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