summaryrefslogtreecommitdiff
path: root/src/stdlib/qsort.c
AgeCommit message (Collapse)AuthorLines
2011-04-29avoid crashing when nel==0 is passed to qsortRich Felker-2/+6
2011-04-27replace heap sort with smoothsort implementation by Valentin OchsRich Felker-32/+193
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.
2011-02-17don't compare elements with themselves during qsort.Rich Felker-1/+1
this is actually a workaround for a bug in gcc, whereby it asserts inequality of the keys being compared...
2011-02-12initial check-in, version 0.5.0v0.5.0Rich Felker-0/+50