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comparison: xpcom/glue/nsQuickSort.cpp
xpcom/glue/nsQuickSort.cpp
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| 1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 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 * 3. 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 /* We need this because Solaris' version of qsort is broken and | |
| 33 * causes array bounds reads. | |
| 34 */ | |
| 35 | |
| 36 #include <stdlib.h> | |
| 37 #include "nsAlgorithm.h" | |
| 38 #include "nsQuickSort.h" | |
| 39 | |
| 40 extern "C" { | |
| 41 | |
| 42 #if !defined(DEBUG) && (defined(__cplusplus) || defined(__gcc)) | |
| 43 # ifndef INLINE | |
| 44 # define INLINE inline | |
| 45 # endif | |
| 46 #else | |
| 47 # define INLINE | |
| 48 #endif | |
| 49 | |
| 50 typedef int cmp_t(const void *, const void *, void *); | |
| 51 static INLINE char *med3(char *, char *, char *, cmp_t *, void *); | |
| 52 static INLINE void swapfunc(char *, char *, int, int); | |
| 53 | |
| 54 /* | |
| 55 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". | |
| 56 */ | |
| 57 #define swapcode(TYPE, parmi, parmj, n) { \ | |
| 58 long i = (n) / sizeof (TYPE); \ | |
| 59 TYPE *pi = (TYPE *) (parmi); \ | |
| 60 TYPE *pj = (TYPE *) (parmj); \ | |
| 61 do { \ | |
| 62 TYPE t = *pi; \ | |
| 63 *pi++ = *pj; \ | |
| 64 *pj++ = t; \ | |
| 65 } while (--i > 0); \ | |
| 66 } | |
| 67 | |
| 68 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ | |
| 69 es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; | |
| 70 | |
| 71 static INLINE void | |
| 72 swapfunc(char *a, char *b, int n, int swaptype) | |
| 73 { | |
| 74 if(swaptype <= 1) | |
| 75 swapcode(long, a, b, n) | |
| 76 else | |
| 77 swapcode(char, a, b, n) | |
| 78 } | |
| 79 | |
| 80 #define swap(a, b) \ | |
| 81 if (swaptype == 0) { \ | |
| 82 long t = *(long *)(a); \ | |
| 83 *(long *)(a) = *(long *)(b); \ | |
| 84 *(long *)(b) = t; \ | |
| 85 } else \ | |
| 86 swapfunc((char *)a, (char*)b, (int)es, swaptype) | |
| 87 | |
| 88 #define vecswap(a, b, n) if ((n) > 0) swapfunc((char *)a, (char *)b, (int)n, swaptype) | |
| 89 | |
| 90 static INLINE char * | |
| 91 med3(char *a, char *b, char *c, cmp_t* cmp, void *data) | |
| 92 { | |
| 93 return cmp(a, b, data) < 0 ? | |
| 94 (cmp(b, c, data) < 0 ? b : (cmp(a, c, data) < 0 ? c : a )) | |
| 95 :(cmp(b, c, data) > 0 ? b : (cmp(a, c, data) < 0 ? a : c )); | |
| 96 } | |
| 97 | |
| 98 void NS_QuickSort ( | |
| 99 void *a, | |
| 100 unsigned int n, | |
| 101 unsigned int es, | |
| 102 cmp_t *cmp, | |
| 103 void *data | |
| 104 ) | |
| 105 { | |
| 106 char *pa, *pb, *pc, *pd, *pl, *pm, *pn; | |
| 107 int d, r, swaptype; | |
| 108 | |
| 109 loop: SWAPINIT(a, es); | |
| 110 /* Use insertion sort when input is small */ | |
| 111 if (n < 7) { | |
| 112 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) | |
| 113 for (pl = pm; pl > (char *)a && cmp(pl - es, pl, data) > 0; | |
| 114 pl -= es) | |
| 115 swap(pl, pl - es); | |
| 116 return; | |
| 117 } | |
| 118 /* Choose pivot */ | |
| 119 pm = (char *)a + (n / 2) * es; | |
| 120 if (n > 7) { | |
| 121 pl = (char *)a; | |
| 122 pn = (char *)a + (n - 1) * es; | |
| 123 if (n > 40) { | |
| 124 d = (n / 8) * es; | |
| 125 pl = med3(pl, pl + d, pl + 2 * d, cmp, data); | |
| 126 pm = med3(pm - d, pm, pm + d, cmp, data); | |
| 127 pn = med3(pn - 2 * d, pn - d, pn, cmp, data); | |
| 128 } | |
| 129 pm = med3(pl, pm, pn, cmp, data); | |
| 130 } | |
| 131 swap(a, pm); | |
| 132 pa = pb = (char *)a + es; | |
| 133 | |
| 134 pc = pd = (char *)a + (n - 1) * es; | |
| 135 /* loop invariants: | |
| 136 * [a, pa) = pivot | |
| 137 * [pa, pb) < pivot | |
| 138 * [pb, pc + es) unprocessed | |
| 139 * [pc + es, pd + es) > pivot | |
| 140 * [pd + es, pn) = pivot | |
| 141 */ | |
| 142 for (;;) { | |
| 143 while (pb <= pc && (r = cmp(pb, a, data)) <= 0) { | |
| 144 if (r == 0) { | |
| 145 swap(pa, pb); | |
| 146 pa += es; | |
| 147 } | |
| 148 pb += es; | |
| 149 } | |
| 150 while (pb <= pc && (r = cmp(pc, a, data)) >= 0) { | |
| 151 if (r == 0) { | |
| 152 swap(pc, pd); | |
| 153 pd -= es; | |
| 154 } | |
| 155 pc -= es; | |
| 156 } | |
| 157 if (pb > pc) | |
| 158 break; | |
| 159 swap(pb, pc); | |
| 160 pb += es; | |
| 161 pc -= es; | |
| 162 } | |
| 163 /* Move pivot values */ | |
| 164 pn = (char *)a + n * es; | |
| 165 r = XPCOM_MIN(pa - (char *)a, pb - pa); | |
| 166 vecswap(a, pb - r, r); | |
| 167 r = XPCOM_MIN<size_t>(pd - pc, pn - pd - es); | |
| 168 vecswap(pb, pn - r, r); | |
| 169 /* Recursively process partitioned items */ | |
| 170 if ((r = pb - pa) > (int)es) | |
| 171 NS_QuickSort(a, r / es, es, cmp, data); | |
| 172 if ((r = pd - pc) > (int)es) { | |
| 173 /* Iterate rather than recurse to save stack space */ | |
| 174 a = pn - r; | |
| 175 n = r / es; | |
| 176 goto loop; | |
| 177 } | |
| 178 /* NS_QuickSort(pn - r, r / es, es, cmp, data);*/ | |
| 179 } | |
| 180 | |
| 181 } | |
| 182 | |
| 183 #undef INLINE | |
| 184 #undef swapcode | |
| 185 #undef SWAPINIT | |
| 186 #undef swap | |
| 187 #undef vecswap |
