2 * qsort taken from FreeBSD, slightly modified to match glibc's
7 * Copyright (c) 1992, 1993
8 * The Regents of the University of California. All rights reserved.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
40 /* $FreeBSD: src/lib/libc/stdlib/qsort.c,v 1.13.2.1.8.1 2010/12/21 17:10:29 kensmith Exp $ */
44 typedef int cmp_t(const void *, const void *, void *);
45 static inline char *med3(char *, char *, char *, cmp_t *, void *);
46 static inline void swapfunc(char *, char *, int, int);
48 #define min(a, b) (a) < (b) ? a : b
51 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
53 #define swapcode(TYPE, parmi, parmj, n) { \
54 long i = (n) / sizeof (TYPE); \
55 TYPE *pi = (TYPE *) (parmi); \
56 TYPE *pj = (TYPE *) (parmj); \
64 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
65 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
68 swapfunc(a, b, n, swaptype)
73 swapcode(long, a, b, n)
75 swapcode(char, a, b, n)
79 if (swaptype == 0) { \
80 long t = *(long *)(a); \
81 *(long *)(a) = *(long *)(b); \
84 swapfunc(a, b, es, swaptype)
86 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
88 #define CMP(t, x, y) (cmp((x), (y), (t)))
91 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk)
93 return CMP(thunk, a, b) < 0 ?
94 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
95 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
99 solv_sort(void *a, size_t n, size_t es, cmp_t *cmp, void *thunk)
101 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
104 int swaptype, swap_cnt;
106 loop: SWAPINIT(a, es);
109 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
111 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
116 pm = (char *)a + (n / 2) * es;
119 pn = (char *)a + (n - 1) * es;
122 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
123 pm = med3(pm - d, pm, pm + d, cmp, thunk);
124 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
126 pm = med3(pl, pm, pn, cmp, thunk);
129 pa = pb = (char *)a + es;
131 pc = pd = (char *)a + (n - 1) * es;
133 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
134 if (cmp_result == 0) {
141 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
142 if (cmp_result == 0) {
156 if (swap_cnt == 0) { /* Switch to insertion sort */
157 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
159 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
165 pn = (char *)a + n * es;
166 r = min(pa - (char *)a, pb - pa);
167 vecswap(a, pb - r, r);
168 r = min(pd - pc, pn - pd - es);
169 vecswap(pb, pn - r, r);
170 if ((r = pb - pa) > es)
171 solv_sort(a, r / es, es, cmp, thunk);
172 if ((r = pd - pc) > es) {
173 /* Iterate rather than recurse to save stack space */
178 /* qsort(pn - r, r / es, es, cmp);*/