common.h

mepg 1 layer3软解码源代码,实现了对MP3文件的软件解码

    int mode_ext;
    int copyright;
    int original;
    int emphasis;
} layer, *the_layer;

/* Parent Structure Interpreting some Frame Parameters in Header */

typedef struct {
    layer       *header;        /* raw header information */
    int         actual_mode;    /* when writing IS, may forget if 0 chs */
    al_table    *alloc;         /* bit allocation table read in */
    int         tab_num;        /* number of table as loaded */
    int         stereo;         /* 1 for mono, 2 for stereo */
    int         jsbound;        /* first band of joint stereo coding */
    int         sblimit;        /* total number of sub bands */
} frame_params;

/* Double and SANE Floating Point Type Definitions */

typedef struct  IEEE_DBL_struct {
    unsigned long   hi;
    unsigned long   lo;
} IEEE_DBL;

typedef struct  SANE_EXT_struct {
    unsigned long   l1;
    unsigned long   l2;
    unsigned short  s1;
} SANE_EXT;

/* AIFF Type Definitions */

typedef char    ID[4];

typedef struct  ChunkHeader_struct {
    ID      ckID;
    long    ckSize;
} ChunkHeader;

typedef struct  Chunk_struct {
    ID      ckID;
    long    ckSize;
    ID      formType;
} Chunk;

typedef struct  CommonChunk_struct {
    ID              ckID;
    long            ckSize;
    short           numChannels;
    unsigned long   numSampleFrames;
    short           sampleSize;
    char            sampleRate[10];
} CommonChunk;

typedef struct  SoundDataChunk_struct {
    ID              ckID;
    long            ckSize;
    unsigned long   offset;
    unsigned long   blockSize;
} SoundDataChunk;

typedef struct  blockAlign_struct {
    unsigned long   offset;
    unsigned long   blockSize;
} blockAlign;

typedef struct  IFF_AIFF_struct {
    short           numChannels;
    unsigned long   numSampleFrames;
    short           sampleSize;
    double          sampleRate;
    unsigned long   sampleType;
    blockAlign      blkAlgn;
} IFF_AIFF;

/* "bit_stream.h" Type Definitions */

typedef struct  bit_stream_struc {
    FILE        *pt;            /* pointer to bit stream device */
    unsigned char *buf;         /* bit stream buffer */
    int         buf_size;       /* size of buffer (in number of bytes) */
    long        totbit;         /* bit counter of bit stream */
    int         buf_byte_idx;   /* pointer to top byte in buffer */
    int         buf_bit_idx;    /* pointer to top bit of top byte in buffer */
    int         mode;           /* bit stream open in read or write mode */
    int         eob;            /* end of buffer index */
    int         eobs;           /* end of bit stream flag */
    char        format;
    
    /* format of file in rd mode (BINARY/ASCII) */
} Bit_stream_struc;

/* Layer III side information. */

typedef struct {
	unsigned main_data_begin;
	unsigned private_bits;
	struct {
	    unsigned scfsi[4];
		struct gr_info_s {
			unsigned part2_3_length;
			unsigned big_values;
			unsigned global_gain;
			unsigned scalefac_compress;
			unsigned window_switching_flag;
			unsigned block_type;
			unsigned mixed_block_flag;
			unsigned table_select[3];
			unsigned subblock_gain[3];
			unsigned region0_count;
			unsigned region1_count;
			unsigned preflag;
			unsigned scalefac_scale;
			unsigned count1table_select;
			} gr[2];
		} ch[2];
	} III_side_info_t;

/* Layer III scale factors. */

typedef struct {
	int l[23];            /* [cb] */
	int s[3][13];         /* [window][cb] */
	} III_scalefac_t[2];  /* [ch] */

/***********************************************************************
*
*  Global Variable External Declarations
*
***********************************************************************/

extern char     *mode_names[4];
extern char     *layer_names[3];
extern double   s_freq[4];
extern int      bitrate[3][15];
extern double FAR multiple[64];

/***********************************************************************
*
*  Global Function Prototype Declarations
*
***********************************************************************/

/* The following functions are in the file "common.c" */

#ifdef  PROTO_ARGS
extern FILE           *OpenTableFile(char*);
extern int            read_bit_alloc(int, al_table*);
extern int            pick_table(frame_params*);
extern int            js_bound(int, int);
extern void           hdr_to_frps(frame_params*);
extern void           WriteHdr(frame_params*, FILE*);
extern void           WriteBitAlloc(unsigned int[2][SBLIMIT], frame_params*,
                        FILE*);
extern void           WriteScale(unsigned int[2][SBLIMIT],
                        unsigned int[2][SBLIMIT], unsigned int[2][3][SBLIMIT],
                        frame_params*, FILE*);
extern void           WriteSamples(int, unsigned int FAR [SBLIMIT],
                        unsigned int[SBLIMIT], frame_params*, FILE*);
extern int            NumericQ(char*);
extern int            BitrateIndex(int, int);
extern int            SmpFrqIndex(long);
extern int            memcheck(char*, int, int);
extern void           FAR *mem_alloc(unsigned long, char*);
extern void           mem_free(void**);
extern void           double_to_extended(double*, char[10]);
extern void           extended_to_double(char[10], double*);
extern int            aiff_read_headers(FILE*, IFF_AIFF*);
extern int            aiff_seek_to_sound_data(FILE*);
extern int            aiff_write_headers(FILE*, IFF_AIFF*);
extern int            refill_buffer(Bit_stream_struc*);
extern void           empty_buffer(Bit_stream_struc*, int);
extern void           open_bit_stream_w(Bit_stream_struc*, char*, int);
extern void           open_bit_stream_r(Bit_stream_struc*, char*, int);
extern void           close_bit_stream_r(Bit_stream_struc*);
extern void           close_bit_stream_w(Bit_stream_struc*);
extern void           alloc_buffer(Bit_stream_struc*, int);
extern void           desalloc_buffer(Bit_stream_struc*);
extern void           back_track_buffer(Bit_stream_struc*, int);
extern unsigned int   get1bit(Bit_stream_struc*);
extern void           put1bit(Bit_stream_struc*, int);
extern unsigned long  look_ahead(Bit_stream_struc*, int);
extern unsigned long  getbits(Bit_stream_struc*, int);
extern void           putbits(Bit_stream_struc*, unsigned int, int);
extern void           byte_ali_putbits(Bit_stream_struc*, unsigned int, int);
extern unsigned long  byte_ali_getbits(Bit_stream_struc*, int);
extern unsigned long  sstell(Bit_stream_struc*);
extern int            end_bs(Bit_stream_struc*);
extern int            seek_sync(Bit_stream_struc*, long, int);
extern void           I_CRC_calc(frame_params*, unsigned int[2][SBLIMIT],
                        unsigned int*);
extern void           II_CRC_calc(frame_params*, unsigned int[2][SBLIMIT],
                        unsigned int[2][SBLIMIT], unsigned int*);
extern void           update_CRC(unsigned int, unsigned int, unsigned int*);
extern void           read_absthr(FLOAT*, int);
extern unsigned int   hget1bit(); /* MI */
extern unsigned long  hgetbits(int);
extern unsigned long  hsstell();
extern void           hputbuf(unsigned int,int);



#ifdef  MACINTOSH
extern void           set_mac_file_attr(char[MAX_NAME_SIZE], short, OsType,
                        OsType);
#endif
#ifdef MS_DOS
extern char           *new_ext(char *filename, char *extname); 
#endif

#else
extern FILE           *OpenTableFile();
extern int            read_bit_alloc();
extern int            pick_table();
extern int            js_bound();
extern void           hdr_to_frps();
extern void           WriteHdr();
extern void           WriteBitAlloc();
extern void           WriteScale();
extern void           WriteSamples();
extern int            NumericQ();
extern int            BitrateIndex();
extern int            SmpFrqIndex();
extern int            memcheck();
extern void           FAR *mem_alloc();
extern void           mem_free();
extern void           double_to_extended();
extern void           extended_to_double();
extern int            aiff_read_headers();
extern int            aiff_seek_to_sound_data();
extern int            aiff_write_headers();
extern int            refill_buffer();
extern void           empty_buffer();
extern void           open_bit_stream_w();
extern void           open_bit_stream_r();
extern void           close_bit_stream_r();
extern void           close_bit_stream_w();
extern void           alloc_buffer();
extern void           desalloc_buffer();
extern void           back_track_buffer();
extern unsigned int   get1bit();
extern void           put1bit();
extern unsigned long  look_ahead();
extern unsigned long  getbits();
extern void           putbits();
extern void           byte_ali_putbits();
extern unsigned long  byte_ali_getbits();
extern unsigned long  sstell();
extern int            end_bs();
extern int            seek_sync();
extern void           I_CRC_calc();
extern void           II_CRC_calc();
extern void           update_CRC();
extern void           read_absthr();

extern unsigned int   hget1bit();
extern unsigned long  hgetbits();
extern unsigned long  hsstell();
extern void           hputbuf();

#ifdef MS_DOS
extern char           *new_ext(); 
#endif
#endif