lzw压缩算法的c语言实现

lzw压缩算法的c语言实现

1 程序由五个模块组成。

(1) lzw.h 定义了一些基本的数据结构，常量，还有变量的初始化等。

#ifndef __LZW_H__

#define __LZW_H__

//------------------------------------------------------------------------------

#include

#include

#include

#include

//------------------------------------------------------------------------------

#define LZW_BASE 0x102// The code base

#define CODE_LEN 12 // Max code length

#define TABLE_LEN 4099 // It must be prime number and bigger than 2^CODE_LEN=4096.

// Such as 5051 is also ok.

#define BUFFERSIZE 1024

//------------------------------------------------------------------------------

typedef struct

{

HANDLE h_sour; // Source file handle.

HANDLE h_dest; // Destination file handle.

HANDLE h_suffix; // Suffix table handle.

HANDLE h_prefix; // Prefix table handle.

HANDLE h_code; // Code table handle.

LPWORD lp_prefix; // Prefix table head pointer.

LPBYTE lp_suffix; // Suffix table head pointer.

LPWORD lp_code; // Code table head pointer.

WORD code;

WORD prefix;

BYTE suffix;

BYTE cur_code_len; // Current code length.[ used in Dynamic-Code-Length mode ] }LZW_DATA,*PLZW_DATA;

typedef struct

{

WORD top;

WORD index;

LPBYTE lp_buffer;

HANDLE h_buffer;

BYTE by_left;

DWORD dw_buffer;

BOOL end_flag;

}BUFFER_DATA,*PBUFFER_DATA;

typedef struct //Stack used in decode

{

WORD index;

HANDLE h_stack;

LPBYTE lp_stack;

}STACK_DATA,*PSTACK_DATA;

//------------------------------------------------------------------------------

VOID stack_create( PSTACK_DATA stack )

{

stack->h_stack = GlobalAlloc( GHND , TABLE_LEN*sizeof(BYTE) );

stack->lp_stack = GlobalLock( stack->h_stack );

stack->index = 0;

}

//------------------------------------------------------------------------------

VOID stack_destory( PSTACK_DATA stack )

{

GlobalUnlock( stack->h_stack );

GlobalFree ( stack->h_stack );

}

//------------------------------------------------------------------------------

VOID buffer_create( PBUFFER_DATA buffer )

{

buffer->h_buffer = GlobalAlloc( GHND, BUFFERSIZE*sizeof(BYTE) ); buffer->lp_buffer = GlobalLock( buffer->h_buffer );

buffer->top = 0;

buffer->index = 0;

buffer->by_left = 0;

buffer->dw_buffer = 0;

buffer->end_flag = FALSE;

}

//------------------------------------------------------------------------------

VOID buffer_destory( PBUFFER_DATA buffer )

{

GlobalUnlock( buffer->h_buffer );

GlobalFree ( buffer->h_buffer );

}

//------------------------------------------------------------------------------

VOID re_init_lzw( PLZW_DATA lzw ) //When code table reached its top it should { //be reinitialized.

memset( lzw->lp_code, 0xFFFF, TABLE_LEN*sizeof(WORD) );

lzw->code = LZW_BASE;

lzw->cur_code_len = 9;

}

//------------------------------------------------------------------------------

VOID lzw_create(PLZW_DATA lzw, HANDLE h_sour, HANDLE h_dest) {

WORD i;

lzw->h_code = GlobalAlloc( GHND, TABLE_LEN*sizeof(WORD) );

lzw->h_prefix = GlobalAlloc( GHND, TABLE_LEN*sizeof(WORD) );

lzw->h_suffix = GlobalAlloc( GHND, TABLE_LEN*sizeof(BYTE) );

lzw->lp_code = GlobalLock( lzw->h_code );

lzw->lp_prefix = GlobalLock( lzw->h_prefix );

lzw->lp_suffix = GlobalLock( lzw->h_suffix );

lzw->code = LZW_BASE;

lzw->cur_code_len = 9;

lzw->h_sour = h_sour;

lzw->h_dest = h_dest;

memset( lzw->lp_code, 0xFFFF, TABLE_LEN*sizeof(WORD) );

}

//------------------------------------------------------------------------------

VOID lzw_destory(PLZW_DATA lzw)

{

GlobalUnlock( lzw->h_code );

GlobalUnlock( lzw->h_prefix );

GlobalUnlock( lzw->h_suffix );

GlobalFree( lzw->h_code );

GlobalFree( lzw->h_prefix );

GlobalFree( lzw->h_suffix );

}