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 * $FreeBSD: src/sys/libkern/qsort.c,v 1.15 2004/07/15 23:58:23 glebius Exp $ 30 */ 31 32 #include <sys/param.h> 33 #include <sys/libkern.h> 34 35 #ifdef I_AM_KQSORT_R 36 typedef int cmp_t(void *, const void *, const void *); 37 #else 38 typedef int cmp_t(const void *, const void *); 39 #endif 40 static __inline char *med3(char *, char *, char *, cmp_t *, void *); 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 #ifdef I_AM_KQSORT_R 82 #define CMP(t, x, y) (cmp((t), (x), (y))) 83 #else 84 #define CMP(t, x, y) (cmp((x), (y))) 85 #endif 86 87 static __inline char * 88 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk 89 #ifndef I_AM_KQSORT_R 90 __unused 91 #endif 92 ) 93 { 94 return CMP(thunk, a, b) < 0 ? 95 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a )) 96 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c )); 97 } 98 99 #ifdef I_AM_KQSORT_R 100 void 101 kqsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp) 102 #else 103 #define thunk NULL 104 void 105 kqsort(void *a, size_t n, size_t es, cmp_t *cmp) 106 #endif 107 { 108 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 109 int d, r, swaptype, swap_cnt; 110 111 loop: SWAPINIT(a, es); 112 swap_cnt = 0; 113 if (n < 7) { 114 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 115 for (pl = pm; pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 116 pl -= es) 117 swap(pl, pl - es); 118 return; 119 } 120 pm = (char *)a + (n / 2) * es; 121 if (n > 7) { 122 pl = a; 123 pn = (char *)a + (n - 1) * es; 124 if (n > 40) { 125 d = (n / 8) * es; 126 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk); 127 pm = med3(pm - d, pm, pm + d, cmp, thunk); 128 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk); 129 } 130 pm = med3(pl, pm, pn, cmp, thunk); 131 } 132 swap(a, pm); 133 pa = pb = (char *)a + es; 134 135 pc = pd = (char *)a + (n - 1) * es; 136 for (;;) { 137 while (pb <= pc && (r = CMP(thunk, pb, a)) <= 0) { 138 if (r == 0) { 139 swap_cnt = 1; 140 swap(pa, pb); 141 pa += es; 142 } 143 pb += es; 144 } 145 while (pb <= pc && (r = CMP(thunk, pc, a)) >= 0) { 146 if (r == 0) { 147 swap_cnt = 1; 148 swap(pc, pd); 149 pd -= es; 150 } 151 pc -= es; 152 } 153 if (pb > pc) 154 break; 155 swap(pb, pc); 156 swap_cnt = 1; 157 pb += es; 158 pc -= es; 159 } 160 if (swap_cnt == 0) { /* Switch to insertion sort */ 161 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 162 for (pl = pm; pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 163 pl -= es) 164 swap(pl, pl - es); 165 return; 166 } 167 168 pn = (char *)a + n * es; 169 r = min(pa - (char *)a, pb - pa); 170 vecswap(a, pb - r, r); 171 r = min(pd - pc, pn - pd - es); 172 vecswap(pb, pn - r, r); 173 if ((r = pb - pa) > es) 174 #ifdef I_AM_KQSORT_R 175 kqsort_r(a, r / es, es, thunk, cmp); 176 #else 177 kqsort(a, r / es, es, cmp); 178 #endif 179 if ((r = pd - pc) > es) { 180 /* Iterate rather than recurse to save stack space */ 181 a = pn - r; 182 n = r / es; 183 goto loop; 184 } 185 } 186