buffer: add support for buffer in memory

Fix the code to support allocating the buffer and memory in one memory block.
Add an extra variable to store the memory of the buffer.
This code is disabled still because of complications.

gst/gstbuffer.c

@@ -144,6 +144,7 @@ struct _GstMetaItem
 #define GST_BUFFER_MEM_LEN(b)      (((GstBufferImpl *)(b))->len)
 #define GST_BUFFER_MEM_ARRAY(b)    (((GstBufferImpl *)(b))->mem)
 #define GST_BUFFER_MEM_PTR(b,i)    (((GstBufferImpl *)(b))->mem[i])
+#define GST_BUFFER_BUFMEM(b)       (((GstBufferImpl *)(b))->bufmem)
 #define GST_BUFFER_META(b)         (((GstBufferImpl *)(b))->item)
 
 typedef struct
@@ -154,6 +155,9 @@ typedef struct
   guint len;
   GstMemory *mem[GST_BUFFER_MEM_MAX];
 
+  /* memory of the buffer when allocated from 1 chunk */
+  GstMemory *bufmem;
+
   /* FIXME, make metadata allocation more efficient by using part of the
    * GstBufferImpl */
   GstMetaItem *item;
@@ -402,6 +406,8 @@ _gst_buffer_free (GstBuffer * buffer)
   /* we set msize to 0 when the buffer is part of the memory block */
   if (msize)
     g_slice_free1 (msize, buffer);
+  else
+    gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
 }
 
 static void
@@ -495,8 +501,6 @@ gst_buffer_new_allocate (GstMemoryAllocator * allocator, gsize size,
     _memory_add (newbuf, mem);
 
   GST_CAT_LOG (GST_CAT_BUFFER, "new %p of size %d", newbuf, size);
-
-  return newbuf;
 #endif
 
 #if 0
@@ -513,14 +517,15 @@ gst_buffer_new_allocate (GstMemoryAllocator * allocator, gsize size,
         size, 0, size);
     _memory_add (newbuf, mem);
   }
-
-  return newbuf;
 #endif
 
 #if 0
-  /* allocate memory and buffer */
+  /* allocate memory and buffer, it might be interesting to do this but there
+   * are many complications. We need to keep the memory mapped to access the
+   * buffer fields and the memory for the buffer might be just very slow. We
+   * also need to do some more magic to get the alignment right. */
   asize = sizeof (GstBufferImpl) + size;
-  mem = gst_memory_new_alloc (asize, 0);
+  mem = gst_memory_allocator_alloc (allocator, asize, align);
   if (G_UNLIKELY (mem == NULL))
     goto no_memory;
 
@@ -534,9 +539,10 @@ gst_buffer_new_allocate (GstMemoryAllocator * allocator, gsize size,
   gst_memory_resize (mem, sizeof (GstBufferImpl), size);
 
   newbuf = GST_BUFFER_CAST (data);
+  GST_BUFFER_BUFMEM (newbuf) = mem;
 
   if (size > 0)
-    _memory_add (newbuf, mem);
+    _memory_add (newbuf, gst_memory_ref (mem));
 #endif
 
   return newbuf;