diff options
Diffstat (limited to 'dummy_drv_video/object_heap.c')
| -rw-r--r-- | dummy_drv_video/object_heap.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/dummy_drv_video/object_heap.c b/dummy_drv_video/object_heap.c new file mode 100644 index 0000000..5e85064 --- /dev/null +++ b/dummy_drv_video/object_heap.c @@ -0,0 +1,192 @@ +/* + * 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 <stdio.h> +#include <string.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; + + new_heap_index = (void *) realloc( heap->heap_index, new_heap_size * heap->object_size ); + if ( NULL == new_heap_index ) + { + return -1; /* Out of memory */ + } + heap->heap_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) (heap->heap_index + i * 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->heap_index = NULL; + heap->next_free = LAST_FREE; + 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; + if ( LAST_FREE == heap->next_free ) + { + if( -1 == object_heap_expand( heap ) ) + { + return -1; /* Out of memory */ + } + } + ASSERT( heap->next_free >= 0 ); + + obj = (object_base_p) (heap->heap_index + heap->next_free * heap->object_size); + heap->next_free = obj->next_free; + 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; + if ( (id < heap->id_offset) || (id > (heap->heap_size+heap->id_offset)) ) + { + return NULL; + } + id &= OBJECT_HEAP_ID_MASK; + obj = (object_base_p) (heap->heap_index + id * heap->object_size); + + /* 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; + while ( i < heap->heap_size) + { + obj = (object_base_p) (heap->heap_index + i * heap->object_size); + if (obj->next_free == ALLOCATED) + { + *iter = i; + return obj; + } + i++; + } + *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 ); + + obj->next_free = heap->next_free; + heap->next_free = obj->id & OBJECT_HEAP_ID_MASK; + } +} + +/* + * Destroys a heap, the heap must be empty. + */ +void object_heap_destroy( object_heap_p heap ) +{ + object_base_p obj; + int i; + /* Check if heap is empty */ + for (i = 0; i < heap->heap_size; i++) + { + /* Check if object is not still allocated */ + obj = (object_base_p) (heap->heap_index + i * heap->object_size); + ASSERT( obj->next_free != ALLOCATED ); + } + free(heap->heap_index); + heap->heap_size = 0; + heap->heap_index = NULL; + heap->next_free = LAST_FREE; +} |