1 /* The following is the NetBSD libc qsort implementation modified in order to 2 * support partial sorting of ranges for Redis. 3 * 4 * Copyright(C) 2009-2012 Salvatore Sanfilippo. All rights reserved. 5 * 6 * The original copyright notice follows. */ 7 8 9 /* $NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $ */ 10 11 /*- 12 * Copyright (c) 1992, 1993 13 * The Regents of the University of California. All rights reserved. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 */ 39 40 #include <sys/types.h> 41 42 #include <errno.h> 43 #include <stdlib.h> 44 45 static inline char *med3 (char *, char *, char *, 46 int (*)(const void *, const void *)); 47 static inline void swapfunc (char *, char *, size_t, int); 48 49 #define min(a, b) (a) < (b) ? a : b 50 51 /* 52 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". 53 */ 54 #define swapcode(TYPE, parmi, parmj, n) { \ 55 size_t i = (n) / sizeof (TYPE); \ 56 TYPE *pi = (TYPE *)(void *)(parmi); \ 57 TYPE *pj = (TYPE *)(void *)(parmj); \ 58 do { \ 59 TYPE t = *pi; \ 60 *pi++ = *pj; \ 61 *pj++ = t; \ 62 } while (--i > 0); \ 63 } 64 65 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ 66 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; 67 68 static inline void 69 swapfunc(char *a, char *b, size_t n, int swaptype) 70 { 71 72 if (swaptype <= 1) 73 swapcode(long, a, b, n) 74 else 75 swapcode(char, a, b, n) 76 } 77 78 #define swap(a, b) \ 79 if (swaptype == 0) { \ 80 long t = *(long *)(void *)(a); \ 81 *(long *)(void *)(a) = *(long *)(void *)(b); \ 82 *(long *)(void *)(b) = t; \ 83 } else \ 84 swapfunc(a, b, es, swaptype) 85 86 #define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype) 87 88 static inline char * 89 med3(char *a, char *b, char *c, 90 int (*cmp) (const void *, const void *)) 91 { 92 93 return cmp(a, b) < 0 ? 94 (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a )) 95 :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c )); 96 } 97 98 static void 99 _pqsort(void *a, size_t n, size_t es, 100 int (*cmp) (const void *, const void *), void *lrange, void *rrange) 101 { 102 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; 103 size_t d, r; 104 int swaptype, cmp_result; 105 106 loop: SWAPINIT(a, es); 107 if (n < 7) { 108 for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es) 109 for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0; 110 pl -= es) 111 swap(pl, pl - es); 112 return; 113 } 114 pm = (char *) a + (n / 2) * es; 115 if (n > 7) { 116 pl = (char *) a; 117 pn = (char *) a + (n - 1) * es; 118 if (n > 40) { 119 d = (n / 8) * es; 120 pl = med3(pl, pl + d, pl + 2 * d, cmp); 121 pm = med3(pm - d, pm, pm + d, cmp); 122 pn = med3(pn - 2 * d, pn - d, pn, cmp); 123 } 124 pm = med3(pl, pm, pn, cmp); 125 } 126 swap(a, pm); 127 pa = pb = (char *) a + es; 128 129 pc = pd = (char *) a + (n - 1) * es; 130 for (;;) { 131 while (pb <= pc && (cmp_result = cmp(pb, a)) <= 0) { 132 if (cmp_result == 0) { 133 swap(pa, pb); 134 pa += es; 135 } 136 pb += es; 137 } 138 while (pb <= pc && (cmp_result = cmp(pc, a)) >= 0) { 139 if (cmp_result == 0) { 140 swap(pc, pd); 141 pd -= es; 142 } 143 pc -= es; 144 } 145 if (pb > pc) 146 break; 147 swap(pb, pc); 148 pb += es; 149 pc -= es; 150 } 151 152 pn = (char *) a + n * es; 153 r = min(pa - (char *) a, pb - pa); 154 vecswap(a, pb - r, r); 155 r = min((size_t)(pd - pc), pn - pd - es); 156 vecswap(pb, pn - r, r); 157 if ((r = pb - pa) > es) { 158 void *_l = a, *_r = ((unsigned char*)a)+r-1; 159 if (!((lrange < _l && rrange < _l) || 160 (lrange > _r && rrange > _r))) 161 _pqsort(a, r / es, es, cmp, lrange, rrange); 162 } 163 if ((r = pd - pc) > es) { 164 void *_l, *_r; 165 166 /* Iterate rather than recurse to save stack space */ 167 a = pn - r; 168 n = r / es; 169 170 _l = a; 171 _r = ((unsigned char*)a)+r-1; 172 if (!((lrange < _l && rrange < _l) || 173 (lrange > _r && rrange > _r))) 174 goto loop; 175 } 176 /* qsort(pn - r, r / es, es, cmp);*/ 177 } 178 179 void 180 pqsort(void *a, size_t n, size_t es, 181 int (*cmp) (const void *, const void *), size_t lrange, size_t rrange) 182 { 183 _pqsort(a,n,es,cmp,((unsigned char*)a)+(lrange*es), 184 ((unsigned char*)a)+((rrange+1)*es)-1); 185 } 186