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