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 * 4. 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 #include <stdlib.h> 31 #include <search.h> 32 33 #define long intptr_t 34 35 #define min(a, b) (a) < (b) ? (a) : (b) 36 37 /* 38 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 39 */ 40 #define swapcode(TYPE, parmi, parmj, n) { \ 41 long i = (n) / sizeof (TYPE); \ 42 register TYPE *pi = (TYPE *) (parmi); \ 43 register TYPE *pj = (TYPE *) (parmj); \ 44 do { \ 45 register TYPE t = *pi; \ 46 *pi++ = *pj; \ 47 *pj++ = t; \ 48 } while (--i > 0); \ 49 } 50 51 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ 52 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; 53 54 static __inline void 55 swapfunc(char *a, char *b, intptr_t n, int swaptype) 56 { 57 if(swaptype <= 1) 58 swapcode(long, a, b, n) 59 else 60 swapcode(char, a, b, n) 61 } 62 63 #define swap(a, b) \ 64 if (swaptype == 0) { \ 65 long t = *(long *)(a); \ 66 *(long *)(a) = *(long *)(b); \ 67 *(long *)(b) = t; \ 68 } else \ 69 swapfunc(a, b, es, swaptype) 70 71 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) 72 73 #define CMP(x, y) (cmp((x), (y))) 74 75 static __inline char * 76 med3(char *a, char *b, char *c, int (__cdecl *cmp)(const void*, const void*)) 77 { 78 return CMP(a, b) < 0 ? 79 (CMP(b, c) < 0 ? b : (CMP(a, c) < 0 ? c : a )) 80 :(CMP(b, c) > 0 ? b : (CMP(a, c) < 0 ? a : c )); 81 } 82 83 /* 84 * qsort: 85 * First, set up some global parameters for qst to share. Then, quicksort 86 * with qst(), and then a cleanup insertion sort ourselves. Sound simple? 87 * It's not... 88 * 89 * @implemented 90 */ 91 void 92 __cdecl 93 qsort(void *a, size_t n, size_t es, int (__cdecl *cmp)(const void*, const void*)) 94 { 95 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 96 int swaptype, swap_cnt; 97 intptr_t d, r; 98 99 loop: SWAPINIT(a, es); 100 swap_cnt = 0; 101 if (n < 7) { 102 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 103 for (pl = pm; pl > (char *)a && CMP(pl - es, pl) > 0; 104 pl -= es) 105 swap(pl, pl - es); 106 return; 107 } 108 pm = (char *)a + (n / 2) * es; 109 if (n > 7) { 110 pl = a; 111 pn = (char *)a + (n - 1) * es; 112 if (n > 40) { 113 d = (n / 8) * es; 114 pl = med3(pl, pl + d, pl + 2 * d, cmp); 115 pm = med3(pm - d, pm, pm + d, cmp); 116 pn = med3(pn - 2 * d, pn - d, pn, cmp); 117 } 118 pm = med3(pl, pm, pn, cmp); 119 } 120 swap(a, pm); 121 pa = pb = (char *)a + es; 122 123 pc = pd = (char *)a + (n - 1) * es; 124 for (;;) { 125 while (pb <= pc && (r = CMP(pb, a)) <= 0) { 126 if (r == 0) { 127 swap_cnt = 1; 128 swap(pa, pb); 129 pa += es; 130 } 131 pb += es; 132 } 133 while (pb <= pc && (r = CMP(pc, a)) >= 0) { 134 if (r == 0) { 135 swap_cnt = 1; 136 swap(pc, pd); 137 pd -= es; 138 } 139 pc -= es; 140 } 141 if (pb > pc) 142 break; 143 swap(pb, pc); 144 swap_cnt = 1; 145 pb += es; 146 pc -= es; 147 } 148 if (swap_cnt == 0) { /* Switch to insertion sort */ 149 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 150 for (pl = pm; pl > (char *)a && CMP(pl - es, pl) > 0; 151 pl -= es) 152 swap(pl, pl - es); 153 return; 154 } 155 156 pn = (char *)a + n * es; 157 r = min(pa - (char *)a, pb - pa); 158 vecswap(a, pb - r, r); 159 r = min(pd - pc, pn - pd - es); 160 vecswap(pb, pn - r, r); 161 if ((r = pb - pa) > es) 162 qsort(a, r / es, es, cmp); 163 if ((r = pd - pc) > es) { 164 /* Iterate rather than recurse to save stack space */ 165 a = pn - r; 166 n = r / es; 167 goto loop; 168 } 169 } 170