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/*
** Zabbix
** Copyright (C) 2001-2014 Zabbix SIA
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**/
#include "common.h"
#include "log.h"
#include "zbxalgo.h"
static void swap(zbx_binary_heap_t *heap, int index_1, int index_2);
static void __binary_heap_ensure_free_space(zbx_binary_heap_t *heap);
static int __binary_heap_bubble_up(zbx_binary_heap_t *heap, int index);
static int __binary_heap_bubble_down(zbx_binary_heap_t *heap, int index);
#define ARRAY_GROWTH_FACTOR 3/2
#define HAS_DIRECT_OPTION(heap) (0 != (heap->options & ZBX_BINARY_HEAP_OPTION_DIRECT))
/* helper functions */
static void swap(zbx_binary_heap_t *heap, int index_1, int index_2)
{
zbx_binary_heap_elem_t tmp;
tmp = heap->elems[index_1];
heap->elems[index_1] = heap->elems[index_2];
heap->elems[index_2] = tmp;
if (HAS_DIRECT_OPTION(heap))
{
zbx_hashmap_set(heap->key_index, heap->elems[index_1].key, index_1);
zbx_hashmap_set(heap->key_index, heap->elems[index_2].key, index_2);
}
}
/* private binary heap functions */
static void __binary_heap_ensure_free_space(zbx_binary_heap_t *heap)
{
if (NULL == heap->elems)
{
heap->elems_num = 0;
heap->elems_alloc = 32;
heap->elems = heap->mem_malloc_func(NULL, heap->elems_alloc * sizeof(zbx_binary_heap_elem_t));
}
else if (heap->elems_num == heap->elems_alloc)
{
heap->elems_alloc = MAX(heap->elems_alloc + 1, heap->elems_alloc * ARRAY_GROWTH_FACTOR);
heap->elems = heap->mem_realloc_func(heap->elems, heap->elems_alloc * sizeof(zbx_binary_heap_elem_t));
}
}
static int __binary_heap_bubble_up(zbx_binary_heap_t *heap, int index)
{
while (0 != index)
{
if (heap->compare_func(&heap->elems[(index - 1) / 2], &heap->elems[index]) <= 0)
break;
swap(heap, (index - 1) / 2, index);
index = (index - 1) / 2;
}
return index;
}
static int __binary_heap_bubble_down(zbx_binary_heap_t *heap, int index)
{
while (1)
{
int left = 2 * index + 1;
int right = 2 * index + 2;
if (left >= heap->elems_num)
break;
if (right >= heap->elems_num)
{
if (heap->compare_func(&heap->elems[index], &heap->elems[left]) > 0)
{
swap(heap, index, left);
index = left;
}
break;
}
if (heap->compare_func(&heap->elems[left], &heap->elems[right]) <= 0)
{
if (heap->compare_func(&heap->elems[index], &heap->elems[left]) > 0)
{
swap(heap, index, left);
index = left;
}
else
break;
}
else
{
if (heap->compare_func(&heap->elems[index], &heap->elems[right]) > 0)
{
swap(heap, index, right);
index = right;
}
else
break;
}
}
return index;
}
/* public binary heap interface */
void zbx_binary_heap_create(zbx_binary_heap_t *heap, zbx_compare_func_t compare_func, int options)
{
zbx_binary_heap_create_ext(heap, compare_func, options,
ZBX_DEFAULT_MEM_MALLOC_FUNC,
ZBX_DEFAULT_MEM_REALLOC_FUNC,
ZBX_DEFAULT_MEM_FREE_FUNC);
}
void zbx_binary_heap_create_ext(zbx_binary_heap_t *heap, zbx_compare_func_t compare_func, int options,
zbx_mem_malloc_func_t mem_malloc_func,
zbx_mem_realloc_func_t mem_realloc_func,
zbx_mem_free_func_t mem_free_func)
{
heap->elems = NULL;
heap->elems_num = 0;
heap->elems_alloc = 0;
heap->compare_func = compare_func;
heap->options = options;
if (HAS_DIRECT_OPTION(heap))
{
heap->key_index = mem_malloc_func(NULL, sizeof(zbx_hashmap_t));
zbx_hashmap_create_ext(heap->key_index, 512,
ZBX_DEFAULT_UINT64_HASH_FUNC,
ZBX_DEFAULT_UINT64_COMPARE_FUNC,
mem_malloc_func,
mem_realloc_func,
mem_free_func);
}
else
heap->key_index = NULL;
heap->mem_malloc_func = mem_malloc_func;
heap->mem_realloc_func = mem_realloc_func;
heap->mem_free_func = mem_free_func;
}
void zbx_binary_heap_destroy(zbx_binary_heap_t *heap)
{
if (NULL != heap->elems)
{
heap->mem_free_func(heap->elems);
heap->elems = NULL;
heap->elems_num = 0;
heap->elems_alloc = 0;
}
heap->compare_func = NULL;
if (HAS_DIRECT_OPTION(heap))
{
zbx_hashmap_destroy(heap->key_index);
heap->mem_free_func(heap->key_index);
heap->key_index = NULL;
heap->options = 0;
}
heap->mem_malloc_func = NULL;
heap->mem_realloc_func = NULL;
heap->mem_free_func = NULL;
}
int zbx_binary_heap_empty(zbx_binary_heap_t *heap)
{
return (0 == heap->elems_num ? SUCCEED : FAIL);
}
zbx_binary_heap_elem_t *zbx_binary_heap_find_min(zbx_binary_heap_t *heap)
{
if (0 == heap->elems_num)
{
zabbix_log(LOG_LEVEL_CRIT, "asking for a minimum in an empty heap");
exit(FAIL);
}
return &heap->elems[0];
}
void zbx_binary_heap_insert(zbx_binary_heap_t *heap, zbx_binary_heap_elem_t *elem)
{
int index;
if (HAS_DIRECT_OPTION(heap) && FAIL != zbx_hashmap_get(heap->key_index, elem->key))
{
zabbix_log(LOG_LEVEL_CRIT, "inserting a duplicate key into a heap with direct option");
exit(FAIL);
}
__binary_heap_ensure_free_space(heap);
index = heap->elems_num++;
heap->elems[index] = *elem;
index = __binary_heap_bubble_up(heap, index);
if (HAS_DIRECT_OPTION(heap) && index == heap->elems_num - 1)
zbx_hashmap_set(heap->key_index, elem->key, index);
}
void zbx_binary_heap_update_direct(zbx_binary_heap_t *heap, zbx_binary_heap_elem_t *elem)
{
int index;
if (!HAS_DIRECT_OPTION(heap))
{
zabbix_log(LOG_LEVEL_CRIT, "direct update operation is not supported for this heap");
exit(FAIL);
}
if (FAIL != (index = zbx_hashmap_get(heap->key_index, elem->key)))
{
heap->elems[index] = *elem;
if (index == __binary_heap_bubble_up(heap, index))
__binary_heap_bubble_down(heap, index);
}
else
{
zabbix_log(LOG_LEVEL_CRIT, "element with key " ZBX_FS_UI64 " not found in heap for update", elem->key);
exit(FAIL);
}
}
void zbx_binary_heap_remove_min(zbx_binary_heap_t *heap)
{
int index;
if (0 == heap->elems_num)
{
zabbix_log(LOG_LEVEL_CRIT, "removing a minimum from an empty heap");
exit(FAIL);
}
if (HAS_DIRECT_OPTION(heap))
zbx_hashmap_remove(heap->key_index, heap->elems[0].key);
if (0 != (--heap->elems_num))
{
heap->elems[0] = heap->elems[heap->elems_num];
index = __binary_heap_bubble_down(heap, 0);
if (HAS_DIRECT_OPTION(heap) && index == 0)
zbx_hashmap_set(heap->key_index, heap->elems[index].key, index);
}
}
void zbx_binary_heap_remove_direct(zbx_binary_heap_t *heap, zbx_uint64_t key)
{
int index;
if (!HAS_DIRECT_OPTION(heap))
{
zabbix_log(LOG_LEVEL_CRIT, "direct remove operation is not supported for this heap");
exit(FAIL);
}
if (FAIL != (index = zbx_hashmap_get(heap->key_index, key)))
{
zbx_hashmap_remove(heap->key_index, key);
if (index != (--heap->elems_num))
{
heap->elems[index] = heap->elems[heap->elems_num];
if (index == __binary_heap_bubble_down(heap, index))
zbx_hashmap_set(heap->key_index, heap->elems[index].key, index);
}
}
else
{
zabbix_log(LOG_LEVEL_CRIT, "element with key " ZBX_FS_UI64 " not found in heap for remove", key);
exit(FAIL);
}
}
void zbx_binary_heap_clear(zbx_binary_heap_t *heap)
{
if (NULL != heap->elems)
{
heap->mem_free_func(heap->elems);
heap->elems = NULL;
heap->elems_num = 0;
heap->elems_alloc = 0;
}
if (HAS_DIRECT_OPTION(heap))
zbx_hashmap_clear(heap->key_index);
}
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