libva-v4l2-request-fourier/src/object_heap.c

/*
 * Copyright (c) 2007 Intel Corporation. All Rights Reserved.
 *
 * 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, sub license, 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 (including the
 * next paragraph) 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 NON-INFRINGEMENT.
 * IN NO EVENT SHALL PRECISION INSIGHT AND/OR ITS SUPPLIERS 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.
 */

#include <stdlib.h>
#include <assert.h>
#include "object_heap.h"

#define ASSERT  assert

#define LAST_FREE   -1
#define ALLOCATED   -2

/*
 * Expands the heap
 * Return 0 on success, -1 on error
 */
static int object_heap_expand(object_heap_p heap)
{
	int i;
	void *new_heap_index;
	int next_free;
	int new_heap_size = heap->heap_size + heap->heap_increment;
	int bucket_index = new_heap_size / heap->heap_increment - 1;

	if (bucket_index >= heap->num_buckets) {
		int new_num_buckets = heap->num_buckets + 8;
		void **new_bucket;

		new_bucket = realloc(heap->bucket, new_num_buckets * sizeof(void *));
		if (NULL == new_bucket) {
			return -1;
		}

		heap->num_buckets = new_num_buckets;
		heap->bucket = new_bucket;
	}

	new_heap_index = (void *) malloc(heap->heap_increment * heap->object_size);
	if (NULL == new_heap_index) {
		return -1; /* Out of memory */
	}

	heap->bucket[bucket_index] = new_heap_index;
	next_free = heap->next_free;
	for (i = new_heap_size; i-- > heap->heap_size;) {
		object_base_p obj = (object_base_p)(new_heap_index + (i - heap->heap_size) * heap->object_size);
		obj->id = i + heap->id_offset;
		obj->next_free = next_free;
		next_free = i;
	}
	heap->next_free = next_free;
	heap->heap_size = new_heap_size;
	return 0; /* Success */
}

/*
 * Return 0 on success, -1 on error
 */
int object_heap_init(object_heap_p heap, int object_size, int id_offset)
{
	pthread_mutex_init(&heap->mutex, NULL);
	heap->object_size = object_size;
	heap->id_offset = id_offset & OBJECT_HEAP_OFFSET_MASK;
	heap->heap_size = 0;
	heap->heap_increment = 16;
	heap->next_free = LAST_FREE;
	heap->num_buckets = 0;
	heap->bucket = NULL;
	return object_heap_expand(heap);
}

/*
 * Allocates an object
 * Returns the object ID on success, returns -1 on error
 */
static int object_heap_allocate_unlocked(object_heap_p heap)
{
	object_base_p obj;
	int bucket_index, obj_index;

	if (LAST_FREE == heap->next_free) {
		if (-1 == object_heap_expand(heap)) {
			return -1; /* Out of memory */
		}
	}
	ASSERT(heap->next_free >= 0);

	bucket_index = heap->next_free / heap->heap_increment;
	obj_index = heap->next_free % heap->heap_increment;

	obj = (object_base_p)(heap->bucket[bucket_index] + obj_index * heap->object_size);
	heap->next_free = obj->next_free;
	obj->next_free = ALLOCATED;
	return obj->id;
}

int object_heap_allocate(object_heap_p heap)
{
	int ret;

	pthread_mutex_lock(&heap->mutex);
	ret = object_heap_allocate_unlocked(heap);
	pthread_mutex_unlock(&heap->mutex);
	return ret;
}

/*
 * Lookup an object by object ID
 * Returns a pointer to the object on success, returns NULL on error
 */
static object_base_p object_heap_lookup_unlocked(object_heap_p heap, int id)
{
	object_base_p obj;
	int bucket_index, obj_index;

	if ((id < heap->id_offset) || (id > (heap->heap_size + heap->id_offset))) {
		return NULL;
	}
	id &= OBJECT_HEAP_ID_MASK;
	bucket_index = id / heap->heap_increment;
	obj_index = id % heap->heap_increment;
	obj = (object_base_p)(heap->bucket[bucket_index] + obj_index * heap->object_size);

	/* Check if the object has in fact been allocated */
	if (obj->next_free != ALLOCATED) {
		return NULL;
	}
	return obj;
}

object_base_p object_heap_lookup(object_heap_p heap, int id)
{
	object_base_p obj;

	pthread_mutex_lock(&heap->mutex);
	obj = object_heap_lookup_unlocked(heap, id);
	pthread_mutex_unlock(&heap->mutex);
	return obj;
}

/*
 * Iterate over all objects in the heap.
 * Returns a pointer to the first object on the heap, returns NULL if heap is empty.
 */
object_base_p object_heap_first(object_heap_p heap, object_heap_iterator *iter)
{
	*iter = -1;
	return object_heap_next(heap, iter);
}

/*
 * Iterate over all objects in the heap.
 * Returns a pointer to the next object on the heap, returns NULL if heap is empty.
 */
static object_base_p object_heap_next_unlocked(object_heap_p heap, object_heap_iterator *iter)
{
	object_base_p obj;
	int bucket_index, obj_index;
	int i = *iter + 1;

	while (i < heap->heap_size) {
		bucket_index = i / heap->heap_increment;
		obj_index = i % heap->heap_increment;

		obj = (object_base_p)(heap->bucket[bucket_index] + obj_index * heap->object_size);
		if (obj->next_free == ALLOCATED) {
			*iter = i;
			return obj;
		}
		i++;
	}
	*iter = i;
	return NULL;
}

object_base_p object_heap_next(object_heap_p heap, object_heap_iterator *iter)
{
	object_base_p obj;

	pthread_mutex_lock(&heap->mutex);
	obj = object_heap_next_unlocked(heap, iter);
	pthread_mutex_unlock(&heap->mutex);
	return obj;
}

/*
 * Frees an object
 */
static void object_heap_free_unlocked(object_heap_p heap, object_base_p obj)
{
	/* Check if the object has in fact been allocated */
	ASSERT(obj->next_free == ALLOCATED);

	obj->next_free = heap->next_free;
}

void object_heap_free(object_heap_p heap, object_base_p obj)
{
	if (!obj)
		return;
	pthread_mutex_lock(&heap->mutex);
	object_heap_free_unlocked(heap, obj);
	pthread_mutex_unlock(&heap->mutex);
}

/*
 * Destroys a heap, the heap must be empty.
 */
void object_heap_destroy(object_heap_p heap)
{
	object_base_p obj;
	int bucket_index, obj_index, i;

	/* Check if heap is empty */
	for (i = 0; i < heap->heap_size; i++) {
		/* Check if object is not still allocated */
		bucket_index = i / heap->heap_increment;
		obj_index = i % heap->heap_increment;
		obj = (object_base_p)(heap->bucket[bucket_index] + obj_index * heap->object_size);
		ASSERT(obj->next_free != ALLOCATED);
	}

	for (i = 0; i < heap->heap_size / heap->heap_increment; i++) {
		free(heap->bucket[i]);
	}

	pthread_mutex_destroy(&heap->mutex);

	free(heap->bucket);
	heap->bucket = NULL;
	heap->heap_size = 0;
	heap->next_free = LAST_FREE;
}