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 34 35 #include <stdlib.h> 36 37 #define min(a, b) (a) < (b) ? a : b 38 39 40 typedef int cmp_t(void const *, void const *); 41 static inline char *med3(char *, char *, char *, cmp_t *); 42 static inline void swapfunc(char *, char *, int, int); 43 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 register TYPE *pi = (TYPE *) (parmi); \ 51 register TYPE *pj = (TYPE *) (parmj); \ 52 do { \ 53 register 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 63 void 64 swapfunc(char *a, char *b, int n, int swaptype) 65 { 66 if(swaptype <= 1) 67 swapcode(long, a, b, n) 68 else 69 swapcode(char, a, b, n) 70 } 71 72 #define swap(a, b) \ 73 if (swaptype == 0) { \ 74 long t = *(long *)(a); \ 75 *(long *)(a) = *(long *)(b); \ 76 *(long *)(b) = t; \ 77 } else \ 78 swapfunc(a, b, es, swaptype) 79 80 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) 81 82 static inline 83 char * 84 med3(char *a, char *b, char *c, cmp_t *cmp) 85 { 86 return cmp(a, b) < 0 ? 87 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a )) 88 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c )); 89 } 90 91 void 92 qsort(void *a, size_t n, size_t es, cmp_t *cmp) 93 { 94 char *pa; 95 char *pb; 96 char *pc; 97 char *pd; 98 char *pl; 99 char *pm; 100 char *pn; 101 int d; 102 int r; 103 int swaptype; 104 int swap_cnt; 105 106 loop: SWAPINIT(a, es); 107 swap_cnt = 0; 108 if (n < 7) { 109 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 110 for (pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; 111 pl -= es) 112 swap(pl, pl - es); 113 return; 114 } 115 pm = (char *)a + (n / 2) * es; 116 if (n > 7) { 117 pl = a; 118 pn = (char *)a + (n - 1) * es; 119 if (n > 40) { 120 d = (n / 8) * es; 121 pl = med3(pl, pl + d, pl + 2 * d, cmp); 122 pm = med3(pm - d, pm, pm + d, cmp); 123 pn = med3(pn - 2 * d, pn - d, pn, cmp); 124 } 125 pm = med3(pl, pm, pn, cmp); 126 } 127 swap(a, pm); 128 pa = pb = (char *)a + es; 129 130 pc = pd = (char *)a + (n - 1) * es; 131 for (;;) { 132 while (pb <= pc && (r = cmp(pb, a)) <= 0) { 133 if (r == 0) { 134 swap_cnt = 1; 135 swap(pa, pb); 136 pa += es; 137 } 138 pb += es; 139 } 140 while (pb <= pc && (r = cmp(pc, a)) >= 0) { 141 if (r == 0) { 142 swap_cnt = 1; 143 swap(pc, pd); 144 pd -= es; 145 } 146 pc -= es; 147 } 148 if (pb > pc) 149 break; 150 swap(pb, pc); 151 swap_cnt = 1; 152 pb += es; 153 pc -= es; 154 } 155 if (swap_cnt == 0) { /* Switch to insertion sort */ 156 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 157 for (pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; 158 pl -= es) 159 swap(pl, pl - es); 160 return; 161 } 162 163 pn = (char *)a + n * es; 164 r = min(pa - (char *)a, pb - pa); 165 vecswap(a, pb - r, r); 166 r = min((int)(pd - pc), (int)(pn - pd - es)); 167 vecswap(pb, pn - r, r); 168 if ((r = pb - pa) > (int)es) 169 qsort(a, r / es, es, cmp); 170 if ((r = pd - pc) > (int)es) { 171 /* Iterate rather than recurse to save stack space */ 172 a = pn - r; 173 n = r / es; 174 goto loop; 175 } 176 /* qsort(pn - r, r / es, es, cmp);*/ 177 } 178