pcm_utils: moved code to pcm_resample.c

Separate the resampling code from the rest of pcm_utils.c.  Create two
sub-libraries: pcm_resample_libsamplerate.c and
pcm_resample_fallback.c.

src/pcm_resample_libsamplerate.c

@@ -0,0 +1,140 @@
+/* the Music Player Daemon (MPD)
+ * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
+ * Copyright (C) 2008 Max Kellermann <max@duempel.org>
+ * This project's homepage is: 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "pcm_resample.h"
+#include "conf.h"
+#include "log.h"
+#include "utils.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+static int pcm_resample_get_converter(void)
+{
+	const char *conf = getConfigParamValue(CONF_SAMPLERATE_CONVERTER);
+	long convalgo;
+	char *test;
+	const char *test2;
+	size_t len;
+
+	if (!conf) {
+		convalgo = SRC_SINC_FASTEST;
+		goto out;
+	}
+
+	convalgo = strtol(conf, &test, 10);
+	if (*test == '\0' && src_get_name(convalgo))
+		goto out;
+
+	len = strlen(conf);
+	for (convalgo = 0 ; ; convalgo++) {
+		test2 = src_get_name(convalgo);
+		if (!test2) {
+			convalgo = SRC_SINC_FASTEST;
+			break;
+		}
+		if (strncasecmp(test2, conf, len) == 0)
+			goto out;
+	}
+
+	ERROR("unknown samplerate converter \"%s\"\n", conf);
+out:
+	DEBUG("selecting samplerate converter \"%s\"\n",
+	      src_get_name(convalgo));
+
+	return convalgo;
+}
+
+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)
+{
+	static int convalgo = -1;
+	SRC_DATA *data = &state->data;
+	size_t data_in_size;
+	size_t data_out_size;
+	int error;
+
+	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 ||
+	    src_rate != state->prev.src_rate ||
+	    dest_rate != state->prev.dest_rate) {
+		state->error = false;
+		state->prev.channels = channels;
+		state->prev.src_rate = src_rate;
+		state->prev.dest_rate = dest_rate;
+
+		if (state->state)
+			state->state = src_delete(state->state);
+
+		state->state = src_new(convalgo, channels, &error);
+		if (!state->state) {
+			ERROR("cannot create new libsamplerate state: %s\n",
+			      src_strerror(error));
+			state->error = true;
+			return 0;
+		}
+
+		data->src_ratio = (double)dest_rate / (double)src_rate;
+		DEBUG("setting samplerate conversion ratio to %.2lf\n",
+		      data->src_ratio);
+		src_set_ratio(state->state, data->src_ratio);
+	}
+
+	/* there was an error previously, and nothing has changed */
+	if (state->error)
+		return 0;
+
+	data->input_frames = src_size / 2 / channels;
+	data_in_size = data->input_frames * sizeof(float) * channels;
+	if (data_in_size > state->data_in_size) {
+		state->data_in_size = data_in_size;
+		data->data_in = xrealloc(data->data_in, data_in_size);
+	}
+
+	data->output_frames = dest_size / 2 / channels;
+	data_out_size = data->output_frames * sizeof(float) * channels;
+	if (data_out_size > state->data_out_size) {
+		state->data_out_size = data_out_size;
+		data->data_out = xrealloc(data->data_out, data_out_size);
+	}
+
+	src_short_to_float_array(src_buffer, data->data_in,
+				 data->input_frames * channels);
+
+	error = src_process(state->state, data);
+	if (error) {
+		ERROR("error processing samples with libsamplerate: %s\n",
+		      src_strerror(error));
+		state->error = true;
+		return 0;
+	}
+
+	src_float_to_short_array(data->data_out, dest_buffer,
+				 data->output_frames_gen * channels);
+
+	return data->output_frames_gen * 2 * channels;
+}