1 files changed, 315 insertions, 0 deletions
diff --git a/src/AudioFormat.hxx b/src/AudioFormat.hxx
new file mode 100644
index 000000000..eb3f9b062
--- /dev/null
+++ b/src/AudioFormat.hxx
@@ -0,0 +1,315 @@
+/*
+ * Copyright (C) 2003-2013 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_AUDIO_FORMAT_HXX
+#define MPD_AUDIO_FORMAT_HXX
+
+#include "gcc.h"
+
+#include <stdint.h>
+#include <assert.h>
+
+#if defined(WIN32) && GCC_CHECK_VERSION(4,6)
+/* on WIN32, "FLOAT" is already defined, and this triggers -Wshadow */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wshadow"
+#endif
+
+enum class SampleFormat : uint8_t {
+	UNDEFINED = 0,
+
+	S8,
+	S16,
+
+	/**
+	 * Signed 24 bit integer samples, packed in 32 bit integers
+	 * (the most significant byte is filled with the sign bit).
+	 */
+	S24_P32,
+
+	S32,
+
+	/**
+	 * 32 bit floating point samples in the host's format.  The
+	 * range is -1.0f to +1.0f.
+	 */
+	FLOAT,
+
+	/**
+	 * Direct Stream Digital.  1-bit samples; each frame has one
+	 * byte (8 samples) per channel.
+	 */
+	DSD,
+};
+
+#if defined(WIN32) && GCC_CHECK_VERSION(4,6)
+#pragma GCC diagnostic pop
+#endif
+
+static constexpr unsigned MAX_CHANNELS = 8;
+
+/**
+ * This structure describes the format of a raw PCM stream.
+ */
+struct AudioFormat {
+	/**
+	 * The sample rate in Hz.  A better name for this attribute is
+	 * "frame rate", because technically, you have two samples per
+	 * frame in stereo sound.
+	 */
+	uint32_t sample_rate;
+
+	/**
+	 * The format samples are stored in.  See the #sample_format
+	 * enum for valid values.
+	 */
+	SampleFormat format;
+
+	/**
+	 * The number of channels.  Only mono (1) and stereo (2) are
+	 * fully supported currently.
+	 */
+	uint8_t channels;
+
+	AudioFormat() = default;
+
+	constexpr AudioFormat(uint32_t _sample_rate,
+			      SampleFormat _format, uint8_t _channels)
+		:sample_rate(_sample_rate),
+		 format(_format), channels(_channels) {}
+
+	static constexpr AudioFormat Undefined() {
+		return AudioFormat(0, SampleFormat::UNDEFINED,0);
+	}
+
+	/**
+	 * Clears the #audio_format object, i.e. sets all attributes to an
+	 * undefined (invalid) value.
+	 */
+	void Clear() {
+		sample_rate = 0;
+		format = SampleFormat::UNDEFINED;
+		channels = 0;
+	}
+
+	/**
+	 * Checks whether the object has a defined value.
+	 */
+	constexpr bool IsDefined() const {
+		return sample_rate != 0;
+	}
+
+	/**
+	 * Checks whether the object is full, i.e. all attributes are
+	 * defined.  This is more complete than IsDefined(), but
+	 * slower.
+	 */
+	constexpr bool IsFullyDefined() const {
+		return sample_rate != 0 && format != SampleFormat::UNDEFINED &&
+			channels != 0;
+	}
+
+	/**
+	 * Checks whether the object has at least one defined value.
+	 */
+	constexpr bool IsMaskDefined() const {
+		return sample_rate != 0 || format != SampleFormat::UNDEFINED ||
+			channels != 0;
+	}
+
+	bool IsValid() const;
+	bool IsMaskValid() const;
+
+	constexpr bool operator==(const AudioFormat other) const {
+		return sample_rate == other.sample_rate &&
+			format == other.format &&
+			channels == other.channels;
+	}
+
+	constexpr bool operator!=(const AudioFormat other) const {
+		return !(*this == other);
+	}
+
+	void ApplyMask(AudioFormat mask);
+
+	/**
+	 * Returns the size of each (mono) sample in bytes.
+	 */
+	unsigned GetSampleSize() const;
+
+	/**
+	 * Returns the size of each full frame in bytes.
+	 */
+	unsigned GetFrameSize() const;
+
+	/**
+	 * Returns the floating point factor which converts a time
+	 * span to a storage size in bytes.
+	 */
+	double GetTimeToSize() const;
+};
+
+/**
+ * Buffer for audio_format_string().
+ */
+struct audio_format_string {
+	char buffer[24];
+};
+
+/**
+ * Checks whether the sample rate is valid.
+ *
+ * @param sample_rate the sample rate in Hz
+ */
+static constexpr inline bool
+audio_valid_sample_rate(unsigned sample_rate)
+{
+	return sample_rate > 0 && sample_rate < (1 << 30);
+}
+
+/**
+ * Checks whether the sample format is valid.
+ *
+ * @param bits the number of significant bits per sample
+ */
+static inline bool
+audio_valid_sample_format(SampleFormat format)
+{
+	switch (format) {
+	case SampleFormat::S8:
+	case SampleFormat::S16:
+	case SampleFormat::S24_P32:
+	case SampleFormat::S32:
+	case SampleFormat::FLOAT:
+	case SampleFormat::DSD:
+		return true;
+
+	case SampleFormat::UNDEFINED:
+		break;
+	}
+
+	return false;
+}
+
+/**
+ * Checks whether the number of channels is valid.
+ */
+static constexpr inline bool
+audio_valid_channel_count(unsigned channels)
+{
+	return channels >= 1 && channels <= MAX_CHANNELS;
+}
+
+/**
+ * Returns false if the format is not valid for playback with MPD.
+ * This function performs some basic validity checks.
+ */
+inline bool
+AudioFormat::IsValid() const
+{
+	return audio_valid_sample_rate(sample_rate) &&
+		audio_valid_sample_format(format) &&
+		audio_valid_channel_count(channels);
+}
+
+/**
+ * Returns false if the format mask is not valid for playback with
+ * MPD.  This function performs some basic validity checks.
+ */
+inline bool
+AudioFormat::IsMaskValid() const
+{
+	return (sample_rate == 0 ||
+		audio_valid_sample_rate(sample_rate)) &&
+		(format == SampleFormat::UNDEFINED ||
+		 audio_valid_sample_format(format)) &&
+		(channels == 0 || audio_valid_channel_count(channels));
+}
+
+gcc_const
+static inline unsigned
+sample_format_size(SampleFormat format)
+{
+	switch (format) {
+	case SampleFormat::S8:
+		return 1;
+
+	case SampleFormat::S16:
+		return 2;
+
+	case SampleFormat::S24_P32:
+	case SampleFormat::S32:
+	case SampleFormat::FLOAT:
+		return 4;
+
+	case SampleFormat::DSD:
+		/* each frame has 8 samples per channel */
+		return 1;
+
+	case SampleFormat::UNDEFINED:
+		return 0;
+	}
+
+	assert(false);
+	gcc_unreachable();
+}
+
+inline unsigned
+AudioFormat::GetSampleSize() const
+{
+	return sample_format_size(format);
+}
+
+inline unsigned
+AudioFormat::GetFrameSize() const
+{
+	return GetSampleSize() * channels;
+}
+
+inline double
+AudioFormat::GetTimeToSize() const
+{
+	return sample_rate * GetFrameSize();
+}
+
+/**
+ * Renders a #sample_format enum into a string, e.g. for printing it
+ * in a log file.
+ *
+ * @param format a #sample_format enum value
+ * @return the string
+ */
+gcc_pure gcc_malloc
+const char *
+sample_format_to_string(SampleFormat format);
+
+/**
+ * Renders the #audio_format object into a string, e.g. for printing
+ * it in a log file.
+ *
+ * @param af the #audio_format object
+ * @param s a buffer to print into
+ * @return the string, or NULL if the #audio_format object is invalid
+ */
+gcc_pure gcc_malloc
+const char *
+audio_format_to_string(AudioFormat af,
+		       struct audio_format_string *s);
+
+#endif