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authorMax Kellermann <max@duempel.org>2009-02-17 22:39:45 +0100
committerMax Kellermann <max@duempel.org>2009-02-17 22:39:45 +0100
commit1a9756156e5f305271536aa7e1fd33be6c774ce2 (patch)
tree3ed82093b956f84132659028ee4d7d97f7b1b2ee /src/decoder_buffer.c
parent66b4a3ab2eb69a048457b7e57374871914fd832d (diff)
downloadmpd-1a9756156e5f305271536aa7e1fd33be6c774ce2.tar.gz
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added the "decoder buffer" library
The decoder buffer library may be used by decoder libraries such as "faad".
Diffstat (limited to 'src/decoder_buffer.c')
-rw-r--r--src/decoder_buffer.c139
1 files changed, 139 insertions, 0 deletions
diff --git a/src/decoder_buffer.c b/src/decoder_buffer.c
new file mode 100644
index 000000000..6d321df10
--- /dev/null
+++ b/src/decoder_buffer.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "decoder_buffer.h"
+#include "decoder_api.h"
+
+#include <glib.h>
+
+#include <assert.h>
+
+struct decoder_buffer {
+ struct decoder *decoder;
+ struct input_stream *is;
+
+ /** the allocated size of the buffer */
+ size_t size;
+
+ /** the current length of the buffer */
+ size_t length;
+
+ /** number of bytes already consumed at the beginning of the
+ buffer */
+ size_t consumed;
+
+ /** the actual buffer (dynamic size) */
+ unsigned char data[sizeof(size_t)];
+};
+
+struct decoder_buffer *
+decoder_buffer_new(struct decoder *decoder, struct input_stream *is,
+ size_t size)
+{
+ struct decoder_buffer *buffer =
+ g_malloc(sizeof(*buffer) - sizeof(buffer->data) + size);
+
+ assert(is != NULL);
+ assert(size > 0);
+
+ buffer->decoder = decoder;
+ buffer->is = is;
+ buffer->size = size;
+ buffer->length = 0;
+ buffer->consumed = 0;
+
+ return buffer;
+}
+
+void
+decoder_buffer_free(struct decoder_buffer *buffer)
+{
+ assert(buffer != NULL);
+
+ g_free(buffer);
+}
+
+bool
+decoder_buffer_is_empty(const struct decoder_buffer *buffer)
+{
+ return buffer->consumed == buffer->length;
+}
+
+bool
+decoder_buffer_is_full(const struct decoder_buffer *buffer)
+{
+ return buffer->consumed == 0 && buffer->length == buffer->size;
+}
+
+static void
+decoder_buffer_shift(struct decoder_buffer *buffer)
+{
+ assert(buffer->consumed > 0);
+
+ buffer->length -= buffer->consumed;
+ memmove(buffer->data, buffer->data + buffer->consumed, buffer->length);
+ buffer->consumed = 0;
+}
+
+bool
+decoder_buffer_fill(struct decoder_buffer *buffer)
+{
+ size_t nbytes;
+
+ if (buffer->consumed > 0)
+ decoder_buffer_shift(buffer);
+
+ if (buffer->length >= buffer->size)
+ /* buffer is full */
+ return false;
+
+ nbytes = decoder_read(buffer->decoder, buffer->is,
+ buffer->data + buffer->length,
+ buffer->size - buffer->length);
+ if (nbytes == 0)
+ /* end of file, I/O error or decoder command
+ received */
+ return false;
+
+ buffer->length += nbytes;
+ assert(buffer->length <= buffer->size);
+
+ return true;
+}
+
+const void *
+decoder_buffer_read(const struct decoder_buffer *buffer, size_t *length_r)
+{
+ if (buffer->consumed >= buffer->length)
+ /* buffer is empty */
+ return NULL;
+
+ *length_r = buffer->length - buffer->consumed;
+ return buffer->data + buffer->consumed;
+}
+
+void
+decoder_buffer_consume(struct decoder_buffer *buffer, size_t nbytes)
+{
+ /* just move the "consumed" pointer - decoder_buffer_shift()
+ will do the real work later (called by
+ decoder_buffer_fill()) */
+ buffer->consumed += nbytes;
+
+ assert(buffer->consumed <= buffer->length);
+}