audio.cpp: Split up into smaller parts

src/vorbissource.cpp

@@ -0,0 +1,283 @@
+/*
+** vorbissource.cpp
+**
+** This file is part of mkxp.
+**
+** Copyright (C) 2014 Jonas Kulla <Nyocurio@gmail.com>
+**
+** mkxp 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.
+**
+** mkxp 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 mkxp.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "aldatasource.h"
+#include "exception.h"
+
+#define OV_EXCLUDE_STATIC_CALLBACKS
+#include <vorbis/vorbisfile.h>
+#include <vector>
+
+static size_t vfRead(void *ptr, size_t size, size_t nmemb, void *ops)
+{
+	return SDL_RWread(static_cast<SDL_RWops*>(ops), ptr, size, nmemb);
+}
+
+static int vfSeek(void *ops, ogg_int64_t offset, int whence)
+{
+	return SDL_RWseek(static_cast<SDL_RWops*>(ops), offset, whence);
+}
+
+static long vfTell(void *ops)
+{
+	return SDL_RWtell(static_cast<SDL_RWops*>(ops));
+}
+
+static ov_callbacks OvCallbacks =
+{
+    vfRead,
+    vfSeek,
+    0,
+    vfTell
+};
+
+
+struct VorbisSource : ALDataSource
+{
+	SDL_RWops &src;
+
+	OggVorbis_File vf;
+
+	uint32_t currentFrame;
+
+	struct
+	{
+		uint32_t start;
+		uint32_t length;
+		uint32_t end;
+		bool valid;
+		bool requested;
+	} loop;
+
+	struct
+	{
+		int channels;
+		int rate;
+		int frameSize;
+		ALenum alFormat;
+	} info;
+
+	std::vector<int16_t> sampleBuf;
+
+	VorbisSource(SDL_RWops &ops,
+	             bool looped)
+	    : src(ops),
+	      currentFrame(0)
+	{
+		int error = ov_open_callbacks(&src, &vf, 0, 0, OvCallbacks);
+
+		if (error)
+		{
+			SDL_RWclose(&src);
+			throw Exception(Exception::MKXPError,
+			                "Vorbisfile: Cannot read ogg file");
+		}
+
+		/* Extract bitstream info */
+		info.channels = vf.vi->channels;
+		info.rate = vf.vi->rate;
+
+		if (info.channels > 2)
+		{
+			ov_clear(&vf);
+			SDL_RWclose(&src);
+			throw Exception(Exception::MKXPError,
+			                "Cannot handle audio with more than 2 channels");
+		}
+
+		info.alFormat = chooseALFormat(sizeof(int16_t), info.channels);
+		info.frameSize = sizeof(int16_t) * info.channels;
+
+		sampleBuf.resize(STREAM_BUF_SIZE);
+
+		loop.requested = looped;
+		loop.valid = false;
+		loop.start = loop.length = 0;
+
+		if (!loop.requested)
+			return;
+
+		/* Try to extract loop info */
+		for (int i = 0; i < vf.vc->comments; ++i)
+		{
+			char *comment = vf.vc->user_comments[i];
+			char *sep = strstr(comment, "=");
+
+			/* No '=' found */
+			if (!sep)
+				continue;
+
+			/* Empty value */
+			if (!*(sep+1))
+				continue;
+
+			*sep = '\0';
+
+			if (!strcmp(comment, "LOOPSTART"))
+				loop.start = strtol(sep+1, 0, 10);
+
+			if (!strcmp(comment, "LOOPLENGTH"))
+				loop.length = strtol(sep+1, 0, 10);
+
+			*sep = '=';
+		}
+
+		loop.end = loop.start + loop.length;
+		loop.valid = (loop.start && loop.length);
+	}
+
+	~VorbisSource()
+	{
+		ov_clear(&vf);
+		SDL_RWclose(&src);
+	}
+
+	int sampleRate()
+	{
+		return info.rate;
+	}
+
+	void seekToOffset(float seconds)
+	{
+		currentFrame = seconds * info.rate;
+
+		if (loop.valid && currentFrame > loop.end)
+			currentFrame = loop.start;
+
+		/* If seeking fails, just seek back to start */
+		if (ov_pcm_seek(&vf, currentFrame) != 0)
+			ov_raw_seek(&vf, 0);
+	}
+
+	Status fillBuffer(AL::Buffer::ID alBuffer)
+	{
+		void *bufPtr = sampleBuf.data();
+		int availBuf = sampleBuf.size();
+		int bufUsed  = 0;
+
+		int canRead = availBuf;
+
+		Status retStatus = ALDataSource::NoError;
+
+		bool readAgain = false;
+
+		if (loop.valid)
+		{
+			int tilLoopEnd = loop.end * info.frameSize;
+
+			canRead = std::min(availBuf, tilLoopEnd);
+		}
+
+		while (canRead > 16)
+		{
+			long res = ov_read(&vf, static_cast<char*>(bufPtr),
+			                   canRead, 0, sizeof(int16_t), 1, 0);
+
+			if (res < 0)
+			{
+				/* Read error */
+				retStatus = ALDataSource::Error;
+
+				break;
+			}
+
+			if (res == 0)
+			{
+				/* EOF */
+				if (loop.requested)
+				{
+					retStatus = ALDataSource::WrapAround;
+					reset();
+				}
+				else
+				{
+					retStatus = ALDataSource::EndOfStream;
+				}
+
+				/* If we sought right to the end of the file,
+				 * we might be EOF without actually having read
+				 * any data at all yet (which mustn't happen),
+				 * so we try to continue reading some data. */
+				if (bufUsed > 0)
+					break;
+
+				if (readAgain)
+				{
+					/* We're still not getting data though.
+					 * Just error out to prevent an endless loop */
+					retStatus = ALDataSource::Error;
+					break;
+				}
+
+				readAgain = true;
+			}
+
+			bufUsed += (res / sizeof(int16_t));
+			bufPtr = &sampleBuf[bufUsed];
+			currentFrame += (res / info.frameSize);
+
+			if (loop.valid && currentFrame >= loop.end)
+			{
+				/* Determine how many frames we're
+				 * over the loop end */
+				int discardFrames = currentFrame - loop.end;
+				bufUsed -= discardFrames * info.channels;
+
+				retStatus = ALDataSource::WrapAround;
+
+				/* Seek to loop start */
+				currentFrame = loop.start;
+				if (ov_pcm_seek(&vf, currentFrame) != 0)
+					retStatus = ALDataSource::Error;
+
+				break;
+			}
+
+			canRead -= res;
+		}
+
+		if (retStatus != ALDataSource::Error)
+			AL::Buffer::uploadData(alBuffer, info.alFormat, sampleBuf.data(),
+			                       bufUsed*sizeof(int16_t), info.rate);
+
+		return retStatus;
+	}
+
+	void reset()
+	{
+		ov_raw_seek(&vf, 0);
+		currentFrame = 0;
+	}
+
+	uint32_t loopStartFrames()
+	{
+		if (loop.valid)
+			return loop.start;
+		else
+			return 0;
+	}
+};
+
+ALDataSource *createVorbisSource(SDL_RWops &ops,
+                                 bool looped)
+{
+	return new VorbisSource(ops, looped);
+}