2 * qsort taken from FreeBSD, slightly modified to match glibc's
6 /* FIXME: should use mergesort instead */
9 * Copyright (c) 1992, 1993
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37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
42 /* $FreeBSD: src/lib/libc/stdlib/qsort.c,v 1.13.2.1.8.1 2010/12/21 17:10:29 kensmith Exp $ */
46 typedef int cmp_t(const void *, const void *, void *);
47 static inline char *med3(char *, char *, char *, cmp_t *, void *);
48 static inline void swapfunc(char *, char *, int, int);
50 #define min(a, b) (a) < (b) ? a : b
53 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
55 #define swapcode(TYPE, parmi, parmj, n) { \
56 long i = (n) / sizeof (TYPE); \
57 TYPE *pi = (TYPE *) (parmi); \
58 TYPE *pj = (TYPE *) (parmj); \
66 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
67 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
70 swapfunc(a, b, n, swaptype)
75 swapcode(long, a, b, n)
77 swapcode(char, a, b, n)
81 if (swaptype == 0) { \
82 long t = *(long *)(a); \
83 *(long *)(a) = *(long *)(b); \
86 swapfunc(a, b, es, swaptype)
88 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
90 #define CMP(t, x, y) (cmp((x), (y), (t)))
93 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk)
95 return CMP(thunk, a, b) < 0 ?
96 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
97 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
101 solv_sort(void *a, size_t n, size_t es, cmp_t *cmp, void *thunk)
103 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
106 int swaptype, swap_cnt;
108 loop: SWAPINIT(a, es);
111 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
113 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
118 pm = (char *)a + (n / 2) * es;
121 pn = (char *)a + (n - 1) * es;
124 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
125 pm = med3(pm - d, pm, pm + d, cmp, thunk);
126 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
128 pm = med3(pl, pm, pn, cmp, thunk);
131 pa = pb = (char *)a + es;
133 pc = pd = (char *)a + (n - 1) * es;
135 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
136 if (cmp_result == 0) {
143 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
144 if (cmp_result == 0) {
158 if (swap_cnt == 0) { /* Switch to insertion sort */
159 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
161 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
167 pn = (char *)a + n * es;
168 r = min(pa - (char *)a, pb - pa);
169 vecswap(a, pb - r, r);
170 r = min(pd - pc, pn - pd - es);
171 vecswap(pb, pn - r, r);
172 if ((r = pb - pa) > es)
173 solv_sort(a, r / es, es, cmp, thunk);
174 if ((r = pd - pc) > es) {
175 /* Iterate rather than recurse to save stack space */
180 /* qsort(pn - r, r / es, es, cmp);*/