BACKENDS: Add a Linux CD-ROM audio player

backends/audiocd/linux/linux-audiocd.cpp

@@ -0,0 +1,350 @@
+/* Cabal - Legacy Game Implementations
+ *
+ * Cabal is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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.
+ *
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <linux/cdrom.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+
+#include "backends/audiocd/linux/linux-audiocd.h"
+
+#include "audio/audiostream.h"
+#include "backends/audiocd/default/default-audiocd.h"
+#include "common/array.h"
+#include "common/str.h"
+#include "common/debug.h"
+
+enum {
+	kLeadoutTrack = 0xAA
+};
+
+enum {
+	kBytesPerFrame = 2352,
+	kSamplesPerFrame = kBytesPerFrame / 2
+};
+
+enum {
+	kSecondsPerMinute = 60,
+	kFramesPerSecond = 75
+};
+
+static int getFrameCount(const cdrom_msf0 &msf) {
+	int time = msf.minute;
+	time *= kSecondsPerMinute;
+	time += msf.second;
+	time *= kFramesPerSecond;
+	time += msf.frame;
+	return time;
+}
+
+class LinuxAudioCDStream : public Audio::SeekableAudioStream {
+public:
+	LinuxAudioCDStream(int fd, const cdrom_tocentry &startEntry, const cdrom_tocentry &endEntry);
+
+	int readBuffer(int16 *buffer, const int numSamples);
+	bool isStereo() const { return true; }
+	int getRate() const { return 44100; }
+	bool endOfData() const;
+	bool seek(const Audio::Timestamp &where);
+	Audio::Timestamp getLength() const;
+
+private:
+	int _fd;
+	const cdrom_tocentry &_startEntry, &_endEntry;
+	int16 _buffer[kSamplesPerFrame];
+	int _frame;
+	uint _bufferPos;
+};
+
+LinuxAudioCDStream::LinuxAudioCDStream(int fd, const cdrom_tocentry &startEntry, const cdrom_tocentry &endEntry) :
+		_fd(fd), _startEntry(startEntry), _endEntry(endEntry), _buffer(), _frame(0), _bufferPos(kSamplesPerFrame) {
+}
+
+int LinuxAudioCDStream::readBuffer(int16 *buffer, const int numSamples) {
+	int samples = 0;
+
+	// See if any data is left first
+	while (_bufferPos < kSamplesPerFrame && samples < numSamples)
+		buffer[samples++] = _buffer[_bufferPos++];
+
+	// Bail out if done
+	if (endOfData())
+		return samples;
+
+	while (samples < numSamples && !endOfData()) {
+		// Figure out the MSF of the frame we're looking for
+		int frame = _frame + getFrameCount(_startEntry.cdte_addr.msf);
+
+		int seconds = frame / kFramesPerSecond;
+		frame %= kFramesPerSecond;
+		int minutes = seconds / kSecondsPerMinute;
+		seconds %= kSecondsPerMinute;
+
+		// Request to read that frame
+		cdrom_read_audio readAudio;
+		readAudio.addr.msf.minute = minutes;
+		readAudio.addr.msf.second = seconds;
+		readAudio.addr.msf.frame = frame;
+		readAudio.addr_format = CDROM_MSF;
+		readAudio.nframes = 1;
+		readAudio.buf = reinterpret_cast<__u8*>(_buffer);
+
+		if (ioctl(_fd, CDROMREADAUDIO, &readAudio) < 0) {
+			warning("Failed to read audio");
+			_frame = getFrameCount(_endEntry.cdte_addr.msf);
+			return samples;
+		}
+
+		_frame++;
+
+		// Copy the samples over
+		for (_bufferPos = 0; _bufferPos < kSamplesPerFrame && samples < numSamples; )
+			buffer[samples++] = _buffer[_bufferPos++];
+	}
+
+	return samples;
+}
+
+bool LinuxAudioCDStream::endOfData() const {
+	return getFrameCount(_startEntry.cdte_addr.msf) + _frame >= getFrameCount(_endEntry.cdte_addr.msf) && _bufferPos == kSamplesPerFrame;
+}
+
+bool LinuxAudioCDStream::seek(const Audio::Timestamp &where) {
+	// Convert to the frame number
+	// Really not much else needed
+	_bufferPos = kSamplesPerFrame;
+	_frame = where.convertToFramerate(kFramesPerSecond).totalNumberOfFrames();
+	return true;
+}
+
+Audio::Timestamp LinuxAudioCDStream::getLength() const {
+	return Audio::Timestamp(0, getFrameCount(_endEntry.cdte_addr.msf) - getFrameCount(_startEntry.cdte_addr.msf), 75);
+}
+
+class LinuxAudioCDManager : public DefaultAudioCDManager {
+public:
+	LinuxAudioCDManager();
+	~LinuxAudioCDManager();
+
+	bool openCD(int drive);
+	void closeCD();
+	void playCD(int track, int numLoops, int startFrame, int duration);
+
+private:
+	struct Device {
+		Device(const Common::String &n, dev_t m) : name(n), mode(m) {}
+		Common::String name;
+		dev_t mode;
+	};
+
+	Common::Array<Device> scanDevices();
+	bool tryAddDrive(const Common::String &drive, Common::Array<Device> &devices);
+	bool loadTOC();
+
+	int _fd;
+	cdrom_tochdr _tocHeader;
+	Common::Array<cdrom_tocentry> _tocEntries;
+};
+
+static bool isTrayEmpty(int errorNumber) {
+	switch (errorNumber) {
+	case EIO:
+	case ENOENT:
+	case EINVAL:
+#ifdef ENOMEDIUM
+	case ENOMEDIUM:
+#endif
+		return true;
+	}
+
+	return false;
+}
+
+LinuxAudioCDManager::LinuxAudioCDManager() {
+	_fd = -1;
+	memset(&_tocHeader, 0, sizeof(_tocHeader));
+}
+
+LinuxAudioCDManager::~LinuxAudioCDManager() {
+	closeCD();
+}
+
+bool LinuxAudioCDManager::openCD(int drive) {
+	closeCD();
+
+	Common::Array<Device> devices = scanDevices();
+	if (devices.empty())
+		return false;
+
+	_fd = open(devices[0].name.c_str(), O_RDONLY | O_NONBLOCK, 0);
+	if (_fd < 0)
+		return false;
+
+	if (!loadTOC()) {
+		closeCD();
+		return false;
+	}
+
+	return true;
+}
+
+void LinuxAudioCDManager::closeCD() {
+	if (_fd < 0)
+		return;
+
+	stop();
+	close(_fd);
+	memset(&_tocHeader, 0, sizeof(_tocHeader));
+	_tocEntries.clear();
+}
+
+void LinuxAudioCDManager::playCD(int track, int numLoops, int startFrame, int duration) {
+	// Stop any previous track
+	stop();
+
+	// HACK: For now, just assume that track number is right
+	// That only works because ScummVM uses the wrong track number anyway	
+
+	if (track >= (int)_tocEntries.size() - 1) {
+		warning("No such track %d", track);
+		return;
+	}
+
+	// Bail if the track isn't an audio track
+	if ((_tocEntries[track].cdte_ctrl & 0x04) != 0) {
+		warning("Track %d is not audio", track);
+		return;
+	}
+
+	// Create the AudioStream and play it
+	debug(1, "Playing CD track %d", track);
+
+	Audio::SeekableAudioStream *audioStream = new LinuxAudioCDStream(_fd, _tocEntries[track], _tocEntries[track + 1]);
+
+	Audio::Timestamp start = Audio::Timestamp(0, startFrame, 75);
+	Audio::Timestamp end = (duration == 0) ? audioStream->getLength() : Audio::Timestamp(0, startFrame + duration, 75);
+
+	// Fake emulation since we're really playing an AudioStream
+	_emulating = true;
+
+	_mixer->playStream(
+		Audio::Mixer::kMusicSoundType,
+		&_handle,
+		Audio::makeLoopingAudioStream(audioStream, start, end, (numLoops < 1) ? numLoops + 1 : numLoops),
+		-1,
+		_cd.volume,
+		_cd.balance,
+		DisposeAfterUse::YES,
+		true);
+}
+
+Common::Array<LinuxAudioCDManager::Device> LinuxAudioCDManager::scanDevices() {
+	Common::Array<Device> devices;
+	tryAddDrive("/dev/cdrom", devices);
+	return devices;
+}
+
+bool LinuxAudioCDManager::tryAddDrive(const Common::String &drive, Common::Array<Device> &devices) {
+	struct stat stbuf;
+	if (stat(drive.c_str(), &stbuf) < 0)
+		return false;
+
+	// Must be a character or block device
+	if (!S_ISCHR(stbuf.st_mode) && !S_ISBLK(stbuf.st_mode))
+		return false;
+
+	// Try opening the device and seeing if it is a CD-ROM drve
+	int fd = open(drive.c_str(), O_RDONLY | O_NONBLOCK, 0);
+	if (fd >= 0) {
+		cdrom_subchnl info;
+		info.cdsc_format = CDROM_MSF;
+
+		bool isCD = ioctl(fd, CDROMSUBCHNL, &info) == 0 || isTrayEmpty(errno);
+		close(fd);
+		if (isCD) {
+			devices.push_back(Device(drive, stbuf.st_rdev));
+			return true;
+		}
+	}
+
+	return false;
+}
+
+bool LinuxAudioCDManager::loadTOC() {
+	if (_fd < 0)
+		return false;
+
+	if (ioctl(_fd, CDROMREADTOCHDR, &_tocHeader) < 0)
+		return false;
+
+	debug(4, "CD: Start Track: %d, End Track %d", _tocHeader.cdth_trk0, _tocHeader.cdth_trk1);
+
+	for (int i = _tocHeader.cdth_trk0; i <= _tocHeader.cdth_trk1; i++) {
+		cdrom_tocentry entry;
+		memset(&entry, 0, sizeof(entry));
+		entry.cdte_track = i;
+		entry.cdte_format = CDROM_MSF;
+
+		if (ioctl(_fd, CDROMREADTOCENTRY, &entry) < 0)
+			return false;
+
+#if 0
+		debug("Entry:");
+		debug("\tTrack: %d", entry.cdte_track);
+		debug("\tAdr: %d", entry.cdte_adr);
+		debug("\tCtrl: %d", entry.cdte_ctrl);
+		debug("\tFormat: %d", entry.cdte_format);
+		debug("\tMSF: %d:%d:%d", entry.cdte_addr.msf.minute, entry.cdte_addr.msf.second, entry.cdte_addr.msf.frame);
+		debug("\tMode: %d\n", entry.cdte_datamode);
+#endif
+
+		_tocEntries.push_back(entry);
+	}
+
+	// Fetch the leadout so we can get the length of the last frame
+	cdrom_tocentry entry;
+	memset(&entry, 0, sizeof(entry));
+	entry.cdte_track = kLeadoutTrack;
+	entry.cdte_format = CDROM_MSF;
+
+	if (ioctl(_fd, CDROMREADTOCENTRY, &entry) < 0)
+		return false;
+
+#if 0
+	debug("Lead out:");
+	debug("\tTrack: %d", entry.cdte_track);
+	debug("\tAdr: %d", entry.cdte_adr);
+	debug("\tCtrl: %d", entry.cdte_ctrl);
+	debug("\tFormat: %d", entry.cdte_format);
+	debug("\tMSF: %d:%d:%d", entry.cdte_addr.msf.minute, entry.cdte_addr.msf.second, entry.cdte_addr.msf.frame);
+	debug("\tMode: %d\n", entry.cdte_datamode);
+#endif
+
+	_tocEntries.push_back(entry);
+	return true;
+}
+
+AudioCDManager *createLinuxAudioCDManager() {
+	return new LinuxAudioCDManager();
+}

backends/audiocd/linux/linux-audiocd.h

@@ -0,0 +1,38 @@
+/* Cabal - Legacy Game Implementations
+ *
+ * Cabal is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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 BACKENDS_AUDIOCD_LINUX_H
+#define BACKENDS_AUDIOCD_LINUX_H
+
+#ifdef USE_LINUXCD
+
+class AudioCDManager;
+
+/**
+ * Create an audio CD manager using the Linux CDROM API
+ */
+AudioCDManager *createLinuxAudioCDManager();
+
+#endif
+
+#endif
+