X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=gst%2Fgstmemory.c;h=5a7f289ea54f00d1dd8bbdcdcc029bf135d09d6f;hb=1074a4e99a473efd5ee690da9ecd797c55cec23a;hp=ebaefc3a42aa09085355f09d69073572d5e44925;hpb=b8e1506b08b1e17493d13abcf7b190fee767267d;p=platform%2Fupstream%2Fgstreamer.git

diff --git a/gst/gstmemory.c b/gst/gstmemory.c
index ebaefc3..5a7f289 100644
--- a/gst/gstmemory.c
+++ b/gst/gstmemory.c
@@ -27,13 +27,19 @@
  * GstMemory is a lightweight refcounted object that wraps a region of memory.
  * They are typically used to manage the data of a #GstBuffer.
  *
+ * A GstMemory object has an allocated region of memory of maxsize. The maximum
+ * size does not change during the lifetime of the memory object. The memory
+ * also has an offset and size property that specifies the valid range of memory
+ * in the allocated region.
+ *
  * 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().
+ * gst_allocator_find(). gst_allocator_set_default() can be used to change the
+ * default allocator.
  *
  * New memory can be created with gst_memory_new_wrapped() that wraps the memory
  * allocated elsewhere.
@@ -45,26 +51,42 @@
  * gst_memory_get_sizes() and gst_memory_resize() respectively.
  *
  * Getting access to the data of the memory is performed with gst_memory_map().
+ * The call will return a pointer to offset bytes into the region of memory.
  * 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
+ * Memory can be copied with gst_memory_copy(), which will return 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)
+ * Last reviewed on 2012-03-28 (0.11.3)
  */
 
+#ifdef HAVE_CONFIG_H
 #include "config.h"
+#endif
+
 #include "gst_private.h"
 #include "gstmemory.h"
 
+#ifndef GST_DISABLE_TRACE
+#include "gsttrace.h"
+static GstAllocTrace *_gst_memory_trace;
+static GstAllocTrace *_gst_allocator_trace;
+#endif
+
+G_DEFINE_BOXED_TYPE (GstMemory, gst_memory, (GBoxedCopyFunc) gst_memory_ref,
+    (GBoxedFreeFunc) gst_memory_unref);
+
+G_DEFINE_BOXED_TYPE (GstAllocator, gst_allocator,
+    (GBoxedCopyFunc) gst_allocator_ref, (GBoxedFreeFunc) gst_allocator_unref);
+
+G_DEFINE_BOXED_TYPE (GstAllocationParams, gst_allocation_params,
+    (GBoxedCopyFunc) gst_allocation_params_copy,
+    (GBoxedFreeFunc) gst_allocation_params_free);
 
-/* 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)
@@ -79,9 +101,12 @@ size_t gst_memory_alignment = 0;
 
 struct _GstAllocator
 {
-  GQuark name;
+  gint refcount;
 
   GstMemoryInfo info;
+
+  gpointer user_data;
+  GDestroyNotify notify;
 };
 
 /* default memory implementation */
@@ -90,40 +115,47 @@ typedef struct
   GstMemory mem;
   gsize slice_size;
   guint8 *data;
-  GFreeFunc free_func;
-  gsize maxsize;
-  gsize offset;
-  gsize size;
+  gpointer user_data;
+  GDestroyNotify notify;
 } GstMemoryDefault;
 
 /* the default allocator */
-static const GstAllocator *_default_allocator;
+static GstAllocator *_default_allocator;
 
 /* our predefined allocators */
-static const GstAllocator *_default_mem_impl;
+static 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)
+    gsize maxsize, gsize offset, gsize size, gsize align,
+    gpointer user_data, GDestroyNotify notify)
 {
   mem->mem.allocator = _default_mem_impl;
   mem->mem.flags = flags;
   mem->mem.refcount = 1;
   mem->mem.parent = parent ? gst_memory_ref (parent) : NULL;
+  mem->mem.state = (flags & GST_MEMORY_FLAG_READONLY ? 0x1 : 0);
+  mem->mem.maxsize = maxsize;
+  mem->mem.align = align;
+  mem->mem.offset = offset;
+  mem->mem.size = size;
   mem->slice_size = slice_size;
   mem->data = data;
-  mem->free_func = free_func;
-  mem->maxsize = maxsize;
-  mem->offset = offset;
-  mem->size = size;
+  mem->user_data = user_data;
+  mem->notify = notify;
+
+  GST_CAT_DEBUG (GST_CAT_MEMORY, "new memory %p, maxsize:%" G_GSIZE_FORMAT
+      " offset:%" G_GSIZE_FORMAT " size:%" G_GSIZE_FORMAT, mem, maxsize,
+      offset, 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)
+    gsize maxsize, gsize offset, gsize size, gsize align, gpointer user_data,
+    GDestroyNotify notify)
 {
   GstMemoryDefault *mem;
   gsize slice_size;
@@ -132,17 +164,18 @@ _default_mem_new (GstMemoryFlags flags, GstMemory * parent, gpointer data,
 
   mem = g_slice_alloc (slice_size);
   _default_mem_init (mem, flags, parent, slice_size,
-      data, free_func, maxsize, offset, size);
+      data, maxsize, offset, size, align, user_data, notify);
 
   return mem;
 }
 
 /* allocate the memory and structure in one block */
 static GstMemoryDefault *
-_default_mem_new_block (gsize maxsize, gsize align, gsize offset, gsize size)
+_default_mem_new_block (GstMemoryFlags flags, gsize maxsize, gsize align,
+    gsize offset, gsize size)
 {
   GstMemoryDefault *mem;
-  gsize aoffset, slice_size;
+  gsize aoffset, slice_size, padding;
   guint8 *data;
 
   /* ensure configured alignment */
@@ -158,69 +191,58 @@ _default_mem_new_block (gsize maxsize, gsize align, gsize offset, gsize size)
 
   data = (guint8 *) mem + sizeof (GstMemoryDefault);
 
-  if ((aoffset = ((guintptr) data & align)))
+  /* do alignment */
+  if ((aoffset = ((guintptr) data & align))) {
     aoffset = (align + 1) - aoffset;
+    data += aoffset;
+    maxsize -= aoffset;
+  }
 
-  _default_mem_init (mem, 0, NULL, slice_size, data, NULL, maxsize,
-      aoffset + offset, size);
+  if (offset && (flags & GST_MEMORY_FLAG_ZERO_PREFIXED))
+    memset (data, 0, offset);
 
-  return mem;
-}
+  padding = maxsize - (offset + size);
+  if (padding && (flags & GST_MEMORY_FLAG_ZERO_PADDED))
+    memset (data + offset + size, 0, padding);
 
-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;
+  _default_mem_init (mem, flags, NULL, slice_size, data, maxsize,
+      offset, size, align, NULL, NULL);
 
-  return mem->size;
+  return mem;
 }
 
-static void
-_default_mem_resize (GstMemoryDefault * mem, gssize offset, gsize size)
+static GstMemory *
+_default_alloc_alloc (GstAllocator * allocator, gsize size,
+    GstAllocationParams * params, gpointer user_data)
 {
-  g_return_if_fail (size + mem->offset + offset <= mem->maxsize);
+  gsize maxsize = size + params->prefix + params->padding;
 
-  mem->offset += offset;
-  mem->size = size;
+  return (GstMemory *) _default_mem_new_block (params->flags,
+      maxsize, params->align, params->prefix, size);
 }
 
 static gpointer
-_default_mem_map (GstMemoryDefault * mem, gsize * size, gsize * maxsize,
-    GstMapFlags flags)
+_default_mem_map (GstMemoryDefault * mem, GstMapFlags flags)
 {
-  if (size)
-    *size = mem->size;
-  if (maxsize)
-    *maxsize = mem->maxsize;
-
-  return mem->data + mem->offset;
+  return mem->data;
 }
 
 static gboolean
-_default_mem_unmap (GstMemoryDefault * mem, gpointer data, gsize size)
+_default_mem_unmap (GstMemoryDefault * mem)
 {
-  if (size != -1)
-    mem->size = size;
   return TRUE;
 }
 
 static void
 _default_mem_free (GstMemoryDefault * mem)
 {
+  GST_CAT_DEBUG (GST_CAT_MEMORY, "free memory %p", mem);
+
   if (mem->mem.parent)
     gst_memory_unref (mem->mem.parent);
 
-  if (mem->free_func)
-    mem->free_func (mem->data);
+  if (mem->notify)
+    mem->notify (mem->user_data);
 
   g_slice_free1 (mem->slice_size, mem);
 }
@@ -231,10 +253,13 @@ _default_mem_copy (GstMemoryDefault * mem, gssize offset, gsize size)
   GstMemoryDefault *copy;
 
   if (size == -1)
-    size = mem->size > offset ? mem->size - offset : 0;
+    size = mem->mem.size > offset ? mem->mem.size - offset : 0;
 
-  copy = _default_mem_new_block (mem->maxsize, 0, mem->offset + offset, size);
-  memcpy (copy->data, mem->data, mem->maxsize);
+  copy =
+      _default_mem_new_block (0, mem->mem.maxsize, 0, mem->mem.offset + offset,
+      size);
+  memcpy (copy->data, mem->data, mem->mem.maxsize);
+  GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy memory %p -> %p", mem, copy);
 
   return copy;
 }
@@ -250,10 +275,12 @@ _default_mem_share (GstMemoryDefault * mem, gssize offset, gsize size)
     parent = (GstMemory *) mem;
 
   if (size == -1)
-    size = mem->size - offset;
+    size = mem->mem.size - offset;
 
-  sub = _default_mem_new (parent->flags, parent, mem->data, NULL, mem->maxsize,
-      mem->offset + offset, size);
+  sub =
+      _default_mem_new (parent->flags, parent, mem->data,
+      mem->mem.maxsize, mem->mem.offset + offset, size, mem->mem.align, NULL,
+      NULL);
 
   return sub;
 }
@@ -268,59 +295,78 @@ _default_mem_is_span (GstMemoryDefault * mem1, GstMemoryDefault * mem2,
 
     parent = (GstMemoryDefault *) mem1->mem.parent;
 
-    *offset = mem1->offset - parent->offset;
+    *offset = mem1->mem.offset - parent->mem.offset;
   }
 
   /* and memory is contiguous */
-  return mem1->data + mem1->offset + mem1->size == mem2->data + mem2->offset;
+  return mem1->data + mem1->mem.offset + mem1->mem.size ==
+      mem2->data + mem2->mem.offset;
 }
 
 static GstMemory *
-_fallback_copy (GstMemory * mem, gssize offset, gsize size)
+_fallback_mem_copy (GstMemory * mem, gssize offset, gssize size)
 {
   GstMemory *copy;
-  guint8 *data, *dest;
-  gsize msize;
+  GstMapInfo sinfo, dinfo;
+  GstAllocationParams params = { 0, 0, 0, mem->align, };
+
+  if (!gst_memory_map (mem, &sinfo, GST_MAP_READ))
+    return NULL;
 
-  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);
+    size = sinfo.size > offset ? sinfo.size - offset : 0;
 
-  gst_memory_unmap (mem, data, msize);
+  /* use the same allocator as the memory we copy  */
+  copy = gst_allocator_alloc (mem->allocator, size, &params);
+  if (!gst_memory_map (copy, &dinfo, GST_MAP_WRITE)) {
+    GST_CAT_WARNING (GST_CAT_MEMORY, "could not write map memory %p", copy);
+    gst_memory_unmap (mem, &sinfo);
+    return NULL;
+  }
+
+  memcpy (dinfo.data, sinfo.data + offset, size);
+  GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy memory %p -> %p", mem, copy);
+  gst_memory_unmap (copy, &dinfo);
+  gst_memory_unmap (mem, &sinfo);
 
-  return (GstMemory *) copy;
+  return copy;
 }
 
 static gboolean
-_fallback_is_span (GstMemory * mem1, GstMemory * mem2, gsize * offset)
+_fallback_mem_is_span (GstMemory * mem1, GstMemory * mem2, gsize * offset)
 {
   return FALSE;
 }
 
-static GStaticRWLock lock = G_STATIC_RW_LOCK_INIT;
+static GRWLock lock;
 static GHashTable *allocators;
 
+static void
+_priv_sysmem_notify (gpointer user_data)
+{
+  g_warning ("The default memory allocator was freed!");
+}
+
 void
 _priv_gst_memory_initialize (void)
 {
   static const GstMemoryInfo _mem_info = {
-    (GstMemoryAllocFunction) _default_mem_alloc,
-    (GstMemoryGetSizesFunction) _default_mem_get_sizes,
-    (GstMemoryResizeFunction) _default_mem_resize,
+    GST_ALLOCATOR_SYSMEM,
+    (GstAllocatorAllocFunction) _default_alloc_alloc,
     (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
   };
 
+#ifndef GST_DISABLE_TRACE
+  _gst_memory_trace = _gst_alloc_trace_register ("GstMemory", -1);
+  _gst_allocator_trace = _gst_alloc_trace_register ("GstAllocator", -1);
+#endif
+
+  g_rw_lock_init (&lock);
   allocators = g_hash_table_new (g_str_hash, g_str_equal);
 
 #ifdef HAVE_GETPAGESIZE
@@ -329,36 +375,50 @@ _priv_gst_memory_initialize (void)
 #endif
 #endif
 
-  GST_DEBUG ("memory alignment: %" G_GSIZE_FORMAT, gst_memory_alignment);
+  GST_CAT_DEBUG (GST_CAT_MEMORY, "memory alignment: %" G_GSIZE_FORMAT,
+      gst_memory_alignment);
 
-  _default_mem_impl = gst_allocator_register (GST_ALLOCATOR_SYSMEM, &_mem_info);
+  _default_mem_impl = gst_allocator_new (&_mem_info, NULL, _priv_sysmem_notify);
 
-  _default_allocator = _default_mem_impl;
+  _default_allocator = gst_allocator_ref (_default_mem_impl);
+  gst_allocator_register (GST_ALLOCATOR_SYSMEM,
+      gst_allocator_ref (_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
+ * @user_data: user_data
+ * @notify: called with @user_data when the memory is freed
  *
  * Allocate a new memory block that wraps the given @data.
  *
+ * The prefix/padding must be filled with 0 if @flags contains
+ * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
+ *
  * Returns: a new #GstMemory.
  */
 GstMemory *
 gst_memory_new_wrapped (GstMemoryFlags flags, gpointer data,
-    GFreeFunc free_func, gsize maxsize, gsize offset, gsize size)
+    gsize maxsize, gsize offset, gsize size, gpointer user_data,
+    GDestroyNotify notify)
 {
   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);
+  mem =
+      _default_mem_new (flags, NULL, data, maxsize, offset, size, 0, user_data,
+      notify);
+
+#ifndef GST_DISABLE_TRACE
+  _gst_alloc_trace_new (_gst_memory_trace, mem);
+#endif
 
   return (GstMemory *) mem;
 }
@@ -376,6 +436,9 @@ gst_memory_ref (GstMemory * mem)
 {
   g_return_val_if_fail (mem != NULL, NULL);
 
+  GST_CAT_TRACE (GST_CAT_MEMORY, "memory %p, %d->%d", mem, mem->refcount,
+      mem->refcount + 1);
+
   g_atomic_int_inc (&mem->refcount);
 
   return mem;
@@ -394,8 +457,32 @@ 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_CAT_TRACE (GST_CAT_MEMORY, "memory %p, %d->%d", mem, mem->refcount,
+      mem->refcount - 1);
+
+  if (g_atomic_int_dec_and_test (&mem->refcount)) {
+    /* there should be no outstanding mappings */
+    g_return_if_fail (g_atomic_int_get (&mem->state) < 4);
+#ifndef GST_DISABLE_TRACE
+    _gst_alloc_trace_free (_gst_memory_trace, mem);
+#endif
+    mem->allocator->info.mem_free (mem);
+  }
+}
+
+/**
+ * gst_memory_is_exclusive:
+ * @mem: a #GstMemory
+ *
+ * Check if the current ref to @mem is exclusive, this means that no other
+ * references exist other than @mem.
+ */
+gboolean
+gst_memory_is_exclusive (GstMemory * mem)
+{
+  g_return_val_if_fail (mem != NULL, FALSE);
+
+  return (g_atomic_int_get (&mem->refcount) == 1);
 }
 
 /**
@@ -413,7 +500,12 @@ 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);
+  if (offset)
+    *offset = mem->offset;
+  if (maxsize)
+    *maxsize = mem->maxsize;
+
+  return mem->size;
 }
 
 /**
@@ -424,66 +516,209 @@ gst_memory_get_sizes (GstMemory * mem, gsize * offset, gsize * maxsize)
  *
  * Resize the memory region. @mem should be writable and offset + size should be
  * less than the maxsize of @mem.
+ *
+ * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED will be
+ * cleared when offset or padding is increased respectively.
  */
 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));
+  g_return_if_fail (offset >= 0 || mem->offset >= -offset);
+  g_return_if_fail (size + mem->offset + offset <= mem->maxsize);
+
+  /* if we increase the prefix, we can't guarantee it is still 0 filled */
+  if ((offset > 0) && GST_MEMORY_IS_ZERO_PREFIXED (mem))
+    GST_MEMORY_FLAG_UNSET (mem, GST_MEMORY_FLAG_ZERO_PREFIXED);
+
+  /* if we increase the padding, we can't guarantee it is still 0 filled */
+  if ((offset + size < mem->size) && GST_MEMORY_IS_ZERO_PADDED (mem))
+    GST_MEMORY_FLAG_UNSET (mem, GST_MEMORY_FLAG_ZERO_PADDED);
 
-  mem->allocator->info.resize (mem, offset, size);
+  mem->offset += offset;
+  mem->size = size;
+}
+
+static gboolean
+gst_memory_lock (GstMemory * mem, GstMapFlags flags)
+{
+  gint access_mode, state, newstate;
+
+  access_mode = flags & 3;
+
+  do {
+    state = g_atomic_int_get (&mem->state);
+    if (state == 0) {
+      /* nothing mapped, set access_mode and refcount */
+      newstate = 4 | access_mode;
+    } else {
+      /* access_mode must match */
+      if ((state & access_mode) != access_mode)
+        goto lock_failed;
+      /* increase refcount */
+      newstate = state + 4;
+    }
+  } while (!g_atomic_int_compare_and_exchange (&mem->state, state, newstate));
+
+  return TRUE;
+
+lock_failed:
+  {
+    GST_CAT_DEBUG (GST_CAT_MEMORY, "lock failed %p: state %d, access_mode %d",
+        mem, state, access_mode);
+    return FALSE;
+  }
 }
 
+static void
+gst_memory_unlock (GstMemory * mem)
+{
+  gint state, newstate;
+
+  do {
+    state = g_atomic_int_get (&mem->state);
+    /* decrease the refcount */
+    newstate = state - 4;
+    /* last refcount, unset access_mode */
+    if (newstate < 4)
+      newstate = 0;
+  } while (!g_atomic_int_compare_and_exchange (&mem->state, state, newstate));
+}
+
+
 /**
- * gst_memory_map:
- * @mem: a #GstMemory
- * @size: pointer for size
- * @maxsize: pointer for maxsize
+ * gst_memory_make_mapped:
+ * @mem: (transfer full): a #GstMemory
+ * @info: (out): pointer for info
  * @flags: mapping flags
  *
- * Get a pointer to the memory of @mem that can be accessed according to @flags.
+ * Create a #GstMemory object that is mapped with @flags. If @mem is mappable
+ * with @flags, this function returns the mapped @mem directly. Otherwise a
+ * mapped copy of @mem is returned.
  *
- * @size and @maxsize will contain the size of the memory and the maximum
- * allocated memory of @mem respectively. They can be set to NULL.
+ * This function takes ownership of old @mem and returns a reference to a new
+ * #GstMemory.
  *
- * Returns: a pointer to the memory of @mem.
+ * Returns: (transfer full): a #GstMemory object mapped with @flags or NULL when
+ * a mapping is not possible.
  */
-gpointer
-gst_memory_map (GstMemory * mem, gsize * size, gsize * maxsize,
-    GstMapFlags flags)
+GstMemory *
+gst_memory_make_mapped (GstMemory * mem, GstMapInfo * info, 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);
+  GstMemory *result;
+
+  if (gst_memory_map (mem, info, flags)) {
+    result = mem;
+  } else {
+    result = gst_memory_copy (mem, 0, -1);
+    gst_memory_unref (mem);
+
+    if (result == NULL)
+      goto cannot_copy;
+
+    if (!gst_memory_map (result, info, flags))
+      goto cannot_map;
+  }
+  return result;
 
-  return mem->allocator->info.map (mem, size, maxsize, flags);
+  /* ERRORS */
+cannot_copy:
+  {
+    GST_CAT_DEBUG (GST_CAT_MEMORY, "cannot copy memory %p", mem);
+    return NULL;
+  }
+cannot_map:
+  {
+    GST_CAT_DEBUG (GST_CAT_MEMORY, "cannot map memory %p with flags %d", mem,
+        flags);
+    gst_memory_unref (result);
+    return NULL;
+  }
 }
 
 /**
- * gst_memory_unmap:
+ * gst_memory_map:
  * @mem: a #GstMemory
- * @data: data to unmap
- * @size: new size of @mem
+ * @info: (out): pointer for info
+ * @flags: mapping flags
+ *
+ * Fill @info with the pointer and sizes of the memory in @mem that can be
+ * accessed according to @flags.
+ *
+ * This function can return %FALSE for various reasons:
+ * - the memory backed by @mem is not accessible with the given @flags.
+ * - the memory was already mapped with a different mapping.
+ *
+ * @info and its contents remain valid for as long as @mem is valid and
+ * until gst_memory_unmap() is called.
  *
- * 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.
+ * For each gst_memory_map() call, a corresponding gst_memory_unmap() call
+ * should be done.
  *
- * Returns: TRUE when the memory was release successfully.
+ * Returns: %TRUE if the map operation was successful.
  */
 gboolean
-gst_memory_unmap (GstMemory * mem, gpointer data, gsize size)
+gst_memory_map (GstMemory * mem, GstMapInfo * info, GstMapFlags flags)
 {
   g_return_val_if_fail (mem != NULL, FALSE);
+  g_return_val_if_fail (info != NULL, FALSE);
 
-  return mem->allocator->info.unmap (mem, data, size);
+  if (!gst_memory_lock (mem, flags))
+    goto lock_failed;
+
+  info->data = mem->allocator->info.mem_map (mem, mem->maxsize, flags);
+
+  if (G_UNLIKELY (info->data == NULL))
+    goto error;
+
+  info->memory = mem;
+  info->flags = flags;
+  info->size = mem->size;
+  info->maxsize = mem->maxsize - mem->offset;
+  info->data = info->data + mem->offset;
+
+  return TRUE;
+
+  /* ERRORS */
+lock_failed:
+  {
+    GST_CAT_DEBUG (GST_CAT_MEMORY, "mem %p: lock %d failed", mem, flags);
+    return FALSE;
+  }
+error:
+  {
+    /* something went wrong, restore the orginal state again */
+    GST_CAT_ERROR (GST_CAT_MEMORY, "mem %p: map failed", mem);
+    gst_memory_unlock (mem);
+    return FALSE;
+  }
+}
+
+/**
+ * gst_memory_unmap:
+ * @mem: a #GstMemory
+ * @info: a #GstMapInfo
+ *
+ * Release the memory obtained with gst_memory_map()
+ */
+void
+gst_memory_unmap (GstMemory * mem, GstMapInfo * info)
+{
+  g_return_if_fail (mem != NULL);
+  g_return_if_fail (info != NULL);
+  g_return_if_fail (info->memory == mem);
+  /* there must be a ref */
+  g_return_if_fail (g_atomic_int_get (&mem->state) >= 4);
+
+  mem->allocator->info.mem_unmap (mem);
+  gst_memory_unlock (mem);
 }
 
 /**
  * gst_memory_copy:
  * @mem: a #GstMemory
  * @offset: an offset to copy
- * @size: size to copy
+ * @size: size to copy or -1 to copy all bytes from offset
  *
  * 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
@@ -492,32 +727,50 @@ gst_memory_unmap (GstMemory * mem, gpointer data, gsize size)
  * Returns: a new #GstMemory.
  */
 GstMemory *
-gst_memory_copy (GstMemory * mem, gssize offset, gsize size)
+gst_memory_copy (GstMemory * mem, gssize offset, gssize size)
 {
+  GstMemory *copy;
+
   g_return_val_if_fail (mem != NULL, NULL);
 
-  return mem->allocator->info.copy (mem, offset, size);
+  copy = mem->allocator->info.mem_copy (mem, offset, size);
+
+#ifndef GST_DISABLE_TRACE
+  _gst_alloc_trace_new (_gst_memory_trace, copy);
+#endif
+
+  return copy;
 }
 
 /**
  * gst_memory_share:
  * @mem: a #GstMemory
  * @offset: an offset to share
- * @size: size to share
+ * @size: size to share or -1 to share bytes from offset
  *
- * 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.
+ * 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)
+gst_memory_share (GstMemory * mem, gssize offset, gssize size)
 {
+  GstMemory *shared;
+
   g_return_val_if_fail (mem != NULL, NULL);
+  g_return_val_if_fail (!GST_MEMORY_FLAG_IS_SET (mem, GST_MEMORY_FLAG_NO_SHARE),
+      NULL);
 
-  return mem->allocator->info.share (mem, offset, size);
+  shared = mem->allocator->info.mem_share (mem, offset, size);
+
+#ifndef GST_DISABLE_TRACE
+  _gst_alloc_trace_new (_gst_memory_trace, shared);
+#endif
+
+  return shared;
 }
 
 /**
@@ -550,128 +803,289 @@ gst_memory_is_span (GstMemory * mem1, GstMemory * mem2, gsize * offset)
     return FALSE;
 
   /* and memory is contiguous */
-  if (!mem1->allocator->info.is_span (mem1, mem2, offset))
+  if (!mem1->allocator->info.mem_is_span (mem1, mem2, offset))
     return FALSE;
 
   return TRUE;
 }
 
 /**
- * gst_allocator_register:
- * @name: the name of the allocator
- * @info: #GstMemoryInfo
+ * gst_allocator_new:
+ * @info: a #GstMemoryInfo
+ * @user_data: user data
+ * @notify: a #GDestroyNotify for @user_data
  *
- * Registers the memory allocator with @name and implementation functions
- * @info.
+ * Create a new memory allocator with @info and @user_data.
  *
  * 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.
+ * The @user_data will be passed to all calls of the alloc function. @notify
+ * will be called with @user_data when the allocator is freed.
  *
  * Returns: a new #GstAllocator.
  */
-const GstAllocator *
-gst_allocator_register (const gchar * name, const GstMemoryInfo * info)
+GstAllocator *
+gst_allocator_new (const GstMemoryInfo * info, gpointer user_data,
+    GDestroyNotify notify)
 {
   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);
+  g_return_val_if_fail (info->mem_map != NULL, NULL);
+  g_return_val_if_fail (info->mem_unmap != NULL, NULL);
+  g_return_val_if_fail (info->mem_free != NULL, NULL);
+  g_return_val_if_fail (info->mem_share != NULL, NULL);
 
   allocator = g_slice_new (GstAllocator);
-  allocator->name = g_quark_from_string (name);
+  allocator->refcount = 1;
   allocator->info = *info;
-  INSTALL_FALLBACK (copy);
-  INSTALL_FALLBACK (is_span);
+  allocator->user_data = user_data;
+  allocator->notify = notify;
+  INSTALL_FALLBACK (mem_copy);
+  INSTALL_FALLBACK (mem_is_span);
 #undef INSTALL_FALLBACK
 
-  GST_DEBUG ("registering allocator \"%s\"", name);
+  GST_CAT_DEBUG (GST_CAT_MEMORY, "new allocator %p", allocator);
 
-  g_static_rw_lock_writer_lock (&lock);
-  g_hash_table_insert (allocators, (gpointer) name, (gpointer) allocator);
-  g_static_rw_lock_writer_unlock (&lock);
+#ifndef GST_DISABLE_TRACE
+  _gst_alloc_trace_new (_gst_allocator_trace, allocator);
+#endif
 
   return allocator;
 }
 
 /**
+ * gst_allocator_get_memory_type:
+ * @allocator: a #GstAllocator
+ *
+ * Get the memory type allocated by this allocator
+ *
+ * Returns: the memory type provided by @allocator
+ */
+const gchar *
+gst_allocator_get_memory_type (GstAllocator * allocator)
+{
+  g_return_val_if_fail (allocator != NULL, NULL);
+
+  return allocator->info.mem_type;
+}
+
+/**
+ * gst_allocator_ref:
+ * @allocator: a #GstAllocator
+ *
+ * Increases the refcount of @allocator.
+ *
+ * Returns: @allocator with increased refcount
+ */
+GstAllocator *
+gst_allocator_ref (GstAllocator * allocator)
+{
+  g_return_val_if_fail (allocator != NULL, NULL);
+
+  GST_CAT_TRACE (GST_CAT_MEMORY, "allocator %p, %d->%d", allocator,
+      allocator->refcount, allocator->refcount + 1);
+
+  g_atomic_int_inc (&allocator->refcount);
+
+  return allocator;
+}
+
+/**
+ * gst_allocator_unref:
+ * @allocator: a #GstAllocator
+ *
+ * Decreases the refcount of @allocator. When the refcount reaches 0, the notify
+ * function of @allocator will be called and the allocator will be freed.
+ */
+void
+gst_allocator_unref (GstAllocator * allocator)
+{
+  g_return_if_fail (allocator != NULL);
+
+  GST_CAT_TRACE (GST_CAT_MEMORY, "allocator %p, %d->%d", allocator,
+      allocator->refcount, allocator->refcount - 1);
+
+  if (g_atomic_int_dec_and_test (&allocator->refcount)) {
+    if (allocator->notify)
+      allocator->notify (allocator->user_data);
+#ifndef GST_DISABLE_TRACE
+    _gst_alloc_trace_free (_gst_allocator_trace, allocator);
+#endif
+    g_slice_free1 (sizeof (GstAllocator), allocator);
+  }
+}
+
+/**
+ * gst_allocator_register:
+ * @name: the name of the allocator
+ * @allocator: (transfer full): #GstAllocator
+ *
+ * Registers the memory @allocator with @name. This function takes ownership of
+ * @allocator.
+ */
+void
+gst_allocator_register (const gchar * name, GstAllocator * allocator)
+{
+  g_return_if_fail (name != NULL);
+  g_return_if_fail (allocator != NULL);
+
+  GST_CAT_DEBUG (GST_CAT_MEMORY, "registering allocator %p with name \"%s\"",
+      allocator, name);
+
+  g_rw_lock_writer_lock (&lock);
+  g_hash_table_insert (allocators, (gpointer) name, (gpointer) allocator);
+  g_rw_lock_writer_unlock (&lock);
+}
+
+/**
  * 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.
+ * Returns: (transfer full): a #GstAllocator or NULL when the allocator with @name was not
+ * registered. Use gst_allocator_unref() to release the allocator after usage.
  */
-const GstAllocator *
+GstAllocator *
 gst_allocator_find (const gchar * name)
 {
-  const GstAllocator *allocator;
+  GstAllocator *allocator;
 
-  g_static_rw_lock_reader_lock (&lock);
+  g_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);
+  if (allocator)
+    gst_allocator_ref (allocator);
+  g_rw_lock_reader_unlock (&lock);
 
   return allocator;
 }
 
 /**
  * gst_allocator_set_default:
- * @allocator: a #GstAllocator
+ * @allocator: (transfer full): a #GstAllocator
  *
- * Set the default allocator.
+ * Set the default allocator. This function takes ownership of @allocator.
  */
 void
-gst_allocator_set_default (const GstAllocator * allocator)
+gst_allocator_set_default (GstAllocator * allocator)
 {
+  GstAllocator *old;
   g_return_if_fail (allocator != NULL);
 
-  g_static_rw_lock_writer_lock (&lock);
+  g_rw_lock_writer_lock (&lock);
+  old = _default_allocator;
   _default_allocator = allocator;
-  g_static_rw_lock_writer_unlock (&lock);
+  g_rw_lock_writer_unlock (&lock);
+
+  if (old)
+    gst_allocator_unref (old);
+}
+
+/**
+ * gst_allocation_params_init:
+ * @params: a #GstAllocationParams
+ *
+ * Initialize @params to its default values
+ */
+void
+gst_allocation_params_init (GstAllocationParams * params)
+{
+  g_return_if_fail (params != NULL);
+
+  memset (params, 0, sizeof (GstAllocationParams));
+}
+
+/**
+ * gst_allocation_params_copy:
+ * @params: (transfer none): a #GstAllocationParams
+ *
+ * Create a copy of @params.
+ *
+ * Free-function: gst_allocation_params_free
+ *
+ * Returns: (transfer full): a new ##GstAllocationParams, free with
+ * gst_allocation_params_free().
+ */
+GstAllocationParams *
+gst_allocation_params_copy (const GstAllocationParams * params)
+{
+  GstAllocationParams *result = NULL;
+
+  if (params) {
+    result =
+        (GstAllocationParams *) g_slice_copy (sizeof (GstAllocationParams),
+        params);
+  }
+  return result;
+}
+
+/**
+ * gst_allocation_params_free:
+ * @params: (in) (transfer full): a #GstAllocationParams
+ *
+ * Free @params
+ */
+void
+gst_allocation_params_free (GstAllocationParams * params)
+{
+  g_slice_free (GstAllocationParams, params);
 }
 
 /**
  * gst_allocator_alloc:
- * @allocator: a #GstAllocator to use
- * @maxsize: allocated size of @data
- * @align: alignment for the data
+ * @allocator: (transfer none) (allow-none): a #GstAllocator to use
+ * @size: size of the visible memory area
+ * @params: (transfer none) (allow-none): optional parameters
  *
  * Use @allocator to allocate a new memory block with memory that is at least
- * @maxsize big and has the given alignment.
+ * @size big.
+ *
+ * The optional @params can specify the prefix and padding for the memory. If
+ * NULL is passed, no flags, no extra prefix/padding and a default alignment is
+ * used.
+ *
+ * The prefix/padding will be filled with 0 if flags contains
+ * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
  *
  * 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.
+ * The alignment in @params 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.
+ * Returns: (transfer full): a new #GstMemory.
  */
 GstMemory *
-gst_allocator_alloc (const GstAllocator * allocator, gsize maxsize, gsize align)
+gst_allocator_alloc (GstAllocator * allocator, gsize size,
+    GstAllocationParams * params)
 {
-  g_return_val_if_fail (((align + 1) & align) == 0, NULL);
+  GstMemory *mem;
+  static GstAllocationParams defparams = { 0, 0, 0, 0, };
+
+  if (params) {
+    g_return_val_if_fail (((params->align + 1) & params->align) == 0, NULL);
+  } else {
+    params = &defparams;
+  }
 
   if (allocator == NULL)
     allocator = _default_allocator;
 
-  return allocator->info.alloc (allocator, maxsize, align,
-      allocator->info.user_data);
+  mem = allocator->info.alloc (allocator, size, params, allocator->user_data);
+
+#ifndef GST_DISABLE_TRACE
+  _gst_alloc_trace_new (_gst_memory_trace, mem);
+#endif
+  return mem;
 }