/[svn]/libgig/trunk/src/gig.h
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revision 353 by schoenebeck, Sat Jan 29 14:25:35 2005 UTC revision 384 by schoenebeck, Thu Feb 17 02:22:26 2005 UTC
# Line 2  Line 2 
2   *                                                                         *   *                                                                         *
3   *   libgig - C++ cross-platform Gigasampler format file loader library    *   *   libgig - C++ cross-platform Gigasampler format file loader library    *
4   *                                                                         *   *                                                                         *
5   *   Copyright (C) 2003, 2004 by Christian Schoenebeck                     *   *   Copyright (C) 2003-2005 by Christian Schoenebeck                      *
6   *                               <cuse@users.sourceforge.net>              *   *                              <cuse@users.sourceforge.net>               *
7   *                                                                         *   *                                                                         *
8   *   This library is free software; you can redistribute it and/or modify  *   *   This library is free software; you can redistribute it and/or modify  *
9   *   it under the terms of the GNU General Public License as published by  *   *   it under the terms of the GNU General Public License as published by  *
# Line 80  namespace gig { Line 80  namespace gig {
80          void*         pStart;            ///< Points to the beginning of the buffer.          void*         pStart;            ///< Points to the beginning of the buffer.
81          unsigned long Size;              ///< Size of the actual data in the buffer in bytes.          unsigned long Size;              ///< Size of the actual data in the buffer in bytes.
82          unsigned long NullExtensionSize; ///< The buffer might be bigger than the actual data, if that's the case that unused space at the end of the buffer is filled with NULLs and NullExtensionSize reflects that unused buffer space in bytes. Those NULL extensions are mandatory for differential algorithms that have to take the following data words into account, thus have to access past the buffer's boundary. If you don't know what I'm talking about, just forget this variable. :)          unsigned long NullExtensionSize; ///< The buffer might be bigger than the actual data, if that's the case that unused space at the end of the buffer is filled with NULLs and NullExtensionSize reflects that unused buffer space in bytes. Those NULL extensions are mandatory for differential algorithms that have to take the following data words into account, thus have to access past the buffer's boundary. If you don't know what I'm talking about, just forget this variable. :)
83            buffer_t() {
84                pStart            = NULL;
85                Size              = 0;
86                NullExtensionSize = 0;
87            }
88      };      };
89    
90      /** Standard types of sample loops. */      /** Standard types of sample loops. */
# Line 483  namespace gig { Line 488  namespace gig {
488              buffer_t      LoadSampleDataWithNullSamplesExtension(uint NullSamplesCount);              buffer_t      LoadSampleDataWithNullSamplesExtension(uint NullSamplesCount);
489              buffer_t      LoadSampleDataWithNullSamplesExtension(unsigned long SampleCount, uint NullSamplesCount);              buffer_t      LoadSampleDataWithNullSamplesExtension(unsigned long SampleCount, uint NullSamplesCount);
490              buffer_t      GetCache();              buffer_t      GetCache();
491                // own static methods
492                static buffer_t CreateDecompressionBuffer(unsigned long MaxReadSize);
493                static void     DestroyDecompressionBuffer(buffer_t& DecompressionBuffer);
494              // overridden methods              // overridden methods
495              void          ReleaseSampleData();              void          ReleaseSampleData();
496              unsigned long SetPos(unsigned long SampleCount, RIFF::stream_whence_t Whence = RIFF::stream_start);              unsigned long SetPos(unsigned long SampleCount, RIFF::stream_whence_t Whence = RIFF::stream_start);
497              unsigned long GetPos();              unsigned long GetPos();
498              unsigned long Read(void* pBuffer, unsigned long SampleCount);              unsigned long Read(void* pBuffer, unsigned long SampleCount, buffer_t* pExternalDecompressionBuffer = NULL);
499              unsigned long ReadAndLoop(void* pBuffer, unsigned long SampleCount, playback_state_t* pPlaybackState);              unsigned long ReadAndLoop(void* pBuffer, unsigned long SampleCount, playback_state_t* pPlaybackState, buffer_t* pExternalDecompressionBuffer = NULL);
500          protected:          protected:
501              static unsigned int  Instances;               ///< Number of instances of class Sample.              static unsigned int  Instances;               ///< Number of instances of class Sample.
502              static unsigned long DecompressionBufferSize; ///< Current size of the decompression buffer.              static buffer_t      InternalDecompressionBuffer; ///< Buffer used for decompression as well as for truncation of 24 Bit -> 16 Bit samples.
             static void*         pDecompressionBuffer;    ///< Small buffer used for decompression only.  
503              unsigned long        FrameOffset;             ///< Current offset (sample points) in current sample frame (for decompression only).              unsigned long        FrameOffset;             ///< Current offset (sample points) in current sample frame (for decompression only).
504              unsigned long*       FrameTable;              ///< For positioning within compressed samples only: stores the offset values for each frame.              unsigned long*       FrameTable;              ///< For positioning within compressed samples only: stores the offset values for each frame.
505              unsigned long        SamplePos;               ///< For compressed samples only: stores the current position (in sample points).              unsigned long        SamplePos;               ///< For compressed samples only: stores the current position (in sample points).
506                unsigned long        SamplesInLastFrame;      ///< For compressed samples only: length of the last sample frame.
507                unsigned long        WorstCaseFrameSize;      ///< For compressed samples only: size (in bytes) of the largest possible sample frame.
508                unsigned long        SamplesPerFrame;         ///< For compressed samples only: number of samples in a full sample frame.
509              buffer_t             RAMCache;                ///< Buffers samples (already uncompressed) in RAM.              buffer_t             RAMCache;                ///< Buffers samples (already uncompressed) in RAM.
510    
511              Sample(File* pFile, RIFF::List* waveList, unsigned long WavePoolOffset);              Sample(File* pFile, RIFF::List* waveList, unsigned long WavePoolOffset);
# Line 560  namespace gig { Line 570  namespace gig {
570                  return (A > B) ? B : A;                  return (A > B) ? B : A;
571              }              }
572              inline long Abs(long val) { return (val > 0) ? val : -val; }              inline long Abs(long val) { return (val > 0) ? val : -val; }
573    
574                // Guess size (in bytes) of a compressed sample
575                inline unsigned long GuessSize(unsigned long samples) {
576                    // 16 bit: assume all frames are compressed - 1 byte
577                    // per sample and 5 bytes header per 2048 samples
578    
579                    // 24 bit: assume next best compression rate - 1.5
580                    // bytes per sample and 13 bytes header per 256
581                    // samples
582                    const unsigned long size =
583                        BitDepth == 24 ? samples + (samples >> 1) + (samples >> 8) * 13
584                                       : samples + (samples >> 10) * 5;
585                    // Double for stereo and add one worst case sample
586                    // frame
587                    return (Channels == 2 ? size << 1 : size) + WorstCaseFrameSize;
588                }
589    
590                // Worst case amount of sample points that can be read with the
591                // given decompression buffer.
592                inline unsigned long WorstCaseMaxSamples(buffer_t* pDecompressionBuffer) {
593                    return (unsigned long) ((float)pDecompressionBuffer->Size / (float)WorstCaseFrameSize * (float)SamplesPerFrame);
594                }
595          private:          private:
596              void ScanCompressedSample();              void ScanCompressedSample();
597              friend class File;              friend class File;
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