1 files changed, 328 insertions, 0 deletions
diff --git a/src/EncoderPlugin.hxx b/src/EncoderPlugin.hxx
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--- /dev/null
+++ b/src/EncoderPlugin.hxx
@@ -0,0 +1,328 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_ENCODER_PLUGIN_HXX
+#define MPD_ENCODER_PLUGIN_HXX
+
+#include "gerror.h"
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+struct EncoderPlugin;
+struct audio_format;
+struct config_param;
+struct tag;
+
+struct Encoder {
+	const EncoderPlugin &plugin;
+
+#ifndef NDEBUG
+	bool open, pre_tag, tag, end;
+#endif
+
+	explicit Encoder(const EncoderPlugin &_plugin)
+		:plugin(_plugin)
+#ifndef NDEBUG
+		, open(false)
+#endif
+	{}
+};
+
+struct EncoderPlugin {
+	const char *name;
+
+	Encoder *(*init)(const struct config_param *param,
+			 GError **error);
+
+	void (*finish)(Encoder *encoder);
+
+	bool (*open)(Encoder *encoder,
+		     struct audio_format *audio_format,
+		     GError **error);
+
+	void (*close)(Encoder *encoder);
+
+	bool (*end)(Encoder *encoder, GError **error);
+
+	bool (*flush)(Encoder *encoder, GError **error);
+
+	bool (*pre_tag)(Encoder *encoder, GError **error);
+
+	bool (*tag)(Encoder *encoder, const struct tag *tag,
+		    GError **error);
+
+	bool (*write)(Encoder *encoder,
+		      const void *data, size_t length,
+		      GError **error);
+
+	size_t (*read)(Encoder *encoder, void *dest, size_t length);
+
+	const char *(*get_mime_type)(Encoder *encoder);
+};
+
+/**
+ * Creates a new encoder object.
+ *
+ * @param plugin the encoder plugin
+ * @param param optional configuration
+ * @param error location to store the error occurring, or NULL to ignore errors.
+ * @return an encoder object on success, NULL on failure
+ */
+static inline Encoder *
+encoder_init(const EncoderPlugin &plugin, const config_param *param,
+	     GError **error_r)
+{
+	return plugin.init(param, error_r);
+}
+
+/**
+ * Frees an encoder object.
+ *
+ * @param encoder the encoder
+ */
+static inline void
+encoder_finish(Encoder *encoder)
+{
+	assert(!encoder->open);
+
+	encoder->plugin.finish(encoder);
+}
+
+/**
+ * Opens an encoder object.  You must call this prior to using it.
+ * Before you free it, you must call encoder_close().  You may open
+ * and close (reuse) one encoder any number of times.
+ *
+ * After this function returns successfully and before the first
+ * encoder_write() call, you should invoke encoder_read() to obtain
+ * the file header.
+ *
+ * @param encoder the encoder
+ * @param audio_format the encoder's input audio format; the plugin
+ * may modify the struct to adapt it to its abilities
+ * @param error location to store the error occurring, or NULL to ignore errors.
+ * @return true on success
+ */
+static inline bool
+encoder_open(Encoder *encoder, struct audio_format *audio_format,
+	     GError **error)
+{
+	assert(!encoder->open);
+
+	bool success = encoder->plugin.open(encoder, audio_format, error);
+#ifndef NDEBUG
+	encoder->open = success;
+	encoder->pre_tag = encoder->tag = encoder->end = false;
+#endif
+	return success;
+}
+
+/**
+ * Closes an encoder object.  This disables the encoder, and readies
+ * it for reusal by calling encoder_open() again.
+ *
+ * @param encoder the encoder
+ */
+static inline void
+encoder_close(Encoder *encoder)
+{
+	assert(encoder->open);
+
+	if (encoder->plugin.close != NULL)
+		encoder->plugin.close(encoder);
+
+#ifndef NDEBUG
+	encoder->open = false;
+#endif
+}
+
+/**
+ * Ends the stream: flushes the encoder object, generate an
+ * end-of-stream marker (if applicable), make everything which might
+ * currently be buffered available by encoder_read().
+ *
+ * After this function has been called, the encoder may not be usable
+ * for more data, and only encoder_read() and encoder_close() can be
+ * called.
+ *
+ * @param encoder the encoder
+ * @param error location to store the error occuring, or NULL to ignore errors.
+ * @return true on success
+ */
+static inline bool
+encoder_end(Encoder *encoder, GError **error)
+{
+	assert(encoder->open);
+	assert(!encoder->end);
+
+#ifndef NDEBUG
+	encoder->end = true;
+#endif
+
+	/* this method is optional */
+	return encoder->plugin.end != NULL
+		? encoder->plugin.end(encoder, error)
+		: true;
+}
+
+/**
+ * Flushes an encoder object, make everything which might currently be
+ * buffered available by encoder_read().
+ *
+ * @param encoder the encoder
+ * @param error location to store the error occurring, or NULL to ignore errors.
+ * @return true on success
+ */
+static inline bool
+encoder_flush(Encoder *encoder, GError **error)
+{
+	assert(encoder->open);
+	assert(!encoder->pre_tag);
+	assert(!encoder->tag);
+	assert(!encoder->end);
+
+	/* this method is optional */
+	return encoder->plugin.flush != NULL
+		? encoder->plugin.flush(encoder, error)
+		: true;
+}
+
+/**
+ * Prepare for sending a tag to the encoder.  This is used by some
+ * encoders to flush the previous sub-stream, in preparation to begin
+ * a new one.
+ *
+ * @param encoder the encoder
+ * @param tag the tag object
+ * @param error location to store the error occuring, or NULL to ignore errors.
+ * @return true on success
+ */
+static inline bool
+encoder_pre_tag(Encoder *encoder, GError **error)
+{
+	assert(encoder->open);
+	assert(!encoder->pre_tag);
+	assert(!encoder->tag);
+	assert(!encoder->end);
+
+	/* this method is optional */
+	bool success = encoder->plugin.pre_tag != NULL
+		? encoder->plugin.pre_tag(encoder, error)
+		: true;
+
+#ifndef NDEBUG
+	encoder->pre_tag = success;
+#endif
+	return success;
+}
+
+/**
+ * Sends a tag to the encoder.
+ *
+ * Instructions: call encoder_pre_tag(); then obtain flushed data with
+ * encoder_read(); finally call encoder_tag().
+ *
+ * @param encoder the encoder
+ * @param tag the tag object
+ * @param error location to store the error occurring, or NULL to ignore errors.
+ * @return true on success
+ */
+static inline bool
+encoder_tag(Encoder *encoder, const struct tag *tag, GError **error)
+{
+	assert(encoder->open);
+	assert(!encoder->pre_tag);
+	assert(encoder->tag);
+	assert(!encoder->end);
+
+#ifndef NDEBUG
+	encoder->tag = false;
+#endif
+
+	/* this method is optional */
+	return encoder->plugin.tag != NULL
+		? encoder->plugin.tag(encoder, tag, error)
+		: true;
+}
+
+/**
+ * Writes raw PCM data to the encoder.
+ *
+ * @param encoder the encoder
+ * @param data the buffer containing PCM samples
+ * @param length the length of the buffer in bytes
+ * @param error location to store the error occurring, or NULL to ignore errors.
+ * @return true on success
+ */
+static inline bool
+encoder_write(Encoder *encoder, const void *data, size_t length,
+	      GError **error)
+{
+	assert(encoder->open);
+	assert(!encoder->pre_tag);
+	assert(!encoder->tag);
+	assert(!encoder->end);
+
+	return encoder->plugin.write(encoder, data, length, error);
+}
+
+/**
+ * Reads encoded data from the encoder.
+ *
+ * Call this repeatedly until no more data is returned.
+ *
+ * @param encoder the encoder
+ * @param dest the destination buffer to copy to
+ * @param length the maximum length of the destination buffer
+ * @return the number of bytes written to #dest
+ */
+static inline size_t
+encoder_read(Encoder *encoder, void *dest, size_t length)
+{
+	assert(encoder->open);
+	assert(!encoder->pre_tag || !encoder->tag);
+
+#ifndef NDEBUG
+	if (encoder->pre_tag) {
+		encoder->pre_tag = false;
+		encoder->tag = true;
+	}
+#endif
+
+	return encoder->plugin.read(encoder, dest, length);
+}
+
+/**
+ * Get mime type of encoded content.
+ *
+ * @param plugin the encoder plugin
+ * @return an constant string, NULL on failure
+ */
+static inline const char *
+encoder_get_mime_type(Encoder *encoder)
+{
+	/* this method is optional */
+	return encoder->plugin.get_mime_type != NULL
+		? encoder->plugin.get_mime_type(encoder)
+		: NULL;
+}
+
+#endif