From 849cfab1c54b56687b4343e5a8448ff7408493b9 Mon Sep 17 00:00:00 2001 From: Manuel Novoa III Date: Wed, 17 Jan 2001 04:47:48 +0000 Subject: UnDOSified file and added assert when debugging. --- libc/stdlib/qsort.c | 143 ++++++++++++++++++++++++++-------------------------- 1 file changed, 71 insertions(+), 72 deletions(-) (limited to 'libc/stdlib/qsort.c') diff --git a/libc/stdlib/qsort.c b/libc/stdlib/qsort.c index 7390c3bd3..cefae8ceb 100644 --- a/libc/stdlib/qsort.c +++ b/libc/stdlib/qsort.c @@ -1,72 +1,71 @@ -/* +++Date last modified: 05-Jul-1997 */ - -/* -** ssort() -- Fast, small, qsort()-compatible Shell sort -** -** by Ray Gardner, public domain 5/90 -*/ - -/* - * Manuel Novoa III Dec 2000 - * - * There were several problems with the qsort code contained in uClibc. - * It assumed sizeof(int) was 2 and sizeof(long) was 4. It then had three - * seperate quiicksort routines based on the width of the data passed: 2, 4, - * or anything else <= 128. If the width was > 128, it returned -1 (although - * qsort should not return a value) and did no sorting. On i386 with - * -Os -fomit-frame-pointer -ffunction-sections, the text segment of qsort.o - * was 1358 bytes, with an additional 4 bytes in bss. - * - * I decided to completely replace the existing code with a small - * implementation of a shell sort. It is a drop-in replacement for the - * standard qsort and, with the same gcc flags as above, the text segment - * size on i386 is only 183 bytes. - * - * Grabbed original file rg_ssort.c from snippets.org. - * Modified original code to avoid possible overflow in wgap calculation. - * Modified wgap calculation in loop and eliminated variables gap and wnel. - */ - - -#include - -void qsort (void *base, - size_t nel, - size_t width, - int (*comp)(const void *, const void *)) -{ - size_t wgap, i, j, k; - char *a, *b, tmp; - -#if 0 - /* Note: still conceivable that nel * width could overflow! */ - assert(width > 0); -#endif - - if (nel > 1) { - for (wgap = 0; ++wgap < (nel-1)/3 ; wgap *= 3) {} - wgap *= width; - nel *= width; /* convert nel to 'wnel' */ - do { - for (i = wgap; i < nel; i += width) { - for (j = i - wgap; ;j -= wgap) { - a = j + ((char *)base); - b = a + wgap; - if ( (*comp)(a, b) <= 0 ) { - break; - } - k = width; - do { - tmp = *a; - *a++ = *b; - *b++ = tmp; - } while ( --k ); - if (j < wgap) { - break; - } - } - } - wgap = (wgap - width)/3; - } while (wgap); - } -} +/* +++Date last modified: 05-Jul-1997 */ + +/* +** ssort() -- Fast, small, qsort()-compatible Shell sort +** +** by Ray Gardner, public domain 5/90 +*/ + +/* + * Manuel Novoa III Dec 2000 + * + * There were several problems with the qsort code contained in uClibc. + * It assumed sizeof(int) was 2 and sizeof(long) was 4. It then had three + * seperate quiicksort routines based on the width of the data passed: 2, 4, + * or anything else <= 128. If the width was > 128, it returned -1 (although + * qsort should not return a value) and did no sorting. On i386 with + * -Os -fomit-frame-pointer -ffunction-sections, the text segment of qsort.o + * was 1358 bytes, with an additional 4 bytes in bss. + * + * I decided to completely replace the existing code with a small + * implementation of a shell sort. It is a drop-in replacement for the + * standard qsort and, with the same gcc flags as above, the text segment + * size on i386 is only 183 bytes. + * + * Grabbed original file rg_ssort.c from snippets.org. + * Modified original code to avoid possible overflow in wgap calculation. + * Modified wgap calculation in loop and eliminated variables gap and wnel. + */ + + +#include +#include + +void qsort (void *base, + size_t nel, + size_t width, + int (*comp)(const void *, const void *)) +{ + size_t wgap, i, j, k; + char *a, *b, tmp; + + /* Note: still conceivable that nel * width could overflow! */ + assert(width > 0); + + if (nel > 1) { + for (wgap = 0; ++wgap < (nel-1)/3 ; wgap *= 3) {} + wgap *= width; + nel *= width; /* convert nel to 'wnel' */ + do { + for (i = wgap; i < nel; i += width) { + for (j = i - wgap; ;j -= wgap) { + a = j + ((char *)base); + b = a + wgap; + if ( (*comp)(a, b) <= 0 ) { + break; + } + k = width; + do { + tmp = *a; + *a++ = *b; + *b++ = tmp; + } while ( --k ); + if (j < wgap) { + break; + } + } + } + wgap = (wgap - width)/3; + } while (wgap); + } +} -- cgit v1.2.3