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 1.10 1999/08/28 00:46:35 peter Exp $ 34 * $DragonFly: src/sys/libkern/qsort.c,v 1.5 2004/01/26 11:09:44 joerg Exp $ 35 */ 36 37 #include <sys/libkern.h> 38 39 typedef int cmp_t(const void *, const void *); 40 static __inline char *med3(char *, char *, char *, cmp_t *); 41 static __inline void swapfunc(char *, char *, int, int); 42 43 #define min(a, b) (a) < (b) ? a : b 44 45 /* 46 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 47 */ 48 #define swapcode(TYPE, parmi, parmj, n) { \ 49 long i = (n) / sizeof (TYPE); \ 50 TYPE *pi = (TYPE *) (parmi); \ 51 TYPE *pj = (TYPE *) (parmj); \ 52 do { \ 53 TYPE t = *pi; \ 54 *pi++ = *pj; \ 55 *pj++ = t; \ 56 } while (--i > 0); \ 57 } 58 59 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ 60 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; 61 62 static __inline void 63 swapfunc(char *a, char *b, int n, int swaptype) 64 { 65 if(swaptype <= 1) 66 swapcode(long, a, b, n) 67 else 68 swapcode(char, a, b, n) 69 } 70 71 #define swap(a, b) \ 72 if (swaptype == 0) { \ 73 long t = *(long *)(a); \ 74 *(long *)(a) = *(long *)(b); \ 75 *(long *)(b) = t; \ 76 } else \ 77 swapfunc(a, b, es, swaptype) 78 79 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) 80 81 static __inline char * 82 med3(char *a, char *b, char *c, cmp_t *cmp) 83 { 84 return cmp(a, b) < 0 ? 85 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a )) 86 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c )); 87 } 88 89 void 90 qsort(void *a, size_t n, size_t es, cmp_t *cmp) 91 { 92 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 93 int d, r, swaptype, swap_cnt; 94 95 loop: SWAPINIT(a, es); 96 swap_cnt = 0; 97 if (n < 7) { 98 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 99 for (pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; 100 pl -= es) 101 swap(pl, pl - es); 102 return; 103 } 104 pm = (char *)a + (n / 2) * es; 105 if (n > 7) { 106 pl = a; 107 pn = (char *)a + (n - 1) * es; 108 if (n > 40) { 109 d = (n / 8) * es; 110 pl = med3(pl, pl + d, pl + 2 * d, cmp); 111 pm = med3(pm - d, pm, pm + d, cmp); 112 pn = med3(pn - 2 * d, pn - d, pn, cmp); 113 } 114 pm = med3(pl, pm, pn, cmp); 115 } 116 swap(a, pm); 117 pa = pb = (char *)a + es; 118 119 pc = pd = (char *)a + (n - 1) * es; 120 for (;;) { 121 while (pb <= pc && (r = cmp(pb, a)) <= 0) { 122 if (r == 0) { 123 swap_cnt = 1; 124 swap(pa, pb); 125 pa += es; 126 } 127 pb += es; 128 } 129 while (pb <= pc && (r = cmp(pc, a)) >= 0) { 130 if (r == 0) { 131 swap_cnt = 1; 132 swap(pc, pd); 133 pd -= es; 134 } 135 pc -= es; 136 } 137 if (pb > pc) 138 break; 139 swap(pb, pc); 140 swap_cnt = 1; 141 pb += es; 142 pc -= es; 143 } 144 if (swap_cnt == 0) { /* Switch to insertion sort */ 145 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 146 for (pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; 147 pl -= es) 148 swap(pl, pl - es); 149 return; 150 } 151 152 pn = (char *)a + n * es; 153 r = min(pa - (char *)a, pb - pa); 154 vecswap(a, pb - r, r); 155 r = min(pd - pc, pn - pd - es); 156 vecswap(pb, pn - r, r); 157 if ((r = pb - pa) > es) 158 qsort(a, r / es, es, cmp); 159 if ((r = pd - pc) > es) { 160 /* Iterate rather than recurse to save stack space */ 161 a = pn - r; 162 n = r / es; 163 goto loop; 164 } 165 /* qsort(pn - r, r / es, es, cmp);*/ 166 } 167