIDTH        8

#define smallbin_index(sz)  (((unsigned long)(sz)) >> 3)

/*
   Requests are `small' if both the corresponding and the next bin are small
*/

#define is_small_request(nb) ((nb) < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH)



/*
    To help compensate for the large number of bins, a one-level index
    structure is used for bin-by-bin searching.  `binblocks' is a
    one-word bitvector recording whether groups of BINBLOCKWIDTH bins
    have any (possibly) non-empty bins, so they can be skipped over
    all at once during during traversals. The bits are NOT always
    cleared as soon as all bins in a block are empty, but instead only
    when all are noticed to be empty during traversal in malloc.
*/

#define BINBLOCKWIDTH     4   /* bins per block */

/* bin<->block macros */

#define idx2binblock(ix)      ((unsigned)1 << ((ix) / BINBLOCKWIDTH))
#define mark_binblock(a, ii)  (binblocks(a) |= idx2binblock(ii))
#define clear_binblock(a, ii) (binblocks(a) &= ~(idx2binblock(ii)))




/* Static bookkeeping data */

/* Helper macro to initialize bins */
#define IAV(i) bin_at(&main_arena, i), bin_at(&main_arena, i)

static arena main_arena = {
    {
 0, 0,
 IAV(0),   IAV(1),   IAV(2),   IAV(3),   IAV(4),   IAV(5),   IAV(6),   IAV(7),
 IAV(8),   IAV(9),   IAV(10),  IAV(11),  IAV(12),  IAV(13),  IAV(14),  IAV(15),
 IAV(16),  IAV(17),  IAV(18),  IAV(19),  IAV(20),  IAV(21),  IAV(22),  IAV(23),
 IAV(24),  IAV(25),  IAV(26),  IAV(27),  IAV(28),  IAV(29),  IAV(30),  IAV(31),
 IAV(32),  IAV(33),  IAV(34),  IAV(35),  IAV(36),  IAV(37),  IAV(38),  IAV(39),
 IAV(40),  IAV(41),  IAV(42),  IAV(43),  IAV(44),  IAV(45),  IAV(46),  IAV(47),
 IAV(48),  IAV(49),  IAV(50),  IAV(51),  IAV(52),  IAV(53),  IAV(54),  IAV(55),
 IAV(56),  IAV(57),  IAV(58),  IAV(59),  IAV(60),  IAV(61),  IAV(62),  IAV(63),
 IAV(64),  IAV(65),  IAV(66),  IAV(67),  IAV(68),  IAV(69),  IAV(70),  IAV(71),
 IAV(72),  IAV(73),  IAV(74),  IAV(75),  IAV(76),  IAV(77),  IAV(78),  IAV(79),
 IAV(80),  IAV(81),  IAV(82),  IAV(83),  IAV(84),  IAV(85),  IAV(86),  IAV(87),
 IAV(88),  IAV(89),  IAV(90),  IAV(91),  IAV(92),  IAV(93),  IAV(94),  IAV(95),
 IAV(96),  IAV(97),  IAV(98),  IAV(99),  IAV(100), IAV(101), IAV(102), IAV(103),
 IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111),
 IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119),
 IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127)
    },
    &main_arena, /* next */
    0, /* size */
#if THREAD_STATS
    0, 0, 0, /* stat_lock_direct, stat_lock_loop, stat_lock_wait */
#endif
    MUTEX_INITIALIZER /* mutex */
};

#undef IAV

/* Thread specific data */

#ifndef NO_THREADS
static tsd_key_t arena_key;
static mutex_t list_lock = MUTEX_INITIALIZER;
#endif

#if THREAD_STATS
static int stat_n_heaps = 0;
#define THREAD_STAT(x) x
#else
#define THREAD_STAT(x) do ; while(0)
#endif

/* variables holding tunable values */

static unsigned long trim_threshold   = DEFAULT_TRIM_THRESHOLD;
static unsigned long top_pad          = DEFAULT_TOP_PAD;
static unsigned int  n_mmaps_max      = DEFAULT_MMAP_MAX;
static unsigned long mmap_threshold   = DEFAULT_MMAP_THRESHOLD;
static int           check_action     = DEFAULT_CHECK_ACTION;

/* The first value returned from sbrk */
static char* sbrk_base = (char*)(-1);

/* The maximum memory obtained from system via sbrk */
static unsigned long max_sbrked_mem = 0;

/* The maximum via either sbrk or mmap (too difficult to track with threads) */
#ifdef NO_THREADS
static unsigned long max_total_mem = 0;
#endif

/* The total memory obtained from system via sbrk */
#define sbrked_mem (main_arena.size)

/* Tracking mmaps */

static unsigned int n_mmaps = 0;
static unsigned int max_n_mmaps = 0;
static unsigned long mmapped_mem = 0;
static unsigned long max_mmapped_mem = 0;



#ifndef _LIBC
#define weak_variable
#else
/* In GNU libc we want the hook variables to be weak definitions to
   avoid a problem with Emacs.  */
#define weak_variable weak_function
#endif

/* Already initialized? */
int __malloc_initialized = 0;


/* Initialization routine. */
#if defined(_LIBC)
#if 0
static void ptmalloc_init __MALLOC_P ((void)) __attribute__ ((constructor));
#endif

static void
ptmalloc_init __MALLOC_P((void))
#else
void
ptmalloc_init __MALLOC_P((void))
#endif
{
#if defined(_LIBC) || defined(MALLOC_HOOKS)
  __malloc_ptr_t (*save_malloc_hook) __MALLOC_P ((size_t __size));
  void (*save_free_hook) __MALLOC_P ((__malloc_ptr_t __ptr));
  const char* s;
#endif

  if(__malloc_initialized) return;
  __malloc_initialized = 1;
#if defined(_LIBC) || defined(MALLOC_HOOKS)
  /* With some threads implementations, creating thread-specific data
     or initializing a mutex may call malloc() itself.  Provide a
     simple starter version (realloc() won't work). */
  save_malloc_hook = __malloc_hook;
  save_free_hook = __free_hook;
  __malloc_hook = malloc_starter;
  __free_hook = free_starter;
#endif
#if defined(_LIBC) && !defined (NO_THREADS)
  /* Initialize the pthreads interface. */
  if (__pthread_initialize != NULL)
    __pthread_initialize();
#endif
#ifndef NO_THREADS
  mutex_init(&main_arena.mutex);
  mutex_init(&list_lock);
  tsd_key_create(&arena_key, NULL);
  tsd_setspecific(arena_key, (Void_t *)&main_arena);
#endif
#if defined(_LIBC) || defined(MALLOC_HOOKS)
  if((s = getenv("MALLOC_TRIM_THRESHOLD_")))
    mALLOPt(M_TRIM_THRESHOLD, atoi(s));
  if((s = getenv("MALLOC_TOP_PAD_")))
    mALLOPt(M_TOP_PAD, atoi(s));
  if((s = getenv("MALLOC_MMAP_THRESHOLD_")))
    mALLOPt(M_MMAP_THRESHOLD, atoi(s));
  if((s = getenv("MALLOC_MMAP_MAX_")))
    mALLOPt(M_MMAP_MAX, atoi(s));
  s = getenv("MALLOC_CHECK_");
  __malloc_hook = save_malloc_hook;
  __free_hook = save_free_hook;
  if(s) {
    if(s[0]) mALLOPt(M_CHECK_ACTION, (int)(s[0] - '0'));
    __malloc_check_init();
  }
  if(__malloc_initialize_hook != NULL)
    (*__malloc_initialize_hook)();
#endif
}

#if defined(_LIBC) || defined(MALLOC_HOOKS)

/* Hooks for debugging versions.  The initial hooks just call the
   initialization routine, then do the normal work. */

static Void_t*
#if __STD_C
malloc_hook_ini(size_t sz)
#else
malloc_hook_ini(sz) size_t sz;
#endif
{
  __malloc_hook = NULL;
  __realloc_hook = NULL;
  __memalign_hook = NULL;
  ptmalloc_init();
  return mALLOc(sz);
}

static Void_t*
#if __STD_C
realloc_hook_ini(Void_t* ptr, size_t sz)
#else
realloc_hook_ini(ptr, sz) Void_t* ptr; size_t sz;
#endif
{
  __malloc_hook = NULL;
  __realloc_hook = NULL;
  __memalign_hook = NULL;
  ptmalloc_init();
  return rEALLOc(ptr, sz);
}

static Void_t*
#if __STD_C
memalign_hook_ini(size_t sz, size_t alignment)
#else
memalign_hook_ini(sz, alignment) size_t sz; size_t alignment;
#endif
{
  __malloc_hook = NULL;
  __realloc_hook = NULL;
  __memalign_hook = NULL;
  ptmalloc_init();
  return mEMALIGn(sz, alignment);
}

void weak_variable (*__malloc_initialize_hook) __MALLOC_P ((void)) = NULL;
void weak_variable (*__free_hook) __MALLOC_P ((__malloc_ptr_t __ptr)) = NULL;
__malloc_ptr_t weak_variable (*__malloc_hook)
 __MALLOC_P ((size_t __size)) = malloc_hook_ini;
__malloc_ptr_t weak_variable (*__realloc_hook)
 __MALLOC_P ((__malloc_ptr_t __ptr, size_t __size)) = realloc_hook_ini;
__malloc_ptr_t weak_variable (*__memalign_hook)
 __MALLOC_P ((size_t __size, size_t __alignment)) = memalign_hook_ini;
void weak_variable (*__after_morecore_hook) __MALLOC_P ((void)) = NULL;

/* Activate a standard set of debugging hooks. */
void
__malloc_check_init()
{
  __malloc_hook = malloc_check;
  __free_hook = free_check;
  __realloc_hook = realloc_check;
  __memalign_hook = memalign_check;
  if(check_action == 1)
    fprintf(stderr, "malloc: using debugging hooks\n");
}

#endif





/* Routines dealing with mmap(). */

#if HAVE_MMAP

#ifndef MAP_ANONYMOUS

static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */

#define MMAP(size, prot) ((dev_zero_fd < 0) ? \
 (dev_zero_fd = open("/dev/zero", O_RDWR), \
  mmap(0, (size), (prot), MAP_PRIVATE, dev_zero_fd, 0)) : \
   mmap(0, (size), (prot), MAP_PRIVATE, dev_zero_fd, 0))

#else

#define MMAP(size, prot) \
 (mmap(0, (size), (prot), MAP_PRIVATE|MAP_ANONYMOUS, -1, 0))

#endif

#if __STD_C
static mchunkptr mmap_chunk(size_t size)
#else
static mchunkptr mmap_chunk(size) size_t size;
#endif
{
  size_t page_mask = malloc_getpagesize - 1;
  mchunkptr p;

  if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */

  /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because
   * there is no following chunk whose prev_size field could be used.
   */
  size = (size + SIZE_SZ + page_mask) & ~page_mask;

  p = (mchunkptr)MMAP(size, PROT_READ|PROT_WRITE);
  if(p == (mchunkptr)-1) return 0;

  n_mmaps++;
  if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps;

  /* We demand that eight bytes into a page must be 8-byte aligned. */
  assert(aligned_OK(chunk2mem(p)));

  /* The offset to the start of the mmapped region is stored
   * in the prev_size field of the chunk; normally it is zero,
   * but that can be changed in memalign().
   */
  p->prev_size = 0;
  set_head(p, size|IS_MMAPPED);

  mmapped_mem += size;
  if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
    max_mmapped_mem = mmapped_mem;
#ifdef NO_THREADS
  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
    max_total_mem = mmapped_mem + sbrked_mem;
#endif
  return p;
}

#if __STD_C
static void munmap_chunk(mchunkptr p)
#else
static void munmap_chunk(p) mchunkptr p;
#endif
{
  INTERNAL_SIZE_T size = chunksize(p);
  int ret;

  assert (chunk_is_mmapped(p));
  assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
  assert((n_mmaps > 0));
  assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0);

  n_mmaps--;
  mmapped_mem -= (size + p->prev_size);

  ret = munmap((char *)p - p->prev_size, size + p->prev_size);

  /* munmap returns non-zero on failure */
  assert(ret == 0);
}

#if HAVE_MREMAP

#if __STD_C
static mchunkptr mremap_chunk(mchunkptr p, size_t new_size)
#else
static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size;
#endif
{
  size_t page_mask = malloc_getpagesize - 1;
  INTERNAL_SIZE_T offset = p->prev_size;
  INTERNAL_SIZE_T size = chunksize(p);
  char *cp;

  assert (chunk_is_mmapped(p));
  assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
  assert((n_mmaps > 0));
  assert(((size + offset) & (malloc_getpagesize-1)) == 0);

  /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
  new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask;

  cp = (char *)mremap((char *)p - offset, size + offset, new_size,
                      MREMAP_MAYMOVE);

  if (cp == (char *)-1) return 0;

  p = (mchunkptr)(cp + offset);

  assert(aligned_OK(chunk2mem(p)));

  assert((p->prev_size == offset));
  set_head(p, (new_size - offset)|IS_MMAPPED);

  mmapped_mem -= size + offset;
  mmapped_mem += new_size;
  if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
    max_mmapped_mem = mmapped_mem;
#ifdef NO_THREADS
  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
    max_total_mem = mmapped_mem + sbrked_mem;
#endif
  return p;
}

#endif /* HAVE_MREMAP */

#endif /* HAVE_MMAP */



/* Managing heaps and arenas (for concurrent threads) */

#ifndef NO_THREADS

/* Create a new heap.  size is automatically rounded up to a multiple
   of the page size. */

static heap_info *
#if __STD_C
new_heap(size_t size)
#else
new_heap(size) size_t size;
#endif
{
  size_t page_mask = malloc_getpagesize - 1;
  char *p1, *p2;
  unsigned long ul;
  heap_info *h;

  if(size < HEAP_MIN_SIZE)
    size = HEAP_MIN_SIZE;
  size = (size + page_mask) & ~page_mask;
  if(size > HEAP_MAX_SIZE)
    return 0;
  p1 = (char *)MMAP(HEAP_MAX_SIZE<<1, PROT_NONE);
  if(p1 == (char *)-1)
    return 0;
  p2 = (char *)(((unsigned long)p1 + HEAP_MAX_SIZE) & ~(HEAP_MAX_SIZE-1));
  ul = p2 - p1;
  munmap(p1, ul);
  munmap(p2 + HEAP_MAX_SIZE, HEAP_MAX_SIZE - ul);
  if(mprotect(p2, size, PROT_READ|PROT_WRITE) != 0) {
    munmap(p2, HEAP_MAX_SIZE);
    return 0;
  }
  h = (heap_info *)p2;
  h->size = size;
  THREAD_STAT(stat_n_heaps++);
  return h;
}

/* Grow or shrink a heap.  size is automatically rounded up to a
   multiple of the page size if it is positive. */

static int
#if __STD_C
grow_heap(heap_info *h, long diff)
#else
grow_heap(h, diff) heap_info *h; long diff;
#endif
{
  size_t page_mask = malloc_getpagesize - 1;
  long new_size;

  if(diff >= 0) {
    diff = (diff + page_mask) & ~page_mask;
    new_size = (long)h->size + diff;
    if(new_size > HEAP_MAX_SIZE)
      return -1;
    if(mprotect((char *)h + h->size, diff, PROT_READ|PROT_WRITE) != 0)
      return -2;
  } else {
    new_size = (long)h->size + diff;
    if(new_size < (long)sizeof(*h))
      return -1;
    if(mprotect((char *)h + new_size, -diff, PROT_NONE) != 0)
      return -2;
  }
  h->size = new_size;
  return 0;
}

/* Delete a heap. */

#define delete_heap(heap) munmap((char*)(heap), HEAP_MAX_SIZE)

/* arena_get() acquires an arena and locks the corresponding mutex.
   First, try the one last locked successfully by this thread.  (This
   is the common case and handled with a macro for speed.)  Then, loop
   once over the circularly linked list of arenas.  If no arena is
   readily available, create a new one. */

#define arena_get(ptr, size) do { \
  Void_t *vptr = NULL; \
  ptr = (arena *)tsd_getspecific(arena_key, vptr); \
  if(ptr && !mutex_trylock(&ptr->mutex)) { \
    THREAD_STAT(++(ptr->stat_lock_direct)); \
  } else \
    ptr = arena_get2(ptr, (size)); \
} while(0)

static arena *
#if __STD_C
arena_get2(arena *a_tsd, size_t size)
#else
arena_get2(a_tsd, size) arena *a_tsd; size_t size;
#endif
{
  arena *a;
  heap_info *h;
  char *ptr;
  int i;
  unsigned long misalign;

  if(!a_tsd)
    a = a_tsd = &main_arena;
  else {
    a = a_tsd->next;
    if(!a) {
      /* This can only happen while initializing the new arena. */
      (void)mutex_lock(&main_arena.mutex);
      THREAD_STAT(++(main_arena.stat_lock_wait));
      return &main_arena;
    }
  }

  /* Check the global, circularly linked list for available arenas. */
  do {
    if(!mutex_trylock(&a->mutex)) {
      THREAD_STAT(++(a->stat_lock_loop));
      tsd_setspecific(arena_key, (Void_t *)a);
      return a;
    }
    a = a->next;
  } while(a != a_tsd);

  /* Nothing immediately available, so generate a new arena. */
  h = new_heap(size + (sizeof(*h) + sizeof(*a) + MALLOC_ALIGNMENT));
  if(!h)
    return 0;
  a = h->ar_ptr = (arena *)(h+1);
  for(i=0; i<NAV; i++)
    init_bin(a, i);
  a->next = NULL;
  a->size = h->size;
  tsd_setspecific(arena_key, (Void_t *)a);
  mutex_init(&a->mutex);
  i = mutex_lock(&a->mutex); /* remember result */

  /* Set up the top chunk, with proper alignment. */
  ptr = (char *)(a + 1);
  misalign = (unsigned long)chunk2mem(ptr) & MALLOC_ALIGN_MASK;
  if (misalign > 0)
    ptr += MALLOC_ALIGNMENT - misalign;
  top(a) = (mchunkptr)ptr;
  set_head(top(a), (((char*)h + h->size) - ptr) | PREV_INUSE);

  /* Add the new arena to the list. */
  (void)mutex_lock(&list_lock);
  a->next = main_arena.next;
  main_arena.next = a;
  (void)mutex_unlock(&list_lock);

  if(i) /* locking failed; keep arena for further attempts later */
    return 0;

  THREAD_STAT(++(a->stat_lock_loop));
  return a;
}

/* find the heap and corresponding arena for a given ptr */

#define heap_for_ptr(ptr) \
 ((heap_info *)((unsigned long)(ptr) & ~(HEAP_MAX_SIZE-1)))
#define arena_for_ptr(ptr) \
 (((mchunkptr)(ptr) < top(&main_arena) && (char *)(ptr) >= sbrk_base) ? \
  &main_arena : heap_for_ptr(ptr)->ar_ptr)

#else /* defined(NO_THREADS) */

/* Without concurrent threads, there is only one arena. */

#define arena_get(ptr, sz) (ptr = &main_arena)
#define arena_for_ptr(ptr) (&main_arena)

#endif /* !defined(NO_THREADS) */



/*
  Debugging support
*/

#if MALLOC_DEBUG


/*
  These routines make a number of assertions about the states
  of data structures that should be true at all times. If any
  are not true, it's very likely that a user program has somehow
  trashed memory. (It's also possible that there is a coding error
  in malloc. In which case, please report it!)
*/

#if __STD_C
static void do_check_chunk(arena *ar_ptr, mchunkptr p)
#else
static void do_check_chunk(ar_ptr, p) arena *ar_ptr; mchunkptr p;
#endif
{
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;

  /* No checkable chunk is mmapped */
  assert(!chunk_is_mmapped(p));

#ifndef NO_THREADS
  if(ar_ptr != &main_arena) {
    heap_info *heap = heap_for_ptr(p);
    assert(heap->ar_ptr == ar_ptr);
    assert((char *)p + sz <= (char *)heap + heap->size);
    return;
  }
#endif

  /* Check for legal address ... */
  assert((char*)p >= sbrk_base);
  if (p != top(ar_ptr))
    assert((char*)p + sz <= (char*)top(ar_ptr));
  else
    assert((char*)p + sz <= sbrk_base + sbrked_mem);

}


#if __STD_C
static void do_check_free_chunk(arena *ar_ptr, mchunkptr p)
#else
static void do_check_free_chunk(ar_ptr, p) arena *ar_ptr; mchunkptr p;
#endif
{
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
  mchunkptr next = chunk_at_offset(p, sz);

  do_check_chunk(ar_ptr, p);

  /* Check whether it claims to be free ... */
  assert(!inuse(p));

  /* Must have OK size and fields */
  assert((long)sz >= (long)MINSIZE);
  assert((sz & MALLOC_ALIGN_MASK) == 0);
  assert(aligned_OK(chunk2mem(p)));
  /* ... matching footer field */
  assert(next->prev_size == sz);
  /* ... and is fully consolidated */
  assert(prev_inuse(p));
  assert (next == top(ar_ptr) || inuse(next));

  /* ... and has minimally sane links */
  assert(p->fd->bk == p);
  assert(p->bk->fd == p);
}

#if __STD_C
static void do_check_inuse_chunk(arena *ar_ptr, mchunkptr p)
#else
static void do_check_inuse_chunk(ar_ptr, p) arena *ar_ptr; mchunkptr p;
#endif
{
  mchunkptr next = next_chunk(p);
  do_check_chunk(ar_ptr, p);

  /* Check whether it claims to be in use ... */
  assert(inuse(p));

  /* ... whether its size is OK (it might be a fencepost) ... */
  assert(chunksize(p) >= MINSIZE || next->size == (0|PREV_INUSE));

  /* ... and is surrounded by OK chunks.
    Since more things can be checked with free chunks than inuse ones,
    if an inuse chunk borders them and debug is on, it's worth doing them.
  */
  if (!prev_inuse(p))
  {
    mchunkptr prv = prev_chunk(p);
    assert(next_chunk(prv) == p);
    do_check_free_chunk(ar_ptr, prv);
  }
  if (next == top(ar_ptr))
  {
    assert(prev_inuse(next));
    assert(chunksize(next) >= MINSIZE);
  }
  else if (!inuse(next))
    do_check_free_chunk(ar_ptr, next);

}

#if __STD_C
static void do_check_malloced_chunk(arena *ar_ptr,
                                    mchunkptr p, INTERNAL_SIZE_T s)
#else
static void do_check_malloced_chunk(ar_ptr, p, s)
arena *ar_ptr; mchunkptr p; INTERNAL_SIZE_T s;
#endif
{
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
  long room = sz - s;

  do_check_inuse_chunk(ar_ptr, p);

  /* Legal size ... */
  assert((long)sz >= (long)MINSIZE);
  assert((sz & MALLOC_ALIGN_MASK) == 0);
  assert(room >= 0);
  assert(room < (long)MINSIZE);

  /* ... and alignment */
  assert(aligned_OK(chunk2mem(p)));


  /* ... and was allocated at front of an available chunk */
  assert(prev_inuse(p));

}


#define check_free_chunk(A,P) do_check_free_chunk(A,P)
#define check_inuse_chunk(A,P) do_check_inuse_chunk(A,P)
#define check_chunk(A,P) do_check_chunk(A,P)
#define check_malloced_chunk(A,P,N) do_check_malloced_chunk(A,P,N)
#else
#define check_free_chunk(A,P)
#define check_inuse_chunk(A,P)
#define check_chunk(A,P)
#define check_malloced_chunk(A,P,N)
#endif



/*
  Macro-based internal utilities
*/


/*
  Linking chunks in bin lists.
  Call these only with variables, not arbitrary expressions, as arguments.
*/

/*
  Place chunk p of size s in its bin, in size order,
  putting it ahead of others of same size.
*/


#define frontlink(A, P, S, IDX, BK, FD)                                       \
{                                                                             \
  if (S < MAX_SMALLBIN_SIZE)                                                  \
  {                                                                           \
    IDX = smallbin_index(S);                                                  \
    mark_binblock(A, IDX);                                                    \
    BK = bin_at(A, IDX);                                                      \
    FD = BK->fd;                                                              \
    P->bk = BK;                                                               \
    P->fd = FD;                                                               \
    FD->bk = BK->fd = P;                                                      \
  }                                                                           \
  else                                                                        \
  {                                                                           \
    IDX = bin_index(S);                                                       \
    BK = bin_at(A, IDX);                                                      \
    FD = BK->fd;                                                              \
    if (FD == BK) mark_binblock(A, IDX);                                      \
    else                                                                      \
    {                                                                         \
      while (FD != BK && S < chunksize(FD)) FD = FD->fd;                      \
      BK = FD->bk;                                                            \
    }                                                                         \
    P->bk = BK;                                                               \
    P->fd = FD;                                                               \
    FD->bk = BK->fd = P;                                                      \
  }                                                                           \
}


/* take a chunk off a list */

#define unlink(P, BK, FD)                                                     \
{                                                                             \
  BK = P->bk;                                                                 \
  FD = P->fd;                                                                 \
  FD->bk = BK;                                                                \
  BK->fd = FD;                                                                \
}                                                                             \

/* Place p as the last remainder */

#define link_last_remainder(A, P)                                             \
{                                                                             \
  last_remainder(A)->fd = last_remainder(A)->bk = P;                          \
  P->fd = P->bk = last_remainder(A);                                          \
}

/* Clear the last_remainder bin */

#define clear_last_remainder(A) \
  (last_remainder(A)->fd = last_remainder(A)->bk = last_remainder(A))





/*
  Extend the top-most chunk by obtaining memory from system.
  Main interface to sbrk (but see also malloc_trim).
*/

#if __STD_C
static void malloc_extend_top(arena *ar_ptr, INTERNAL_SIZE_T nb)
#else
static void malloc_extend_top(ar_ptr, nb) arena *ar_ptr; INTERNAL_SIZE_T nb;
#endif
{
  unsigned long pagesz   = malloc_getpagesize;
  mchunkptr old_top      = top(ar_ptr);        /* Record state of old top */
  INTERNAL_SIZE_T old_top_size = chunksize(old_top);
  INTERNAL_SIZE_T top_size;                    /* new size of top chunk */

#ifndef NO_THREADS
  if(ar_ptr == &main_arena) {
#endif

    char*     brk;                  /* return value from sbrk */
    INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */
    INTERNAL_SIZE_T correction;     /* bytes for 2nd sbrk call */
    char*     new_brk;              /* return of 2nd sbrk call */
    char*     old_end = (char*)(chunk_at_offset(old_top, old_top_size));

    /* Pad request with top_pad plus minimal overhead */
    INTERNAL_SIZE_T sbrk_size = nb + top_pad + MINSIZE;

    /* If not the first time through, round to preserve page boundary */
    /* Otherwise, we need to correct to a page size below anyway. */
    /* (We also correct below if an intervening foreign sbrk call.) */

    if (sbrk_base != (char*)(-1))
      sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1);

    brk = (char*)(MORECORE (sbrk_size));

    /* Fail if sbrk failed or if a foreign sbrk call killed our space */
    if (brk == (char*)(MORECORE_FAILURE) ||
        (brk < old_end && old_top != initial_top(&main_arena)))
      return;

    /* Call the `morecore' hook if necessary.  */
    if (__after_morecore_hook)
      (*__after_morecore_hook) ();

    sbrked_mem += sbrk_size;

    if (brk == old_end) { /* can just add bytes to current top */
      top_size = sbrk_size + old_top_size;
      set_head(old_top, top_size | PREV_INUSE);
      old_top = 0; /* don't free below */
    } else {
      if (sbrk_base == (char*)(-1)) /* First time through. Record base */
        sbrk_base = brk;
      else
        /* Someone else called sbrk().  Count those bytes as sbrked_mem. */
        sbrked_mem += brk - (char*)old_end;

      /* Guarantee alignment of first new chunk made from this space */
      front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK;
      if (front_misalign > 0) {
        correction = (MALLOC_ALIGNMENT) - front_misalign;
        brk += correction;
      } else
        correction = 0;

      /* Guarantee the next brk will be at a page boundary */
      correction += pagesz - ((unsigned long)(brk + sbrk_size) & (pagesz - 1));

      /* Allocate correction */
      new_brk = (char*)(MORECORE (correction));
      if (new_brk == (char*)(MORECORE_FAILURE)) return;

      /* Call the `morecore' hook if necessary.  */
      if (__after_morecore_hook)
	(*__after_morecore_hook) ();

      sbrked_mem += correction;

      top(&main_arena) = (mchunkptr)brk;
      top_size = new_brk - brk + correction;
      set_head(top(&main_arena), top_size | PREV_INUSE);

      if (old_top == initial_top(&main_arena))
        old_top = 0; /* don't free below */
    }

    if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem)
      max_sbrked_mem = sbrked_mem;
#ifdef NO_THREADS
    if ((unsigned long)(mmapped_mem + sbrked_mem) >
        (unsigned long)max_total_mem)
      max_total_mem = mmapped_mem + sbrked_mem;
#endif

#ifndef NO_THREADS
  } else { /* ar_ptr != &main_arena */
    heap_info *old_heap, *heap;
    size_t old_heap_size;

    if(old_top_size < MINSIZE) /* this should never happen */
      return;

    /* First try to extend the current heap. */
    if(MINSIZE + nb <= old_top_size)
      return;
    old_heap = heap_for_ptr(old_top);
    old_heap_size = old_heap->size;
    if(grow_heap(old_heap, MINSIZE + nb - old_top_size) == 0) {
      ar_ptr->size += old_heap->size - old_heap_size;
      top_size = ((char *)old_heap + old_heap->size) - (char *)old_top;
      set_head(old_top, top_size | PREV_INUSE);
      return;
    }

    /* A new heap must be created. */
    heap = new_heap(nb + top_pad + (MINSIZE + sizeof(*heap)));
    if(!heap)
      return;
    heap->ar_ptr = ar_ptr;
    heap->prev = old_heap;
    ar_ptr->size += heap->size;

    /* Set up the new top, so we can safely use chunk_free() below. */
    top(ar_ptr) = chunk_at_offset(heap, sizeof(*heap));
    top_size = heap->size - sizeof(*heap);
    set_head(top(ar_ptr), top_size | PREV_INUSE);
  }
#endif /* !defined(NO_THREADS) */

  /* We always land on a page boundary */
  assert(((unsigned long)((char*)top(ar_ptr) + top_size) & (pagesz-1)) == 0);

  /* Setup fencepost and free the old top chunk. */
  if(old_top) {
    /* The fencepost takes at least MINSIZE bytes, because it might
       become the top chunk again later.  Note that a footer is set
       up, too, although the chunk is marked in use. */
    old_top_size -= MINSIZE;
    set_head(chunk_at_offset(old_top, old_top_size + 2*SIZE_SZ), 0|PREV_INUSE);
    if(old_top_size >= MINSIZE) {
      set_head(chunk_at_offset(old_top, old_top_size), (2*SIZE_SZ)|PREV_INUSE);
      set_foot(chunk_at_offset(old_top, old_top_size), (2*SIZE_SZ));
      set_head_size(old_top, old_top_size);
      chunk_free(ar_ptr, old_top);
    } else {
      set_head(old_top, (old_top_size + 2*SIZE_SZ)|PREV_INUSE);
      set_foot(old_top, (old_top_size + 2*SIZE_SZ));
    }
  }
}




/* Main public routines */


/*
  Malloc Algorithm:

    The requested size is first converted into a usable form, `nb'.
    This currently means to add 4 bytes overhead plus possibly more to
    obtain 8-byte alignment and/or to obtain a size of at least
    MINSIZE (currently 16, 24, or 32 bytes), the smallest allocatable
    size.  (All fits are considered `exact' if they are within MINSIZE
    bytes.)

    From there, the first successful of the following steps is taken:

      1. The bin corresponding to the request size is scanned, and if
         a chunk of exactly the right size is found, it is taken.

      2. The most recently remaindered chunk is used if it is big
         enough.  This is a form of (roving) first fit, used only in
         the absence of exact fits. Runs of consecutive requests use
         the remainder of the chunk used for the previous such request
         whenever possible. This limited use of a first-fit style
         allocation strategy tends to give contiguous chunks
         coextensive lifetimes, which improves locality and can reduce
         fragmentation in the long run.

      3. Other bins are scanned in increasing size order, using a
         chunk big enough to fulfill the request, and splitting off
         any remainder.  This search is strictly by best-fit; i.e.,
         the smallest (with ties going to approximately the least
         recently used) chunk that fits is selected.

      4. If large enough, the chunk bordering the end of memory
         (`top') is split off. (This use of `top' is in accord with
         the best-fit search rule.  In effect, `top' is treated as
         larger (and thus less well fitting) than any other available
         chunk since it can be extended to be as large as necessary
         (up to system limitations).

      5. If the request size meets the mmap threshold and the
         system supports mmap, and there are few enough currently
         allocated mmapped regions, and a call to mmap succeeds,
         the request is allocated via direct memory mapping.

      6. Otherwise, the top of memory is extended by
         obtaining more space from the system (normally using sbrk,
         but definable to anything else via the MORECORE macro).
         Memory is gathered from the system (in system page-sized
         units) in a way that allows chunks obtained across different
         sbrk calls to be consolidated, but does not require
         contiguous memory. Thus, it should be safe to intersperse
         mallocs with other sbrk calls.


      All allocations are made from the the `lowest' part of any found
      chunk. (The implementation invariant is that prev_inuse is
      always true of any allocated chunk; i.e., that each allocated
      chunk borders either a previously allocated and still in-use chunk,
      or the base of its memory arena.)

*/

#if __STD_C
Void_t* mALLOc(size_t bytes)
#else
Void_t* mALLOc(bytes) size_t bytes;
#endif
{
  arena *ar_ptr;
  INTERNAL_SIZE_T nb; /* padded request size */
  mchunkptr victim;

#if defined(_LIBC) || defined(MALLOC_HOOKS)
  if (__malloc_hook != NULL) {
    Void_t* result;

    result = (*__malloc_hook)(bytes);
    return result;
  }
#endif

  nb = request2size(bytes);
  arena_get(ar_ptr, nb + top_pad);
  if(!ar_ptr)
    return 0;
  victim = chunk_alloc(ar_ptr, nb);
  (void)mutex_unlock(&ar_ptr->mutex);
  return victim ? chunk2mem(victim) : 0;
}

static mchunkptr
#if __STD_C
chunk_alloc(arena *ar_ptr, INTERNAL_SIZE_T nb)
#else
chunk_alloc(ar_ptr, nb) arena *ar_ptr; INTERNAL_SIZE_T nb;
#endif
{
  mchunkptr victim;                  /* inspected/selected chunk */
  INTERNAL_SIZE_T victim_size;       /* its size */
  int       idx;                     /* index for bin traversal */
  mbinptr   bin;                     /* associated bin */
  mchunkptr remainder;               /* remainder from a split */
  long      remainder_size;          /* its size */
  int       remainder_index;         /* its bin index */
  unsigned long block;               /* block traverser bit */
  int       startidx;                /* first bin of a traversed block */
  mchunkptr fwd;                     /* misc temp for linking */
  mchunkptr bck;                     /* misc temp for linking */
  mbinptr q;                         /* misc temp */


  /* Check for exact match in a bin */

  if (is_small_request(nb))  /* Faster version for small requests */
  {
    idx = smallbin_index(nb);

    /* No traversal or size check necessary for small bins.  */

    q = bin_at(ar_ptr, idx);
    victim = last(q);

    /* Also scan the next one, since it would have a remainder < MINSIZE */
    if (victim == q)
    {
      q = next_bin(q);
      victim = last(q);
    }
    if (victim != q)
    {
      victim_size = chunksize(victim);
      unlink(victim, bck, fwd);
      set_inuse_bit_at_offset(victim, victim_size);
      check_malloced_chunk(ar_ptr, victim, nb);
      return victim;
    }

    idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */

  }
  else
  {
    idx = bin_index(nb);
    bin = bin_at(ar_ptr, idx);

    for (victim = last(bin); victim != bin; victim = victim->bk)
    {
      victim_size = chunksize(victim);
      remainder_size = victim_size - nb;

      if (remainder_size >= (long)MINSIZE) /* too big */
      {
        --idx; /* adjust to rescan below after checking last remainder */
        break;
      }

      else if (remainder_size >= 0) /* exact fit */
      {
        unlink(victim, bck, fwd);
        set_inuse_bit_at_offset(victim, victim_size);
        check_malloced_chunk(ar_ptr, victim, nb);
        return victim;
      }
    }

    ++idx;

  }

  /* Try to use the last split-off remainder */

  if ( (victim = last_remainder(ar_ptr)->fd) != last_remainder(ar_ptr))
  {
    victim_size = chunksize(victim);
    remainder_size = victim_size - nb;

    if (remainder_size >= (long)MINSIZE) /* re-split */
    {
      remainder = chunk_at_offset(victim, nb);
      set_head(victim, nb | PREV_INUSE);
      link_last_remainder(ar_ptr, remainder);
      set_head(remainder, remainder_size | PREV_INUSE);
      set_foot(remainder, remainder_size);
      check_malloced_chunk(ar_ptr, victim, nb);
      return victim;
    }

    clear_last_remainder(ar_ptr);

    if (remainder_size >= 0)  /* exhaust */
    {
      set_inuse_bit_at_offset(victim, victim_size);
      check_malloced_chunk(ar_ptr, victim, nb);
      return victim;
    }

    /* Else place in bin */

    frontlink(ar_ptr, victim, victim_size, remainder_index, bck, fwd);
  }

  /*
     If there are any possibly nonempty big-enough blocks,
     search for best fitting chunk by scanning bins in blockwidth units.
  */

  if ( (block = idx2binblock(idx)) <= binblocks(ar_ptr))
  {

    /* Get to the first marked block */

    if ( (block & binblocks(ar_ptr)) == 0)
    {
      /* force to an even block boundary */
      idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH;
      block <<= 1;
      while ((block & binblocks(ar_ptr)) == 0)
      {
        idx += BINBLOCKWIDTH;
        block <<= 1;
      }
    }

    /* For each possibly nonempty block ... */
    for (;;)
    {
      startidx = idx;          /* (track incomplete blocks) */
      q = bin = bin_at(ar_ptr, idx);

      /* For each bin in this block ... */
      do
      {
        /* Find and use first big enough chunk ... */

        for (victim = last(bin); victim != bin; victim = victim->bk)
        {
          victim_size = chunksize(victim);
          remainder_size = victim_size - nb;

          if (remainder_size >= (long)MINSIZE) /* split */
          {
            remainder = chunk_at_offset(victim, nb);
            set_head(victim, nb | PREV_INUSE);
            unlink(victim, bck, fwd);
            link_last_remainder(ar_ptr, remainder);
            set_head(remainder, remainder_size | PREV_INUSE);
            set_foot(remainder, remainder_size);
            check_malloced_chunk(ar_ptr, victim, nb);
            return victim;
          }

          else if (remainder_size >= 0)  /* take */
          {
            set_inuse_bit_at_offset(victim, victim_size);
            unlink(victim, bck, fwd);
            check_malloced_chunk(ar_ptr, victim, nb);
            return victim;
          }

        }

       bin = next_bin(bin);

      } while ((++idx & (BINBLOCKWIDTH - 1)) != 0);

      /* Clear out the block bit. */

      do   /* Possibly backtrack to try to clear a partial block */
      {
        if ((startidx & (BINBLOCKWIDTH - 1)) == 0)
        {
          binblocks(ar_ptr) &= ~block;
          break;
        }
        --startidx;
        q = prev_bin(q);
      } while (first(q) == q);

      /* Get to the next possibly nonempty block */

      if ( (block <<= 1) <= binblocks(ar_ptr) && (block != 0) )
      {
        while ((block & binblocks(ar_ptr)) == 0)
        {
          idx += BINBLOCKWIDTH;
          block <<= 1;
        }
      }
      else
        break;
    }
  }


  /* Try to use top chunk */

  /* Require that there be a remainder, ensuring top always exists  */
  if ( (remainder_size = chunksize(top(ar_ptr)) - nb) < (long)MINSIZE)
  {

#if HAVE_MMAP
    /* If big and would otherwise need to extend, try to use mmap instead */
    if ((unsigned long)nb >= (unsigned long)mmap_threshold &&
        (victim = mmap_chunk(nb)) != 0)
      return victim;
#endif

    /* Try to extend */
    malloc_extend_top(ar_ptr, nb);
    if ((remainder_size = chunksize(top(ar_ptr)) - nb) < (long)MINSIZE)
      return 0; /* propagate failure */
  }

  victim = top(ar_ptr);
  set_head(victim, nb | PREV_INUSE);
  top(ar_ptr) = chunk_at_offset(victim, nb);
  set_head(top(ar_ptr), remainder_size | PREV_INUSE);
  check_malloced_chunk(ar_ptr, victim, nb);
  return victim;

}




/*

  free() algorithm :

    cases:

       1. free(0) has no effect.

       2. If the chunk was allocated via mmap, it is released via munmap().

       3. If a returned chunk borders the current high end of memory,
          it is consolidated into the top, and if the total unused
          topmost memory exceeds the trim threshold, malloc_trim is
          called.

       4. Other chunks are consolidated as they arrive, and
          placed in corresponding bins. (This includes the case of
          consolidating with the current `last_remainder').

*/


#if __STD_C
void fREe(Void_t* mem)
#else
void fREe(mem) Void_t* mem;
#endif
{
  arena *ar_ptr;
  mchunkptr p;                          /* chunk corresponding to mem */

#if defined(_LIBC) || defined(MALLOC_HOOKS)
  if (__free_hook != NULL) {
    (*__free_hook)(mem);
    return;
  }
#endif

  if (mem == 0)                              /* free(0) has no effect */
    return;

  p = mem2chunk(mem);

#if HAVE_MMAP
  if (chunk_is_mmapped(p))                       /* release mmapped memory. */
  {
    munmap_chunk(p);
    return;
  }
#endif

  ar_ptr = arena_for_ptr(p);
#if THREAD_STATS
  if(!mutex_trylock(&ar_ptr->mutex))
    ++(ar_ptr->stat_lock_direct);
  else {
    (void)mutex_lock(&ar_ptr->mutex);
    ++(ar_ptr->stat_lock_wait);
  }
#else
  (void)mutex_lock(&ar_ptr->mutex);
#endif
  chunk_free(ar_ptr, p);
  (void)mutex_unlock(&ar_ptr->mutex);
}

static void
#if __STD_C
chunk_free(arena *ar_ptr, mchunkptr p)
#else
chunk_free(ar_ptr, p) arena *ar_ptr; mchunkptr p;
#endif
{
  INTERNAL_SIZE_T hd = p->size; /* its head field */
  INTERNAL_SIZE_T sz;  /* its size */
  int       idx;       /* its bin index */
  mchunkptr next;      /* next contiguous chunk */
  INTERNAL_SIZE_T nextsz; /* its size */
  INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */
  mchunkptr bck;       /* misc temp for linking */
  mchunkptr fwd;       /* misc temp for linking */
  int       islr;      /* track whether merging with last_remainder */

  check_inuse_chunk(ar_ptr, p);

  sz = hd & ~PREV_INUSE;
  next = chunk_at_offset(p, sz);
  nextsz = chunksize(next);

  if (next == top(ar_ptr))                         /* merge with top */
  {
    sz += nextsz;

    if (!(hd & PREV_INUSE))                    /* consolidate backward */
    {
      prevsz = p->prev_size;
      p = chunk_at_offset(p, -prevsz);
      sz += prevsz;
      unlink(p, bck, fwd);
    }

    set_head(p, sz | PREV_INUSE);
    top(ar_ptr) = p;

#ifndef NO_THREADS
    if(ar_ptr == &main_arena) {
#endif
      if ((unsigned long)(sz) >= (unsigned long)trim_threshold)
        main_trim(top_pad);
#ifndef NO_THREADS
    } else {
      heap_info *heap = heap_for_ptr(p);

      assert(heap->ar_ptr == ar_ptr);

      /* Try to get rid of completely empty heaps, if possible. */
      if((unsigned long)(sz) >= (unsigned long)trim_threshold ||
         p == chunk_at_offset(heap, sizeof(*heap)))
        heap_trim(heap, top_pad);
    }
#endif
    return;
  }

  set_head(next, nextsz);                    /* clear inuse bit */

  islr = 0;

  if (!(hd & PREV_INUSE))                    /* consolidate backward */
  {
    prevsz = p->prev_size;
    p = chunk_at_offset(p, -prevsz);
    sz += prevsz;

    if (p->fd == last_remainder(ar_ptr))     /* keep as last_remainder */
      islr = 1;
    else
      unlink(p, bck, fwd);
  }

  if (!(inuse_bit_at_offset(next, nextsz)))   /* consolidate forward */
  {
    sz += nextsz;

    if (!islr && next->fd == last_remainder(ar_ptr))
                                              /* re-insert last_remainder */
    {
      islr = 1;
      link_last_remainder(ar_ptr, p);
    }
    else
      unlink(next, bck, fwd);
  }

  set_head(p, sz | PREV_INUSE);
  set_foot(p, sz);
  if (!islr)
    frontlink(ar_ptr, p, sz, idx, bck, fwd);
}





/*

  Realloc algorithm:

    Chunks that were obtained via mmap cannot be extended or shrunk
    unless HAVE_MREMAP is defined, in which case mremap is used.
    Otherwise, if their reallocation is for additional space, they are
    copied.  If for less, they are just left alone.

    Otherwise, if the reallocation is for additional space, and the
    chunk can be extended, it is, else a malloc-copy-free sequence is
    taken.  There are several different ways that a chunk could be
    extended. All are tried:

       * Extending forward into following adjacent free chunk.
       * Shifting backwards, joining preceding adjacent space
       * Both shifting backwards and extending forward.
       * Extending into newly sbrked space

    Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a
    size argument of zero (re)allocates a minimum-sized chunk.

    If the reallocation is for less space, and the new request is for
    a `small' (<512 bytes) size, then the newly unused space is lopped
    off and freed.

    The old unix realloc convention of allowing the last-free'd chunk
    to be used as an argument to realloc is no longer supported.
    I don't know of any programs still relying on this feature,
    and allowing it would also allow too many other incorrect
    usages of realloc to be sensible.


*/


#if __STD_C
Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
#else
Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
#endif
{
  arena *ar_ptr;
  INTERNAL_SIZE_T    nb;      /* padded request size */

  mchunkptr oldp;             /* chunk corresponding to oldmem */
  INTERNAL_SIZE_T    oldsize; /* its size */

  mchunkptr newp;             /* chunk to return */

#if defined(_LIBC) || defined(MALLOC_HOOKS)
  if (__realloc_hook != NULL) {
    Void_t* result;

    result = (*__realloc_hook)(oldmem, bytes);
    return result;
  }
#endif

#ifdef REALLOC_ZERO_BYTES_FREES
  if (bytes == 0) { fREe(oldmem); return 0; }
#endif

  /* realloc of null is supposed to be same as malloc */
  if (oldmem == 0) return mALLOc(bytes);

  oldp    = mem2chunk(oldmem);
  oldsize = chunksize(oldp);

  nb = request2size(bytes);

#if HAVE_MMAP
  if (chunk_is_mmapped(oldp))
  {
    Void_t* newmem;

#if HAVE_MREMAP
    newp = mremap_chunk(oldp, nb);
    if(newp) return chunk2mem(newp);
#endif
    /* Note the extra SIZE_SZ overhead. */
    if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */
    /* Must alloc, copy, free. */
    newmem = mALLOc(bytes);
    if (newmem == 0) return 0; /* propagate failure */
    MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ);
    munmap_chunk(oldp);
    return newmem;
  }
#endif

  ar_ptr = arena_for_ptr(oldp);
#if THREAD_STATS
  if(!mutex_trylock(&ar_ptr->mutex))
    ++(ar_ptr->stat_lock_direct);
  else {
    (void)mutex_lock(&ar_ptr->mutex);
    ++(ar_ptr->stat_lock_wait);
  }
#else
  (void)mutex_lock(&ar_ptr->mutex);
#endif

#ifndef NO_THREADS
  /* As in malloc(), remember this arena for the next allocation. */
  tsd_setspecific(arena_key, (Void_t *)ar_ptr);
#endif

  newp = chunk_realloc(ar_ptr, oldp, oldsize, nb);

  (void)mutex_unlock(&ar_ptr->mutex);
  return newp ? chunk2mem(newp) : NULL;
}

static mchunkptr
#if __STD_C
chunk_realloc(arena* ar_ptr, mchunkptr oldp, INTERNAL_SIZE_T oldsize,
              INTERNAL_SIZE_T nb)
#else
chunk_realloc(ar_ptr, oldp, oldsize, nb)
arena* ar_ptr; mchunkptr oldp; INTERNAL_SIZE_T oldsize, nb;
#endif
{
  mchunkptr newp = oldp;      /* chunk to return */
  INTERNAL_SIZE_T newsize = oldsize; /* its size */

  mchunkptr next;             /* next contiguous chunk after oldp */
  INTERNAL_SIZE_T  nextsize;  /* its size */

  mchunkptr prev;             /* previous contiguous chunk before oldp */
  INTERNAL_SIZE_T  prevsize;  /* its size */

  mchunkptr remainder;        /* holds split off extra space from newp */
  INTERNAL_SIZE_T  remainder_size;   /* its size */

  mchunkptr bck;              /* misc temp for linking */
  mchunkptr fwd;              /* misc temp for linking */

  check_inuse_chunk(ar_ptr, oldp);

  if ((long)(oldsize) < (long)(nb))
  {

    /* Try expanding forward */

    next = chunk_at_offset(oldp, oldsize);
    if (next == top(ar_ptr) || !inuse(next))
    {
      nextsize = chunksize(next);

      /* Forward into top only if a remainder */
      if (next == top(ar_ptr))
      {
        if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE))
        {
          newsize += nextsize;
          top(ar_ptr) = chunk_at_offset(oldp, nb);
          set_head(top(ar_ptr), (newsize - nb) | PREV_INUSE);
          set_head_size(oldp, nb);
          return oldp;
        }
      }

      /* Forward into next chunk */
      else if (((long)(nextsize + newsize) >= (long)(nb)))
      {
        unlink(next, bck, fwd);
        newsize  += nextsize;
        goto split;
      }
    }
    else
    {
      next = 0;
      nextsize = 0;
    }

    /* Try shifting backwards. */

    if (!prev_inuse(oldp))
    {
      prev = prev_chunk(oldp);
      prevsize = chunksize(prev);

      /* try forward + backward first to save a later consolidation */

      if (next != 0)
      {
        /* into top */
        if (next == top(ar_ptr))
        {
          if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE))
          {
            unlink(prev, bck, fwd);
            newp = prev;
            newsize += prevsize + nextsize;
            MALLOC_COPY(chunk2mem(newp), chunk2mem(oldp), oldsize - SIZE_SZ);
            top(ar_ptr) = chunk_at_offset(newp, nb);
            set_head(top(ar_ptr), (newsize - nb) | PREV_INUSE);
            set_head_size(newp, nb);
            return newp;
          }
        }

        /* into next chunk */
        else if (((long)(nextsize + prevsize + newsize) >= (long)(nb)))
        {
          unlink(next, bck, fwd);
          unlink(prev, bck, fwd);
          newp = prev;
          newsize += nextsize + prevsize;
          MALLOC_COPY(chunk2mem(newp), chunk2mem(oldp), oldsize - SIZE_SZ);
          goto split;
        }
      }

      /* backward only */
      if (prev != 0 && (long)(prevsize + newsize) >= (long)nb)
      {
        unlink(prev, bck, fwd);
        newp = prev;
        newsize += prevsize;
        MALLOC_COPY(chunk2mem(newp), chunk2mem(oldp), oldsize - SIZE_SZ);
        goto split;
      }
    }

    /* Must allocate */

    newp = chunk_alloc (ar_ptr, nb);

    if (newp == 0)  /* propagate failure */
      return 0;

    /* Avoid copy if newp is next chunk after oldp. */
    /* (This can only happen when new chunk is sbrk'ed.) */

    if ( newp == next_chunk(oldp))
    {
      newsize += chunksize(newp);
      newp = oldp;
      goto split;
    }

    /* Otherwise copy, free, and exit */
    MALLOC_COPY(chunk2mem(newp), chunk2mem(oldp), oldsize - SIZE_SZ);
    chunk_free(ar_ptr, oldp);
    return newp;
  }


 split:  /* split off extra room in old or expanded chunk */

  if (newsize - nb >= MINSIZE) /* split off remainder */
  {
    remainder = chunk_at_offset(newp, nb);
    remainder_size = newsize - nb;
    set_head_size(newp, nb);
    set_head(remainder, remainder_size | PREV_INUSE);
    set_inuse_bit_at_offset(remainder, remainder_size);
    chunk_free(ar_ptr, remainder);
  }
  else
  {
    set_head_size(newp, newsize);
    set_inuse_bit_at_offset(newp, newsize);
  }

  check_inuse_chunk(ar_ptr, newp);
  return newp;
}




/*

  memalign algorithm:

    memalign requests more than enough space from malloc, finds a spot
    within that chunk that meets the alignment request, and then
    possibly frees the leading and trailing space.

    The alignment argument must be a power of two. This property is not
    checked by memalign, so misuse may result in random runtime errors.

    8-byte alignment is guaranteed by normal malloc calls, so don't
    bother calling memalign with an argument of 8 or less.

    Overreliance on memalign is a sure way to fragment space.

*/


#if __STD_C
Void_t* mEMALIGn(size_t alignment, size_t bytes)
#else
Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
#endif
{
  arena *ar_ptr;
  INTERNAL_SIZE_T    nb;      /* padded  request size */
  mchunkptr p;

#if defined(_LIBC) || defined(MALLOC_HOOKS)
  if (__memalign_hook != NULL) {
    Void_t* result;

    result = (*__memalign_hook)(alignment, bytes);
    return result;
  }
#endif

  /* If need less alignment than we give anyway, just relay to malloc */

  if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes);

  /* Otherwise, ensure that it is at least a minimum chunk size */

  if (alignment <  MINSIZE) alignment = MINSIZE;

  nb = request2size(bytes);
  arena_get(ar_ptr, nb + alignment + MINSIZE);
  if(!ar_ptr)
    return 0;
  p = chunk_align(ar_ptr, nb, alignment);
  (void)mutex_unlock(&ar_ptr->mutex);
  return p ? chunk2mem(p) : NULL;
}

static mchunkptr
#if __STD_C
chunk_align(arena* ar_ptr, INTERNAL_SIZE_T nb, size_t alignment)
#else
chunk_align(ar_ptr, nb, alignment)
arena* ar_ptr; INTERNAL_SIZE_T nb; size_t alignment;
#endif
{
  char*     m;                /* memory returned by malloc call */
  mchunkptr p;                /* corresponding chunk */
  char*     brk;              /* alignment point within p */
  mchunkptr newp;             /* chunk to return */
  INTERNAL_SIZE_T  newsize;   /* its size */
  INTERNAL_SIZE_T  leadsize;  /* leading space befor alignment point */
  mchunkptr remainder;        /* spare room at end to split off */
  long      remainder_size;   /* its size */

  /* Call chunk_alloc with worst case padding to hit alignment. */
  p = chunk_alloc(ar_ptr, nb + alignment + MINSIZE);
  if (p == 0)
    return 0; /* propagate failure */

  m = chunk2mem(p);

  if ((((unsigned long)(m)) % alignment) == 0) /* aligned */
  {
#if HAVE_MMAP
    if(chunk_is_mmapped(p)) {
      return p; /* nothing more to do */
    }
#endif
  }
  else /* misaligned */
  {
    /*
      Find an aligned spot inside chunk.
      Since we need to give back leading space in a chunk of at
      least MINSIZE, if the first calculation places us at
      a spot with less than MINSIZE leader, we can move to the
      next aligned spot -- we've allocated enough total room so that
      this is always possible.
    */

    brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -alignment);
    if ((long)(brk - (char*)(p)) < (long)MINSIZE) brk += alignment;

    newp = (mchunkptr)brk;
    leadsize = brk - (char*)(p);
    newsize = chunksize(p) - leadsize;

#if HAVE_MMAP
    if(chunk_is_mmapped(p))
    {
      newp->prev_size = p->prev_size + leadsize;
      set_head(newp, newsize|IS_MMAPPED);
      return newp;
    }
#endif

    /* give back leader, use the rest */

    set_head(newp, newsize | PREV_INUSE);
    set_inuse_bit_at_offset(newp, newsize);
    set_head_size(p, leadsize);
    chunk_free(ar_ptr, p);
    p = newp;

    assert (newsize>=nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0);
  }

  /* Also give back spare room at the end */

  remainder_size = chunksize(p) - nb;

  if (remainder_size >= (long)MINSIZE)
  {
    remainder = chunk_at_offset(p, nb);
    set_head(remainder, remainder_size | PREV_INUSE);
    set_head_size(p, nb);
    chunk_free(ar_ptr, remainder);
  }

  check_inuse_chunk(ar_ptr, p);
  return p;
}




/*
    valloc just invokes memalign with alignment argument equal
    to the page size of the system (or as near to this as can
    be figured out from all the includes/defines above.)
*/

#if __STD_C
Void_t* vALLOc(size_t bytes)
#else
Void_t* vALLOc(bytes) size_t bytes;
#endif
{
  return mEMALIGn (malloc_getpagesize, bytes);
}

/*
  pvalloc just invokes valloc for the nearest pagesize
  that will accommodate request
*/


#if __STD_C
Void_t* pvALLOc(size_t bytes)
#else
Void_t* pvALLOc(bytes) size_t bytes;
#endif
{
  size_t pagesize = malloc_getpagesize;
  return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1));
}

/*

  calloc calls chunk_alloc, then zeroes out the allocated chunk.

*/

#if __STD_C
Void_t* cALLOc(size_t n, size_t elem_size)
#else
Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size;
#endif
{
  arena *ar_ptr;
  mchunkptr p, oldtop;
  INTERNAL_SIZE_T sz, csz, oldtopsize;
  Void_t* mem;

#if defined(_LIBC) || defined(MALLOC_HOOKS)
  if (__malloc_hook != NULL) {
    sz = n * elem_size;
    mem = (*__malloc_hook)(sz);
    if(mem == 0)
      return 0;
#ifdef HAVE_MEMCPY
    memset(mem, 0, sz);
#else
    while(sz > 0) ((char*)mem)[--sz] = 0; /* rather inefficient */
#endif
    return mem;
  }
#endif

  sz = request2size(n * elem_size);
  arena_get(ar_ptr, sz);
  if(!ar_ptr)
    return 0;

  /* check if expand_top called, in which case don't need to clear */
#if MORECORE_CLEARS
  oldtop = top(ar_ptr);
  oldtopsize = chunksize(top(ar_ptr));
#endif
  p = chunk_alloc (ar_ptr, sz);

  /* Only clearing follows, so we can unlock early. */
  (void)mutex_unlock(&ar_ptr->mutex);

  if (p == 0)
    return 0;
  else
  {
    mem = chunk2mem(p);

    /* Two optional cases in which clearing not necessary */

#if HAVE_MMAP
    if (chunk_is_mmapped(p)) return mem;
#endif

    csz = chunksize(p);

#if MORECORE_CLEARS
    if (p == oldtop && csz > oldtopsize)
    {
      /* clear only the bytes from non-freshly-sbrked memory */
      csz = oldtopsize;
    }
#endif

    MALLOC_ZERO(mem, csz - SIZE_SZ);
    return mem;
  }
}

/*

  cfree just calls free. It is needed/defined on some systems
  that pair it with calloc, presumably for odd historical reasons.

*/

#if !defined(_LIBC)
#if __STD_C
void cfree(Void_t *mem)
#else
void cfree(mem) Void_t *mem;
#endif
{
  free(mem);
}
#endif



/*

    Malloc_trim gives memory back to the system (via negative
    arguments to sbrk) if there is unused memory at the `high' end of
    the malloc pool. You can call this after freeing large blocks of
    memory to potentially reduce the system-level memory requirements
    of a program. However, it cannot guarantee to reduce memory. Under
    some allocation patterns, some large free blocks of memory will be
    locked between two used chunks, so they cannot be given back to
    the system.

    The `pad' argument to malloc_trim represents the amount of free
    trailing space to leave untrimmed. If this argument is zero,
    only the minimum amount of memory to maintain internal data
    structures will be left (one page or less). Non-zero arguments
    can be supplied to maintain enough trailing space to service
    future expected allocations without having to re-obtain memory
    from the system.

    Malloc_trim returns 1 if it actually released any memory, else 0.

*/

#if __STD_C
int mALLOC_TRIm(size_t pad)
#else
int mALLOC_TRIm(pad) size_t pad;
#endif
{
  int res;

  (void)mutex_lock(&main_arena.mutex);
  res = main_trim(pad);
  (void)mutex_unlock(&main_arena.mutex);
  return res;
}

/* Trim the main arena. */

static int
#if __STD_C
main_trim(size_t pad)
#else
main_trim(pad) size_t pad;
#endif
{
  mchunkptr top_chunk;   /* The current top chunk */
  long  top_size;        /* Amount of top-most memory */
  long  extra;           /* Amount to release */
  char* current_brk;     /* address returned by pre-check sbrk call */
  char* new_brk;         /* address returned by negative sbrk call */

  unsigned long pagesz = malloc_getpagesize;

  top_chunk = top(&main_arena);
  top_size = chunksize(top_chunk);
  extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;

  if (extra < (long)pagesz) /* Not enough memory to release */
    return 0;

  /* Test to make sure no one else called sbrk */
  current_brk = (char*)(MORECORE (0));
  if (current_brk != (char*)(top_chunk) + top_size)
    return 0;     /* Apparently we don't own memory; must fail */

  new_brk = (char*)(MORECORE (-extra));

  /* Call the `morecore' hook if necessary.  */
  if (__after_morecore_hook)
    (*__after_morecore_hook) ();

  if (new_brk == (char*)(MORECORE_FAILURE)) { /* sbrk failed? */
    /* Try to figure out what we have */
    current_brk = (char*)(MORECORE (0));
    top_size = current_brk - (char*)top_chunk;
    if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */
    {
      sbrked_mem = current_brk - sbrk_base;
      set_head(top_chunk, top_size | PREV_INUSE);
    }
    check_chunk(&main_arena, top_chunk);
    return 0;
  }
  sbrked_mem -= extra;

  /* Success. Adjust top accordingly. */
  set_head(top_chunk, (top_size - extra) | PREV_INUSE);
  check_chunk(&main_arena, top_chunk);
  return 1;
}

#ifndef NO_THREADS

static int
#if __STD_C
heap_trim(heap_info *heap, size_t pad)
#else
heap_trim(heap, pad) heap_info *heap; size_t pad;
#endif
{
  unsigned long pagesz = malloc_getpagesize;
  arena *ar_ptr = heap->ar_ptr;
  mchunkptr top_chunk = top(ar_ptr), p, bck, fwd;
  heap_info *prev_heap;
  long new_size, top_size, extra;

  /* Can this heap go away completely ? */
  while(top_chunk == chunk_at_offset(heap, sizeof(*heap))) {
    prev_heap = heap->prev;
    p = chunk_at_offset(prev_heap, prev_heap->size - (MINSIZE-2*SIZE_SZ));
    assert(p->size == (0|PREV_INUSE)); /* must be fencepost */
    p = prev_chunk(p);
    new_size = chunksize(p) + (MINSIZE-2*SIZE_SZ);
    assert(new_size>0 && new_size<(long)(2*MINSIZE));
    if(!prev_inuse(p))
      new_size += p->prev_size;
    assert(new_size>0 && new_size<HEAP_MAX_SIZE);
    if(new_size + (HEAP_MAX_SIZE - prev_heap->size) < pad + MINSIZE + pagesz)
      break;
    ar_ptr->size -= heap->size;
    delete_heap(heap);
    heap = prev_heap;
    if(!prev_inuse(p)) { /* consolidate backward */
      p = prev_chunk(p);
      unlink(p, bck, fwd);
    }
    assert(((unsigned long)((char*)p + new_size) & (pagesz-1)) == 0);
    assert( ((char*)p + new_size) == ((char*)heap + heap->size) );
    top(ar_ptr) = top_chunk = p;
    set_head(top_chunk, new_size | PREV_INUSE);
    check_chunk(ar_ptr, top_chunk);
  }
  top_size = chunksize(top_chunk);
  extra = ((top_size - pad - MINSIZE + (pagesz-1))/pagesz - 1) * pagesz;
  if(extra < (long)pagesz)
    return 0;
  /* Try to shrink. */
  if(grow_heap(heap, -extra) != 0)
    return 0;
  ar_ptr->size -= extra;

  /* Success. Adjust top accordingly. */
  set_head(top_chunk, (top_size - extra) | PREV_INUSE);
  check_chunk(ar_ptr, top_chunk);
  return 1;
}

#endif



/*
  malloc_usable_size:

    This routine tells you how many bytes you can actually use in an
    allocated chunk, which may be more than you requested (although
    often not). You can use this many bytes without worrying about
    overwriting other allocated objects. Not a particularly great
    programming practice, but still sometimes useful.

*/

#if __STD_C
size_t mALLOC_USABLE_SIZe(Void_t* mem)
#else
size_t mALLOC_USABLE_SIZe(mem) Void_t* mem;
#endif
{
  mchunkptr p;

  if (mem == 0)
    return 0;
  else
  {
    p = mem2chunk(mem);
    if(!chunk_is_mmapped(p))
    {
      if (!inuse(p)) return 0;
      check_inuse_chunk(arena_for_ptr(mem), p);
      return chunksize(p) - SIZE_SZ;
    }
    return chunksize(p) - 2*SIZE_SZ;
  }
}




/* Utility to update mallinfo for malloc_stats() and mallinfo() */

static void
#if __STD_C
malloc_update_mallinfo(arena *ar_ptr, struct mallinfo *mi)
#else
malloc_update_mallinfo(ar_ptr, mi) arena *ar_ptr; struct mallinfo *mi;
#endif
{
  int i, navail;
  mbinptr b;
  mchunkptr p;
#if MALLOC_DEBUG
  mchunkptr q;
#endif
  INTERNAL_SIZE_T avail;

  (void)mutex_lock(&ar_ptr->mutex);
  avail = chunksize(top(ar_ptr));
  navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0;

  for (i = 1; i < NAV; ++i)
  {
    b = bin_at(ar_ptr, i);
    for (p = last(b); p != b; p = p->bk)
    {
#if MALLOC_DEBUG
      check_free_chunk(ar_ptr, p);
      for (q = next_chunk(p);
           q != top(ar_ptr) && inuse(q) && (long)chunksize(q) > 0;
           q = next_chunk(q))
        check_inuse_chunk(ar_ptr, q);
#endif
      avail += chunksize(p);
      navail++;
    }
  }

  mi->arena = ar_ptr->size;
  mi->ordblks = navail;
  mi->uordblks = ar_ptr->size - avail;
  mi->fordblks = avail;
  mi->hblks = n_mmaps;
  mi->hblkhd = mmapped_mem;
  mi->keepcost = chunksize(top(ar_ptr));

  (void)mutex_unlock(&ar_ptr->mutex);
}

#if !defined(NO_THREADS) && MALLOC_DEBUG > 1

/* Print the complete contents of a single heap to stderr. */

static void
#if __STD_C
dump_heap(heap_info *heap)
#else
dump_heap(heap) heap_info *heap;
#endif
{
  char *ptr;
  mchunkptr p;

  fprintf(stderr, "Heap %p, size %10lx:\n", heap, (long)heap->size);
  ptr = (heap->ar_ptr != (arena*)(heap+1)) ?
    (char*)(heap + 1) : (char*)(heap + 1) + sizeof(arena);
  p = (mchunkptr)(((unsigned long)ptr + MALLOC_ALIGN_MASK) &
                  ~MALLOC_ALIGN_MASK);
  for(;;) {
    fprintf(stderr, "chunk %p size %10lx", p, (long)p->size);
    if(p == top(heap->ar_ptr)) {
      fprintf(stderr, " (top)\n");
      break;
    } else if(p->size == (0|PREV_INUSE)) {
      fprintf(stderr, " (fence)\n");
      break;
    }
    fprintf(stderr, "\n");
    p = next_chunk(p);
  }
}

#endif



/*

  malloc_stats:

    For all arenas separately and in total, prints on stderr the
    amount of space obtained from the system, and the current number
    of bytes allocated via malloc (or realloc, etc) but not yet
    freed. (Note that this is the number of bytes allocated, not the
    number requested. It will be larger than the number requested
    because of alignment and bookkeeping overhead.)  When not compiled
    for multiple threads, the maximum amount of allocated memory
    (which may be more than current if malloc_trim and/or munmap got
    called) is also reported.  When using mmap(), prints the maximum
    number of simultaneous mmap regions used, too.

*/

void mALLOC_STATs()
{
  int i;
  arena *ar_ptr;
  struct mallinfo mi;
  unsigned int in_use_b = mmapped_mem, system_b = in_use_b;
#if THREAD_STATS
  long stat_lock_direct = 0, stat_lock_loop = 0, stat_lock_wait = 0;
#endif

  for(i=0, ar_ptr = &main_arena;; i++) {
    malloc_update_mallinfo(ar_ptr, &mi);
    fprintf(stderr, "Arena %d:\n", i);
    fprintf(stderr, "system bytes     = %10u\n", (unsigned int)mi.arena);
    fprintf(stderr, "in use bytes     = %10u\n", (unsigned int)mi.uordblks);
    system_b += mi.arena;
    in_use_b += mi.uordblks;
#if THREAD_STATS
    stat_lock_direct += ar_ptr->stat_lock_direct;
    stat_lock_loop += ar_ptr->stat_lock_loop;
    stat_lock_wait += ar_ptr->stat_lock_wait;
#endif
#if !defined(NO_THREADS) && MALLOC_DEBUG > 1
    if(ar_ptr != &main_arena) {
      (void)mutex_lock(&ar_ptr->mutex);
      heap_info *heap = heap_for_ptr(top(ar_ptr));
      while(heap) { dump_heap(heap); heap = heap->prev; }
      (void)mutex_unlock(&ar_ptr->mutex);
    }
#endif
    ar_ptr = ar_ptr->next;
    if(ar_ptr == &main_arena) break;
  }
  fprintf(stderr, "Total (incl. mmap):\n");
  fprintf(stderr, "system bytes     = %10u\n", system_b);
  fprintf(stderr, "in use bytes     = %10u\n", in_use_b);
#ifdef NO_THREADS
  fprintf(stderr, "max system bytes = %10u\n", (unsigned int)max_total_mem);
#endif
#if HAVE_MMAP
  fprintf(stderr, "max mmap regions = %10u\n", (unsigned int)max_n_mmaps);
#endif
#if THREAD_STATS
  fprintf(stderr, "heaps created    = %10d\n",  stat_n_heaps);
  fprintf(stderr, "locked directly  = %10ld\n", stat_lock_direct);
  fprintf(stderr, "locked in loop   = %10ld\n", stat_lock_loop);
  fprintf(stderr, "locked waiting   = %10ld\n", stat_lock_wait);
  fprintf(stderr, "locked total     = %10ld\n",
          stat_lock_direct + stat_lock_loop + stat_lock_wait);
#endif
}

/*
  mallinfo returns a copy of updated current mallinfo.
  The information reported is for the arena last used by the thread.
*/

struct mallinfo mALLINFo()
{
  struct mallinfo mi;
  Void_t *vptr = NULL;

#ifndef NO_THREADS
  tsd_getspecific(arena_key, vptr);
#endif
  malloc_update_mallinfo((vptr ? (arena*)vptr : &main_arena), &mi);
  return mi;
}




/*
  mallopt:

    mallopt is the general SVID/XPG interface to tunable parameters.
    The format is to provide a (parameter-number, parameter-value) pair.
    mallopt then sets the corresponding parameter to the argument
    value if it can (i.e., so long as the value is meaningful),
    and returns 1 if successful else 0.

    See descriptions of tunable parameters above.

*/

#if __STD_C
int mALLOPt(int param_number, int value)
#else
int mALLOPt(param_number, value) int param_number; int value;
#endif
{
  switch(param_number)
  {
    case M_TRIM_THRESHOLD:
      trim_threshold = value; return 1;
    case M_TOP_PAD:
      top_pad = value; return 1;
    case M_MMAP_THRESHOLD:
#ifndef NO_THREADS
      /* Forbid setting the threshold too high. */
      if((unsigned long)value > HEAP_MAX_SIZE/2) return 0;
#endif
      mmap_threshold = value; return 1;
    case M_MMAP_MAX:
#if HAVE_MMAP
      n_mmaps_max = value; return 1;
#else
      if (value != 0) return 0; else  n_mmaps_max = value; return 1;
#endif
    case M_CHECK_ACTION:
      check_action = value; return 1;

    default:
      return 0;
  }
}



/* Get/set state: malloc_get_state() records the current state of all
   malloc variables (_except_ for the actual heap contents and `hook'
   function pointers) in a system dependent, opaque data structure.
   This data structure is dynamically allocated and can be free()d
   after use.  malloc_set_state() restores the state of all malloc
   variables to the previously obtained state.  This is especially
   useful when using this malloc as part of a shared library, and when
   the heap contents are saved/restored via some other method.  The
   primary example for this is GNU Emacs with its `dumping' procedure.
   `Hook' function pointers are never saved or restored by these
   functions. */

#define MALLOC_STATE_MAGIC   0x444c4541l
#define MALLOC_STATE_VERSION (0*0x100l + 0l) /* major*0x100 + minor */

struct malloc_state {
  long          magic;
  long          version;
  mbinptr       av[NAV * 2 + 2];
  char*         sbrk_base;
  int           sbrked_mem_bytes;
  unsigned long trim_threshold;
  unsigned long top_pad;
  unsigned int  n_mmaps_max;
  unsigned long mmap_threshold;
  int           check_action;
  unsigned long max_sbrked_mem;
  unsigned long max_total_mem;
  unsigned int  n_mmaps;
  unsigned int  max_n_mmaps;
  unsigned long mmapped_mem;
  unsigned long max_mmapped_mem;
};

Void_t*
mALLOC_GET_STATe()
{
  mchunkptr victim;
  struct malloc_state* ms;
  int i;
  mbinptr b;

  ptmalloc_init();
  (void)mutex_lock(&main_arena.mutex);
  victim = chunk_alloc(&main_arena, request2size(sizeof(*ms)));
  if(!victim) {
    (void)mutex_unlock(&main_arena.mutex);
    return 0;
  }
  ms = (struct malloc_state*)chunk2mem(victim);
  ms->magic = MALLOC_STATE_MAGIC;
  ms->version = MALLOC_STATE_VERSION;
  ms->av[0] = main_arena.av[0];
  ms->av[1] = main_arena.av[1];
  for(i=0; i<NAV; i++) {
    b = bin_at(&main_arena, i);
    if(first(b) == b)
      ms->av[2*i+2] = ms->av[2*i+3] = 0; /* empty bin (or initial top) */
    else {
      ms->av[2*i+2] = first(b);
      ms->av[2*i+3] = last(b);
    }
  }
  ms->sbrk_base = sbrk_base;
  ms->sbrked_mem_bytes = sbrked_mem;
  ms->trim_threshold = trim_threshold;
  ms->top_pad = top_pad;
  ms->n_mmaps_max = n_mmaps_max;
  ms->mmap_threshold = mmap_threshold;
  ms->check_action = check_action;
  ms->max_sbrked_mem = max_sbrked_mem;
#ifdef NO_THREADS
  ms->max_total_mem = max_total_mem;
#else
  ms->max_total_mem = 0;
#endif
  ms->n_mmaps = n_mmaps;
  ms->max_n_mmaps = max_n_mmaps;
  ms->mmapped_mem = mmapped_mem;
  ms->max_mmapped_mem = max_mmapped_mem;
  (void)mutex_unlock(&main_arena.mutex);
  return (Void_t*)ms;
}

int
#if __STD_C
mALLOC_SET_STATe(Void_t* msptr)
#else
mALLOC_SET_STATe(msptr) Void_t* msptr;
#endif
{
  struct malloc_state* ms = (struct malloc_state*)msptr;
  int i;
  mbinptr b;

  ptmalloc_init();
  if(ms->magic != MALLOC_STATE_MAGIC) return -1;
  /* Must fail if the major version is too high. */
  if((ms->version & ~0xffl) > (MALLOC_STATE_VERSION & ~0xffl)) return -2;
  (void)mutex_lock(&main_arena.mutex);
  main_arena.av[0] = ms->av[0];
  main_arena.av[1] = ms->av[1];
  for(i=0; i<NAV; i++) {
    b = bin_at(&main_arena, i);
    if(ms->av[2*i+2] == 0)
      first(b) = last(b) = b;
    else {
      first(b) = ms->av[2*i+2];
      last(b) = ms->av[2*i+3];
      if(i > 0) {
        /* Make sure the links to the `av'-bins in the heap are correct. */
        first(b)->bk = b;
        last(b)->fd = b;
      }
    }
  }
  sbrk_base = ms->sbrk_base;
  sbrked_mem = ms->sbrked_mem_bytes;
  trim_threshold = ms->trim_threshold;
  top_pad = ms->top_pad;
  n_mmaps_max = ms->n_mmaps_max;
  mmap_threshold = ms->mmap_threshold;
  check_action = ms->check_action;
  max_sbrked_mem = ms->max_sbrked_mem;
#ifdef NO_THREADS
  max_total_mem = ms->max_total_mem;
#endif
  n_mmaps = ms->n_mmaps;
  max_n_mmaps = ms->max_n_mmaps;
  mmapped_mem = ms->mmapped_mem;
  max_mmapped_mem = ms->max_mmapped_mem;
  /* add version-dependent code here */
  (void)mutex_unlock(&main_arena.mutex);
  return 0;
}



#if defined(_LIBC) || defined(MALLOC_HOOKS)

/* A simple, standard set of debugging hooks.  Overhead is `only' one
   byte per chunk; still this will catch most cases of double frees or
   overruns. */

#define MAGICBYTE(p) ( ( ((size_t)p >> 3) ^ ((size_t)p >> 11)) & 0xFF )

/* Convert a pointer to be free()d or realloc()ed to a valid chunk
   pointer.  If the provided pointer is not valid, return NULL.  The
   goal here is to avoid crashes, unlike in the MALLOC_DEBUG code. */

static mchunkptr
#if __STD_C
mem2chunk_check(Void_t* mem)
#else
mem2chunk_check(mem) Void_t* mem;
#endif
{
  mchunkptr p;
  INTERNAL_SIZE_T sz;

  p = mem2chunk(mem);
  if(!aligned_OK(p)) return NULL;
  if( (char*)p>=sbrk_base && (char*)p<(sbrk_base+sbrked_mem) ) {
    /* Must be a chunk in conventional heap memory. */
    if(chunk_is_mmapped(p) ||
       ( (sz = chunksize(p)), ((char*)p + sz)>=(sbrk_base+sbrked_mem) ) ||
       sz<MINSIZE || sz&MALLOC_ALIGN_MASK || !inuse(p) ||
       ( !prev_inuse(p) && (p->prev_size&MALLOC_ALIGN_MASK ||
                            (long)prev_chunk(p)<(long)sbrk_base ||
                            next_chunk(prev_chunk(p))!=p) ))
      return NULL;
    if(*((unsigned char*)p + sz + (SIZE_SZ-1)) != MAGICBYTE(p))
      return NULL;
    *((unsigned char*)p + sz + (SIZE_SZ-1)) ^= 0xFF;
  } else {
    unsigned long offset, page_mask = malloc_getpagesize-1;

    /* mmap()ed chunks have MALLOC_ALIGNMENT or higher power-of-two
       alignment relative to the beginning of a page.  Check this
       first. */
    offset = (unsigned long)mem & page_mask;
    if((offset!=MALLOC_ALIGNMENT && offset!=0 && offset!=0x10 &&
        offset!=0x20 && offset!=0x40 && offset!=0x80 && offset!=0x100 &&
        offset!=0x200 && offset!=0x400 && offset!=0x800 && offset!=0x1000 &&
        offset<0x2000) ||
       !chunk_is_mmapped(p) || (p->size & PREV_INUSE) ||
       ( (((unsigned long)p - p->prev_size) & page_mask) != 0 ) ||
       ( (sz = chunksize(p)), ((p->prev_size + sz) & page_mask) != 0 ) )
      return NULL;
    if(*((unsigned char*)p + sz - 1) != MAGICBYTE(p))
      return NULL;
    *((unsigned char*)p + sz - 1) ^= 0xFF;
  }
  return p;
}

static Void_t*
#if __STD_C
malloc_check(size_t sz)
#else
malloc_check(sz) size_t sz;
#endif
{
  mchunkptr victim;
  INTERNAL_SIZE_T nb = request2size(sz + 1);

  (void)mutex_lock(&main_arena.mutex);
  victim = chunk_alloc(&main_arena, nb);
  (void)mutex_unlock(&main_arena.mutex);
  if(!victim) return NULL;
  nb = chunksize(victim);
  if(chunk_is_mmapped(victim))
    --nb;
  else
    nb += SIZE_SZ - 1;
  *((unsigned char*)victim + nb) = MAGICBYTE(victim);
  return chunk2mem(victim);
}

static void
#if __STD_C
free_check(Void_t* mem)
#else
free_check(mem) Void_t* mem;
#endif
{
  mchunkptr p;

  if(!mem) return;
  (void)mutex_lock(&main_arena.mutex);
  p = mem2chunk_check(mem);
  if(!p) {
    (void)mutex_unlock(&main_arena.mutex);
    switch(check_action) {
    case 1:
      fprintf(stderr, "free(): invalid pointer %lx!\n", (long)(mem));
      break;
    case 2:
      abort();
    }
    return;
  }
#if HAVE_MMAP
  if (chunk_is_mmapped(p)) {
    (void)mutex_unlock(&main_arena.mutex);
    munmap_chunk(p);
    return;
  }
#endif
#if 0 /* Erase freed memory. */
  memset(mem, 0, chunksize(p) - (SIZE_SZ+1));
#endif
  chunk_free(&main_arena, p);
  (void)mutex_unlock(&main_arena.mutex);
}

static Void_t*
#if __STD_C
realloc_check(Void_t* oldmem, size_t bytes)
#else
realloc_check(oldmem, bytes) Void_t* oldmem; size_t bytes;
#endif
{
  mchunkptr oldp, newp;
  INTERNAL_SIZE_T nb, oldsize;

  if (oldmem == 0) return malloc_check(bytes);
  (void)mutex_lock(&main_arena.mutex);
  oldp = mem2chunk_check(oldmem);
  if(!oldp) {
    (void)mutex_unlock(&main_arena.mutex);
    switch(check_action) {
    case 1:
      fprintf(stderr, "realloc(): invalid pointer %lx!\n", (long)(oldmem));
      break;
    case 2:
      abort();
    }
    return malloc_check(bytes);
  }
  oldsize = chunksize(oldp);

  nb = request2size(bytes+1);

#if HAVE_MMAP
  if (chunk_is_mmapped(oldp)) {
#if HAVE_MREMAP
    newp = mremap_chunk(oldp, nb);
    if(!newp) {
#endif
      /* Note the extra SIZE_SZ overhead. */
      if(oldsize - SIZE_SZ >= nb) newp = oldp; /* do nothing */
      else {
        /* Must alloc, copy, free. */
        newp = chunk_alloc(&main_arena, nb);
        if (newp) {
          MALLOC_COPY(chunk2mem(newp), oldmem, oldsize - 2*SIZE_SZ);
          munmap_chunk(oldp);
        }
      }
#if HAVE_MREMAP
    }
#endif
  } else {
#endif /* HAVE_MMAP */
    newp = chunk_realloc(&main_arena, oldp, oldsize, nb);
#if 0 /* Erase freed memory. */
    nb = chunksize(newp);
    if(oldp<newp || oldp>=chunk_at_offset(newp, nb)) {
      memset((char*)oldmem + 2*sizeof(mbinptr), 0,
             oldsize - (2*sizeof(mbinptr)+2*SIZE_SZ+1));
    } else if(nb > oldsize+SIZE_SZ) {
      memset((char*)chunk2mem(newp) + oldsize, 0, nb - (oldsize+SIZE_SZ));
    }
#endif
#if HAVE_MMAP
  }
#endif
  (void)mutex_unlock(&main_arena.mutex);

  if(!newp) return NULL;
  nb = chunksize(newp);
  if(chunk_is_mmapped(newp))
    --nb;
  else
    nb += SIZE_SZ - 1;
  *((unsigned char*)newp + nb) = MAGICBYTE(newp);
  return chunk2mem(newp);
}

static Void_t*
#if __STD_C
memalign_check(size_t alignment, size_t bytes)
#else
memalign_check(alignment, bytes) size_t alignment; size_t bytes;
#endif
{
  INTERNAL_SIZE_T nb;
  mchunkptr p;

  if (alignment <= MALLOC_ALIGNMENT) return malloc_check(bytes);
  if (alignment <  MINSIZE) alignment = MINSIZE;

  nb = request2size(bytes+1);
  (void)mutex_lock(&main_arena.mutex);
  p = chunk_align(&main_arena, nb, alignment);
  (void)mutex_unlock(&main_arena.mutex);
  if(!p) return NULL;
  nb = chunksize(p);
  if(chunk_is_mmapped(p))
    --nb;
  else
    nb += SIZE_SZ - 1;
  *((unsigned char*)p + nb) = MAGICBYTE(p);
  return chunk2mem(p);
}

/* The following hooks are used when the global initialization in
   ptmalloc_init() hasn't completed yet. */

static Void_t*
#if __STD_C
malloc_starter(size_t sz)
#else
malloc_starter(sz) size_t sz;
#endif
{
  mchunkptr victim = chunk_alloc(&main_arena, request2size(sz));

  return victim ? chunk2mem(victim) : 0;
}

static void
#if __STD_C
free_starter(Void_t* mem)
#else
free_starter(mem) Void_t* mem;
#endif
{
  mchunkptr p;

  if(!mem) return;
  p = mem2chunk(mem);
#if HAVE_MMAP
  if (chunk_is_mmapped(p)) {
    munmap_chunk(p);
    return;
  }
#endif
  chunk_free(&main_arena, p);
}

#endif /* defined(_LIBC) || defined(MALLOC_HOOKS) */



#ifdef _LIBC
weak_alias (__libc_calloc, __calloc) weak_alias (__libc_calloc, calloc)
weak_alias (__libc_free, __cfree) weak_alias (__libc_free, cfree)
weak_alias (__libc_free, __free) weak_alias (__libc_free, free)
weak_alias (__libc_malloc, __malloc) weak_alias (__libc_malloc, malloc)
weak_alias (__libc_memalign, __memalign) weak_alias (__libc_memalign, memalign)
weak_alias (__libc_realloc, __realloc) weak_alias (__libc_realloc, realloc)
weak_alias (__libc_valloc, __valloc) weak_alias (__libc_valloc, valloc)
weak_alias (__libc_pvalloc, __pvalloc) weak_alias (__libc_pvalloc, pvalloc)
weak_alias (__libc_mallinfo, __mallinfo) weak_alias (__libc_mallinfo, mallinfo)
weak_alias (__libc_mallopt, __mallopt) weak_alias (__libc_mallopt, mallopt)

weak_alias (__malloc_stats, malloc_stats)
weak_alias (__malloc_usable_size, malloc_usable_size)
weak_alias (__malloc_trim, malloc_trim)
weak_alias (__malloc_get_state, malloc_get_state)
weak_alias (__malloc_set_state, malloc_set_state)
#endif

/*

History:

    V2.6.4-pt3 Thu Feb 20 1997 Wolfram Gloger (wmglo@dent.med.uni-muenchen.de)
      * Added malloc_get/set_state() (mainly for use in GNU emacs),
        using interface from Marcus Daniels
      * All parameters are now adjustable via environment variables

    V2.6.4-pt2 Sat Dec 14 1996 Wolfram Gloger (wmglo@dent.med.uni-muenchen.de)
      * Added debugging hooks
      * Fixed possible deadlock in realloc() when out of memory
      * Don't pollute namespace in glibc: use __getpagesize, __mmap, etc.

    V2.6.4-pt Wed Dec  4 1996 Wolfram Gloger (wmglo@dent.med.uni-muenchen.de)
      * Very minor updates from the released 2.6.4 version.
      * Trimmed include file down to exported data structures.
      * Changes from H.J. Lu for glibc-2.0.

    V2.6.3i-pt Sep 16 1996  Wolfram Gloger (wmglo@dent.med.uni-muenchen.de)
      * Many changes for multiple threads
      * Introduced arenas and heaps

    V2.6.3 Sun May 19 08:17:58 1996  Doug Lea  (dl at gee)
      * Added pvalloc, as recommended by H.J. Liu
      * Added 64bit pointer support mainly from Wolfram Gloger
      * Added anonymously donated WIN32 sbrk emulation
      * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
      * malloc_extend_top: fix mask error that caused wastage after
        foreign sbrks
      * Add linux mremap support code from HJ Liu

    V2.6.2 Tue Dec  5 06:52:55 1995  Doug Lea  (dl at gee)
      * Integrated most documentation with the code.
      * Add support for mmap, with help from
        Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
      * Use last_remainder in more cases.
      * Pack bins using idea from  colin@nyx10.cs.du.edu
      * Use ordered bins instead of best-fit threshold
      * Eliminate block-local decls to simplify tracing and debugging.
      * Support another case of realloc via move into top
      * Fix error occurring when initial sbrk_base not word-aligned.
      * Rely on page size for units instead of SBRK_UNIT to
        avoid surprises about sbrk alignment conventions.
      * Add mallinfo, mallopt. Thanks to Raymond Nijssen
        (raymond@es.ele.tue.nl) for the suggestion.
      * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
      * More precautions for cases where other routines call sbrk,
        courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
      * Added macros etc., allowing use in linux libc from
        H.J. Lu (hjl@gnu.ai.mit.edu)
      * Inverted this history list

    V2.6.1 Sat Dec  2 14:10:57 1995  Doug Lea  (dl at gee)
      * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
      * Removed all preallocation code since under current scheme
        the work required to undo bad preallocations exceeds
        the work saved in good cases for most test programs.
      * No longer use return list or unconsolidated bins since
        no scheme using them consistently outperforms those that don't
        given above changes.
      * Use best fit for very large chunks to prevent some worst-cases.
      * Added some support for debugging

    V2.6.0 Sat Nov  4 07:05:23 1995  Doug Lea  (dl at gee)
      * Removed footers when chunks are in use. Thanks to
        Paul Wilson (wilson@cs.texas.edu) for the suggestion.

    V2.5.4 Wed Nov  1 07:54:51 1995  Doug Lea  (dl at gee)
      * Added malloc_trim, with help from Wolfram Gloger
        (wmglo@Dent.MED.Uni-Muenchen.DE).

    V2.5.3 Tue Apr 26 10:16:01 1994  Doug Lea  (dl at g)

    V2.5.2 Tue Apr  5 16:20:40 1994  Doug Lea  (dl at g)
      * realloc: try to expand in both directions
      * malloc: swap order of clean-bin strategy;
      * realloc: only conditionally expand backwards
      * Try not to scavenge used bins
      * Use bin counts as a guide to preallocation
      * Occasionally bin return list chunks in first scan
      * Add a few optimizations from colin@nyx10.cs.du.edu

    V2.5.1 Sat Aug 14 15:40:43 1993  Doug Lea  (dl at g)
      * faster bin computation & slightly different binning
      * merged all consolidations to one part of malloc proper
         (eliminating old malloc_find_space & malloc_clean_bin)
      * Scan 2 returns chunks (not just 1)
      * Propagate failure in realloc if malloc returns 0
      * Add stuff to allow compilation on non-ANSI compilers
          from kpv@research.att.com

    V2.5 Sat Aug  7 07:41:59 1993  Doug Lea  (dl at g.oswego.edu)
      * removed potential for odd address access in prev_chunk
      * removed dependency on getpagesize.h
      * misc cosmetics and a bit more internal documentation
      * anticosmetics: mangled names in macros to evade debugger strangeness
      * tested on sparc, hp-700, dec-mips, rs6000
          with gcc & native cc (hp, dec only) allowing
          Detlefs & Zorn comparison study (in SIGPLAN Notices.)

    Trial version Fri Aug 28 13:14:29 1992  Doug Lea  (dl at g.oswego.edu)
      * Based loosely on libg++-1.2X malloc. (It retains some of the overall
         structure of old version,  but most details differ.)

*/