X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;ds=sidebyside;f=src%2Fstdlib%2Fqsort.c;h=da58fd3177814634d7e1b9b06ea2135ee633295f;hb=de7dc1318f493184b20f7661bc12b1829b957b67;hp=866af0ecd6c2a394f896a8e3d8a0403e9da94577;hpb=22263709eda9f7d692a0f484fd759f757418dbd7;p=musl

diff --git a/src/stdlib/qsort.c b/src/stdlib/qsort.c
index 866af0ec..da58fd31 100644
--- a/src/stdlib/qsort.c
+++ b/src/stdlib/qsort.c
@@ -21,6 +21,9 @@
 
 /* Minor changes by Rich Felker for integration in musl, 2011-04-27. */
 
+/* Smoothsort, an adaptive variant of Heapsort.  Memory usage: O(1).
+   Run time: Worst case O(n log n), close to O(n) in the mostly-sorted case. */
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
@@ -155,12 +158,16 @@ void qsort(void *base, size_t nel, size_t width, cmpfun cmp)
 {
 	size_t lp[12*sizeof(size_t)];
 	size_t i, size = width * nel;
-	unsigned char *head = base,
-	              *high = head + size - width;
+	unsigned char *head, *high;
 	size_t p[2] = {1, 0};
 	int pshift = 1;
 	int trail;
 
+	if (!size) return;
+
+	head = base;
+	high = head + size - width;
+
 	/* Precompute Leonardo numbers, scaled by element width */
 	for(lp[0]=lp[1]=width, i=2; (lp[i]=lp[i-2]+lp[i-1]+width) < size; i++);