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/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <string.h> /* memset */
#include "gstlog.h"
#include "gstutils.h"
#include "gstmemchunk.h"
#define __GST_TRASH_STACK_C__
#include "gsttrashstack.h"
#define GST_MEM_CHUNK_AREA(chunk) (((GstMemChunkElement*)(chunk))->area)
#define GST_MEM_CHUNK_DATA(chunk) ((gpointer)(((GstMemChunkElement*)(chunk)) + 1))
#define GST_MEM_CHUNK_LINK(mem) ((GstMemChunkElement*)((guint8*)(mem) - sizeof (GstMemChunkElement)))
typedef struct _GstMemChunkElement GstMemChunkElement;
struct _GstMemChunkElement
{
GstTrashStackElement elem; /* make sure we can safely push it on the trashstack */
gpointer area; /* pointer to data areas */
};
struct _GstMemChunk
{
GstTrashStack stack;
gchar *name;
gulong area_size;
gulong chunk_size;
gulong atom_size;
gboolean cleanup;
};
/*******************************************************
* area size
* +-------------------------------------------------------+
* chunk size
* +-----------------+
*
* !next!area|data... !next!area!data.... !next!area!data...
* ! ^ ! ^ !
* +------------------+ +-----------------+ +--------> NULL
*
*/
static gboolean
populate (GstMemChunk *mem_chunk)
{
guint8 *area;
gint i;
if (mem_chunk->cleanup)
return FALSE;
area = (guint8 *) g_malloc0 (mem_chunk->area_size);
for (i=0; i < mem_chunk->area_size; i += mem_chunk->chunk_size) {
GST_MEM_CHUNK_AREA (area + i) = area;
gst_trash_stack_push (&mem_chunk->stack, area + i);
}
return TRUE;
}
/**
* gst_mem_chunk_new:
* @name: the name of the chunk
* @atom_size: the size of the allocated atoms
* @area_size: the initial size of the memory area
* @type: the allocation strategy to use
*
* Creates a new memchunk that will allocate atom_sized memchunks.
* The initial area is set to area_size and will grow automatically
* when it is too small (with a small overhead when that happens)
*
* Returns: a new #GstMemChunk
*/
GstMemChunk*
gst_mem_chunk_new (gchar* name, gint atom_size, gulong area_size, gint type)
{
GstMemChunk *mem_chunk;
g_return_val_if_fail (atom_size > 0, NULL);
g_return_val_if_fail (area_size >= atom_size, NULL);
mem_chunk = g_malloc (sizeof (GstMemChunk));
mem_chunk->chunk_size = atom_size + sizeof (GstMemChunkElement);
area_size = (area_size/atom_size) * mem_chunk->chunk_size;
mem_chunk->name = g_strdup (name);
mem_chunk->atom_size = atom_size;
mem_chunk->area_size = area_size;
mem_chunk->cleanup = FALSE;
gst_trash_stack_init (&mem_chunk->stack);
populate (mem_chunk);
return mem_chunk;
}
static gboolean
free_area (gpointer key, gpointer value, gpointer user_data)
{
g_free (key);
return TRUE;
}
/**
* gst_mem_chunk_destroy:
* @mem_chunk: the GstMemChunk to destroy
*
* Free the memory allocated by the memchunk
*/
void
gst_mem_chunk_destroy (GstMemChunk *mem_chunk)
{
GHashTable *elements = g_hash_table_new (NULL, NULL);
gpointer data;
mem_chunk->cleanup = TRUE;
data = gst_mem_chunk_alloc (mem_chunk);
while (data) {
GstMemChunkElement *elem = GST_MEM_CHUNK_LINK (data);
g_hash_table_insert (elements, GST_MEM_CHUNK_AREA (elem), NULL);
data = gst_mem_chunk_alloc (mem_chunk);
}
g_hash_table_foreach_remove (elements, free_area, NULL);
g_hash_table_destroy (elements);
g_free (mem_chunk->name);
g_free (mem_chunk);
}
/**
* gst_mem_chunk_alloc:
* @mem_chunk: the mem chunk to use
*
* Allocate a new memory region from the chunk. The size
* of the allocated memory was specified when the memchunk
* was created.
*
* Returns: a pointer to the allocated memory region.
*/
gpointer
gst_mem_chunk_alloc (GstMemChunk *mem_chunk)
{
GstMemChunkElement *chunk;
g_return_val_if_fail (mem_chunk != NULL, NULL);
again:
chunk = gst_trash_stack_pop (&mem_chunk->stack);
/* chunk is empty, try to refill */
if (!chunk) {
if (populate (mem_chunk))
goto again;
else
return NULL;
}
return GST_MEM_CHUNK_DATA (chunk);
}
/**
* gst_mem_chunk_alloc0:
* @mem_chunk: the mem chunk to use
*
* Allocate a new memory region from the chunk. The size
* of the allocated memory was specified when the memchunk
* was created. The memory will be set to all zeroes.
*
* Returns: a pointer to the allocated memory region.
*/
gpointer
gst_mem_chunk_alloc0 (GstMemChunk *mem_chunk)
{
gpointer mem = gst_mem_chunk_alloc (mem_chunk);
if (mem)
memset (mem, 0, mem_chunk->atom_size);
return mem;
}
/**
* gst_mem_chunk_free:
* @mem_chunk: the mem chunk to use
* @mem: the memory region to hand back to the chunk
*
* Free the memeory region allocated from the chunk.
*/
void
gst_mem_chunk_free (GstMemChunk *mem_chunk, gpointer mem)
{
GstMemChunkElement *chunk;
g_return_if_fail (mem_chunk != NULL);
g_return_if_fail (mem != NULL);
chunk = GST_MEM_CHUNK_LINK (mem);
gst_trash_stack_push (&mem_chunk->stack, chunk);
}
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