about summary refs log tree commit diff
path: root/iconv/iconv_charmap.c
blob: 7392e1316128d51d4a0530558b57c4dff5cebfe3 (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
/* Convert using charmaps and possibly iconv().
   Copyright (C) 2001-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

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

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, see <https://www.gnu.org/licenses/>.  */

#include <assert.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <iconv.h>
#include <libintl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include "iconv_prog.h"


/* Prototypes for a few program-wide used functions.  */
#include <programs/xmalloc.h>


struct convtable
{
  int term[256 / 8];
  union
  {
    struct convtable *sub;
    struct charseq *out;
  } val[256];
};


static inline struct convtable *
allocate_table (void)
{
  return (struct convtable *) xcalloc (1, sizeof (struct convtable));
}

static inline void
free_table (struct convtable *tbl)
{
  free (tbl);
}


static inline int
is_term (struct convtable *tbl, unsigned int idx)
{
  return tbl->term[idx / 8] & (1 << (idx % 8));
}


static inline void
clear_term (struct convtable *tbl, unsigned int idx)
{
  tbl->term[idx / 8] &= ~(1 << (idx % 8));
}


static inline void
set_term (struct convtable *tbl, unsigned int idx)
{
  tbl->term[idx / 8] |= 1 << (idx % 8);
}


/* Generate the conversion table.  */
static struct convtable *use_from_charmap (struct charmap_t *from_charmap,
					   const char *to_code);
static struct convtable *use_to_charmap (const char *from_code,
					 struct charmap_t *to_charmap);
static struct convtable *use_both_charmaps (struct charmap_t *from_charmap,
					    struct charmap_t *to_charmap);

/* Prototypes for the functions doing the actual work.  */
static int process_block (struct convtable *tbl, char *addr, size_t len,
			  FILE *output);
static int process_fd (struct convtable *tbl, int fd, FILE *output);
static int process_file (struct convtable *tbl, FILE *input, FILE *output);


int
charmap_conversion (const char *from_code, struct charmap_t *from_charmap,
		    const char *to_code, struct charmap_t *to_charmap,
		    int argc, int remaining, char *argv[],
		    const char *output_file)
{
  struct convtable *cvtbl;
  int status = EXIT_SUCCESS;

  /* We have three different cases to handle:

     - both, from_charmap and to_charmap, are available.  This means we
       can assume that the symbolic names match and use them to create
       the mapping.

     - only from_charmap is available.  In this case we can only hope that
       the symbolic names used are of the <Uxxxx> form in which case we
       can use a UCS4->"to_code" iconv() conversion for the second step.

     - only to_charmap is available.  This is similar, only that we would
       use iconv() for the "to_code"->UCS4 conversion.

       We first create a table which maps input bytes into output bytes.
       Once this is done we can handle all three of the cases above
       equally.  */
  if (from_charmap != NULL)
    {
      if (to_charmap == NULL)
	cvtbl = use_from_charmap (from_charmap, to_code);
      else
	cvtbl = use_both_charmaps (from_charmap, to_charmap);
    }
  else
    {
      assert (to_charmap != NULL);
      cvtbl = use_to_charmap (from_code, to_charmap);
    }

  /* If we couldn't generate a table stop now.  */
  if (cvtbl == NULL)
    return EXIT_FAILURE;

  /* Determine output file.  */
  FILE *output;
  if (output_file != NULL && strcmp (output_file, "-") != 0)
    {
      output = fopen (output_file, "w");
      if (output == NULL)
	error (EXIT_FAILURE, errno, _("cannot open output file"));
    }
  else
    output = stdout;

  /* We can now start the conversion.  */
  if (remaining == argc)
    {
      if (process_file (cvtbl, stdin, output) != 0)
	status = EXIT_FAILURE;
    }
  else
    do
      {
	int fd;

	if (verbose)
	  printf ("%s:\n", argv[remaining]);
	if (strcmp (argv[remaining], "-") == 0)
	  fd = 0;
	else
	  {
	    fd = open (argv[remaining], O_RDONLY);

	    if (fd == -1)
	      {
		error (0, errno, _("cannot open input file `%s'"),
		       argv[remaining]);
		status = EXIT_FAILURE;
		continue;
	      }
	  }

#ifdef _POSIX_MAPPED_FILES
	struct stat64 st;
	char *addr;
	/* We have possibilities for reading the input file.  First try
	   to mmap() it since this will provide the fastest solution.  */
	if (fstat64 (fd, &st) == 0
	    && ((addr = mmap (NULL, st.st_size, PROT_READ, MAP_PRIVATE,
			      fd, 0)) != MAP_FAILED))
	  {
	    /* Yes, we can use mmap().  The descriptor is not needed
	       anymore.  */
	    if (close (fd) != 0)
	      error (EXIT_FAILURE, errno,
		     _("error while closing input `%s'"), argv[remaining]);

	    if (process_block (cvtbl, addr, st.st_size, output) < 0)
	      {
		/* Something went wrong.  */
		status = EXIT_FAILURE;

		/* We don't need the input data anymore.  */
		munmap ((void *) addr, st.st_size);

		/* We cannot go on with producing output since it might
		   lead to problem because the last output might leave
		   the output stream in an undefined state.  */
		break;
	      }

	    /* We don't need the input data anymore.  */
	    munmap ((void *) addr, st.st_size);
	  }
	else
#endif	/* _POSIX_MAPPED_FILES */
	  {
	    /* Read the file in pieces.  */
	    if (process_fd (cvtbl, fd, output) != 0)
	      {
		/* Something went wrong.  */
		status = EXIT_FAILURE;

		/* We don't need the input file anymore.  */
		close (fd);

		/* We cannot go on with producing output since it might
		   lead to problem because the last output might leave
		   the output stream in an undefined state.  */
		break;
	      }

	    /* Now close the file.  */
	    close (fd);
	  }
      }
    while (++remaining < argc);

  /* All done.  */
  if (output != stdout)
    fclose (output);
  free_table (cvtbl);
  return status;
}


/* Add the IN->OUT mapping to TBL.  OUT is potentially stored in the table.
   IN is used only here, so it need not be kept live afterwards.  */
static void
add_bytes (struct convtable *tbl, const struct charseq *in, struct charseq *out)
{
  int n = 0;
  unsigned int byte;

  assert (in->nbytes > 0);

  byte = ((unsigned char *) in->bytes)[n];
  while (n + 1 < in->nbytes)
    {
      if (is_term (tbl, byte) || tbl->val[byte].sub == NULL)
	{
	  /* Note that we simply ignore a definition for a byte sequence
	     which is also the prefix for a longer one.  */
	  clear_term (tbl, byte);
	  tbl->val[byte].sub =
	    (struct convtable *) xcalloc (1, sizeof (struct convtable));
	}

      tbl = tbl->val[byte].sub;

      byte = ((unsigned char *) in->bytes)[++n];
    }

  /* Only add the new sequence if there is none yet and the byte sequence
     is not part of an even longer one.  */
  if (! is_term (tbl, byte) && tbl->val[byte].sub == NULL)
    {
      set_term (tbl, byte);
      tbl->val[byte].out = out;
    }
}

/* Try to convert SEQ from WCHAR_T format using CD.
   Returns a malloc'd struct or NULL.  */
static struct charseq *
convert_charseq (iconv_t cd, const struct charseq *seq)
{
  struct charseq *result = NULL;

  if (seq->ucs4 != UNINITIALIZED_CHAR_VALUE)
    {
      /* There is a chance.  Try the iconv module.  */
      wchar_t inbuf[1] = { seq->ucs4 };
      unsigned char outbuf[64];
      char *inptr = (char *) inbuf;
      size_t inlen = sizeof (inbuf);
      char *outptr = (char *) outbuf;
      size_t outlen = sizeof (outbuf);

      (void) iconv (cd, &inptr, &inlen, &outptr, &outlen);

      if (outptr != (char *) outbuf)
        {
          /* We got some output.  Good, use it.  */
          outlen = sizeof (outbuf) - outlen;
          assert ((char *) outbuf + outlen == outptr);

          result = xmalloc (sizeof (struct charseq) + outlen);
          result->name = seq->name;
          result->ucs4 = seq->ucs4;
          result->nbytes = outlen;
          memcpy (result->bytes, outbuf, outlen);
        }

      /* Clear any possible state left behind.  */
      (void) iconv (cd, NULL, NULL, NULL, NULL);
    }

  return result;
}


static struct convtable *
use_from_charmap (struct charmap_t *from_charmap, const char *to_code)
{
  /* We iterate over all entries in the from_charmap and for those which
     have a known UCS4 representation we use an iconv() call to determine
     the mapping to the to_code charset.  */
  struct convtable *rettbl;
  iconv_t cd;
  void *ptr = NULL;
  const void *key;
  size_t keylen;
  void *data;

  cd = iconv_open (to_code, "WCHAR_T");
  if (cd == (iconv_t) -1)
    /* We cannot do anything.  */
    return NULL;

  rettbl = allocate_table ();

  while (iterate_table (&from_charmap->char_table, &ptr, &key, &keylen, &data)
	 >= 0)
    {
      struct charseq *in = data;
      struct charseq *newp = convert_charseq (cd, in);
      if (newp != NULL)
        add_bytes (rettbl, in, newp);
    }

  iconv_close (cd);

  return rettbl;
}


static struct convtable *
use_to_charmap (const char *from_code, struct charmap_t *to_charmap)
{
  /* We iterate over all entries in the to_charmap and for those which
     have a known UCS4 representation we use an iconv() call to determine
     the mapping to the from_code charset.  */
  struct convtable *rettbl;
  iconv_t cd;
  void *ptr = NULL;
  const void *key;
  size_t keylen;
  void *data;

  /* Note that the conversion we use here is the reverse direction.  Without
     exhaustive search we cannot figure out which input yields the UCS4
     character we are looking for.  Therefore we determine it the other
     way round.  */
  cd = iconv_open (from_code, "WCHAR_T");
  if (cd == (iconv_t) -1)
    /* We cannot do anything.  */
    return NULL;

  rettbl = allocate_table ();

  while (iterate_table (&to_charmap->char_table, &ptr, &key, &keylen, &data)
	 >= 0)
    {
      struct charseq *out = data;
      struct charseq *newp = convert_charseq (cd, out);
      if (newp != NULL)
        {
          add_bytes (rettbl, newp, out);
          free (newp);
        }
    }

  iconv_close (cd);

  return rettbl;
}


static struct convtable *
use_both_charmaps (struct charmap_t *from_charmap,
		   struct charmap_t *to_charmap)
{
  /* In this case we iterate over all the entries in the from_charmap,
     determine the internal name, and find an appropriate entry in the
     to_charmap (if it exists).  */
  struct convtable *rettbl = allocate_table ();
  void *ptr = NULL;
  const void *key;
  size_t keylen;
  void *data;

  while (iterate_table (&from_charmap->char_table, &ptr, &key, &keylen, &data)
	 >= 0)
    {
      struct charseq *in = (struct charseq *) data;
      struct charseq *out = charmap_find_value (to_charmap, key, keylen);

      if (out != NULL)
	add_bytes (rettbl, in, out);
    }

  return rettbl;
}


static int
process_block (struct convtable *tbl, char *addr, size_t len, FILE *output)
{
  size_t n = 0;

  while (n < len)
    {
      struct convtable *cur = tbl;
      unsigned char *curp = (unsigned char *) addr;
      unsigned int byte = *curp;
      int cnt;
      struct charseq *out;

      while (! is_term (cur, byte))
	if (cur->val[byte].sub == NULL)
	  {
	    /* This is an invalid sequence.  Skip the first byte if we are
	       ignoring errors.  Otherwise punt.  */
	    if (! omit_invalid)
	      {
		error (0, 0, _("illegal input sequence at position %Zd"), n);
		return -1;
	      }

	    n -= curp - (unsigned char *) addr;

	    byte = *(curp = (unsigned char *) ++addr);
	    if (++n >= len)
	      /* All converted.  */
	      return 0;

	    cur = tbl;
	  }
	else
	  {
	    cur = cur->val[byte].sub;

	    if (++n >= len)
	      {
		error (0, 0, _("\
incomplete character or shift sequence at end of buffer"));
		return -1;
	      }

	    byte = *++curp;
	  }

      /* We found a final byte.  Write the output bytes.  */
      out = cur->val[byte].out;
      for (cnt = 0; cnt < out->nbytes; ++cnt)
	fputc_unlocked (out->bytes[cnt], output);

      addr = (char *) curp + 1;
      ++n;
    }

  return 0;
}


static int
process_fd (struct convtable *tbl, int fd, FILE *output)
{
  /* We have a problem with reading from a descriptor since we must not
     provide the iconv() function an incomplete character or shift
     sequence at the end of the buffer.  Since we have to deal with
     arbitrary encodings we must read the whole text in a buffer and
     process it in one step.  */
  static char *inbuf = NULL;
  static size_t maxlen = 0;
  char *inptr = inbuf;
  size_t actlen = 0;

  while (actlen < maxlen)
    {
      ssize_t n = read (fd, inptr, maxlen - actlen);

      if (n == 0)
	/* No more text to read.  */
	break;

      if (n == -1)
	{
	  /* Error while reading.  */
	  error (0, errno, _("error while reading the input"));
	  return -1;
	}

      inptr += n;
      actlen += n;
    }

  if (actlen == maxlen)
    while (1)
      {
	ssize_t n;
	char *new_inbuf;

	/* Increase the buffer.  */
	new_inbuf = (char *) realloc (inbuf, maxlen + 32768);
	if (new_inbuf == NULL)
	  {
	    error (0, errno, _("unable to allocate buffer for input"));
	    return -1;
	  }
	inbuf = new_inbuf;
	maxlen += 32768;
	inptr = inbuf + actlen;

	do
	  {
	    n = read (fd, inptr, maxlen - actlen);

	    if (n == 0)
	      /* No more text to read.  */
	      break;

	    if (n == -1)
	      {
		/* Error while reading.  */
		error (0, errno, _("error while reading the input"));
		return -1;
	      }

	    inptr += n;
	    actlen += n;
	  }
	while (actlen < maxlen);

	if (n == 0)
	  /* Break again so we leave both loops.  */
	  break;
      }

  /* Now we have all the input in the buffer.  Process it in one run.  */
  return process_block (tbl, inbuf, actlen, output);
}


static int
process_file (struct convtable *tbl, FILE *input, FILE *output)
{
  /* This should be safe since we use this function only for `stdin' and
     we haven't read anything so far.  */
  return process_fd (tbl, fileno (input), output);
}