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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93"; 34 * Id: qsort.c,v 1.4 1996/04/19 18:40:20 bde 35 */ 36 37#include "db_config.h" 38 39#include "db_int.h" 40 41static char *med3 __P((char *, 42 char *, char *, int (*)(const void *, const void *))); 43static void swapfunc __P((char *, char *, int, int)); 44 45#define min(a, b) (a) < (b) ? a : b 46 47/* 48 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 49 */ 50#define swapcode(TYPE, parmi, parmj, n) { \ 51 long i = (n) / sizeof(TYPE); \ 52 register TYPE *pi = (TYPE *) (parmi); \ 53 register TYPE *pj = (TYPE *) (parmj); \ 54 do { \ 55 register TYPE t = *pi; \ 56 *pi++ = *pj; \ 57 *pj++ = t; \ 58 } while (--i > 0); \ 59} 60 61#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ 62 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; 63 64static inline void 65swapfunc(a, b, n, swaptype) 66 char *a, *b; 67 int n, swaptype; 68{ 69 if (swaptype <= 1) 70 swapcode(long, a, b, n) 71 else 72 swapcode(char, a, b, n) 73} 74 75#define swap(a, b) \ 76 if (swaptype == 0) { \ 77 long t = *(long *)(a); \ 78 *(long *)(a) = *(long *)(b); \ 79 *(long *)(b) = t; \ 80 } else \ 81 swapfunc(a, b, es, swaptype) 82 83#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) 84 85static inline char * 86med3(a, b, c, cmp) 87 char *a, *b, *c; 88 int (*cmp)(const void *, const void *); 89{ 90 return cmp(a, b) < 0 ? 91 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a )) 92 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c )); 93} 94 95/* 96 * PUBLIC: #ifndef HAVE_QSORT 97 * PUBLIC: void qsort __P((void *, 98 * PUBLIC: size_t, size_t, int(*)(const void *, const void *))); 99 * PUBLIC: #endif 100 */ 101void 102qsort(a, n, es, cmp) 103 void *a; 104 size_t n, es; 105 int (*cmp) __P((const void *, const void *)); 106{ 107 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 108 int d, r, swaptype, swap_cnt; 109 110loop: SWAPINIT(a, es); 111 swap_cnt = 0; 112 if (n < 7) { 113 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 114 for (pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; 115 pl -= es) 116 swap(pl, pl - es); 117 return; 118 } 119 pm = (char *)a + (n / 2) * es; 120 if (n > 7) { 121 pl = a; 122 pn = (char *)a + (n - 1) * es; 123 if (n > 40) { 124 d = (n / 8) * es; 125 pl = med3(pl, pl + d, pl + 2 * d, cmp); 126 pm = med3(pm - d, pm, pm + d, cmp); 127 pn = med3(pn - 2 * d, pn - d, pn, cmp); 128 } 129 pm = med3(pl, pm, pn, cmp); 130 } 131 swap(a, pm); 132 pa = pb = (char *)a + es; 133 134 pc = pd = (char *)a + (n - 1) * es; 135 for (;;) { 136 while (pb <= pc && (r = cmp(pb, a)) <= 0) { 137 if (r == 0) { 138 swap_cnt = 1; 139 swap(pa, pb); 140 pa += es; 141 } 142 pb += es; 143 } 144 while (pb <= pc && (r = cmp(pc, a)) >= 0) { 145 if (r == 0) { 146 swap_cnt = 1; 147 swap(pc, pd); 148 pd -= es; 149 } 150 pc -= es; 151 } 152 if (pb > pc) 153 break; 154 swap(pb, pc); 155 swap_cnt = 1; 156 pb += es; 157 pc -= es; 158 } 159 if (swap_cnt == 0) { /* Switch to insertion sort */ 160 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 161 for (pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; 162 pl -= es) 163 swap(pl, pl - es); 164 return; 165 } 166 167 pn = (char *)a + n * es; 168 r = min(pa - (char *)a, pb - pa); 169 vecswap(a, pb - r, r); 170 r = min((int)(pd - pc), (int)(pn - pd - es)); 171 vecswap(pb, pn - r, r); 172 if ((r = (int)(pb - pa)) > (int)es) 173 qsort(a, r / es, es, cmp); 174 if ((r = (int)(pd - pc)) > (int)es) { 175 /* Iterate rather than recurse to save stack space */ 176 a = pn - r; 177 n = r / es; 178 goto loop; 179 } 180/* qsort(pn - r, r / es, es, cmp);*/ 181} 182