added the "decoder buffer" library

The decoder buffer library may be used by decoder libraries such as
"faad".

1 files changed, 95 insertions, 0 deletions

diff --git a/src/decoder_buffer.h b/src/decoder_buffer.h
new file mode 100644
index 00000000..9d8834ca
--- /dev/null
+++ b/src/decoder_buffer.h
@@ -0,0 +1,95 @@
+/*
+ * 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
+ */
+
+#ifndef MPD_DECODER_BUFFER_H
+#define MPD_DECODER_BUFFER_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+/**
+ * This objects handles buffered reads in decoder plugins easily.  You
+ * create a buffer object, and use its high-level methods to fill and
+ * read it.  It will automatically handle shifting the buffer.
+ */
+struct decoder_buffer;
+
+struct decoder;
+struct input_stream;
+
+/**
+ * Creates a new buffer.
+ *
+ * @param decoder the decoder object, used for decoder_read(), may be NULL
+ * @param is the input stream object where we should read from
+ * @param size the maximum size of the buffer
+ * @return the new decoder_buffer object
+ */
+struct decoder_buffer *
+decoder_buffer_new(struct decoder *decoder, struct input_stream *is,
+		   size_t size);
+
+/**
+ * Frees resources used by the decoder_buffer object.
+ */
+void
+decoder_buffer_free(struct decoder_buffer *buffer);
+
+bool
+decoder_buffer_is_empty(const struct decoder_buffer *buffer);
+
+bool
+decoder_buffer_is_full(const struct decoder_buffer *buffer);
+
+/**
+ * Read data from the input_stream and append it to the buffer.
+ *
+ * @return true if data was appended; false if there is no data
+ * available (yet), end of file, I/O error or a decoder command was
+ * received
+ */
+bool
+decoder_buffer_fill(struct decoder_buffer *buffer);
+
+/**
+ * Reads data from the buffer.  This data is not yet consumed, you
+ * have to call decoder_buffer_consume() to do that.  The returned
+ * buffer becomes invalid after a decoder_buffer_fill() or a
+ * decoder_buffer_consume() call.
+ *
+ * @param buffer the decoder_buffer object
+ * @param length_r pointer to a size_t where you will receive the
+ * number of bytes available
+ * @return a pointer to the read buffer, or NULL if there is no data
+ * available
+ */
+const void *
+decoder_buffer_read(const struct decoder_buffer *buffer, size_t *length_r);
+
+/**
+ * Consume (delete, invalidate) a part of the buffer.  The "nbytes"
+ * parameter must not be larger than the length returned by
+ * decoder_buffer_read().
+ *
+ * @param buffer the decoder_buffer object
+ * @param nbytes the number of bytes to consume
+ */
+void
+decoder_buffer_consume(struct decoder_buffer *buffer, size_t nbytes);
+
+#endif