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authorRich Felker <dalias@aerifal.cx>2011-04-27 13:27:04 -0400
committerRich Felker <dalias@aerifal.cx>2011-04-27 13:27:04 -0400
commit22263709eda9f7d692a0f484fd759f757418dbd7 (patch)
tree0a801dc54d32eb32e5104377909da1283cdea72c /COPYRIGHT
parent4bb9b4f3b4a6794da3091f58acbd938ff66fc15b (diff)
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replace heap sort with smoothsort implementation by Valentin Ochs
Smoothsort is an adaptive variant of heapsort. This version was written by Valentin Ochs (apo) specifically for inclusion in musl. I worked with him to get it working in O(1) memory usage even with giant array element widths, and to optimize it heavily for size and speed. It's still roughly 4 times as large as the old heap sort implementation, but roughly 20 times faster given an almost-sorted array of 1M elements (20 being the base-2 log of 1M), i.e. it really does reduce O(n log n) to O(n) in the mostly-sorted case. It's still somewhat slower than glibc's Introsort for random input, but now considerably faster than glibc when the input is already sorted, or mostly sorted.
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@@ -19,6 +19,10 @@ The implementation of DES for crypt (src/misc/crypt.c) is Copyright ©
1994 David Burren. It is licensed under a BSD license compatible with
the GNU LGPL.
+The smoothsort implementation (src/stdlib/qsort.c) is Copyright © 2011
+Valentin Ochs and is licensed under an MIT-style license compatible
+with the GNU LGPL.
+
The x86_64 port was written by Nicholas J. Kain. See individual files
for their copyright status.