| /* GStreamer |
| * Copyright (C) 2011 Wim Taymans <wim.taymans@gmail.be> |
| * |
| * gstmemory.c: memory block handling |
| * |
| * 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. |
| */ |
| |
| /** |
| * SECTION:gstmemory |
| * @short_description: refcounted wrapper for memory blocks |
| * @see_also: #GstBuffer |
| * |
| * GstMemory is a lightweight refcounted object that wraps a region of memory. |
| * They are typically used to manage the data of a #GstBuffer. |
| * |
| * Memory is usually created by allocators with a gst_allocator_alloc() |
| * method call. When NULL is used as the allocator, the default allocator will |
| * be used. |
| * |
| * New allocators can be registered with gst_allocator_register(). |
| * Allocators are identified by name and can be retrieved with |
| * gst_allocator_find(). |
| * |
| * New memory can be created with gst_memory_new_wrapped() that wraps the memory |
| * allocated elsewhere. |
| * |
| * Refcounting of the memory block is performed with gst_memory_ref() and |
| * gst_memory_unref(). |
| * |
| * The size of the memory can be retrieved and changed with |
| * gst_memory_get_sizes() and gst_memory_resize() respectively. |
| * |
| * Getting access to the data of the memory is performed with gst_memory_map(). |
| * After the memory access is completed, gst_memory_unmap() should be called. |
| * |
| * Memory can be copied with gst_memory_copy(), which will returnn a writable |
| * copy. gst_memory_share() will create a new memory block that shares the |
| * memory with an existing memory block at a custom offset and with a custom |
| * size. |
| * |
| * Memory can be efficiently merged when gst_memory_is_span() returns TRUE. |
| * |
| * Last reviewed on 2011-06-08 (0.11.0) |
| */ |
| |
| #include "config.h" |
| #include "gst_private.h" |
| #include "gstmemory.h" |
| |
| |
| /* buffer alignment in bytes - 1 |
| * an alignment of 7 would be the same as malloc() guarantees |
| */ |
| #if defined(MEMORY_ALIGNMENT_MALLOC) |
| size_t gst_memory_alignment = 7; |
| #elif defined(MEMORY_ALIGNMENT_PAGESIZE) |
| /* we fill this in in the _init method */ |
| size_t gst_memory_alignment = 0; |
| #elif defined(MEMORY_ALIGNMENT) |
| size_t gst_memory_alignment = MEMORY_ALIGNMENT - 1; |
| #else |
| #error "No memory alignment configured" |
| size_t gst_memory_alignment = 0; |
| #endif |
| |
| struct _GstAllocator |
| { |
| GQuark name; |
| |
| GstMemoryInfo info; |
| }; |
| |
| /* default memory implementation */ |
| typedef struct |
| { |
| GstMemory mem; |
| gsize slice_size; |
| guint8 *data; |
| GFreeFunc free_func; |
| gsize maxsize; |
| gsize offset; |
| gsize size; |
| } GstMemoryDefault; |
| |
| /* the default allocator */ |
| static const GstAllocator *_default_allocator; |
| |
| /* our predefined allocators */ |
| static const GstAllocator *_default_mem_impl; |
| |
| /* initialize the fields */ |
| static void |
| _default_mem_init (GstMemoryDefault * mem, GstMemoryFlags flags, |
| GstMemory * parent, gsize slice_size, gpointer data, |
| GFreeFunc free_func, gsize maxsize, gsize offset, gsize size) |
| { |
| mem->mem.allocator = _default_mem_impl; |
| mem->mem.flags = flags; |
| mem->mem.refcount = 1; |
| mem->mem.parent = parent ? gst_memory_ref (parent) : NULL; |
| mem->slice_size = slice_size; |
| mem->data = data; |
| mem->free_func = free_func; |
| mem->maxsize = maxsize; |
| mem->offset = offset; |
| mem->size = size; |
| } |
| |
| /* create a new memory block that manages the given memory */ |
| static GstMemoryDefault * |
| _default_mem_new (GstMemoryFlags flags, GstMemory * parent, gpointer data, |
| GFreeFunc free_func, gsize maxsize, gsize offset, gsize size) |
| { |
| GstMemoryDefault *mem; |
| gsize slice_size; |
| |
| slice_size = sizeof (GstMemoryDefault); |
| |
| mem = g_slice_alloc (slice_size); |
| _default_mem_init (mem, flags, parent, slice_size, |
| data, free_func, maxsize, offset, size); |
| |
| return mem; |
| } |
| |
| /* allocate the memory and structure in one block */ |
| static GstMemoryDefault * |
| _default_mem_new_block (gsize maxsize, gsize align, gsize offset, gsize size) |
| { |
| GstMemoryDefault *mem; |
| gsize aoffset, slice_size; |
| guint8 *data; |
| |
| /* ensure configured alignment */ |
| align |= gst_memory_alignment; |
| /* allocate more to compensate for alignment */ |
| maxsize += align; |
| /* alloc header and data in one block */ |
| slice_size = sizeof (GstMemoryDefault) + maxsize; |
| |
| mem = g_slice_alloc (slice_size); |
| if (mem == NULL) |
| return NULL; |
| |
| data = (guint8 *) mem + sizeof (GstMemoryDefault); |
| |
| if ((aoffset = ((guintptr) data & align))) |
| aoffset = (align + 1) - aoffset; |
| |
| _default_mem_init (mem, 0, NULL, slice_size, data, NULL, maxsize, |
| aoffset + offset, size); |
| |
| return mem; |
| } |
| |
| static GstMemory * |
| _default_mem_alloc (const GstAllocator * allocator, gsize maxsize, gsize align) |
| { |
| return (GstMemory *) _default_mem_new_block (maxsize, align, 0, maxsize); |
| } |
| |
| static gsize |
| _default_mem_get_sizes (GstMemoryDefault * mem, gsize * offset, gsize * maxsize) |
| { |
| if (offset) |
| *offset = mem->offset; |
| if (maxsize) |
| *maxsize = mem->maxsize; |
| |
| return mem->size; |
| } |
| |
| static void |
| _default_mem_resize (GstMemoryDefault * mem, gssize offset, gsize size) |
| { |
| g_return_if_fail (size + mem->offset + offset <= mem->maxsize); |
| |
| mem->offset += offset; |
| mem->size = size; |
| } |
| |
| static gpointer |
| _default_mem_map (GstMemoryDefault * mem, gsize * size, gsize * maxsize, |
| GstMapFlags flags) |
| { |
| if (size) |
| *size = mem->size; |
| if (maxsize) |
| *maxsize = mem->maxsize; |
| |
| return mem->data + mem->offset; |
| } |
| |
| static gboolean |
| _default_mem_unmap (GstMemoryDefault * mem, gpointer data, gsize size) |
| { |
| if (size != -1) |
| mem->size = size; |
| return TRUE; |
| } |
| |
| static void |
| _default_mem_free (GstMemoryDefault * mem) |
| { |
| if (mem->mem.parent) |
| gst_memory_unref (mem->mem.parent); |
| |
| if (mem->free_func) |
| mem->free_func (mem->data); |
| |
| g_slice_free1 (mem->slice_size, mem); |
| } |
| |
| static GstMemoryDefault * |
| _default_mem_copy (GstMemoryDefault * mem, gssize offset, gsize size) |
| { |
| GstMemoryDefault *copy; |
| |
| if (size == -1) |
| size = mem->size > offset ? mem->size - offset : 0; |
| |
| copy = _default_mem_new_block (mem->maxsize, 0, mem->offset + offset, size); |
| memcpy (copy->data, mem->data, mem->maxsize); |
| |
| return copy; |
| } |
| |
| static GstMemoryDefault * |
| _default_mem_share (GstMemoryDefault * mem, gssize offset, gsize size) |
| { |
| GstMemoryDefault *sub; |
| GstMemory *parent; |
| |
| /* find the real parent */ |
| if ((parent = mem->mem.parent) == NULL) |
| parent = (GstMemory *) mem; |
| |
| if (size == -1) |
| size = mem->size - offset; |
| |
| sub = _default_mem_new (parent->flags, parent, mem->data, NULL, mem->maxsize, |
| mem->offset + offset, size); |
| |
| return sub; |
| } |
| |
| static gboolean |
| _default_mem_is_span (GstMemoryDefault * mem1, GstMemoryDefault * mem2, |
| gsize * offset) |
| { |
| |
| if (offset) { |
| GstMemoryDefault *parent; |
| |
| parent = (GstMemoryDefault *) mem1->mem.parent; |
| |
| *offset = mem1->offset - parent->offset; |
| } |
| |
| /* and memory is contiguous */ |
| return mem1->data + mem1->offset + mem1->size == mem2->data + mem2->offset; |
| } |
| |
| static GstMemory * |
| _fallback_copy (GstMemory * mem, gssize offset, gsize size) |
| { |
| GstMemory *copy; |
| guint8 *data, *dest; |
| gsize msize; |
| |
| data = gst_memory_map (mem, &msize, NULL, GST_MAP_READ); |
| if (size == -1) |
| size = msize > offset ? msize - offset : 0; |
| /* use the same allocator as the memory we copy, FIXME, alignment? */ |
| copy = gst_allocator_alloc (mem->allocator, size, 0); |
| dest = gst_memory_map (copy, NULL, NULL, GST_MAP_WRITE); |
| memcpy (dest, data + offset, size); |
| gst_memory_unmap (copy, dest, size); |
| |
| gst_memory_unmap (mem, data, msize); |
| |
| return (GstMemory *) copy; |
| } |
| |
| static gboolean |
| _fallback_is_span (GstMemory * mem1, GstMemory * mem2, gsize * offset) |
| { |
| return FALSE; |
| } |
| |
| static GStaticRWLock lock = G_STATIC_RW_LOCK_INIT; |
| static GHashTable *allocators; |
| |
| void |
| _priv_gst_memory_initialize (void) |
| { |
| static const GstMemoryInfo _mem_info = { |
| (GstMemoryAllocFunction) _default_mem_alloc, |
| (GstMemoryGetSizesFunction) _default_mem_get_sizes, |
| (GstMemoryResizeFunction) _default_mem_resize, |
| (GstMemoryMapFunction) _default_mem_map, |
| (GstMemoryUnmapFunction) _default_mem_unmap, |
| (GstMemoryFreeFunction) _default_mem_free, |
| (GstMemoryCopyFunction) _default_mem_copy, |
| (GstMemoryShareFunction) _default_mem_share, |
| (GstMemoryIsSpanFunction) _default_mem_is_span, |
| NULL |
| }; |
| |
| allocators = g_hash_table_new (g_str_hash, g_str_equal); |
| |
| #ifdef HAVE_GETPAGESIZE |
| #ifdef MEMORY_ALIGNMENT_PAGESIZE |
| gst_memory_alignment = getpagesize () - 1; |
| #endif |
| #endif |
| |
| GST_DEBUG ("memory alignment: %" G_GSIZE_FORMAT, gst_memory_alignment); |
| |
| _default_mem_impl = gst_allocator_register (GST_ALLOCATOR_SYSMEM, &_mem_info); |
| |
| _default_allocator = _default_mem_impl; |
| } |
| |
| /** |
| * gst_memory_new_wrapped: |
| * @flags: #GstMemoryFlags |
| * @data: data to wrap |
| * @free_func: function to free @data |
| * @maxsize: allocated size of @data |
| * @offset: offset in @data |
| * @size: size of valid data |
| * |
| * Allocate a new memory block that wraps the given @data. |
| * |
| * Returns: a new #GstMemory. |
| */ |
| GstMemory * |
| gst_memory_new_wrapped (GstMemoryFlags flags, gpointer data, |
| GFreeFunc free_func, gsize maxsize, gsize offset, gsize size) |
| { |
| GstMemoryDefault *mem; |
| |
| g_return_val_if_fail (data != NULL, NULL); |
| g_return_val_if_fail (offset + size <= maxsize, NULL); |
| |
| mem = _default_mem_new (flags, NULL, data, free_func, maxsize, offset, size); |
| |
| return (GstMemory *) mem; |
| } |
| |
| /** |
| * gst_memory_ref: |
| * @mem: a #GstMemory |
| * |
| * Increases the refcount of @mem. |
| * |
| * Returns: @mem with increased refcount |
| */ |
| GstMemory * |
| gst_memory_ref (GstMemory * mem) |
| { |
| g_return_val_if_fail (mem != NULL, NULL); |
| |
| g_atomic_int_inc (&mem->refcount); |
| |
| return mem; |
| } |
| |
| /** |
| * gst_memory_unref: |
| * @mem: a #GstMemory |
| * |
| * Decreases the refcount of @mem. When the refcount reaches 0, the free |
| * function of @mem will be called. |
| */ |
| void |
| gst_memory_unref (GstMemory * mem) |
| { |
| g_return_if_fail (mem != NULL); |
| g_return_if_fail (mem->allocator != NULL); |
| |
| if (g_atomic_int_dec_and_test (&mem->refcount)) |
| mem->allocator->info.free (mem); |
| } |
| |
| /** |
| * gst_memory_get_sizes: |
| * @mem: a #GstMemory |
| * @offset: pointer to offset |
| * @maxsize: pointer to maxsize |
| * |
| * Get the current @size, @offset and @maxsize of @mem. |
| * |
| * Returns: the current sizes of @mem |
| */ |
| gsize |
| gst_memory_get_sizes (GstMemory * mem, gsize * offset, gsize * maxsize) |
| { |
| g_return_val_if_fail (mem != NULL, 0); |
| |
| return mem->allocator->info.get_sizes (mem, offset, maxsize); |
| } |
| |
| /** |
| * gst_memory_resize: |
| * @mem: a #GstMemory |
| * @offset: a new offset |
| * @size: a new size |
| * |
| * Resize the memory region. @mem should be writable and offset + size should be |
| * less than the maxsize of @mem. |
| */ |
| void |
| gst_memory_resize (GstMemory * mem, gssize offset, gsize size) |
| { |
| g_return_if_fail (mem != NULL); |
| g_return_if_fail (GST_MEMORY_IS_WRITABLE (mem)); |
| |
| mem->allocator->info.resize (mem, offset, size); |
| } |
| |
| /** |
| * gst_memory_map: |
| * @mem: a #GstMemory |
| * @size: pointer for size |
| * @maxsize: pointer for maxsize |
| * @flags: mapping flags |
| * |
| * Get a pointer to the memory of @mem that can be accessed according to @flags. |
| * |
| * @size and @maxsize will contain the size of the memory and the maximum |
| * allocated memory of @mem respectively. They can be set to NULL. |
| * |
| * Returns: a pointer to the memory of @mem. |
| */ |
| gpointer |
| gst_memory_map (GstMemory * mem, gsize * size, gsize * maxsize, |
| GstMapFlags flags) |
| { |
| g_return_val_if_fail (mem != NULL, NULL); |
| g_return_val_if_fail (!(flags & GST_MAP_WRITE) || |
| GST_MEMORY_IS_WRITABLE (mem), NULL); |
| |
| return mem->allocator->info.map (mem, size, maxsize, flags); |
| } |
| |
| /** |
| * gst_memory_unmap: |
| * @mem: a #GstMemory |
| * @data: data to unmap |
| * @size: new size of @mem |
| * |
| * Release the memory pointer obtained with gst_memory_map() and set the size of |
| * the memory to @size. @size can be set to -1 when the size should not be |
| * updated. |
| * |
| * Returns: TRUE when the memory was release successfully. |
| */ |
| gboolean |
| gst_memory_unmap (GstMemory * mem, gpointer data, gsize size) |
| { |
| g_return_val_if_fail (mem != NULL, FALSE); |
| |
| return mem->allocator->info.unmap (mem, data, size); |
| } |
| |
| /** |
| * gst_memory_copy: |
| * @mem: a #GstMemory |
| * @offset: an offset to copy |
| * @size: size to copy |
| * |
| * Return a copy of @size bytes from @mem starting from @offset. This copy is |
| * guaranteed to be writable. @size can be set to -1 to return a copy all bytes |
| * from @offset. |
| * |
| * Returns: a new #GstMemory. |
| */ |
| GstMemory * |
| gst_memory_copy (GstMemory * mem, gssize offset, gsize size) |
| { |
| g_return_val_if_fail (mem != NULL, NULL); |
| |
| return mem->allocator->info.copy (mem, offset, size); |
| } |
| |
| /** |
| * gst_memory_share: |
| * @mem: a #GstMemory |
| * @offset: an offset to share |
| * @size: size to share |
| * |
| * Return a shared copy of @size bytes from @mem starting from @offset. No memory |
| * copy is performed and the memory region is simply shared. The result is |
| * guaranteed to be not-writable. @size can be set to -1 to return a share all bytes |
| * from @offset. |
| * |
| * Returns: a new #GstMemory. |
| */ |
| GstMemory * |
| gst_memory_share (GstMemory * mem, gssize offset, gsize size) |
| { |
| g_return_val_if_fail (mem != NULL, NULL); |
| |
| return mem->allocator->info.share (mem, offset, size); |
| } |
| |
| /** |
| * gst_memory_is_span: |
| * @mem1: a #GstMemory |
| * @mem2: a #GstMemory |
| * @offset: a pointer to a result offset |
| * |
| * Check if @mem1 and mem2 share the memory with a common parent memory object |
| * and that the memory is contiguous. |
| * |
| * If this is the case, the memory of @mem1 and @mem2 can be merged |
| * efficiently by performing gst_memory_share() on the parent object from |
| * the returned @offset. |
| * |
| * Returns: %TRUE if the memory is contiguous and of a common parent. |
| */ |
| gboolean |
| gst_memory_is_span (GstMemory * mem1, GstMemory * mem2, gsize * offset) |
| { |
| g_return_val_if_fail (mem1 != NULL, FALSE); |
| g_return_val_if_fail (mem2 != NULL, FALSE); |
| |
| /* need to have the same allocators */ |
| if (mem1->allocator != mem2->allocator) |
| return FALSE; |
| |
| /* need to have the same parent */ |
| if (mem1->parent == NULL || mem1->parent != mem2->parent) |
| return FALSE; |
| |
| /* and memory is contiguous */ |
| if (!mem1->allocator->info.is_span (mem1, mem2, offset)) |
| return FALSE; |
| |
| return TRUE; |
| } |
| |
| /** |
| * gst_allocator_register: |
| * @name: the name of the allocator |
| * @info: #GstMemoryInfo |
| * |
| * Registers the memory allocator with @name and implementation functions |
| * @info. |
| * |
| * All functions in @info are mandatory exept the copy and is_span |
| * functions, which will have a default implementation when left NULL. |
| * |
| * The user_data field in @info will be passed to all calls of the alloc |
| * function. |
| * |
| * Returns: a new #GstAllocator. |
| */ |
| const GstAllocator * |
| gst_allocator_register (const gchar * name, const GstMemoryInfo * info) |
| { |
| GstAllocator *allocator; |
| |
| #define INSTALL_FALLBACK(_t) \ |
| if (allocator->info._t == NULL) allocator->info._t = _fallback_ ##_t; |
| |
| g_return_val_if_fail (name != NULL, NULL); |
| g_return_val_if_fail (info != NULL, NULL); |
| g_return_val_if_fail (info->alloc != NULL, NULL); |
| g_return_val_if_fail (info->get_sizes != NULL, NULL); |
| g_return_val_if_fail (info->resize != NULL, NULL); |
| g_return_val_if_fail (info->map != NULL, NULL); |
| g_return_val_if_fail (info->unmap != NULL, NULL); |
| g_return_val_if_fail (info->free != NULL, NULL); |
| g_return_val_if_fail (info->share != NULL, NULL); |
| |
| allocator = g_slice_new (GstAllocator); |
| allocator->name = g_quark_from_string (name); |
| allocator->info = *info; |
| INSTALL_FALLBACK (copy); |
| INSTALL_FALLBACK (is_span); |
| #undef INSTALL_FALLBACK |
| |
| GST_DEBUG ("registering allocator \"%s\"", name); |
| |
| g_static_rw_lock_writer_lock (&lock); |
| g_hash_table_insert (allocators, (gpointer) name, (gpointer) allocator); |
| g_static_rw_lock_writer_unlock (&lock); |
| |
| return allocator; |
| } |
| |
| /** |
| * gst_allocator_find: |
| * @name: the name of the allocator |
| * |
| * Find a previously registered allocator with @name. When @name is NULL, the |
| * default allocator will be returned. |
| * |
| * Returns: a #GstAllocator or NULL when the allocator with @name was not |
| * registered. |
| */ |
| const GstAllocator * |
| gst_allocator_find (const gchar * name) |
| { |
| const GstAllocator *allocator; |
| |
| g_static_rw_lock_reader_lock (&lock); |
| if (name) { |
| allocator = g_hash_table_lookup (allocators, (gconstpointer) name); |
| } else { |
| allocator = _default_allocator; |
| } |
| g_static_rw_lock_reader_unlock (&lock); |
| |
| return allocator; |
| } |
| |
| /** |
| * gst_allocator_set_default: |
| * @allocator: a #GstAllocator |
| * |
| * Set the default allocator. |
| */ |
| void |
| gst_allocator_set_default (const GstAllocator * allocator) |
| { |
| g_return_if_fail (allocator != NULL); |
| |
| g_static_rw_lock_writer_lock (&lock); |
| _default_allocator = allocator; |
| g_static_rw_lock_writer_unlock (&lock); |
| } |
| |
| /** |
| * gst_allocator_alloc: |
| * @allocator: a #GstAllocator to use |
| * @maxsize: allocated size of @data |
| * @align: alignment for the data |
| * |
| * Use @allocator to allocate a new memory block with memory that is at least |
| * @maxsize big and has the given alignment. |
| * |
| * When @allocator is NULL, the default allocator will be used. |
| * |
| * @align is given as a bitmask so that @align + 1 equals the amount of bytes to |
| * align to. For example, to align to 8 bytes, use an alignment of 7. |
| * |
| * Returns: a new #GstMemory. |
| */ |
| GstMemory * |
| gst_allocator_alloc (const GstAllocator * allocator, gsize maxsize, gsize align) |
| { |
| g_return_val_if_fail (((align + 1) & align) == 0, NULL); |
| |
| if (allocator == NULL) |
| allocator = _default_allocator; |
| |
| return allocator->info.alloc (allocator, maxsize, align, |
| allocator->info.user_data); |
| } |