xpcom/glue/nsQuickSort.cpp@97036ab72558 (annotated)
xpcom/glue/nsQuickSort.cpp
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | |
| michael@0 | 3 | /*- |
| michael@0 | 4 | * Copyright (c) 1992, 1993 |
| michael@0 | 5 | * The Regents of the University of California. All rights reserved. |
| michael@0 | 6 | * |
| michael@0 | 7 | * Redistribution and use in source and binary forms, with or without |
| michael@0 | 8 | * modification, are permitted provided that the following conditions |
| michael@0 | 9 | * are met: |
| michael@0 | 10 | * 1. Redistributions of source code must retain the above copyright |
| michael@0 | 11 | * notice, this list of conditions and the following disclaimer. |
| michael@0 | 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| michael@0 | 13 | * notice, this list of conditions and the following disclaimer in the |
| michael@0 | 14 | * documentation and/or other materials provided with the distribution. |
| michael@0 | 15 | * 3. Neither the name of the University nor the names of its contributors |
| michael@0 | 16 | * may be used to endorse or promote products derived from this software |
| michael@0 | 17 | * without specific prior written permission. |
| michael@0 | 18 | * |
| michael@0 | 19 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| michael@0 | 20 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| michael@0 | 21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| michael@0 | 22 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| michael@0 | 23 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| michael@0 | 24 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| michael@0 | 25 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| michael@0 | 26 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| michael@0 | 27 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| michael@0 | 28 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| michael@0 | 29 | * SUCH DAMAGE. |
| michael@0 | 30 | */ |
| michael@0 | 31 | |
| michael@0 | 32 | /* We need this because Solaris' version of qsort is broken and |
| michael@0 | 33 | * causes array bounds reads. |
| michael@0 | 34 | */ |
| michael@0 | 35 | |
| michael@0 | 36 | #include <stdlib.h> |
| michael@0 | 37 | #include "nsAlgorithm.h" |
| michael@0 | 38 | #include "nsQuickSort.h" |
| michael@0 | 39 | |
| michael@0 | 40 | extern "C" { |
| michael@0 | 41 | |
| michael@0 | 42 | #if !defined(DEBUG) && (defined(__cplusplus) || defined(__gcc)) |
| michael@0 | 43 | # ifndef INLINE |
| michael@0 | 44 | # define INLINE inline |
| michael@0 | 45 | # endif |
| michael@0 | 46 | #else |
| michael@0 | 47 | # define INLINE |
| michael@0 | 48 | #endif |
| michael@0 | 49 | |
| michael@0 | 50 | typedef int cmp_t(const void *, const void *, void *); |
| michael@0 | 51 | static INLINE char *med3(char *, char *, char *, cmp_t *, void *); |
| michael@0 | 52 | static INLINE void swapfunc(char *, char *, int, int); |
| michael@0 | 53 | |
| michael@0 | 54 | /* |
| michael@0 | 55 | * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". |
| michael@0 | 56 | */ |
| michael@0 | 57 | #define swapcode(TYPE, parmi, parmj, n) { \ |
| michael@0 | 58 | long i = (n) / sizeof (TYPE); \ |
| michael@0 | 59 | TYPE *pi = (TYPE *) (parmi); \ |
| michael@0 | 60 | TYPE *pj = (TYPE *) (parmj); \ |
| michael@0 | 61 | do { \ |
| michael@0 | 62 | TYPE t = *pi; \ |
| michael@0 | 63 | *pi++ = *pj; \ |
| michael@0 | 64 | *pj++ = t; \ |
| michael@0 | 65 | } while (--i > 0); \ |
| michael@0 | 66 | } |
| michael@0 | 67 | |
| michael@0 | 68 | #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ |
| michael@0 | 69 | es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; |
| michael@0 | 70 | |
| michael@0 | 71 | static INLINE void |
| michael@0 | 72 | swapfunc(char *a, char *b, int n, int swaptype) |
| michael@0 | 73 | { |
| michael@0 | 74 | if(swaptype <= 1) |
| michael@0 | 75 | swapcode(long, a, b, n) |
| michael@0 | 76 | else |
| michael@0 | 77 | swapcode(char, a, b, n) |
| michael@0 | 78 | } |
| michael@0 | 79 | |
| michael@0 | 80 | #define swap(a, b) \ |
| michael@0 | 81 | if (swaptype == 0) { \ |
| michael@0 | 82 | long t = *(long *)(a); \ |
| michael@0 | 83 | *(long *)(a) = *(long *)(b); \ |
| michael@0 | 84 | *(long *)(b) = t; \ |
| michael@0 | 85 | } else \ |
| michael@0 | 86 | swapfunc((char *)a, (char*)b, (int)es, swaptype) |
| michael@0 | 87 | |
| michael@0 | 88 | #define vecswap(a, b, n) if ((n) > 0) swapfunc((char *)a, (char *)b, (int)n, swaptype) |
| michael@0 | 89 | |
| michael@0 | 90 | static INLINE char * |
| michael@0 | 91 | med3(char *a, char *b, char *c, cmp_t* cmp, void *data) |
| michael@0 | 92 | { |
| michael@0 | 93 | return cmp(a, b, data) < 0 ? |
| michael@0 | 94 | (cmp(b, c, data) < 0 ? b : (cmp(a, c, data) < 0 ? c : a )) |
| michael@0 | 95 | :(cmp(b, c, data) > 0 ? b : (cmp(a, c, data) < 0 ? a : c )); |
| michael@0 | 96 | } |
| michael@0 | 97 | |
| michael@0 | 98 | void NS_QuickSort ( |
| michael@0 | 99 | void *a, |
| michael@0 | 100 | unsigned int n, |
| michael@0 | 101 | unsigned int es, |
| michael@0 | 102 | cmp_t *cmp, |
| michael@0 | 103 | void *data |
| michael@0 | 104 | ) |
| michael@0 | 105 | { |
| michael@0 | 106 | char *pa, *pb, *pc, *pd, *pl, *pm, *pn; |
| michael@0 | 107 | int d, r, swaptype; |
| michael@0 | 108 | |
| michael@0 | 109 | loop: SWAPINIT(a, es); |
| michael@0 | 110 | /* Use insertion sort when input is small */ |
| michael@0 | 111 | if (n < 7) { |
| michael@0 | 112 | for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es) |
| michael@0 | 113 | for (pl = pm; pl > (char *)a && cmp(pl - es, pl, data) > 0; |
| michael@0 | 114 | pl -= es) |
| michael@0 | 115 | swap(pl, pl - es); |
| michael@0 | 116 | return; |
| michael@0 | 117 | } |
| michael@0 | 118 | /* Choose pivot */ |
| michael@0 | 119 | pm = (char *)a + (n / 2) * es; |
| michael@0 | 120 | if (n > 7) { |
| michael@0 | 121 | pl = (char *)a; |
| michael@0 | 122 | pn = (char *)a + (n - 1) * es; |
| michael@0 | 123 | if (n > 40) { |
| michael@0 | 124 | d = (n / 8) * es; |
| michael@0 | 125 | pl = med3(pl, pl + d, pl + 2 * d, cmp, data); |
| michael@0 | 126 | pm = med3(pm - d, pm, pm + d, cmp, data); |
| michael@0 | 127 | pn = med3(pn - 2 * d, pn - d, pn, cmp, data); |
| michael@0 | 128 | } |
| michael@0 | 129 | pm = med3(pl, pm, pn, cmp, data); |
| michael@0 | 130 | } |
| michael@0 | 131 | swap(a, pm); |
| michael@0 | 132 | pa = pb = (char *)a + es; |
| michael@0 | 133 | |
| michael@0 | 134 | pc = pd = (char *)a + (n - 1) * es; |
| michael@0 | 135 | /* loop invariants: |
| michael@0 | 136 | * [a, pa) = pivot |
| michael@0 | 137 | * [pa, pb) < pivot |
| michael@0 | 138 | * [pb, pc + es) unprocessed |
| michael@0 | 139 | * [pc + es, pd + es) > pivot |
| michael@0 | 140 | * [pd + es, pn) = pivot |
| michael@0 | 141 | */ |
| michael@0 | 142 | for (;;) { |
| michael@0 | 143 | while (pb <= pc && (r = cmp(pb, a, data)) <= 0) { |
| michael@0 | 144 | if (r == 0) { |
| michael@0 | 145 | swap(pa, pb); |
| michael@0 | 146 | pa += es; |
| michael@0 | 147 | } |
| michael@0 | 148 | pb += es; |
| michael@0 | 149 | } |
| michael@0 | 150 | while (pb <= pc && (r = cmp(pc, a, data)) >= 0) { |
| michael@0 | 151 | if (r == 0) { |
| michael@0 | 152 | swap(pc, pd); |
| michael@0 | 153 | pd -= es; |
| michael@0 | 154 | } |
| michael@0 | 155 | pc -= es; |
| michael@0 | 156 | } |
| michael@0 | 157 | if (pb > pc) |
| michael@0 | 158 | break; |
| michael@0 | 159 | swap(pb, pc); |
| michael@0 | 160 | pb += es; |
| michael@0 | 161 | pc -= es; |
| michael@0 | 162 | } |
| michael@0 | 163 | /* Move pivot values */ |
| michael@0 | 164 | pn = (char *)a + n * es; |
| michael@0 | 165 | r = XPCOM_MIN(pa - (char *)a, pb - pa); |
| michael@0 | 166 | vecswap(a, pb - r, r); |
| michael@0 | 167 | r = XPCOM_MIN<size_t>(pd - pc, pn - pd - es); |
| michael@0 | 168 | vecswap(pb, pn - r, r); |
| michael@0 | 169 | /* Recursively process partitioned items */ |
| michael@0 | 170 | if ((r = pb - pa) > (int)es) |
| michael@0 | 171 | NS_QuickSort(a, r / es, es, cmp, data); |
| michael@0 | 172 | if ((r = pd - pc) > (int)es) { |
| michael@0 | 173 | /* Iterate rather than recurse to save stack space */ |
| michael@0 | 174 | a = pn - r; |
| michael@0 | 175 | n = r / es; |
| michael@0 | 176 | goto loop; |
| michael@0 | 177 | } |
| michael@0 | 178 | /* NS_QuickSort(pn - r, r / es, es, cmp, data);*/ |
| michael@0 | 179 | } |
| michael@0 | 180 | |
| michael@0 | 181 | } |
| michael@0 | 182 | |
| michael@0 | 183 | #undef INLINE |
| michael@0 | 184 | #undef swapcode |
| michael@0 | 185 | #undef SWAPINIT |
| michael@0 | 186 | #undef swap |
| michael@0 | 187 | #undef vecswap |
