gstreamer/gst/gstmemory.h

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/* GStreamer
* Copyright (C) 2009 Wim Taymans <wim.taymans@gmail.be>
*
* gstmemory.h: Header for memory blocks
*
* 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.
*/
#ifndef __GST_MEMORY_H__
#define __GST_MEMORY_H__
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#include <gst/gstconfig.h>
#include <glib-object.h>
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G_BEGIN_DECLS
typedef struct _GstMemory GstMemory;
typedef struct _GstMemoryInfo GstMemoryInfo;
typedef struct _GstAllocator GstAllocator;
extern gsize gst_memory_alignment;
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/**
* GstMemoryFlags:
* @GST_MEMORY_FLAG_READONLY: memory is readonly. It is not allowed to map the
* memory with #GST_MAP_WRITE.
* @GST_MEMORY_FLAG_NO_SHARE: memory must not be shared. Copies will have to be
* made when this memory needs to be shared between buffers.
* @GST_MEMORY_FLAG_LAST: first flag that can be used for custom purposes
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*
* Flags for wrapped memory.
*/
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typedef enum {
GST_MEMORY_FLAG_READONLY = (1 << 0),
GST_MEMORY_FLAG_NO_SHARE = (1 << 1),
GST_MEMORY_FLAG_LAST = (1 << 24)
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} GstMemoryFlags;
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/**
* GST_MEMORY_IS_WRITABLE:
* @mem: a #GstMemory
*
* Check if @mem is writable.
*/
#define GST_MEMORY_IS_WRITABLE(mem) (((mem)->refcount == 1) && \
(((mem)->parent == NULL) || ((mem)->parent->refcount == 1)) && \
(((mem)->flags & GST_MEMORY_FLAG_READONLY) == 0))
/**
* GstMemory:
* @allocator: pointer to the #GstAllocator
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* @flags: memory flags
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* @refcount: refcount
* @parent: parent memory block
*
* Base structure for memory implementations. Custom memory will put this structure
* as the first member of their structure.
*/
struct _GstMemory {
const GstAllocator *allocator;
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GstMemoryFlags flags;
gint refcount;
GstMemory *parent;
};
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/**
* GstMapFlags:
* @GST_MAP_READ: map for read access
* @GST_MAP_WRITE: map for write access
*
* Flags used when mapping memory
*/
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typedef enum {
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GST_MAP_READ = (1 << 0),
GST_MAP_WRITE = (1 << 1),
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} GstMapFlags;
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/**
* GST_MAP_READWRITE:
*
* Map for readwrite access
*/
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#define GST_MAP_READWRITE (GST_MAP_READ | GST_MAP_WRITE)
/**
* GST_ALLOCATOR_SYSMEM:
*
* The allocator name for the default system memory allocator
*/
#define GST_ALLOCATOR_SYSMEM "SystemMemory"
/**
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* GstMemoryAllocFunction:
* @allocator: a #GstAllocator
* @maxsize: the maxsize
* @align: the alignment
* @user_data: user data
*
* Allocate a new #GstMemory from @allocator that can hold at least @maxsize bytes
* and is aligned to (@align + 1) bytes.
*
* @user_data is the data that was used when registering @allocator.
*
* Returns: a newly allocated #GstMemory. Free with gst_memory_unref()
*/
typedef GstMemory * (*GstMemoryAllocFunction) (const GstAllocator *allocator,
gsize maxsize, gsize align,
gpointer user_data);
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/**
* GstMemoryGetSizesFunction:
* @mem: a #GstMemory
* @offset: result pointer for offset
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* @maxsize: result pointer for maxsize
*
* Retrieve the size, offset and maxsize of @mem.
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*
* Returns: the size of @mem, the offset and the maximum allocated size in @maxsize.
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*/
typedef gsize (*GstMemoryGetSizesFunction) (GstMemory *mem, gsize *offset, gsize *maxsize);
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/**
* GstMemoryResizeFunction:
* @mem: a #GstMemory
* @offset: the offset adjustement
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* @size: the new size
*
* Adjust the size and offset of @mem. @offset bytes will be adjusted from the
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* current first byte in @mem as retrieved with gst_memory_map() and the new
* size will be set to @size.
*
* @size can be set to -1, which will only adjust the offset.
*/
typedef void (*GstMemoryResizeFunction) (GstMemory *mem, gssize offset, gsize size);
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/**
* GstMemoryMapFunction:
* @mem: a #GstMemory
* @size: pointer for the size
* @maxsize: pointer for the maxsize
* @flags: access mode for the memory
*
* Get the memory of @mem that can be accessed according to the mode specified
* in @flags. @size and @maxsize will respectively contain the current amount of
* valid bytes in the returned memory and the maximum allocated memory.
* @size and @maxsize can optionally be set to NULL.
*
* Returns: a pointer to memory. @size bytes are currently used from the
* returned pointer and @maxsize bytes can potentially be used.
*/
typedef gpointer (*GstMemoryMapFunction) (GstMemory *mem, gsize *size, gsize *maxsize,
GstMapFlags flags);
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/**
* GstMemoryUnmapFunction:
* @mem: a #GstMemory
* @data: the data pointer
* @size: the new size
*
* Return the pointer previously retrieved with gst_memory_map() and adjust the
* size of the memory with @size. @size can optionally be set to -1 to not
* modify the size.
*
* Returns: %TRUE on success.
*/
typedef gboolean (*GstMemoryUnmapFunction) (GstMemory *mem, gpointer data, gsize size);
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/**
* GstMemoryFreeFunction:
* @mem: a #GstMemory
*
* Free the memory used by @mem. This function is usually called when the
* refcount of the @mem has reached 0.
*/
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typedef void (*GstMemoryFreeFunction) (GstMemory *mem);
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/**
* GstMemoryCopyFunction:
* @mem: a #GstMemory
* @offset: an offset
* @size: a size
*
* Copy @size bytes from @mem starting at @offset and return them wrapped in a
* new GstMemory object.
* If @size is set to -1, all bytes starting at @offset are copied.
*
* Returns: a new #GstMemory object wrapping a copy of the requested region in
* @mem.
*/
typedef GstMemory * (*GstMemoryCopyFunction) (GstMemory *mem, gssize offset, gsize size);
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/**
* GstMemoryShareFunction:
* @mem: a #GstMemory
* @offset: an offset
* @size: a size
*
* Share @size bytes from @mem starting at @offset and return them wrapped in a
* new GstMemory object. If @size is set to -1, all bytes starting at @offset are
* shared. This function does not make a copy of the bytes in @mem.
*
* Returns: a new #GstMemory object sharing the requested region in @mem.
*/
typedef GstMemory * (*GstMemoryShareFunction) (GstMemory *mem, gssize offset, gsize size);
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/**
* GstMemoryIsSpanFunction:
* @mem1: a #GstMemory
* @mem2: a #GstMemory
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* @offset: a result offset
*
* Check if @mem1 and @mem2 occupy contiguous memory and return the offset of
* @mem1 in the parent buffer in @offset.
*
* Returns: %TRUE if @mem1 and @mem2 are in contiguous memory.
*/
typedef gboolean (*GstMemoryIsSpanFunction) (GstMemory *mem1, GstMemory *mem2, gsize *offset);
/**
* GstMemoryInfo:
* @alloc: the implementation of the GstMemoryAllocFunction
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* @get_sizes: the implementation of the GstMemoryGetSizesFunction
* @resize: the implementation of the GstMemoryResizeFunction
* @map: the implementation of the GstMemoryMapFunction
* @unmap: the implementation of the GstMemoryUnmapFunction
* @free: the implementation of the GstMemoryFreeFunction
* @copy: the implementation of the GstMemoryCopyFunction
* @share: the implementation of the GstMemoryShareFunction
* @is_span: the implementation of the GstMemoryIsSpanFunction
* @user_data: generic user data for the allocator
*
* The #GstMemoryInfo is used to register new memory allocators and contain
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* the implementations for various memory operations.
*/
struct _GstMemoryInfo {
GstMemoryAllocFunction alloc;
GstMemoryGetSizesFunction get_sizes;
GstMemoryResizeFunction resize;
GstMemoryMapFunction map;
GstMemoryUnmapFunction unmap;
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GstMemoryFreeFunction free;
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GstMemoryCopyFunction copy;
GstMemoryShareFunction share;
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GstMemoryIsSpanFunction is_span;
gpointer user_data;
};
void _gst_memory_init (void);
/* allocators */
const GstAllocator * gst_allocator_register (const gchar *name, const GstMemoryInfo *info);
const GstAllocator * gst_allocator_find (const gchar *name);
void gst_allocator_set_default (const GstAllocator * allocator);
/* allocating memory blocks */
GstMemory * gst_allocator_alloc (const GstAllocator * allocator,
gsize maxsize, gsize align);
GstMemory * gst_memory_new_wrapped (GstMemoryFlags flags, gpointer data, GFreeFunc free_func,
gsize maxsize, gsize offset, gsize size);
/* refcounting */
GstMemory * gst_memory_ref (GstMemory *mem);
void gst_memory_unref (GstMemory *mem);
/* getting/setting memory properties */
gsize gst_memory_get_sizes (GstMemory *mem, gsize *offset, gsize *maxsize);
void gst_memory_resize (GstMemory *mem, gssize offset, gsize size);
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/* retrieving data */
gpointer gst_memory_map (GstMemory *mem, gsize *size, gsize *maxsize,
GstMapFlags flags);
gboolean gst_memory_unmap (GstMemory *mem, gpointer data, gsize size);
/* copy and subregions */
GstMemory * gst_memory_copy (GstMemory *mem, gssize offset, gsize size);
GstMemory * gst_memory_share (GstMemory *mem, gssize offset, gsize size);
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/* span memory */
gboolean gst_memory_is_span (GstMemory *mem1, GstMemory *mem2, gsize *offset);
G_END_DECLS
#endif /* __GST_MEMORY_H__ */