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 * $FreeBSD: src/sys/libkern/qsort.c,v 1.12 2002/11/09 12:55:06 alfred Exp $ 34 * $NetBSD: qsort.c,v 1.1 2004/05/19 23:37:41 abs Exp $ 35 */ 36 37 #include <sys/cdefs.h> 38 #include <sys/types.h> 39 40 typedef int cmp_t(const void *, const void *); 41 static __inline char *med3(char *, char *, char *, cmp_t *); 42 static __inline void swapfunc(char *, char *, int, int); 43 44 #define min(a, b) (a) < (b) ? (a) : (b) 45 46 void qsort(void *a, size_t n, size_t es, cmp_t *cmp); 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 register TYPE *pi = (TYPE *) (parmi); \ 54 register TYPE *pj = (TYPE *) (parmj); \ 55 do { \ 56 register 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 static __inline char * 87 med3(a, b, c, cmp) 88 char *a, *b, *c; 89 cmp_t *cmp; 90 { 91 return cmp(a, b) < 0 ? 92 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a )) 93 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c )); 94 } 95 96 void 97 qsort(void *a, size_t n, size_t es, cmp_t *cmp) 98 { 99 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 100 int d, r, swaptype, swap_cnt; 101 102 loop: SWAPINIT(a, es); 103 swap_cnt = 0; 104 if (n < 7) { 105 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 106 for (pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; 107 pl -= es) 108 swap(pl, pl - es); 109 return; 110 } 111 pm = (char *)a + (n / 2) * es; 112 if (n > 7) { 113 pl = a; 114 pn = (char *)a + (n - 1) * es; 115 if (n > 40) { 116 d = (n / 8) * es; 117 pl = med3(pl, pl + d, pl + 2 * d, cmp); 118 pm = med3(pm - d, pm, pm + d, cmp); 119 pn = med3(pn - 2 * d, pn - d, pn, cmp); 120 } 121 pm = med3(pl, pm, pn, cmp); 122 } 123 swap(a, pm); 124 pa = pb = (char *)a + es; 125 126 pc = pd = (char *)a + (n - 1) * es; 127 for (;;) { 128 while (pb <= pc && (r = cmp(pb, a)) <= 0) { 129 if (r == 0) { 130 swap_cnt = 1; 131 swap(pa, pb); 132 pa += es; 133 } 134 pb += es; 135 } 136 while (pb <= pc && (r = cmp(pc, a)) >= 0) { 137 if (r == 0) { 138 swap_cnt = 1; 139 swap(pc, pd); 140 pd -= es; 141 } 142 pc -= es; 143 } 144 if (pb > pc) 145 break; 146 swap(pb, pc); 147 swap_cnt = 1; 148 pb += es; 149 pc -= es; 150 } 151 if (swap_cnt == 0) { /* Switch to insertion sort */ 152 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 153 for (pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; 154 pl -= es) 155 swap(pl, pl - es); 156 return; 157 } 158 159 pn = (char *)a + n * es; 160 r = min(pa - (char *)a, pb - pa); 161 vecswap(a, pb - r, r); 162 r = min(pd - pc, pn - pd - es); 163 vecswap(pb, pn - r, r); 164 if ((r = pb - pa) > es) 165 qsort(a, r / es, es, cmp); 166 if ((r = pd - pc) > es) { 167 /* Iterate rather than recurse to save stack space */ 168 a = pn - r; 169 n = r / es; 170 goto loop; 171 } 172 /* qsort(pn - r, r / es, es, cmp);*/ 173 } 174