2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/libkern.h>
39 typedef int cmp_t(void *, const void *, const void *);
41 typedef int cmp_t(const void *, const void *);
43 static inline char *med3(char *, char *, char *, cmp_t *, void *);
44 static inline void swapfunc(char *, char *, size_t, int, int);
47 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
49 #define swapcode(TYPE, parmi, parmj, n) { \
50 size_t i = (n) / sizeof (TYPE); \
51 TYPE *pi = (TYPE *) (parmi); \
52 TYPE *pj = (TYPE *) (parmj); \
60 #define SWAPINIT(TYPE, a, es) swaptype_ ## TYPE = \
61 ((char *)a - (char *)0) % sizeof(TYPE) || \
62 es % sizeof(TYPE) ? 2 : es == sizeof(TYPE) ? 0 : 1;
65 swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int)
67 if (swaptype_long <= 1)
68 swapcode(long, a, b, n)
69 else if (swaptype_int <= 1)
70 swapcode(int, a, b, n)
72 swapcode(char, a, b, n)
76 if (swaptype_long == 0) { \
77 long t = *(long *)(a); \
78 *(long *)(a) = *(long *)(b); \
80 } else if (swaptype_int == 0) { \
81 int t = *(int *)(a); \
82 *(int *)(a) = *(int *)(b); \
85 swapfunc(a, b, es, swaptype_long, swaptype_int)
87 #define vecswap(a, b, n) \
88 if ((n) > 0) swapfunc(a, b, n, swaptype_long, swaptype_int)
91 #define CMP(t, x, y) (cmp((t), (x), (y)))
93 #define CMP(t, x, y) (cmp((x), (y)))
97 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
103 return CMP(thunk, a, b) < 0 ?
104 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
105 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
110 qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
114 qsort(void *a, size_t n, size_t es, cmp_t *cmp)
117 char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
120 int swaptype_long, swaptype_int, swap_cnt;
122 loop: SWAPINIT(long, a, es);
123 SWAPINIT(int, a, es);
126 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
128 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
133 pm = (char *)a + (n / 2) * es;
136 pn = (char *)a + (n - 1) * es;
138 size_t d = (n / 8) * es;
140 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
141 pm = med3(pm - d, pm, pm + d, cmp, thunk);
142 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
144 pm = med3(pl, pm, pn, cmp, thunk);
147 pa = pb = (char *)a + es;
149 pc = pd = (char *)a + (n - 1) * es;
151 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
152 if (cmp_result == 0) {
159 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
160 if (cmp_result == 0) {
174 if (swap_cnt == 0) { /* Switch to insertion sort */
175 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
177 pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
183 pn = (char *)a + n * es;
184 d1 = MIN(pa - (char *)a, pb - pa);
185 vecswap(a, pb - d1, d1);
186 d1 = MIN(pd - pc, pn - pd - es);
187 vecswap(pb, pn - d1, d1);
192 /* Recurse on left partition, then iterate on right partition */
195 qsort_r(a, d1 / es, es, thunk, cmp);
197 qsort(a, d1 / es, es, cmp);
201 /* Iterate rather than recurse to save stack space */
202 /* qsort(pn - d2, d2 / es, es, cmp); */
208 /* Recurse on right partition, then iterate on left partition */
211 qsort_r(pn - d2, d2 / es, es, thunk, cmp);
213 qsort(pn - d2, d2 / es, es, cmp);
217 /* Iterate rather than recurse to save stack space */
218 /* qsort(a, d1 / es, es, cmp); */