diff options
Diffstat (limited to 'xpcom/ds/nsQuickSort.cpp')
| -rw-r--r-- | xpcom/ds/nsQuickSort.cpp | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/xpcom/ds/nsQuickSort.cpp b/xpcom/ds/nsQuickSort.cpp new file mode 100644 index 0000000000..1fb3dede88 --- /dev/null +++ b/xpcom/ds/nsQuickSort.cpp @@ -0,0 +1,175 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ + +/*- + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* We need this because Solaris' version of qsort is broken and + * causes array bounds reads. + */ + +#include <stdlib.h> +#include "nsAlgorithm.h" +#include "nsQuickSort.h" + +extern "C" { + +#if !defined(DEBUG) && (defined(__cplusplus) || defined(__gcc)) +# ifndef INLINE +# define INLINE inline +# endif +#else +# define INLINE +#endif + +typedef int cmp_t(const void*, const void*, void*); +static INLINE char* med3(char*, char*, char*, cmp_t*, void*); +static INLINE void swapfunc(char*, char*, int, int); + +/* + * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function". + */ +#define swapcode(TYPE, parmi, parmj, n) \ + { \ + long i = (n) / sizeof(TYPE); \ + TYPE* pi = (TYPE*)(parmi); \ + TYPE* pj = (TYPE*)(parmj); \ + do { \ + TYPE t = *pi; \ + *pi++ = *pj; \ + *pj++ = t; \ + } while (--i > 0); \ + } + +#define SWAPINIT(a, es) \ + swaptype = ((char*)a - (char*)0) % sizeof(long) || es % sizeof(long) ? 2 \ + : es == sizeof(long) ? 0 \ + : 1; + +static INLINE void swapfunc(char* a, char* b, int n, int swaptype) { + if (swaptype <= 1) swapcode(long, a, b, n) else swapcode(char, a, b, n) +} + +#define swap(a, b) \ + if (swaptype == 0) { \ + long t = *(long*)(a); \ + *(long*)(a) = *(long*)(b); \ + *(long*)(b) = t; \ + } else \ + swapfunc((char*)a, (char*)b, (int)es, swaptype) + +#define vecswap(a, b, n) \ + if ((n) > 0) swapfunc((char*)a, (char*)b, (int)n, swaptype) + +static INLINE char* med3(char* a, char* b, char* c, cmp_t* cmp, void* data) { + return cmp(a, b, data) < 0 + ? (cmp(b, c, data) < 0 ? b : (cmp(a, c, data) < 0 ? c : a)) + : (cmp(b, c, data) > 0 ? b : (cmp(a, c, data) < 0 ? a : c)); +} + +void NS_QuickSort(void* a, unsigned int n, unsigned int es, cmp_t* cmp, + void* data) { + char *pa, *pb, *pc, *pd, *pl, *pm, *pn; + int d, r, swaptype; + +loop: + SWAPINIT(a, es); + /* Use insertion sort when input is small */ + if (n < 7) { + for (pm = (char*)a + es; pm < (char*)a + n * es; pm += es) + for (pl = pm; pl > (char*)a && cmp(pl - es, pl, data) > 0; pl -= es) + swap(pl, pl - es); + return; + } + /* Choose pivot */ + pm = (char*)a + (n / 2) * es; + if (n > 7) { + pl = (char*)a; + pn = (char*)a + (n - 1) * es; + if (n > 40) { + d = (n / 8) * es; + pl = med3(pl, pl + d, pl + 2 * d, cmp, data); + pm = med3(pm - d, pm, pm + d, cmp, data); + pn = med3(pn - 2 * d, pn - d, pn, cmp, data); + } + pm = med3(pl, pm, pn, cmp, data); + } + swap(a, pm); + pa = pb = (char*)a + es; + + pc = pd = (char*)a + (n - 1) * es; + /* loop invariants: + * [a, pa) = pivot + * [pa, pb) < pivot + * [pb, pc + es) unprocessed + * [pc + es, pd + es) > pivot + * [pd + es, pn) = pivot + */ + for (;;) { + while (pb <= pc && (r = cmp(pb, a, data)) <= 0) { + if (r == 0) { + swap(pa, pb); + pa += es; + } + pb += es; + } + while (pb <= pc && (r = cmp(pc, a, data)) >= 0) { + if (r == 0) { + swap(pc, pd); + pd -= es; + } + pc -= es; + } + if (pb > pc) break; + swap(pb, pc); + pb += es; + pc -= es; + } + /* Move pivot values */ + pn = (char*)a + n * es; + r = XPCOM_MIN(pa - (char*)a, pb - pa); + vecswap(a, pb - r, r); + r = XPCOM_MIN<size_t>(pd - pc, pn - pd - es); + vecswap(pb, pn - r, r); + /* Recursively process partitioned items */ + if ((r = pb - pa) > (int)es) NS_QuickSort(a, r / es, es, cmp, data); + if ((r = pd - pc) > (int)es) { + /* Iterate rather than recurse to save stack space */ + a = pn - r; + n = r / es; + goto loop; + } + /* NS_QuickSort(pn - r, r / es, es, cmp, data);*/ +} +} + +#undef INLINE +#undef swapcode +#undef SWAPINIT +#undef swap +#undef vecswap |