buffer: add index to _take_memory()

Add an index to gst_buffer_take_memory() so that we can also insert memory at a
certain offset. This is mostly interesting to prepend a header memory block to
the buffer.

gst/gstbuffer.c

@@ -197,9 +197,9 @@ _replace_memory (GstBuffer * buffer, GstMemory * mem)
 }
 
 static inline void
-_memory_add (GstBuffer * buffer, GstMemory * mem)
+_memory_add (GstBuffer * buffer, guint idx, GstMemory * mem)
 {
-  guint len = GST_BUFFER_MEM_LEN (buffer);
+  guint i, len = GST_BUFFER_MEM_LEN (buffer);
 
   if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
     /* too many buffer, span them. */
@@ -210,8 +210,16 @@ _memory_add (GstBuffer * buffer, GstMemory * mem)
     /* we now have 1 single spanned buffer */
     len = 1;
   }
-  /* and append the new buffer */
+
-  GST_BUFFER_MEM_PTR (buffer, len) = mem;
+  if (idx == -1)
+    idx = len;
+
+  for (i = len; i > idx; i--) {
+    /* move buffers to insert, FIXME, we need to insert first and then merge */
+    GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
+  }
+  /* and insert the new buffer */
+  GST_BUFFER_MEM_PTR (buffer, idx) = mem;
   GST_BUFFER_MEM_LEN (buffer) = len + 1;
 }
 
@@ -319,7 +327,7 @@ gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
         } else {
           mem = gst_memory_ref (mem);
         }
-        _memory_add (dest, mem);
+        _memory_add (dest, -1, mem);
         left -= tocopy;
       }
     }
@@ -498,7 +506,7 @@ gst_buffer_new_allocate (const GstMemoryAllocator * allocator, gsize size,
   newbuf = gst_buffer_new ();
 
   if (mem != NULL)
-    _memory_add (newbuf, mem);
+    _memory_add (newbuf, -1, mem);
 
   GST_CAT_LOG (GST_CAT_BUFFER, "new %p of size %d from allocator %p", newbuf,
       size, allocator);
@@ -516,7 +524,7 @@ gst_buffer_new_allocate (const GstMemoryAllocator * allocator, gsize size,
   if (size > 0) {
     mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
         size, 0, size);
-    _memory_add (newbuf, mem);
+    _memory_add (newbuf, -1, mem);
   }
 #endif
 
@@ -543,7 +551,7 @@ gst_buffer_new_allocate (const GstMemoryAllocator * allocator, gsize size,
   GST_BUFFER_BUFMEM (newbuf) = mem;
 
   if (size > 0)
-    _memory_add (newbuf, gst_memory_ref (mem));
+    _memory_add (newbuf, -1, gst_memory_ref (mem));
 #endif
 
   return newbuf;
@@ -575,19 +583,21 @@ gst_buffer_n_memory (GstBuffer * buffer)
 /**
  * gst_buffer_take_memory:
  * @buffer: a #GstBuffer.
+ * @idx: the index to add the memory
  * @mem: a #GstMemory.
  *
- * Add the memory block @mem to @buffer. This function takes ownership of @mem
+ * Add the memory block @mem to @buffer at @idx. This function takes ownership of @mem
  * and thus doesn't increase its refcount.
  */
 void
-gst_buffer_take_memory (GstBuffer * buffer, GstMemory * mem)
+gst_buffer_take_memory (GstBuffer * buffer, guint idx, GstMemory * mem)
 {
   g_return_if_fail (GST_IS_BUFFER (buffer));
   g_return_if_fail (gst_buffer_is_writable (buffer));
   g_return_if_fail (mem != NULL);
+  g_return_if_fail (idx == -1 || idx < GST_BUFFER_MEM_LEN (buffer));
 
-  _memory_add (buffer, mem);
+  _memory_add (buffer, idx, mem);
 }
 
 static GstMemory *
@@ -1004,6 +1014,8 @@ gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
  * @size: the size to compare
  *
  * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
+ *
+ * Returns: 0 if the memory is equal.
  */
 gint
 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
@@ -1255,7 +1267,7 @@ gst_buffer_span (GstBuffer * buf1, gsize offset, GstBuffer * buf2, gsize size)
   span = _gst_buffer_arr_span (mem, len, 2, offset, size, FALSE);
 
   newbuf = gst_buffer_new ();
-  _memory_add (newbuf, span);
+  _memory_add (newbuf, -1, span);
 
 #if 0
   /* if the offset is 0, the new buffer has the same timestamp as buf1 */

gst/gstbuffer.h

@@ -230,7 +230,7 @@ GstBuffer * gst_buffer_new_allocate        (const GstMemoryAllocator * allocator
 
 /* memory blocks */
 guint       gst_buffer_n_memory            (GstBuffer *buffer);
-void        gst_buffer_take_memory         (GstBuffer *buffer, GstMemory *mem);
+void        gst_buffer_take_memory         (GstBuffer *buffer, guint idx, GstMemory *mem);
 GstMemory * gst_buffer_peek_memory         (GstBuffer *buffer, guint idx, GstMapFlags flags);
 void        gst_buffer_remove_memory_range (GstBuffer *buffer, guint idx, guint length);
 

gst/gstbufferpool.c

@@ -167,7 +167,7 @@ default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
   mem =
       gst_memory_allocator_alloc (NULL, priv->size + priv->prefix, priv->align);
   gst_memory_resize (mem, priv->prefix, priv->size);
-  gst_buffer_take_memory (*buffer, mem);
+  gst_buffer_take_memory (*buffer, -1, mem);
 
   return GST_FLOW_OK;
 }

libs/gst/base/gstadapter.c

@@ -732,7 +732,7 @@ gst_adapter_take_buffer (GstAdapter * adapter, gsize nbytes)
   data = gst_adapter_take_internal (adapter, nbytes);
 
   buffer = gst_buffer_new ();
-  gst_buffer_take_memory (buffer,
+  gst_buffer_take_memory (buffer, -1,
       gst_memory_new_wrapped (0, data, g_free, nbytes, 0, nbytes));
 
 done:

libs/gst/base/gstbaseparse.c

@@ -2261,7 +2261,7 @@ gst_base_parse_chain (GstPad * pad, GstBuffer * buffer)
 
       /* always pass all available data */
       data = gst_adapter_map (parse->priv->adapter, av);
-      gst_buffer_take_memory (tmpbuf,
+      gst_buffer_take_memory (tmpbuf, -1,
           gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY,
               (gpointer) data, NULL, av, 0, av));
       GST_BUFFER_OFFSET (tmpbuf) = parse->priv->offset;

libs/gst/base/gstbytewriter.c

@@ -260,7 +260,7 @@ gst_byte_writer_reset_and_get_buffer (GstByteWriter * writer)
 
   buffer = gst_buffer_new ();
   if (data != NULL) {
-    gst_buffer_take_memory (buffer,
+    gst_buffer_take_memory (buffer, -1,
         gst_memory_new_wrapped (0, data, g_free, size, 0, size));
   }
 

plugins/elements/gstfakesrc.c

@@ -686,7 +686,7 @@ gst_fake_src_alloc_buffer (GstFakeSrc * src, guint size)
     if (do_prepare)
       gst_fake_src_prepare_buffer (src, data, size);
 
-    gst_buffer_take_memory (buf,
+    gst_buffer_take_memory (buf, -1,
         gst_memory_new_wrapped (0, data, g_free, size, 0, size));
   }
 

tests/check/gst/gstbuffer.c

@@ -246,7 +246,7 @@ create_read_only_buffer (void)
   buf = gst_buffer_new ();
 
   /* assign some read-only data to the new buffer */
-  gst_buffer_take_memory (buf,
+  gst_buffer_take_memory (buf, -1,
       gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY,
           (gpointer) ro_memory, NULL,
           sizeof (ro_memory), 0, sizeof (ro_memory)));

tests/check/libs/bitreader.c

@@ -49,7 +49,7 @@ GST_START_TEST (test_initialization)
   guint8 *bdata;
   gsize bsize;
 
-  gst_buffer_take_memory (buffer,
+  gst_buffer_take_memory (buffer, -1,
       gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY, data, NULL, 4, 0, 4));
 
   fail_unless (gst_bit_reader_get_bits_uint8 (&reader, &x, 8));

tests/check/libs/bytereader.c

@@ -49,7 +49,7 @@ GST_START_TEST (test_initialization)
   guint8 *bdata;
   gsize bsize;
 
-  gst_buffer_take_memory (buffer,
+  gst_buffer_take_memory (buffer, -1,
       gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY, data, NULL, 4, 0, 4));
 
   fail_unless (gst_byte_reader_get_uint8 (&reader, &x));

tests/check/libs/typefindhelper.c

@@ -55,7 +55,7 @@ GST_START_TEST (test_buffer_range)
   buf = gst_buffer_new ();
   fail_unless (buf != NULL);
 
-  gst_buffer_take_memory (buf,
+  gst_buffer_take_memory (buf, -1,
       gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY,
           (gpointer) vorbisid, NULL, 30, 0, 30));