+++ /dev/null
-/**
- * collectd - src/utils_heap.c
- * Copyright (C) 2009 Florian octo Forster
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
- * Authors:
- * Florian octo Forster <octo at collectd.org>
- **/
-
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <assert.h>
-#include <pthread.h>
-
-#include "utils_heap.h"
-
-struct c_heap_s
-{
- pthread_mutex_t lock;
- int (*compare) (const void *, const void *);
-
- void **list;
- size_t list_len; /* # entries used */
- size_t list_size; /* # entries allocated */
-};
-
-enum reheap_direction
-{
- DIR_UP,
- DIR_DOWN
-};
-
-static void reheap (c_heap_t *h, size_t root, enum reheap_direction dir)
-{
- size_t left;
- size_t right;
- size_t min;
- int status;
-
- /* Calculate the positions of the children */
- left = (2 * root) + 1;
- if (left >= h->list_len)
- left = 0;
-
- right = (2 * root) + 2;
- if (right >= h->list_len)
- right = 0;
-
- /* Check which one of the children is smaller. */
- if ((left == 0) && (right == 0))
- return;
- else if (left == 0)
- min = right;
- else if (right == 0)
- min = left;
- else
- {
- status = h->compare (h->list[left], h->list[right]);
- if (status > 0)
- min = right;
- else
- min = left;
- }
-
- status = h->compare (h->list[root], h->list[min]);
- if (status <= 0)
- {
- /* We didn't need to change anything, so the rest of the tree should be
- * okay now. */
- return;
- }
- else /* if (status > 0) */
- {
- void *tmp;
-
- tmp = h->list[root];
- h->list[root] = h->list[min];
- h->list[min] = tmp;
- }
-
- if ((dir == DIR_UP) && (root == 0))
- return;
-
- if (dir == DIR_UP)
- reheap (h, (root - 1) / 2, dir);
- else if (dir == DIR_DOWN)
- reheap (h, min, dir);
-} /* void reheap */
-
-c_heap_t *c_heap_create (int (*compare) (const void *, const void *))
-{
- c_heap_t *h;
-
- if (compare == NULL)
- return (NULL);
-
- h = malloc (sizeof (*h));
- if (h == NULL)
- return (NULL);
-
- memset (h, 0, sizeof (*h));
- pthread_mutex_init (&h->lock, /* attr = */ NULL);
- h->compare = compare;
-
- h->list = NULL;
- h->list_len = 0;
- h->list_size = 0;
-
- return (h);
-} /* c_heap_t *c_heap_create */
-
-void c_heap_destroy (c_heap_t *h)
-{
- if (h == NULL)
- return;
-
- h->list_len = 0;
- h->list_size = 0;
- free (h->list);
- h->list = NULL;
-
- pthread_mutex_destroy (&h->lock);
-
- free (h);
-} /* void c_heap_destroy */
-
-int c_heap_insert (c_heap_t *h, void *ptr)
-{
- size_t index;
-
- if ((h == NULL) || (ptr == NULL))
- return (-EINVAL);
-
- pthread_mutex_lock (&h->lock);
-
- assert (h->list_len <= h->list_size);
- if (h->list_len == h->list_size)
- {
- void **tmp;
-
- tmp = realloc (h->list, (h->list_size + 16) * sizeof (*h->list));
- if (tmp == NULL)
- {
- pthread_mutex_unlock (&h->lock);
- return (-ENOMEM);
- }
-
- h->list = tmp;
- h->list_size += 16;
- }
-
- /* Insert the new node as a leaf. */
- index = h->list_len;
- h->list[index] = ptr;
- h->list_len++;
-
- /* Reorganize the heap from bottom up. */
- reheap (h, /* parent of this node = */ (index - 1) / 2, DIR_UP);
-
- pthread_mutex_unlock (&h->lock);
- return (0);
-} /* int c_heap_insert */
-
-void *c_heap_get_root (c_heap_t *h)
-{
- void *ret = NULL;
-
- if (h == NULL)
- return (NULL);
-
- pthread_mutex_lock (&h->lock);
-
- if (h->list_len == 0)
- {
- pthread_mutex_unlock (&h->lock);
- return (NULL);
- }
- else if (h->list_len == 1)
- {
- ret = h->list[0];
- h->list[0] = NULL;
- h->list_len = 0;
- }
- else /* if (h->list_len > 1) */
- {
- ret = h->list[0];
- h->list[0] = h->list[h->list_len - 1];
- h->list[h->list_len - 1] = NULL;
- h->list_len--;
-
- reheap (h, /* root = */ 0, DIR_DOWN);
- }
-
- /* free some memory */
- if ((h->list_len + 32) < h->list_size)
- {
- void **tmp;
-
- tmp = realloc (h->list, (h->list_len + 16) * sizeof (*h->list));
- if (tmp != NULL)
- {
- h->list = tmp;
- h->list_size = h->list_len + 16;
- }
- }
-
- pthread_mutex_unlock (&h->lock);
-
- return (ret);
-} /* void *c_heap_get_root */
-
-/* vim: set sw=2 sts=2 et fdm=marker : */
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