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 34   * ***** END LICENSE BLOCK ***** */ 
 35  
 36  /**************************************************************************************
 37   * Fixed-point MP3 decoder
 38   * Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
 39   * June 2003
 40   *
 41   * mp3common.h - implementation-independent API's, datatypes, and definitions
 42   **************************************************************************************/
 43  
 44  #ifndef _MP3COMMON_H
 45  #define _MP3COMMON_H
 46  
 47  #include "mp3dec.h"
 48  #include "statname.h"	/* do name-mangling for static linking */
 49  
 50  #define MAX_SCFBD		4		/* max scalefactor bands per channel */
 51  #define NGRANS_MPEG1	2
 52  #define NGRANS_MPEG2	1
 53  
 54  /* 11-bit syncword if MPEG 2.5 extensions are enabled */
 55  #define	SYNCWORDH		0xff
 56  #define	SYNCWORDL		0xe0
 57  
 58  /* 12-bit syncword if MPEG 1,2 only are supported 
 59   * #define	SYNCWORDH		0xff
 60   * #define	SYNCWORDL		0xf0
 61   */
 62  
 63  typedef struct _MP3DecInfo {
 64  	/* pointers to platform-specific data structures */
 65  	void *FrameHeaderPS;
 66  	void *SideInfoPS;
 67  	void *ScaleFactorInfoPS;
 68  	void *HuffmanInfoPS;
 69  	void *DequantInfoPS;
 70  	void *IMDCTInfoPS;
 71  	void *SubbandInfoPS;
 72  
 73  	/* buffer which must be large enough to hold largest possible main_data section */
 74  	unsigned char mainBuf[MAINBUF_SIZE];
 75  
 76  	/* special info for "free" bitrate files */
 77  	int freeBitrateFlag;
 78  	int freeBitrateSlots;
 79  
 80  	/* user-accessible info */
 81  	int bitrate;
 82  	int nChans;
 83  	int samprate;
 84  	int nGrans;				/* granules per frame */
 85  	int nGranSamps;			/* samples per granule */
 86  	int nSlots;
 87  	int layer;
 88  	MPEGVersion version;
 89  
 90  	int mainDataBegin;
 91  	int mainDataBytes;
 92  
 93  	int part23Length[MAX_NGRAN][MAX_NCHAN];
 94  
 95  } MP3DecInfo;
 96  
 97  typedef struct _SFBandTable {
 98  	short l[23];
 99  	short s[14];
100  } SFBandTable;
101  
102  /* decoder functions which must be implemented for each platform */
103  MP3DecInfo *AllocateBuffers(void);
104  void FreeBuffers(MP3DecInfo *mp3DecInfo);
105  int CheckPadBit(MP3DecInfo *mp3DecInfo);
106  int UnpackFrameHeader(MP3DecInfo *mp3DecInfo, unsigned char *buf);
107  int UnpackSideInfo(MP3DecInfo *mp3DecInfo, unsigned char *buf);
108  int DecodeHuffman(MP3DecInfo *mp3DecInfo, unsigned char *buf, int *bitOffset, int huffBlockBits, int gr, int ch);
109  int Dequantize(MP3DecInfo *mp3DecInfo, int gr);
110  int IMDCT(MP3DecInfo *mp3DecInfo, int gr, int ch);
111  int UnpackScaleFactors(MP3DecInfo *mp3DecInfo, unsigned char *buf, int *bitOffset, int bitsAvail, int gr, int ch);
112  int Subband(MP3DecInfo *mp3DecInfo, short *pcmBuf);
113  
114  /* mp3tabs.c - global ROM tables */
115  extern const int samplerateTab[3][3];
116  extern const short bitrateTab[3][3][15];
117  extern const short samplesPerFrameTab[3][3];
118  extern const short bitsPerSlotTab[3];
119  extern const short sideBytesTab[3][2];
120  extern const short slotTab[3][3][15];
121  extern const SFBandTable sfBandTable[3][3];
122  
123  #endif	/* _MP3COMMON_H */