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/*

 * 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 "object_heap.h"

#include "assert.h"

#include 

#include 

#include 

#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)

{

    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;

    _i965InitMutex(&heap->mutex);

    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

 */

int object_heap_allocate( object_heap_p heap )

{

    object_base_p obj;

    int bucket_index, obj_index;

    _i965LockMutex(&heap->mutex);

    if ( LAST_FREE == heap->next_free )

    {

        if( -1 == object_heap_expand( heap ) )

        {

            _i965UnlockMutex(&heap->mutex);

            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;

    _i965UnlockMutex(&heap->mutex);

    obj->next_free = ALLOCATED;

    return obj->id;

}

/*

 * Lookup an object by object ID

 * Returns a pointer to the object on success, returns NULL on error

 */

object_base_p object_heap_lookup( object_heap_p heap, int id )

{

    object_base_p obj;

    int bucket_index, obj_index;

    _i965LockMutex(&heap->mutex);

    if ( (id < heap->id_offset) || (id > (heap->heap_size+heap->id_offset)) )

    {

        _i965UnlockMutex(&heap->mutex);

        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);

    _i965UnlockMutex(&heap->mutex);

	/* Check if the object has in fact been allocated */

	if ( obj->next_free != ALLOCATED )

    {

        return NULL;

    }

    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.

 */

object_base_p object_heap_next( object_heap_p heap, object_heap_iterator *iter )

{

    object_base_p obj;

    int i = *iter + 1;

    int bucket_index, obj_index;

    _i965LockMutex(&heap->mutex);

    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)

        {

            _i965UnlockMutex(&heap->mutex);

            *iter = i;

            return obj;

        }

        i++;

    }

    _i965UnlockMutex(&heap->mutex);

    *iter = i;

    return NULL;

}

/*

 * Frees an object

 */

void object_heap_free( object_heap_p heap, object_base_p obj )

{

    /* Don't complain about NULL pointers */

    if (NULL != obj)

    {

        /* Check if the object has in fact been allocated */

        ASSERT( obj->next_free == ALLOCATED );

        _i965LockMutex(&heap->mutex);

        obj->next_free = heap->next_free;

        heap->next_free = obj->id & OBJECT_HEAP_ID_MASK;

        _i965UnlockMutex(&heap->mutex);

    }

}

/*

 * Destroys a heap, the heap must be empty.

 */

void object_heap_destroy( object_heap_p heap )

{

    object_base_p obj;

    int i;

    int bucket_index, obj_index;

    _i965DestroyMutex(&heap->mutex);

    /* 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]);

    }

    free(heap->bucket);

    heap->bucket = NULL;

    heap->heap_size = 0;

    heap->next_free = LAST_FREE;

}