replay_gain: refactor API, move code to replay_gain_state.c

The replay_gain_state struct holds the precalculated scale factor,
which is removed from struct replay_gain_info.

8 files changed, 209 insertions, 76 deletions

diff --git a/Makefile.am b/Makefile.am
index 12bed50f3..9137ece95 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -169,6 +169,7 @@ mpd_headers = \
 	src/queue_print.h \
 	src/queue_save.h \
 	src/replay_gain.h \
+	src/replay_gain_state.h \
 	src/sig_handlers.h \
 	src/song.h \
 	src/song_print.h \
@@ -295,6 +296,7 @@ src_mpd_SOURCES = \
 	src/queue_print.c \
 	src/queue_save.c \
 	src/replay_gain.c \
+	src/replay_gain_state.c \
 	src/sig_handlers.c \
 	src/song.c \
 	src/song_update.c \
diff --git a/src/decoder_api.c b/src/decoder_api.c
index 5106b564f..8e1e22f9d 100644
--- a/src/decoder_api.c
+++ b/src/decoder_api.c
@@ -27,6 +27,7 @@
 #include "buffer.h"
 #include "pipe.h"
 #include "chunk.h"
+#include "replay_gain_state.h"
 
 #include <glib.h>
 
@@ -352,10 +353,10 @@ decoder_data(struct decoder *decoder,
 
 		/* apply replay gain or normalization */
 
-		if (replay_gain_mode != REPLAY_GAIN_OFF)
-			replay_gain_apply(decoder->replay_gain,
-					  dest, nbytes,
-					  &dc->out_audio_format);
+		replay_gain_state_set_mode(decoder->replay_gain,
+					   replay_gain_mode);
+		replay_gain_state_apply(decoder->replay_gain,
+					dest, nbytes, &dc->out_audio_format);
 
 		/* expand the music pipe chunk */
 
@@ -425,10 +426,5 @@ decoder_replay_gain(struct decoder *decoder,
 {
 	assert(decoder != NULL);
 
-	if (decoder->replay_gain != NULL)
-		replay_gain_info_free(decoder->replay_gain);
-
-	decoder->replay_gain = replay_gain_info != NULL
-		? replay_gain_info_dup(replay_gain_info)
-		: NULL;
+	replay_gain_state_set_info(decoder->replay_gain, replay_gain_info);
 }
diff --git a/src/decoder_internal.h b/src/decoder_internal.h
index b15b06888..159b40b92 100644
--- a/src/decoder_internal.h
+++ b/src/decoder_internal.h
@@ -53,7 +53,7 @@ struct decoder {
 	/** the chunk currently being written to */
 	struct music_chunk *chunk;
 
-	struct replay_gain_info *replay_gain;
+	struct replay_gain_state *replay_gain;
 };
 
 /**
diff --git a/src/decoder_thread.c b/src/decoder_thread.c
index f793fd032..625ec46cc 100644
--- a/src/decoder_thread.c
+++ b/src/decoder_thread.c
@@ -31,7 +31,7 @@
 #include "mapper.h"
 #include "path.h"
 #include "uri.h"
-#include "replay_gain.h"
+#include "replay_gain_state.h"
 
 #include <glib.h>
 
@@ -303,7 +303,8 @@ decoder_run_song(struct decoder_control *dc,
 {
 	struct decoder decoder = {
 		.dc = dc,
-		.replay_gain = NULL,
+		.replay_gain = replay_gain_state_new(replay_gain_preamp,
+						     replay_gain_missing_preamp),
 	};
 	int ret;
 
@@ -332,7 +333,7 @@ decoder_run_song(struct decoder_control *dc,
 
 	/* flush the last chunk */
 	if (decoder.replay_gain != NULL)
-		replay_gain_info_free(decoder.replay_gain);
+		replay_gain_state_free(decoder.replay_gain);
 
 	if (decoder.chunk != NULL)
 		decoder_flush_chunk(&decoder);
diff --git a/src/replay_gain.c b/src/replay_gain.c
index 482cd4bd3..3537a96ed 100644
--- a/src/replay_gain.c
+++ b/src/replay_gain.c
@@ -23,8 +23,6 @@
 #include "config.h"
 #include "replay_gain.h"
 #include "conf.h"
-#include "audio_format.h"
-#include "pcm_volume.h"
 #include "idle.h"
 
 #include <glib.h>
@@ -41,8 +39,8 @@ static const char *const replay_gain_mode_names[] = {
 
 enum replay_gain_mode replay_gain_mode = REPLAY_GAIN_OFF;
 
-static float replay_gain_preamp = 1.0;
-static float replay_gain_missing_preamp = 1.0;
+float replay_gain_preamp = 1.0;
+float replay_gain_missing_preamp = 1.0;
 
 const char *
 replay_gain_get_mode_string(void)
@@ -130,23 +128,6 @@ void replay_gain_global_init(void)
 	}
 }
 
-static float calc_replay_gain_scale(float gain, float peak)
-{
-	float scale;
-
-	if (gain == 0.0)
-		return (1);
-	scale = pow(10.0, gain / 20.0);
-	scale *= replay_gain_preamp;
-	if (scale > 15.0)
-		scale = 15.0;
-
-	if (scale * peak > 1.0) {
-		scale = 1.0 / peak;
-	}
-	return (scale);
-}
-
 struct replay_gain_info *replay_gain_info_new(void)
 {
 	struct replay_gain_info *ret = g_new(struct replay_gain_info, 1);
@@ -156,9 +137,6 @@ struct replay_gain_info *replay_gain_info_new(void)
 		ret->tuples[i].peak = 0.0;
 	}
 
-	/* set to -1 so that we know in replay_gain_apply to compute the scale */
-	ret->scale = -1.0;
-
 	return ret;
 }
 
@@ -172,32 +150,3 @@ void replay_gain_info_free(struct replay_gain_info *info)
 {
 	g_free(info);
 }
-
-void
-replay_gain_apply(struct replay_gain_info *info, char *buffer, int size,
-		  const struct audio_format *format)
-{
-	float scale;
-
-	if (replay_gain_mode == REPLAY_GAIN_OFF)
-		return;
-
-	if (info) {
-	    if (info->scale < 0) {
-		    const struct replay_gain_tuple *tuple =
-			    &info->tuples[replay_gain_mode];
-
-		    g_debug("computing ReplayGain %s scale with gain %f, peak %f\n",
-			    replay_gain_mode_names[replay_gain_mode],
-			    tuple->gain, tuple->peak);
-
-		    info->scale = calc_replay_gain_scale(tuple->gain, tuple->peak);
-	    }
-	    scale = info->scale;
-	}
-	else {
-	    scale = replay_gain_missing_preamp;
-	}
-
-	pcm_volume(buffer, size, format, pcm_float_to_volume(scale));
-}
diff --git a/src/replay_gain.h b/src/replay_gain.h
index b26512975..c27e2be06 100644
--- a/src/replay_gain.h
+++ b/src/replay_gain.h
@@ -31,9 +31,9 @@ enum replay_gain_mode {
 	REPLAY_GAIN_TRACK,
 };
 
-struct audio_format;
-
 extern enum replay_gain_mode replay_gain_mode;
+extern float replay_gain_preamp;
+extern float replay_gain_missing_preamp;
 
 struct replay_gain_tuple {
 	float gain;
@@ -42,9 +42,6 @@ struct replay_gain_tuple {
 
 struct replay_gain_info {
 	struct replay_gain_tuple tuples[2];
-
-	/* used internally by mpd, to mess with it */
-	float scale;
 };
 
 struct replay_gain_info *
@@ -74,8 +71,4 @@ replay_gain_get_mode_string(void);
 bool
 replay_gain_set_mode_string(const char *p);
 
-void
-replay_gain_apply(struct replay_gain_info *info, char *buffer, int bufferSize,
-		  const struct audio_format *format);
-
 #endif
diff --git a/src/replay_gain_state.c b/src/replay_gain_state.c
new file mode 100644
index 000000000..c14ff6e10
--- /dev/null
+++ b/src/replay_gain_state.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2003-2010 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 "replay_gain_state.h"
+#include "pcm_volume.h"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <math.h>
+
+struct replay_gain_state {
+	float preamp, missing_preamp;
+
+	enum replay_gain_mode mode;
+
+	struct replay_gain_info *info;
+
+	float scale;
+};
+
+struct replay_gain_state *
+replay_gain_state_new(float preamp, float missing_preamp)
+{
+	struct replay_gain_state *state = g_new(struct replay_gain_state, 1);
+
+	state->preamp = preamp;
+	state->missing_preamp = missing_preamp;
+	state->mode = REPLAY_GAIN_OFF;
+	state->info = NULL;
+
+	return state;
+}
+
+void
+replay_gain_state_free(struct replay_gain_state *state)
+{
+	assert(state != NULL);
+
+	if (state->info != NULL)
+		replay_gain_info_free(state->info);
+
+	g_free(state);
+}
+
+static float
+calc_replay_gain_scale(float gain, float peak, float preamp)
+{
+	float scale;
+
+	if (gain == 0.0)
+		return (1);
+	scale = pow(10.0, gain / 20.0);
+	scale *= preamp;
+	if (scale > 15.0)
+		scale = 15.0;
+
+	if (scale * peak > 1.0) {
+		scale = 1.0 / peak;
+	}
+	return (scale);
+}
+
+static void
+replay_gain_state_calc_scale(struct replay_gain_state *state)
+{
+	assert(state != NULL);
+
+	if (state->mode == REPLAY_GAIN_OFF || state->info == NULL)
+		return;
+
+	const struct replay_gain_tuple *tuple =
+		&state->info->tuples[state->mode];
+
+	g_debug("computing ReplayGain scale with gain %f, peak %f",
+		tuple->gain, tuple->peak);
+
+	state->scale = calc_replay_gain_scale(tuple->gain, tuple->peak,
+					      state->preamp);
+}
+
+void
+replay_gain_state_set_mode(struct replay_gain_state *state,
+			   enum replay_gain_mode mode)
+{
+	assert(state != NULL);
+
+	if (mode == state->mode)
+		return;
+
+	state->mode = mode;
+
+	replay_gain_state_calc_scale(state);
+}
+
+void
+replay_gain_state_set_info(struct replay_gain_state *state,
+			   const struct replay_gain_info *info)
+{
+	assert(state != NULL);
+
+	if (state->info != NULL)
+		replay_gain_info_free(state->info);
+
+	state->info = info != NULL
+		? replay_gain_info_dup(info)
+		: NULL;
+
+	replay_gain_state_calc_scale(state);
+}
+
+void
+replay_gain_state_apply(const struct replay_gain_state *state,
+			void *buffer, size_t size,
+			const struct audio_format *format)
+{
+	assert(state != NULL);
+
+	if (state->mode == REPLAY_GAIN_OFF)
+		return;
+
+	float scale = state->info != NULL
+		? state->scale : state->missing_preamp;
+	pcm_volume(buffer, size, format, pcm_float_to_volume(scale));
+}
diff --git a/src/replay_gain_state.h b/src/replay_gain_state.h
new file mode 100644
index 000000000..7fa476095
--- /dev/null
+++ b/src/replay_gain_state.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2003-2010 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_REPLAY_GAIN_STATE_H
+#define MPD_REPLAY_GAIN_STATE_H
+
+#include "check.h"
+#include "replay_gain.h"
+
+#include <stddef.h>
+
+struct replay_gain_state;
+struct audio_format;
+
+struct replay_gain_state *
+replay_gain_state_new(float preamp, float missing_preamp);
+
+void
+replay_gain_state_free(struct replay_gain_state *state);
+
+void
+replay_gain_state_set_mode(struct replay_gain_state *state,
+			   enum replay_gain_mode mode);
+
+void
+replay_gain_state_set_info(struct replay_gain_state *state,
+			   const struct replay_gain_info *info);
+
+void
+replay_gain_state_apply(const struct replay_gain_state *state,
+			void *buffer, size_t size,
+			const struct audio_format *format);
+
+#endif