Filter*: move to filter/

1 files changed, 296 insertions, 0 deletions

diff --git a/src/filter/plugins/RouteFilterPlugin.cxx b/src/filter/plugins/RouteFilterPlugin.cxx
new file mode 100644
index 000000000..38c4ec43b
--- /dev/null
+++ b/src/filter/plugins/RouteFilterPlugin.cxx
@@ -0,0 +1,296 @@
+/*
+ * Copyright (C) 2003-2014 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.
+ */
+
+/** \file
+ *
+ * This filter copies audio data between channels. Useful for
+ * upmixing mono/stereo audio to surround speaker configurations.
+ *
+ * Its configuration consists of a "filter" section with a single
+ * "routes" entry, formatted as: \\
+ * routes "0>1, 1>0, 2>2, 3>3, 3>4" \\
+ * where each pair of numbers signifies a set of channels.
+ * Each source>dest pair leads to the data from channel #source
+ * being copied to channel #dest in the output.
+ *
+ * Example: \\
+ * routes "0>0, 1>1, 0>2, 1>3"\\
+ * upmixes stereo audio to a 4-speaker system, copying the front-left
+ * (0) to front left (0) and rear left (2), copying front-right (1) to
+ * front-right (1) and rear-right (3).
+ *
+ * If multiple sources are copied to the same destination channel, only
+ * one of them takes effect.
+ */
+
+#include "config.h"
+#include "config/ConfigError.hxx"
+#include "config/ConfigData.hxx"
+#include "AudioFormat.hxx"
+#include "filter/FilterPlugin.hxx"
+#include "filter/FilterInternal.hxx"
+#include "filter/FilterRegistry.hxx"
+#include "pcm/PcmBuffer.hxx"
+#include "util/StringUtil.hxx"
+#include "util/Error.hxx"
+
+#include <algorithm>
+
+#include <assert.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+class RouteFilter final : public Filter {
+	/**
+	 * The minimum number of channels we need for output
+	 * to be able to perform all the copies the user has specified
+	 */
+	unsigned min_output_channels;
+
+	/**
+	 * The minimum number of input channels we need to
+	 * copy all the data the user has requested. If fewer
+	 * than this many are supplied by the input, undefined
+	 * copy operations are given zeroed sources in stead.
+	 */
+	unsigned min_input_channels;
+
+	/**
+	 * The set of copy operations to perform on each sample
+	 * The index is an output channel to use, the value is
+	 * a corresponding input channel from which to take the
+	 * data. A -1 means "no source"
+	 */
+	int8_t sources[MAX_CHANNELS];
+
+	/**
+	 * The actual input format of our signal, once opened
+	 */
+	AudioFormat input_format;
+
+	/**
+	 * The decided upon output format, once opened
+	 */
+	AudioFormat output_format;
+
+	/**
+	 * The size, in bytes, of each multichannel frame in the
+	 * input buffer
+	 */
+	size_t input_frame_size;
+
+	/**
+	 * The size, in bytes, of each multichannel frame in the
+	 * output buffer
+	 */
+	size_t output_frame_size;
+
+	/**
+	 * The output buffer used last time around, can be reused if the size doesn't differ.
+	 */
+	PcmBuffer output_buffer;
+
+public:
+	/**
+	 * Parse the "routes" section, a string on the form
+	 *  a>b, c>d, e>f, ...
+	 * where a... are non-unique, non-negative integers
+	 * and input channel a gets copied to output channel b, etc.
+	 * @param param the configuration block to read
+	 * @param filter a route_filter whose min_channels and sources[] to set
+	 * @return true on success, false on error
+	 */
+	bool Configure(const config_param &param, Error &error);
+
+	virtual AudioFormat Open(AudioFormat &af, Error &error) override;
+	virtual void Close();
+	virtual const void *FilterPCM(const void *src, size_t src_size,
+				      size_t *dest_size_r, Error &error);
+};
+
+bool
+RouteFilter::Configure(const config_param &param, Error &error) {
+
+	/* TODO:
+	 * With a more clever way of marking "don't copy to output N",
+	 * This could easily be merged into a single loop with some
+	 * dynamic realloc() instead of one count run and one malloc().
+	 */
+
+	std::fill_n(sources, MAX_CHANNELS, -1);
+
+	min_input_channels = 0;
+	min_output_channels = 0;
+
+	// A cowardly default, just passthrough stereo
+	const char *routes = param.GetBlockValue("routes", "0>0, 1>1");
+	while (true) {
+		routes = strchug_fast(routes);
+
+		char *endptr;
+		const unsigned source = strtoul(routes, &endptr, 10);
+		endptr = strchug_fast(endptr);
+		if (endptr == routes || *endptr != '>') {
+			error.Set(config_domain,
+				  "Malformed 'routes' specification");
+			return false;
+		}
+
+		if (source >= MAX_CHANNELS) {
+			error.Format(config_domain,
+				     "Invalid source channel number: %u",
+				     source);
+			return false;
+		}
+
+		if (source >= min_input_channels)
+			min_input_channels = source + 1;
+
+		routes = strchug_fast(endptr + 1);
+
+		unsigned dest = strtoul(routes, &endptr, 10);
+		endptr = strchug_fast(endptr);
+		if (endptr == routes) {
+			error.Set(config_domain,
+				  "Malformed 'routes' specification");
+			return false;
+		}
+
+		if (dest >= MAX_CHANNELS) {
+			error.Format(config_domain,
+				     "Invalid destination channel number: %u",
+				     dest);
+			return false;
+		}
+
+		if (dest >= min_output_channels)
+			min_output_channels = dest + 1;
+
+		sources[dest] = source;
+
+		routes = endptr;
+
+		if (*routes == 0)
+			break;
+
+		if (*routes != ',') {
+			error.Set(config_domain,
+				  "Malformed 'routes' specification");
+			return false;
+		}
+
+		++routes;
+	}
+
+	return true;
+}
+
+static Filter *
+route_filter_init(const config_param &param, Error &error)
+{
+	RouteFilter *filter = new RouteFilter();
+	if (!filter->Configure(param, error)) {
+		delete filter;
+		return nullptr;
+	}
+
+	return filter;
+}
+
+AudioFormat
+RouteFilter::Open(AudioFormat &audio_format, gcc_unused Error &error)
+{
+	// Copy the input format for later reference
+	input_format = audio_format;
+	input_frame_size = input_format.GetFrameSize();
+
+	// Decide on an output format which has enough channels,
+	// and is otherwise identical
+	output_format = audio_format;
+	output_format.channels = min_output_channels;
+
+	// Precalculate this simple value, to speed up allocation later
+	output_frame_size = output_format.GetFrameSize();
+
+	return output_format;
+}
+
+void
+RouteFilter::Close()
+{
+	output_buffer.Clear();
+}
+
+const void *
+RouteFilter::FilterPCM(const void *src, size_t src_size,
+		       size_t *dest_size_r, gcc_unused Error &error)
+{
+	size_t number_of_frames = src_size / input_frame_size;
+
+	const size_t bytes_per_frame_per_channel = input_format.GetSampleSize();
+
+	// A moving pointer that always refers to channel 0 in the input, at the currently handled frame
+	const uint8_t *base_source = (const uint8_t *)src;
+
+	// Grow our reusable buffer, if needed, and set the moving pointer
+	*dest_size_r = number_of_frames * output_frame_size;
+	void *const result = output_buffer.Get(*dest_size_r);
+
+	// A moving pointer that always refers to the currently filled channel of the currently handled frame, in the output
+	uint8_t *chan_destination = (uint8_t *)result;
+
+	// Perform our copy operations, with N input channels and M output channels
+	for (unsigned int s=0; s<number_of_frames; ++s) {
+
+		// Need to perform one copy per output channel
+		for (unsigned int c=0; c<min_output_channels; ++c) {
+			if (sources[c] == -1 ||
+			    (unsigned)sources[c] >= input_format.channels) {
+				// No source for this destination output,
+				// give it zeroes as input
+				memset(chan_destination,
+					0x00,
+					bytes_per_frame_per_channel);
+			} else {
+				// Get the data from channel sources[c]
+				// and copy it to the output
+				const uint8_t *data = base_source +
+					(sources[c] * bytes_per_frame_per_channel);
+				memcpy(chan_destination,
+					  data,
+					  bytes_per_frame_per_channel);
+			}
+			// Move on to the next output channel
+			chan_destination += bytes_per_frame_per_channel;
+		}
+
+
+		// Go on to the next N input samples
+		base_source += input_frame_size;
+	}
+
+	// Here it is, ladies and gentlemen! Rerouted data!
+	return result;
+}
+
+const struct filter_plugin route_filter_plugin = {
+	"route",
+	route_filter_init,
+};