replay_gain_state: moved code to replay_gain_tuple_scale()

Moved (and renamed) the function calc_replay_gain_scale() to
replay_gain_info.c.

src/replay_gain_info.c

@@ -21,6 +21,7 @@
 #include "replay_gain_info.h"
 
 #include <glib.h>
+#include <math.h>
 
 struct replay_gain_info *
 replay_gain_info_new(void)
@@ -46,3 +47,19 @@ replay_gain_info_free(struct replay_gain_info *info)
 {
 	g_free(info);
 }
+
+float
+replay_gain_tuple_scale(const struct replay_gain_tuple *tuple, float preamp)
+{
+	float scale;
+
+	scale = pow(10.0, tuple->gain / 20.0);
+	scale *= preamp;
+	if (scale > 15.0)
+		scale = 15.0;
+
+	if (scale * tuple->peak > 1.0)
+		scale = 1.0 / tuple->peak;
+
+	return scale;
+}

src/replay_gain_info.h

@@ -57,4 +57,7 @@ replay_gain_tuple_defined(const struct replay_gain_tuple *tuple)
 	return tuple->gain > 0.0;
 }
 
+float
+replay_gain_tuple_scale(const struct replay_gain_tuple *tuple, float preamp);
+
 #endif

src/replay_gain_state.c

@@ -24,7 +24,6 @@
 #include <glib.h>
 
 #include <assert.h>
-#include <math.h>
 
 struct replay_gain_state {
 	float preamp, missing_preamp;
@@ -60,22 +59,6 @@ replay_gain_state_free(struct replay_gain_state *state)
 	g_free(state);
 }
 
-static float
-calc_replay_gain_scale(float gain, float peak, float preamp)
-{
-	float scale;
-
-	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)
 {
@@ -90,8 +73,7 @@ replay_gain_state_calc_scale(struct replay_gain_state *state)
 		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);
+		state->scale = replay_gain_tuple_scale(tuple, state->preamp);
 	} else
 		state->scale = state->missing_preamp;
 }