+++ /dev/null
-/*
- * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-/*
- * Copyright (c) 1991, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * Ronnie Kon at Mindcraft Inc., Kevin Lew and Elmer Yglesias.
- *
- * 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. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. 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.
- */
-
-
-#include <sys/types.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <stddef.h>
-
-/*
- * Swap two areas of size number of bytes. Although qsort(3) permits random
- * blocks of memory to be sorted, sorting pointers is almost certainly the
- * common case (and, were it not, could easily be made so). Regardless, it
- * isn't worth optimizing; the SWAP's get sped up by the cache, and pointer
- * arithmetic gets lost in the time required for comparison function calls.
- */
-#define SWAP(a, b, count, size, tmp) { \
- count = size; \
- do { \
- tmp = *a; \
- *a++ = *b; \
- *b++ = tmp; \
- } while (--count); \
-}
-
-/* Copy one block of size size to another. */
-#define COPY(a, b, count, size, tmp1, tmp2) { \
- count = size; \
- tmp1 = a; \
- tmp2 = b; \
- do { \
- *tmp1++ = *tmp2++; \
- } while (--count); \
-}
-
-/*
- * Build the list into a heap, where a heap is defined such that for
- * the records K1 ... KN, Kj/2 >= Kj for 1 <= j/2 <= j <= N.
- *
- * There two cases. If j == nmemb, select largest of Ki and Kj. If
- * j < nmemb, select largest of Ki, Kj and Kj+1.
- */
-#define CREATE(initval, nmemb, par_i, child_i, par, child, size, count, tmp) { \
- for (par_i = initval; (child_i = par_i * 2) <= nmemb; \
- par_i = child_i) { \
- child = base + child_i * size; \
- if (child_i < nmemb && compar(child, child + size) < 0) { \
- child += size; \
- ++child_i; \
- } \
- par = base + par_i * size; \
- if (compar(child, par) <= 0) \
- break; \
- SWAP(par, child, count, size, tmp); \
- } \
-}
-
-/*
- * Select the top of the heap and 'heapify'. Since by far the most expensive
- * action is the call to the compar function, a considerable optimization
- * in the average case can be achieved due to the fact that k, the displaced
- * elememt, is ususally quite small, so it would be preferable to first
- * heapify, always maintaining the invariant that the larger child is copied
- * over its parent's record.
- *
- * Then, starting from the *bottom* of the heap, finding k's correct place,
- * again maintianing the invariant. As a result of the invariant no element
- * is 'lost' when k is assigned its correct place in the heap.
- *
- * The time savings from this optimization are on the order of 15-20% for the
- * average case. See Knuth, Vol. 3, page 158, problem 18.
- *
- * XXX Don't break the #define SELECT line, below. Reiser cpp gets upset.
- */
-#define SELECT(par_i, child_i, nmemb, par, child, size, k, count, tmp1, tmp2) { \
- for (par_i = 1; (child_i = par_i * 2) <= nmemb; par_i = child_i) { \
- child = base + child_i * size; \
- if (child_i < nmemb && compar(child, child + size) < 0) { \
- child += size; \
- ++child_i; \
- } \
- par = base + par_i * size; \
- COPY(par, child, count, size, tmp1, tmp2); \
- } \
- for (;;) { \
- child_i = par_i; \
- par_i = child_i / 2; \
- child = base + child_i * size; \
- par = base + par_i * size; \
- if (child_i == 1 || compar(k, par) < 0) { \
- COPY(child, k, count, size, tmp1, tmp2); \
- break; \
- } \
- COPY(child, par, count, size, tmp1, tmp2); \
- } \
-}
-
-/*
- * Heapsort -- Knuth, Vol. 3, page 145. Runs in O (N lg N), both average
- * and worst. While heapsort is faster than the worst case of quicksort,
- * the BSD quicksort does median selection so that the chance of finding
- * a data set that will trigger the worst case is nonexistent. Heapsort's
- * only advantage over quicksort is that it requires little additional memory.
- */
-int
-heapsort(vbase, nmemb, size, compar)
- void *vbase;
- size_t nmemb, size;
- int (*compar) __P((const void *, const void *));
-{
- register int cnt, i, j, l;
- register char tmp, *tmp1, *tmp2;
- char *base, *k, *p, *t;
-
- if (nmemb <= 1)
- return (0);
-
- if (!size) {
- errno = EINVAL;
- return (-1);
- }
-
- if ((k = malloc(size)) == NULL)
- return (-1);
-
- /*
- * Items are numbered from 1 to nmemb, so offset from size bytes
- * below the starting address.
- */
- base = (char *)vbase - size;
-
- for (l = nmemb / 2 + 1; --l;)
- CREATE(l, nmemb, i, j, t, p, size, cnt, tmp);
-
- /*
- * For each element of the heap, save the largest element into its
- * final slot, save the displaced element (k), then recreate the
- * heap.
- */
- while (nmemb > 1) {
- COPY(k, base + nmemb * size, cnt, size, tmp1, tmp2);
- COPY(base + nmemb * size, base + size, cnt, size, tmp1, tmp2);
- --nmemb;
- SELECT(i, j, nmemb, t, p, size, k, cnt, tmp1, tmp2);
- }
- free(k);
- return (0);
-}
projects / apple / libc.git / blobdiff