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