git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@184512 65c4cc65-6c06-0410-ace0-fbb531ad65f3
340 lines
6 KiB
C
340 lines
6 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2009, Digium, Inc.
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*
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* Russell Bryant <russell@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief Max Heap data structure
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*
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* \author Russell Bryant <russell@digium.com>
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*/
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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#include "asterisk/heap.h"
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#include "asterisk/utils.h"
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#include "asterisk/cli.h"
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struct ast_heap {
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ast_rwlock_t lock;
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ast_heap_cmp_fn cmp_fn;
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ssize_t index_offset;
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size_t cur_len;
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size_t avail_len;
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void **heap;
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};
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static inline int left_node(int i)
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{
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return 2 * i;
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}
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static inline int right_node(int i)
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{
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return 2 * i + 1;
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}
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static inline int parent_node(int i)
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{
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return i / 2;
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}
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static inline void *heap_get(struct ast_heap *h, int i)
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{
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return h->heap[i - 1];
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}
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static inline ssize_t get_index(struct ast_heap *h, void *elm)
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{
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ssize_t *index;
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if (h->index_offset < 0) {
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return -1;
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}
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index = elm + h->index_offset;
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return *index;
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}
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static inline void heap_set(struct ast_heap *h, int i, void *elm)
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{
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h->heap[i - 1] = elm;
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if (h->index_offset >= 0) {
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ssize_t *index = elm + h->index_offset;
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*index = i;
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}
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}
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int ast_heap_verify(struct ast_heap *h)
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{
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unsigned int i;
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for (i = 1; i <= (h->cur_len / 2); i++) {
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int l = left_node(i);
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int r = right_node(i);
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if (l <= h->cur_len) {
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if (h->cmp_fn(heap_get(h, i), heap_get(h, l)) <= 0) {
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return -1;
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}
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}
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if (r <= h->cur_len) {
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if (h->cmp_fn(heap_get(h, i), heap_get(h, r)) <= 0) {
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return -1;
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}
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}
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}
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return 0;
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}
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#ifdef MALLOC_DEBUG
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struct ast_heap *_ast_heap_create(unsigned int init_height, ast_heap_cmp_fn cmp_fn,
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ssize_t index_offset, const char *file, int lineno, const char *func)
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#else
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struct ast_heap *ast_heap_create(unsigned int init_height, ast_heap_cmp_fn cmp_fn,
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ssize_t index_offset)
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#endif
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{
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struct ast_heap *h;
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if (!cmp_fn) {
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ast_log(LOG_ERROR, "A comparison function must be provided\n");
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return NULL;
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}
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if (!init_height) {
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init_height = 8;
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}
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if (!(h =
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#ifdef MALLOC_DEBUG
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__ast_calloc(1, sizeof(*h), file, lineno, func)
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#else
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ast_calloc(1, sizeof(*h))
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#endif
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)) {
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return NULL;
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}
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h->cmp_fn = cmp_fn;
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h->index_offset = index_offset;
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h->avail_len = (1 << init_height) - 1;
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if (!(h->heap =
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#ifdef MALLOC_DEBUG
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__ast_calloc(1, h->avail_len * sizeof(void *), file, lineno, func)
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#else
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ast_calloc(1, h->avail_len * sizeof(void *))
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#endif
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)) {
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ast_free(h);
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return NULL;
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}
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ast_rwlock_init(&h->lock);
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return h;
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}
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struct ast_heap *ast_heap_destroy(struct ast_heap *h)
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{
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ast_free(h->heap);
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h->heap = NULL;
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ast_rwlock_destroy(&h->lock);
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ast_free(h);
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return NULL;
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}
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/*!
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* \brief Add a row of additional storage for the heap.
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*/
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static int grow_heap(struct ast_heap *h
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#ifdef MALLOC_DEBUG
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, const char *file, int lineno, const char *func
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#endif
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)
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{
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h->avail_len = h->avail_len * 2 + 1;
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if (!(h->heap =
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#ifdef MALLOC_DEBUG
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__ast_realloc(h->heap, h->avail_len * sizeof(void *), file, lineno, func)
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#else
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ast_realloc(h->heap, h->avail_len * sizeof(void *))
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#endif
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)) {
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h->cur_len = h->avail_len = 0;
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return -1;
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}
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return 0;
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}
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static inline void heap_swap(struct ast_heap *h, int i, int j)
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{
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void *tmp;
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tmp = heap_get(h, i);
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heap_set(h, i, heap_get(h, j));
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heap_set(h, j, tmp);
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}
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static inline void max_heapify(struct ast_heap *h, int i)
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{
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for (;;) {
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int l = left_node(i);
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int r = right_node(i);
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int max;
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if (l <= h->cur_len && h->cmp_fn(heap_get(h, l), heap_get(h, i)) > 0) {
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max = l;
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} else {
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max = i;
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}
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if (r <= h->cur_len && h->cmp_fn(heap_get(h, r), heap_get(h, max)) > 0) {
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max = r;
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}
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if (max == i) {
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break;
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}
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heap_swap(h, i, max);
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i = max;
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}
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}
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#ifdef MALLOC_DEBUG
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int _ast_heap_push(struct ast_heap *h, void *elm, const char *file, int lineno, const char *func)
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#else
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int ast_heap_push(struct ast_heap *h, void *elm)
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#endif
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{
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int i;
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if (h->cur_len == h->avail_len && grow_heap(h
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#ifdef MALLOC_DEBUG
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, file, lineno, func
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#endif
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)) {
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return -1;
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}
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heap_set(h, ++(h->cur_len), elm);
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for (i = h->cur_len;
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i > 1 && h->cmp_fn(heap_get(h, parent_node(i)), heap_get(h, i)) < 0;
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i = parent_node(i)) {
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heap_swap(h, i, parent_node(i));
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}
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return 0;
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}
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static void *_ast_heap_remove(struct ast_heap *h, unsigned int index)
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{
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void *ret;
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if (!index || index > h->cur_len) {
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return NULL;
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}
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ret = heap_get(h, index);
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heap_set(h, index, heap_get(h, (h->cur_len)--));
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max_heapify(h, index);
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return ret;
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}
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void *ast_heap_remove(struct ast_heap *h, void *elm)
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{
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ssize_t i = get_index(h, elm);
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if (i == -1) {
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return NULL;
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}
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return _ast_heap_remove(h, i);
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}
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void *ast_heap_pop(struct ast_heap *h)
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{
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return _ast_heap_remove(h, 1);
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}
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void *ast_heap_peek(struct ast_heap *h, unsigned int index)
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{
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if (!h->cur_len || !index || index > h->cur_len) {
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return NULL;
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}
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return heap_get(h, index);
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}
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size_t ast_heap_size(struct ast_heap *h)
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{
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return h->cur_len;
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}
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#ifndef DEBUG_THREADS
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int ast_heap_wrlock(struct ast_heap *h)
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{
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return ast_rwlock_wrlock(&h->lock);
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}
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int ast_heap_rdlock(struct ast_heap *h)
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{
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return ast_rwlock_rdlock(&h->lock);
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}
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int ast_heap_unlock(struct ast_heap *h)
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{
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return ast_rwlock_unlock(&h->lock);
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}
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#else /* DEBUG_THREADS */
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int __ast_heap_wrlock(struct ast_heap *h, const char *file, const char *func, int line)
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{
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return _ast_rwlock_wrlock(&h->lock, "&h->lock", file, line, func);
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}
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int __ast_heap_rdlock(struct ast_heap *h, const char *file, const char *func, int line)
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{
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return _ast_rwlock_rdlock(&h->lock, "&h->lock", file, line, func);
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}
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int __ast_heap_unlock(struct ast_heap *h, const char *file, const char *func, int line)
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{
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return _ast_rwlock_unlock(&h->lock, "&h->lock", file, line, func);
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}
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#endif /* DEBUG_THREADS */
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