Make sound format support optional

[libs/al.git] / source / sounddecoder.h

diff --git a/source/sounddecoder.h b/source/sounddecoder.h
index ad56646b30dc149c9bfe48ef3fb243f3d811121f..20b9d0fb7f4e3d6afa4bd2d9a3dc8806e5477c5e 100644 (file)
--- a/source/sounddecoder.h
+++ b/source/sounddecoder.h
@@ -1,42 +1,61 @@
-#ifndef MSP_AL_SOUND_H_
-#define MSP_AL_SOUND_H_
+#ifndef MSP_AL_SOUNDDECODER_H_
+#define MSP_AL_SOUNDDECODER_H_
 
 #include <string>
-#include <vorbis/vorbisfile.h>
+#include <msp/io/seekable.h>
 #include "format.h"
 
 namespace Msp {
 namespace AL {
 
+class unsupported_sound: public std::runtime_error
+{
+public:
+       unsupported_sound(const std::string &);
+       virtual ~unsupported_sound() throw() { }
+};
+
+
 /**
-This class facilitates loading sound files.  Currently only Ogg Vorbis is
-supported.
+Base class for sound decoders.
 */
 class SoundDecoder
 {
 private:
-       OggVorbis_File ovfile;
+       IO::Seekable *source;
+protected:
        unsigned freq;
        unsigned size;
        Format format;
        bool eof_flag;
 
-public:
        SoundDecoder();
-       ~SoundDecoder();
-
-       void open_file(const std::string &);
-       void open_memory(const void *, unsigned);
-private:
-       void open_common();
 public:
-       void close();
-       void rewind();
-       unsigned read(char *, unsigned);
+       virtual ~SoundDecoder();
+
+       /** Opens a file and creates a decoder of an appropriate type for it. */
+       static SoundDecoder *open_file(const std::string &);
+
+       /** Creates a decoder for an already-opened audio file. */
+       static SoundDecoder *open_io(IO::Seekable &);
+
+       /** Restarts decoding from the beginning of the file. */
+       virtual void rewind() { seek(0); }
+
+       /** Sets decoding position expressed in PCM bytes.  This may involve seeking
+       to the beginning and skipping until the desired position is reached.*/
+       virtual void seek(unsigned) = 0;
+
+       /** Reads decoded sound data.  Length is specified in bytes. */
+       virtual unsigned read(char *, unsigned) = 0;
+
        bool eof() const { return eof_flag; }
 
        Format get_format() const { return format; }
        unsigned get_frequency() const { return freq; }
+
+       /** Returns the total length of the sound data in bytes.  Some decoders may
+       not be able to provide this information. */
        unsigned get_size() const { return size; }
 };