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 *, 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 long 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(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ 63 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; 64 65 static inline void 66 swapfunc(a, b, n, swaptype) 67 char *a, *b; 68 int n, swaptype; 69 { 70 if(swaptype <= 1) 71 swapcode(long, a, b, n) 72 else 73 swapcode(char, a, b, n) 74 } 75 76 #define swap(a, b) \ 77 if (swaptype == 0) { \ 78 long t = *(long *)(a); \ 79 *(long *)(a) = *(long *)(b); \ 80 *(long *)(b) = t; \ 81 } else \ 82 swapfunc(a, b, es, swaptype) 83 84 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) 85 86 #ifdef I_AM_QSORT_R 87 #define CMP(t, x, y) (cmp((t), (x), (y))) 88 #else 89 #define CMP(t, x, y) (cmp((x), (y))) 90 #endif 91 92 static inline char * 93 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk 94 #ifndef I_AM_QSORT_R 95 __unused 96 #endif 97 ) 98 { 99 return CMP(thunk, a, b) < 0 ? 100 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a )) 101 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c )); 102 } 103 104 #ifdef I_AM_QSORT_R 105 void 106 qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp) 107 #else 108 #define thunk NULL 109 void 110 qsort(void *a, size_t n, size_t es, cmp_t *cmp) 111 #endif 112 { 113 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 114 size_t d, r; 115 int cmp_result; 116 int swaptype, swap_cnt; 117 118 loop: SWAPINIT(a, es); 119 swap_cnt = 0; 120 if (n < 7) { 121 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 122 for (pl = pm; 123 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 124 pl -= es) 125 swap(pl, pl - es); 126 return; 127 } 128 pm = (char *)a + (n / 2) * es; 129 if (n > 7) { 130 pl = a; 131 pn = (char *)a + (n - 1) * es; 132 if (n > 40) { 133 d = (n / 8) * es; 134 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk); 135 pm = med3(pm - d, pm, pm + d, cmp, thunk); 136 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk); 137 } 138 pm = med3(pl, pm, pn, cmp, thunk); 139 } 140 swap(a, pm); 141 pa = pb = (char *)a + es; 142 143 pc = pd = (char *)a + (n - 1) * es; 144 for (;;) { 145 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) { 146 if (cmp_result == 0) { 147 swap_cnt = 1; 148 swap(pa, pb); 149 pa += es; 150 } 151 pb += es; 152 } 153 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) { 154 if (cmp_result == 0) { 155 swap_cnt = 1; 156 swap(pc, pd); 157 pd -= es; 158 } 159 pc -= es; 160 } 161 if (pb > pc) 162 break; 163 swap(pb, pc); 164 swap_cnt = 1; 165 pb += es; 166 pc -= es; 167 } 168 if (swap_cnt == 0) { /* Switch to insertion sort */ 169 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 170 for (pl = pm; 171 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 172 pl -= es) 173 swap(pl, pl - es); 174 return; 175 } 176 177 pn = (char *)a + n * es; 178 r = min(pa - (char *)a, pb - pa); 179 vecswap(a, pb - r, r); 180 r = min(pd - pc, pn - pd - es); 181 vecswap(pb, pn - r, r); 182 if ((r = pb - pa) > es) 183 #ifdef I_AM_QSORT_R 184 qsort_r(a, r / es, es, thunk, cmp); 185 #else 186 qsort(a, r / es, es, cmp); 187 #endif 188 if ((r = pd - pc) > es) { 189 /* Iterate rather than recurse to save stack space */ 190 a = pn - r; 191 n = r / es; 192 goto loop; 193 } 194 /* qsort(pn - r, r / es, es, cmp);*/ 195 } 196