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Import OpenBSD sorting algorithms
OpenBSD's qsort() function is more secure than the ones used by FreeBSD, NetBSD and MacOS. The best part is it goes faster too! This change also imports the OpenBSD mergesort() and heapsort()
This commit is contained in:
Justine Tunney
parent
dbf12c30b0
commit
d861d2787b
11 changed files with 912 additions and 215 deletions
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/mem/alg.h"
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/**
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* Sorts array.
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*
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* This implementation uses the Quicksort routine from Bentley &
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* McIlroy's "Engineering a Sort Function", 1992, Bell Labs.
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*
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* @param base points to an array to sort in-place
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* @param count is the item count
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* @param width is the size of each item
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* @param cmp is a callback returning <0, 0, or >0
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* @see smoothsort()
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* @see djbsort()
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*/
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void qsort(void *a, size_t n, size_t es,
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int (*cmp)(const void *, const void *)) {
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qsort_r(a, n, es, (void *)cmp, 0);
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}
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@ -1,178 +0,0 @@
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright (c) 1992, 1993 │
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│ The Regents of the University of California. All rights reserved. │
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│ │
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│ Redistribution and use in source and binary forms, with or without │
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│ modification, are permitted provided that the following conditions │
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│ are met: │
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│ 1. Redistributions of source code must retain the above copyright │
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│ notice, this list of conditions and the following disclaimer. │
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│ 2. Redistributions in binary form must reproduce the above copyright │
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│ notice, this list of conditions and the following disclaimer in the │
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│ documentation and/or other materials provided with the distribution. │
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│ 3. Neither the name of the University nor the names of its contributors │
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│ may be used to endorse or promote products derived from this software │
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│ without specific prior written permission. │
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│ │
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│ THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND │
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│ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE │
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│ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE │
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│ ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE │
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│ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL │
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│ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS │
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│ OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) │
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│ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT │
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│ LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY │
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│ OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF │
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│ SUCH DAMAGE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/macros.internal.h"
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#include "libc/mem/alg.h"
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#include "libc/str/str.h"
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asm(".ident\t\"\\n\\n\
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NetBSD qsort (BSD-3)\\n\
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Copyright 1992 The Regents of the University of California\"");
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asm(".include \"libc/disclaimer.inc\"");
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#define SWAPINIT(a, es) \
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swaptype = ((char *)a - (char *)0) % sizeof(long) || es % sizeof(long) ? 2 \
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: es == sizeof(long) ? 0 \
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: 1;
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#define swapcode(TYPE, parmi, parmj, n) \
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size_t i = (n) / sizeof(TYPE); \
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TYPE *pi = (TYPE *)(void *)(parmi); \
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TYPE *pj = (TYPE *)(void *)(parmj); \
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do { \
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TYPE t = *pi; \
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*pi++ = *pj; \
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*pj++ = t; \
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} while (--i > 0)
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#define swap(a, b) \
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if (swaptype == 0) { \
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long t = *(long *)(void *)(a); \
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*(long *)(void *)(a) = *(long *)(void *)(b); \
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*(long *)(void *)(b) = t; \
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} else \
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swapfunc(a, b, es, swaptype)
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#define vecswap(a, b, n) \
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if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype)
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static inline void swapfunc(char *a, char *b, size_t n, int swaptype) {
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if (swaptype <= 1) {
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swapcode(long, a, b, n);
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} else {
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swapcode(char, a, b, n);
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}
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}
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static inline char *med3(char *a, char *b, char *c,
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int (*cmp)(const void *, const void *, void *),
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void *z) {
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if (cmp(a, b, z) < 0) {
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return cmp(b, c, z) < 0 ? b : (cmp(a, c, z) < 0 ? c : a);
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} else {
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return cmp(b, c, z) > 0 ? b : (cmp(a, c, z) < 0 ? a : c);
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}
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}
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/**
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* Sorts array.
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*
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* This implementation uses the Quicksort routine from Bentley &
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* McIlroy's "Engineering a Sort Function", 1992, Bell Labs. This
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* implementation is also used on systems like NetBSD and MacOS.
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*
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* @param a is base which points to an array to sort in-place
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* @param n is item count
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* @param es is width of each item
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* @param cmp is a callback returning <0, 0, or >0
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* @param arg will optionally be passed as the third argument to cmp
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* @see smoothsort_r()
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*/
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void qsort_r(void *a, size_t n, size_t es,
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int (*cmp)(const void *, const void *, void *), void *arg) {
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size_t d, r, s;
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int swaptype, cmp_result;
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char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
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loop:
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SWAPINIT(a, es);
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if (n < 7) {
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for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
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for (pl = pm; pl > (char *)a && cmp(pl - es, pl, arg) > 0; pl -= es)
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swap(pl, pl - es);
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return;
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}
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pm = (char *)a + (n / 2) * es;
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if (n > 7) {
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pl = (char *)a;
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pn = (char *)a + (n - 1) * es;
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if (n > 40) {
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d = (n / 8) * es;
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pl = med3(pl, pl + d, pl + 2 * d, cmp, arg);
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pm = med3(pm - d, pm, pm + d, cmp, arg);
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pn = med3(pn - 2 * d, pn - d, pn, cmp, arg);
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}
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pm = med3(pl, pm, pn, cmp, arg);
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}
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swap(a, pm);
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pa = pb = (char *)a + es;
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pc = pd = (char *)a + (n - 1) * es;
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for (;;) {
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while (pb <= pc && (cmp_result = cmp(pb, a, arg)) <= 0) {
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if (cmp_result == 0) {
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swap(pa, pb);
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pa += es;
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}
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pb += es;
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}
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while (pb <= pc && (cmp_result = cmp(pc, a, arg)) >= 0) {
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if (cmp_result == 0) {
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swap(pc, pd);
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pd -= es;
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}
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pc -= es;
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}
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if (pb > pc) break;
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swap(pb, pc);
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pb += es;
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pc -= es;
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}
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pn = (char *)a + n * es;
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r = MIN(pa - (char *)a, pb - pa);
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vecswap(a, pb - r, r);
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r = MIN((size_t)(pd - pc), pn - pd - es);
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vecswap(pb, pn - r, r);
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/*
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* To save stack space we sort the smaller side of the partition first
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* using recursion and eliminate tail recursion for the larger side.
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*/
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r = pb - pa;
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s = pd - pc;
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if (r < s) {
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/* Recurse for 1st side, iterate for 2nd side. */
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if (s > es) {
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if (r > es) qsort_r(a, r / es, es, cmp, arg);
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a = pn - s;
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n = s / es;
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goto loop;
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}
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} else {
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/* Recurse for 2nd side, iterate for 1st side. */
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if (r > es) {
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if (s > es) qsort_r(pn - s, s / es, es, cmp, arg);
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n = r / es;
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goto loop;
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}
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}
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}
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