Tag*: move libtag.a sources to src/tag/

1 files changed, 150 insertions, 0 deletions

diff --git a/src/tag/TagRva2.cxx b/src/tag/TagRva2.cxx
new file mode 100644
index 000000000..f41119c35
--- /dev/null
+++ b/src/tag/TagRva2.cxx
@@ -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.
+ */
+
+#include "config.h"
+#include "TagRva2.hxx"
+#include "replay_gain_info.h"
+
+#include <stdint.h>
+#include <string.h>
+#include <glib.h>
+#include <id3tag.h>
+
+enum rva2_channel {
+	CHANNEL_OTHER = 0x00,
+	CHANNEL_MASTER_VOLUME = 0x01,
+	CHANNEL_FRONT_RIGHT = 0x02,
+	CHANNEL_FRONT_LEFT = 0x03,
+	CHANNEL_BACK_RIGHT = 0x04,
+	CHANNEL_BACK_LEFT = 0x05,
+	CHANNEL_FRONT_CENTRE = 0x06,
+	CHANNEL_BACK_CENTRE = 0x07,
+	CHANNEL_SUBWOOFER = 0x08
+};
+
+struct rva2_data {
+	uint8_t type;
+	uint8_t volume_adjustment[2];
+	uint8_t peak_bits;
+};
+
+static inline id3_length_t
+rva2_peak_bytes(const struct rva2_data *data)
+{
+	return (data->peak_bits + 7) / 8;
+}
+
+static inline int
+rva2_fixed_volume_adjustment(const struct rva2_data *data)
+{
+	signed int voladj_fixed;
+	voladj_fixed = (data->volume_adjustment[0] << 8) |
+		data->volume_adjustment[1];
+	voladj_fixed |= -(voladj_fixed & 0x8000);
+	return voladj_fixed;
+}
+
+static inline float
+rva2_float_volume_adjustment(const struct rva2_data *data)
+{
+	/*
+	 * "The volume adjustment is encoded as a fixed point decibel
+	 * value, 16 bit signed integer representing (adjustment*512),
+	 * giving +/- 64 dB with a precision of 0.001953125 dB."
+	 */
+
+	return (float)rva2_fixed_volume_adjustment(data) / (float)512;
+}
+
+static inline bool
+rva2_apply_data(struct replay_gain_info *replay_gain_info,
+		const struct rva2_data *data, const id3_latin1_t *id)
+{
+	if (data->type != CHANNEL_MASTER_VOLUME)
+		return false;
+
+	float volume_adjustment = rva2_float_volume_adjustment(data);
+
+	if (strcmp((const char *)id, "album") == 0)  {
+		replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = volume_adjustment;
+	} else if (strcmp((const char *)id, "track") == 0) {
+		replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = volume_adjustment;
+	} else {
+		replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = volume_adjustment;
+		replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = volume_adjustment;
+	}
+
+	return true;
+}
+
+static bool
+rva2_apply_frame(struct replay_gain_info *replay_gain_info,
+		 const struct id3_frame *frame)
+{
+	const id3_latin1_t *id = id3_field_getlatin1(id3_frame_field(frame, 0));
+	id3_length_t length;
+	const id3_byte_t *data =
+		id3_field_getbinarydata(id3_frame_field(frame, 1), &length);
+
+	if (id == nullptr || data == nullptr)
+		return false;
+
+	/*
+	 * "The 'identification' string is used to identify the
+	 * situation and/or device where this adjustment should apply.
+	 * The following is then repeated for every channel
+	 *
+	 *   Type of channel         $xx
+	 *   Volume adjustment       $xx xx
+	 *   Bits representing peak  $xx
+	 *   Peak volume             $xx (xx ...)"
+	 */
+
+	while (length >= 4) {
+		const struct rva2_data *d = (const struct rva2_data *)data;
+		unsigned int peak_bytes = rva2_peak_bytes(d);
+		if (4 + peak_bytes > length)
+			break;
+
+		if (rva2_apply_data(replay_gain_info, d, id))
+			return true;
+
+		data   += 4 + peak_bytes;
+		length -= 4 + peak_bytes;
+	}
+
+	return false;
+}
+
+bool
+tag_rva2_parse(struct id3_tag *tag, struct replay_gain_info *replay_gain_info)
+{
+	bool found = false;
+
+	/* Loop through all RVA2 frames as some programs (e.g. mp3gain) store
+	   track and album gain in separate tags */
+	const struct id3_frame *frame;
+	for (unsigned i = 0;
+	     (frame = id3_tag_findframe(tag, "RVA2", i)) != nullptr;
+	     ++i)
+		if (rva2_apply_frame(replay_gain_info, frame))
+			found = true;
+
+	return found;
+}