ar.h

使用LZ压缩算法的完整应用

/***********************************************************
	ar.h
***********************************************************/
#include <stdio.h>
#include <limits.h>
typedef unsigned char  uchar;   /*  8 bits or more */
typedef unsigned int   uint;    /* 16 bits or more */
typedef unsigned short ushort;  /* 16 bits or more */
typedef unsigned long  ulong;   /* 32 bits or more */

/* ar.c */

extern int unpackable;
extern ulong origsize, compsize;

/* io.c */

#define INIT_CRC  0  /* CCITT: 0xFFFF */
extern FILE *arcfile, *infile, *outfile;
extern uint crc, bitbuf;
#define BITBUFSIZ (CHAR_BIT * sizeof bitbuf)

void error(char *fmt, ...);
void make_crctable(void);
void fillbuf(int n);
uint getbits(int n);
/* void putbit(int bit); */
void putbits(int n, uint x);
int fread_crc(uchar *p, int n, FILE *f);
void fwrite_crc(uchar *p, int n, FILE *f);
void init_getbits(void);
void init_putbits(void);

/* encode.c and decode.c */

#define DICBIT    13    /* 12(-lh4-) or 13(-lh5-) */
#define DICSIZ (1U << DICBIT)
#define MATCHBIT   8    /* bits for MAXMATCH - THRESHOLD */
#define MAXMATCH 256    /* formerly F (not more than UCHAR_MAX + 1) */
#define THRESHOLD  3    /* choose optimal value */
#define PERC_FLAG 0x8000U

void encode(void);
void decode_start(void);
void decode(uint count, uchar text[]);

/* huf.c */

#define NC (UCHAR_MAX + MAXMATCH + 2 - THRESHOLD)
	/* alphabet = {0, 1, 2, ..., NC - 1} */
#define CBIT 9  /* $\lfloor \log_2 NC \rfloor + 1$ */
#define CODE_BIT  16  /* codeword length */

extern ushort left[], right[];

void huf_encode_start(void);
void huf_decode_start(void);
uint decode_c(void);
uint decode_p(void);
void output(uint c, uint p);
void huf_encode_end(void);

/* maketbl.c */

void make_table(int nchar, uchar bitlen[],
				int tablebits, ushort table[]);

/* maketree.c */

int make_tree(int nparm, ushort freqparm[],
				uchar lenparm[], ushort codeparm[]);