1 /* $NetBSD: qsort.c,v 1.1.1.1 2011/04/13 18:15:42 elric Exp $ */ 2 3 /*- 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 4. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #if 0 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 #endif 39 40 #include <config.h> 41 42 #ifdef NEED_QSORT 43 44 #include <krb5/roken.h> 45 46 #include <stdlib.h> 47 48 #ifdef I_AM_QSORT_R 49 typedef int cmp_t(void *, const void *, const void *); 50 #else 51 typedef int cmp_t(const void *, const void *); 52 #endif 53 static inline char *med3(char *, char *, char *, cmp_t *, void *); 54 static inline void swapfunc(char *, char *, int, int); 55 56 /* 57 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 58 */ 59 #define swapcode(TYPE, parmi, parmj, n) { \ 60 long i = (n) / sizeof (TYPE); \ 61 TYPE *pi = (TYPE *) (parmi); \ 62 TYPE *pj = (TYPE *) (parmj); \ 63 do { \ 64 TYPE t = *pi; \ 65 *pi++ = *pj; \ 66 *pj++ = t; \ 67 } while (--i > 0); \ 68 } 69 70 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ 71 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; 72 73 static inline void 74 swapfunc(a, b, n, swaptype) 75 char *a, *b; 76 int n, swaptype; 77 { 78 if(swaptype <= 1) 79 swapcode(long, a, b, n) 80 else 81 swapcode(char, a, b, n) 82 } 83 84 #define swap(a, b) \ 85 if (swaptype == 0) { \ 86 long t = *(long *)(a); \ 87 *(long *)(a) = *(long *)(b); \ 88 *(long *)(b) = t; \ 89 } else \ 90 swapfunc(a, b, es, swaptype) 91 92 #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype) 93 94 #ifdef I_AM_QSORT_R 95 #define CMP(t, x, y) (cmp((t), (x), (y))) 96 #else 97 #define CMP(t, x, y) (cmp((x), (y))) 98 #endif 99 100 static inline char * 101 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk 102 #ifndef I_AM_QSORT_R 103 /* __unused */ 104 #endif 105 ) 106 { 107 return CMP(thunk, a, b) < 0 ? 108 (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a )) 109 :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c )); 110 } 111 112 #ifdef I_AM_QSORT_R 113 void 114 rk_qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp) 115 #else 116 #define thunk NULL 117 void 118 rk_qsort(void *a, size_t n, size_t es, cmp_t *cmp) 119 #endif 120 { 121 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 122 size_t d, r; 123 int cmp_result; 124 int swaptype, swap_cnt; 125 126 loop: SWAPINIT(a, es); 127 swap_cnt = 0; 128 if (n < 7) { 129 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 130 for (pl = pm; 131 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 132 pl -= es) 133 swap(pl, pl - es); 134 return; 135 } 136 pm = (char *)a + (n / 2) * es; 137 if (n > 7) { 138 pl = a; 139 pn = (char *)a + (n - 1) * es; 140 if (n > 40) { 141 d = (n / 8) * es; 142 pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk); 143 pm = med3(pm - d, pm, pm + d, cmp, thunk); 144 pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk); 145 } 146 pm = med3(pl, pm, pn, cmp, thunk); 147 } 148 swap(a, pm); 149 pa = pb = (char *)a + es; 150 151 pc = pd = (char *)a + (n - 1) * es; 152 for (;;) { 153 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) { 154 if (cmp_result == 0) { 155 swap_cnt = 1; 156 swap(pa, pb); 157 pa += es; 158 } 159 pb += es; 160 } 161 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) { 162 if (cmp_result == 0) { 163 swap_cnt = 1; 164 swap(pc, pd); 165 pd -= es; 166 } 167 pc -= es; 168 } 169 if (pb > pc) 170 break; 171 swap(pb, pc); 172 swap_cnt = 1; 173 pb += es; 174 pc -= es; 175 } 176 if (swap_cnt == 0) { /* Switch to insertion sort */ 177 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) 178 for (pl = pm; 179 pl > (char *)a && CMP(thunk, pl - es, pl) > 0; 180 pl -= es) 181 swap(pl, pl - es); 182 return; 183 } 184 185 pn = (char *)a + n * es; 186 r = min(pa - (char *)a, pb - pa); 187 vecswap(a, pb - r, r); 188 r = min(pd - pc, pn - pd - es); 189 vecswap(pb, pn - r, r); 190 if ((r = pb - pa) > es) 191 #ifdef I_AM_QSORT_R 192 rk_qsort_r(a, r / es, es, thunk, cmp); 193 #else 194 rk_qsort(a, r / es, es, cmp); 195 #endif 196 if ((r = pd - pc) > es) { 197 /* Iterate rather than recurse to save stack space */ 198 a = pn - r; 199 n = r / es; 200 goto loop; 201 } 202 /* rk_qsort(pn - r, r / es, es, cmp);*/ 203 } 204 205 #endif /* NEED_QSORT */ 206