pcm_resample: moved code to pcm_resample_set()

A future patch will implement a 24 bit resampler.  To unify code, move
code which can be shared to a separate function.

src/pcm_resample_libsamplerate.c

@@ -62,30 +62,23 @@ out:
 	return convalgo;
 }
 
-size_t
+static void
-pcm_resample_16(uint8_t channels,
+pcm_resample_set(struct pcm_resample_state *state,
-		unsigned src_rate,
+		 uint8_t channels, unsigned src_rate, unsigned dest_rate)
-		const int16_t *src_buffer, size_t src_size,
-		unsigned dest_rate,
-		int16_t *dest_buffer, size_t dest_size,
-		struct pcm_resample_state *state)
 {
 	static int convalgo = -1;
-	SRC_DATA *data = &state->data;
-	size_t data_in_size;
-	size_t data_out_size;
 	int error;
-
+	SRC_DATA *data = &state->data;
-	assert((src_size % (sizeof(*src_buffer) * channels)) == 0);
-	assert((dest_size % (sizeof(*dest_buffer) * channels)) == 0);
 
 	if (convalgo < 0)
 		convalgo = pcm_resample_get_converter();
 
 	/* (re)set the state/ratio if the in or out format changed */
-	if (channels != state->prev.channels ||
+	if (channels == state->prev.channels &&
-	    src_rate != state->prev.src_rate ||
+	    src_rate == state->prev.src_rate &&
-	    dest_rate != state->prev.dest_rate) {
+	    dest_rate == state->prev.dest_rate)
+		return;
+
 	state->error = false;
 	state->prev.channels = channels;
 	state->prev.src_rate = src_rate;
@@ -99,7 +92,7 @@ pcm_resample_16(uint8_t channels,
 		ERROR("cannot create new libsamplerate state: %s\n",
 		      src_strerror(error));
 		state->error = true;
-			return 0;
+		return;
 	}
 
 	data->src_ratio = (double)dest_rate / (double)src_rate;
@@ -108,6 +101,24 @@ pcm_resample_16(uint8_t channels,
 	src_set_ratio(state->state, data->src_ratio);
 }
 
+size_t
+pcm_resample_16(uint8_t channels,
+		unsigned src_rate,
+		const int16_t *src_buffer, size_t src_size,
+		unsigned dest_rate,
+		int16_t *dest_buffer, size_t dest_size,
+		struct pcm_resample_state *state)
+{
+	SRC_DATA *data = &state->data;
+	size_t data_in_size;
+	size_t data_out_size;
+	int error;
+
+	assert((src_size % (sizeof(*src_buffer) * channels)) == 0);
+	assert((dest_size % (sizeof(*dest_buffer) * channels)) == 0);
+
+	pcm_resample_set(state, channels, src_rate, dest_rate);
+
 	/* there was an error previously, and nothing has changed */
 	if (state->error)
 		return 0;