Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/libkern/qsort.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
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1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 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. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include <sys/param.h> 36 #include <sys/libkern.h> 37 38 #ifdef I_AM_QSORT_R 39 typedef int cmp_t(void *, const void *, const void *); 40 #else 41 typedef int cmp_t(const void *, const void *); 42 #endif 43 static inline char *med3(char *, char *, char *, cmp_t *, void *); 44 static inline void swapfunc(char *, char *, size_t, int, int); 45 46 /* 47 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 48 */ 49 #define swapcode(TYPE, parmi, parmj, n) { \ 50 size_t i = (n) / sizeof (TYPE); \ 51 TYPE *pi = (TYPE *) (parmi); \ 52 TYPE *pj = (TYPE *) (parmj); \ 53 do { \ 54 TYPE t = *pi; \ 55 *pi++ = *pj; \ 56 *pj++ = t; \ 57 } while (--i > 0); \ 58 } 59 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; 63 64 static inline void 65 swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int) 66 { 67 if (swaptype_long <= 1) 68 swapcode(long, a, b, n) 69 else if (swaptype_int <= 1) 70 swapcode(int, a, b, n) 71 else 72 swapcode(char, a, b, n) 73 } 74 75 #define swap(a, b) \ 76 if (swaptype_long == 0) { \ 77 long t = *(long *)(a); \ 78 *(long *)(a) = *(long *)(b); \ 79 *(long *)(b) = t; \ 80 } else if (swaptype_int == 0) { \ 81 int t = *(int *)(a); \ 82 *(int *)(a) = *(int *)(b); \ 83 *(int *)(b) = t; \ 84 } else \ 85 swapfunc(a, b, es, swaptype_long, swaptype_int) 86 87 #define vecswap(a, b, n) \ 88 if ((n) > 0) swapfunc(a, b, n, swaptype_long, swaptype_int) 89 90 #ifdef I_AM_QSORT_R 91 #define CMP(t, x, y) (cmp((t), (x), (y))) 92 #else 93 #define CMP(t, x, y) (cmp((x), (y))) 94 #endif 95 96 static inline char * 97 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk 98 #ifndef I_AM_QSORT_R 99 __unused 100 #endif 101 ) 102 { 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 )); 106 } 107 108 #ifdef I_AM_QSORT_R 109 void 110 qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp) 111 #else 112 #define thunk NULL 113 void 114 qsort(void *a, size_t n, size_t es, cmp_t *cmp) 115 #endif 116 { 117 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 118 size_t d1, d2; 119 int cmp_result; 120 int swaptype_long, swaptype_int, swap_cnt; 121 122 loop: SWAPINIT(long, a, es); 123 SWAPINIT(int, a, es); 124 swap_cnt = 0; 125 if (n < 7) { 126 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 127 for (pl = pm; 128 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 129 pl -= es) 130 swap(pl, pl - es); 131 return; 132 } 133 pm = (char *)a + (n / 2) * es; 134 if (n > 7) { 135 pl = a; 136 pn = (char *)a + (n - 1) * es; 137 if (n > 40) { 138 size_t d = (n / 8) * es; 139 140 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); 143 } 144 pm = med3(pl, pm, pn, cmp, thunk); 145 } 146 swap(a, pm); 147 pa = pb = (char *)a + es; 148 149 pc = pd = (char *)a + (n - 1) * es; 150 for (;;) { 151 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) { 152 if (cmp_result == 0) { 153 swap_cnt = 1; 154 swap(pa, pb); 155 pa += es; 156 } 157 pb += es; 158 } 159 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) { 160 if (cmp_result == 0) { 161 swap_cnt = 1; 162 swap(pc, pd); 163 pd -= es; 164 } 165 pc -= es; 166 } 167 if (pb > pc) 168 break; 169 swap(pb, pc); 170 swap_cnt = 1; 171 pb += es; 172 pc -= es; 173 } 174 if (swap_cnt == 0) { /* Switch to insertion sort */ 175 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 176 for (pl = pm; 177 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 178 pl -= es) 179 swap(pl, pl - es); 180 return; 181 } 182 183 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); 188 189 d1 = pb - pa; 190 d2 = pd - pc; 191 if (d1 <= d2) { 192 /* Recurse on left partition, then iterate on right partition */ 193 if (d1 > es) { 194 #ifdef I_AM_QSORT_R 195 qsort_r(a, d1 / es, es, thunk, cmp); 196 #else 197 qsort(a, d1 / es, es, cmp); 198 #endif 199 } 200 if (d2 > es) { 201 /* Iterate rather than recurse to save stack space */ 202 /* qsort(pn - d2, d2 / es, es, cmp); */ 203 a = pn - d2; 204 n = d2 / es; 205 goto loop; 206 } 207 } else { 208 /* Recurse on right partition, then iterate on left partition */ 209 if (d2 > es) { 210 #ifdef I_AM_QSORT_R 211 qsort_r(pn - d2, d2 / es, es, thunk, cmp); 212 #else 213 qsort(pn - d2, d2 / es, es, cmp); 214 #endif 215 } 216 if (d1 > es) { 217 /* Iterate rather than recurse to save stack space */ 218 /* qsort(a, d1 / es, es, cmp); */ 219 n = d1 / es; 220 goto loop; 221 } 222 } 223 }
Cache object: 5015f379b103d2c4eb64ac7189e602eb
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