buffer, pipe: convert to C++

src/MusicChunk.hxx

@@ -0,0 +1,150 @@
+/*
+ * 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_MUSIC_CHUNK_HXX
+#define MPD_MUSIC_CHUNK_HXX
+
+#include "replay_gain_info.h"
+
+#ifndef NDEBUG
+#include "audio_format.h"
+#endif
+
+#include <stdint.h>
+#include <stddef.h>
+
+enum {
+	CHUNK_SIZE = 4096,
+};
+
+struct audio_format;
+
+/**
+ * A chunk of music data.  Its format is defined by the
+ * music_pipe_append() caller.
+ */
+struct music_chunk {
+	/** the next chunk in a linked list */
+	struct music_chunk *next;
+
+	/**
+	 * An optional chunk which should be mixed into this chunk.
+	 * This is used for cross-fading.
+	 */
+	struct music_chunk *other;
+
+	/**
+	 * The current mix ratio for cross-fading: 1.0 means play 100%
+	 * of this chunk, 0.0 means play 100% of the "other" chunk.
+	 */
+	float mix_ratio;
+
+	/** number of bytes stored in this chunk */
+	uint16_t length;
+
+	/** current bit rate of the source file */
+	uint16_t bit_rate;
+
+	/** the time stamp within the song */
+	float times;
+
+	/**
+	 * An optional tag associated with this chunk (and the
+	 * following chunks); appears at song boundaries.  The tag
+	 * object is owned by this chunk, and must be freed when this
+	 * chunk is deinitialized in music_chunk_free()
+	 */
+	struct tag *tag;
+
+	/**
+	 * Replay gain information associated with this chunk.
+	 * Only valid if the serial is not 0.
+	 */
+	struct replay_gain_info replay_gain_info;
+
+	/**
+	 * A serial number for checking if replay gain info has
+	 * changed since the last chunk.  The magic value 0 indicates
+	 * that there is no replay gain info available.
+	 */
+	unsigned replay_gain_serial;
+
+	/** the data (probably PCM) */
+	char data[CHUNK_SIZE];
+
+#ifndef NDEBUG
+	struct audio_format audio_format;
+#endif
+};
+
+void
+music_chunk_init(struct music_chunk *chunk);
+
+void
+music_chunk_free(struct music_chunk *chunk);
+
+static inline bool
+music_chunk_is_empty(const struct music_chunk *chunk)
+{
+	return chunk->length == 0 && chunk->tag == NULL;
+}
+
+#ifndef NDEBUG
+/**
+ * Checks if the audio format if the chunk is equal to the specified
+ * audio_format.
+ */
+bool
+music_chunk_check_format(const struct music_chunk *chunk,
+			 const struct audio_format *audio_format);
+#endif
+
+/**
+ * Prepares appending to the music chunk.  Returns a buffer where you
+ * may write into.  After you are finished, call music_chunk_expand().
+ *
+ * @param chunk the music_chunk object
+ * @param audio_format the audio format for the appended data; must
+ * stay the same for the life cycle of this chunk
+ * @param data_time the time within the song
+ * @param bit_rate the current bit rate of the source file
+ * @param max_length_r the maximum write length is returned here
+ * @return a writable buffer, or NULL if the chunk is full
+ */
+void *
+music_chunk_write(struct music_chunk *chunk,
+		  const struct audio_format *audio_format,
+		  float data_time, uint16_t bit_rate,
+		  size_t *max_length_r);
+
+/**
+ * Increases the length of the chunk after the caller has written to
+ * the buffer returned by music_chunk_write().
+ *
+ * @param chunk the music_chunk object
+ * @param audio_format the audio format for the appended data; must
+ * stay the same for the life cycle of this chunk
+ * @param length the number of bytes which were appended
+ * @return true if the chunk is full
+ */
+bool
+music_chunk_expand(struct music_chunk *chunk,
+		   const struct audio_format *audio_format, size_t length);
+
+#endif