1 /*- 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93"; 32 #endif /* LIBC_SCCS and not lint */ 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <stdlib.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 #define MIN(a, b) ((a) < (b) ? a : b) 47 48 /* 49 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 50 */ 51 #define swapcode(TYPE, parmi, parmj, n) { \ 52 size_t i = (n) / sizeof (TYPE); \ 53 TYPE *pi = (TYPE *) (parmi); \ 54 TYPE *pj = (TYPE *) (parmj); \ 55 do { \ 56 TYPE t = *pi; \ 57 *pi++ = *pj; \ 58 *pj++ = t; \ 59 } while (--i > 0); \ 60 } 61 62 #define SWAPINIT(TYPE, a, es) swaptype_ ## TYPE = \ 63 ((char *)a - (char *)0) % sizeof(TYPE) || \ 64 es % sizeof(TYPE) ? 2 : es == sizeof(TYPE) ? 0 : 1; 65 66 static inline void 67 swapfunc(char *a, char *b, size_t n, int swaptype_long, int swaptype_int) 68 { 69 if (swaptype_long <= 1) 70 swapcode(long, a, b, n) 71 else if (swaptype_int <= 1) 72 swapcode(int, a, b, n) 73 else 74 swapcode(char, a, b, n) 75 } 76 77 #define swap(a, b) \ 78 if (swaptype_long == 0) { \ 79 long t = *(long *)(a); \ 80 *(long *)(a) = *(long *)(b); \ 81 *(long *)(b) = t; \ 82 } else if (swaptype_int == 0) { \ 83 int t = *(int *)(a); \ 84 *(int *)(a) = *(int *)(b); \ 85 *(int *)(b) = t; \ 86 } else \ 87 swapfunc(a, b, es, swaptype_long, swaptype_int) 88 89 #define vecswap(a, b, n) \ 90 if ((n) > 0) swapfunc(a, b, n, swaptype_long, swaptype_int) 91 92 #ifdef I_AM_QSORT_R 93 #define CMP(t, x, y) (cmp((t), (x), (y))) 94 #else 95 #define CMP(t, x, y) (cmp((x), (y))) 96 #endif 97 98 static inline char * 99 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk 100 #ifndef I_AM_QSORT_R 101 __unused 102 #endif 103 ) 104 { 105 return CMP(thunk, a, b) < 0 ? 106 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a )) 107 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c )); 108 } 109 110 #ifdef I_AM_QSORT_R 111 void 112 qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp) 113 #else 114 #define thunk NULL 115 void 116 qsort(void *a, size_t n, size_t es, cmp_t *cmp) 117 #endif 118 { 119 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 120 size_t d1, d2; 121 int cmp_result; 122 int swaptype_long, swaptype_int, swap_cnt; 123 124 loop: SWAPINIT(long, a, es); 125 SWAPINIT(int, a, es); 126 swap_cnt = 0; 127 if (n < 7) { 128 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 129 for (pl = pm; 130 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 131 pl -= es) 132 swap(pl, pl - es); 133 return; 134 } 135 pm = (char *)a + (n / 2) * es; 136 if (n > 7) { 137 pl = a; 138 pn = (char *)a + (n - 1) * es; 139 if (n > 40) { 140 size_t d = (n / 8) * es; 141 142 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk); 143 pm = med3(pm - d, pm, pm + d, cmp, thunk); 144 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk); 145 } 146 pm = med3(pl, pm, pn, cmp, thunk); 147 } 148 swap(a, pm); 149 pa = pb = (char *)a + es; 150 151 pc = pd = (char *)a + (n - 1) * es; 152 for (;;) { 153 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) { 154 if (cmp_result == 0) { 155 swap_cnt = 1; 156 swap(pa, pb); 157 pa += es; 158 } 159 pb += es; 160 } 161 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) { 162 if (cmp_result == 0) { 163 swap_cnt = 1; 164 swap(pc, pd); 165 pd -= es; 166 } 167 pc -= es; 168 } 169 if (pb > pc) 170 break; 171 swap(pb, pc); 172 swap_cnt = 1; 173 pb += es; 174 pc -= es; 175 } 176 if (swap_cnt == 0) { /* Switch to insertion sort */ 177 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 178 for (pl = pm; 179 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 180 pl -= es) 181 swap(pl, pl - es); 182 return; 183 } 184 185 pn = (char *)a + n * es; 186 d1 = MIN(pa - (char *)a, pb - pa); 187 vecswap(a, pb - d1, d1); 188 d1 = MIN(pd - pc, pn - pd - es); 189 vecswap(pb, pn - d1, d1); 190 191 d1 = pb - pa; 192 d2 = pd - pc; 193 if (d1 <= d2) { 194 /* Recurse on left partition, then iterate on right partition */ 195 if (d1 > es) { 196 #ifdef I_AM_QSORT_R 197 qsort_r(a, d1 / es, es, thunk, cmp); 198 #else 199 qsort(a, d1 / es, es, cmp); 200 #endif 201 } 202 if (d2 > es) { 203 /* Iterate rather than recurse to save stack space */ 204 /* qsort(pn - d2, d2 / es, es, cmp); */ 205 a = pn - d2; 206 n = d2 / es; 207 goto loop; 208 } 209 } else { 210 /* Recurse on right partition, then iterate on left partition */ 211 if (d2 > es) { 212 #ifdef I_AM_QSORT_R 213 qsort_r(pn - d2, d2 / es, es, thunk, cmp); 214 #else 215 qsort(pn - d2, d2 / es, es, cmp); 216 #endif 217 } 218 if (d1 > es) { 219 /* Iterate rather than recurse to save stack space */ 220 /* qsort(a, d1 / es, es, cmp); */ 221 n = d1 / es; 222 goto loop; 223 } 224 } 225 } 226
