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 #if defined(LIBC_SCCS) && !defined(lint) 33 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93"; 34 #endif /* LIBC_SCCS and not lint */ 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <stdlib.h> 39 40 #ifdef I_AM_QSORT_R 41 typedef int cmp_t(void *, const void *, const void *); 42 #else 43 typedef int cmp_t(const void *, const void *); 44 #endif 45 static inline char *med3(char *, char *, char *, cmp_t *, void *); 46 static inline void swapfunc(char *, char *, size_t, int, int); 47 48 #define MIN(a, b) ((a) < (b) ? a : b) 49 50 /* 51 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 52 */ 53 #define swapcode(TYPE, parmi, parmj, n) { \ 54 size_t i = (n) / sizeof (TYPE); \ 55 TYPE *pi = (TYPE *) (parmi); \ 56 TYPE *pj = (TYPE *) (parmj); \ 57 do { \ 58 TYPE t = *pi; \ 59 *pi++ = *pj; \ 60 *pj++ = t; \ 61 } while (--i > 0); \ 62 } 63 64 #define SWAPINIT(TYPE, a, es) swaptype_ ## TYPE = \ 65 ((char *)a - (char *)0) % sizeof(TYPE) || \ 66 es % sizeof(TYPE) ? 2 : es == sizeof(TYPE) ? 0 : 1; 67 68 static inline void 69 swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int) 70 { 71 if (swaptype_long <= 1) 72 swapcode(long, a, b, n) 73 else if (swaptype_int <= 1) 74 swapcode(int, a, b, n) 75 else 76 swapcode(char, a, b, n) 77 } 78 79 #define swap(a, b) \ 80 if (swaptype_long == 0) { \ 81 long t = *(long *)(a); \ 82 *(long *)(a) = *(long *)(b); \ 83 *(long *)(b) = t; \ 84 } else if (swaptype_int == 0) { \ 85 int t = *(int *)(a); \ 86 *(int *)(a) = *(int *)(b); \ 87 *(int *)(b) = t; \ 88 } else \ 89 swapfunc(a, b, es, swaptype_long, swaptype_int) 90 91 #define vecswap(a, b, n) \ 92 if ((n) > 0) swapfunc(a, b, n, swaptype_long, swaptype_int) 93 94 #ifdef I_AM_QSORT_R 95 #define CMP(t, x, y) (cmp((t), (x), (y))) 96 #else 97 #define CMP(t, x, y) (cmp((x), (y))) 98 #endif 99 100 static inline char * 101 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk 102 #ifndef I_AM_QSORT_R 103 __unused 104 #endif 105 ) 106 { 107 return CMP(thunk, a, b) < 0 ? 108 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a )) 109 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c )); 110 } 111 112 #ifdef I_AM_QSORT_R 113 void 114 qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp) 115 #else 116 #define thunk NULL 117 void 118 qsort(void *a, size_t n, size_t es, cmp_t *cmp) 119 #endif 120 { 121 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 122 size_t d1, d2; 123 int cmp_result; 124 int swaptype_long, swaptype_int, swap_cnt; 125 126 loop: SWAPINIT(long, a, es); 127 SWAPINIT(int, a, es); 128 swap_cnt = 0; 129 if (n < 7) { 130 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 131 for (pl = pm; 132 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 133 pl -= es) 134 swap(pl, pl - es); 135 return; 136 } 137 pm = (char *)a + (n / 2) * es; 138 if (n > 7) { 139 pl = a; 140 pn = (char *)a + (n - 1) * es; 141 if (n > 40) { 142 size_t d = (n / 8) * es; 143 144 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk); 145 pm = med3(pm - d, pm, pm + d, cmp, thunk); 146 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk); 147 } 148 pm = med3(pl, pm, pn, cmp, thunk); 149 } 150 swap(a, pm); 151 pa = pb = (char *)a + es; 152 153 pc = pd = (char *)a + (n - 1) * es; 154 for (;;) { 155 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) { 156 if (cmp_result == 0) { 157 swap_cnt = 1; 158 swap(pa, pb); 159 pa += es; 160 } 161 pb += es; 162 } 163 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) { 164 if (cmp_result == 0) { 165 swap_cnt = 1; 166 swap(pc, pd); 167 pd -= es; 168 } 169 pc -= es; 170 } 171 if (pb > pc) 172 break; 173 swap(pb, pc); 174 swap_cnt = 1; 175 pb += es; 176 pc -= es; 177 } 178 if (swap_cnt == 0) { /* Switch to insertion sort */ 179 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 180 for (pl = pm; 181 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 182 pl -= es) 183 swap(pl, pl - es); 184 return; 185 } 186 187 pn = (char *)a + n * es; 188 d1 = MIN(pa - (char *)a, pb - pa); 189 vecswap(a, pb - d1, d1); 190 d1 = MIN(pd - pc, pn - pd - es); 191 vecswap(pb, pn - d1, d1); 192 193 d1 = pb - pa; 194 d2 = pd - pc; 195 if (d1 <= d2) { 196 /* Recurse on left partition, then iterate on right partition */ 197 if (d1 > es) { 198 #ifdef I_AM_QSORT_R 199 qsort_r(a, d1 / es, es, thunk, cmp); 200 #else 201 qsort(a, d1 / es, es, cmp); 202 #endif 203 } 204 if (d2 > es) { 205 /* Iterate rather than recurse to save stack space */ 206 /* qsort(pn - d2, d2 / es, es, cmp); */ 207 a = pn - d2; 208 n = d2 / es; 209 goto loop; 210 } 211 } else { 212 /* Recurse on right partition, then iterate on left partition */ 213 if (d2 > es) { 214 #ifdef I_AM_QSORT_R 215 qsort_r(pn - d2, d2 / es, es, thunk, cmp); 216 #else 217 qsort(pn - d2, d2 / es, es, cmp); 218 #endif 219 } 220 if (d1 > es) { 221 /* Iterate rather than recurse to save stack space */ 222 /* qsort(a, d1 / es, es, cmp); */ 223 n = d1 / es; 224 goto loop; 225 } 226 } 227 } 228