求 LZ78 & LZW 压缩算法源码

2008-02-22 05:08:48 693 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

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跪求！
标准c调试通过的。谢谢。

...全文

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sexisnothing

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切换为时间正序

tianzhuxiong 2011-10-06

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回看一看答案。

sexisnothing 2008-02-28

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同志，你贴的代码有点问题啊。我在linux下gcc没通过，暂时找不出原因。

laolaoliu2002 2008-02-27

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/*

** This routine simply decodes a string from the string table, storing

** it in a buffer.  The buffer can then be output in reverse order by

** the expansion program.

*/



char *decode_string(unsigned char *buffer,unsigned int code)

{

int i;



  i=0;

  while (code > 255)

  {

    *buffer++ = append_character[code];

    code=prefix_code[code];

    if (i++>=4094)

    {

      printf("Fatal error during code expansion.\n");

      exit(0);

    }

  }

  *buffer=code;

  return(buffer);

}



/*

** The following two routines are used to output variable length

** codes.  They are written strictly for clarity, and are not

** particularyl efficient.

*/



unsigned int input_code(FILE *input)

{

unsigned int return_value;

static int input_bit_count=0;

static unsigned long input_bit_buffer=0L;



  while (input_bit_count <= 24)

  {

    input_bit_buffer |= 

        (unsigned long) getc(input) << (24-input_bit_count);

    input_bit_count += 8;

  }

  return_value=input_bit_buffer >> (32-BITS);

  input_bit_buffer <<= BITS;

  input_bit_count -= BITS;

  return(return_value);

}



void output_code(FILE *output,unsigned int code)

{

static int output_bit_count=0;

static unsigned long output_bit_buffer=0L;



  output_bit_buffer |= (unsigned long) code << (32-BITS-output_bit_count);

  output_bit_count += BITS;

  while (output_bit_count >= 8)

  {

    putc(output_bit_buffer >> 24,output);

    output_bit_buffer <<= 8;

    output_bit_count -= 8;

  }

}

laolaoliu2002 2008-02-27

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[code=C/C++]

/***********************************************************************************************************

	LZW.c



本演示程序提供了LZW编码法的压缩和解压缩函数，并实现了对图象

文件的压缩和解压缩

**********************************************************************************************************/



#include <stdio.h>

#include <string.h>

#include <stdlib.h>



#define BITS 12                   /* Setting the number of bits to 12, 13*/

#define HASHING_SHIFT BITS-8      /* or 14 affects several constants.    */

#define MAX_VALUE (1 << BITS) - 1 /* Note that MS-DOS machines need to   */

#define MAX_CODE MAX_VALUE - 1    /* compile their code in large model if*/

                                  /* 14 bits are selected.               */

#if BITS == 14

  #define TABLE_SIZE 18041        /* The string table size needs to be a */

#endif                            /* prime number that is somewhat larger*/

#if BITS == 13                    /* than 2**BITS.                       */

  #define TABLE_SIZE 9029

#endif

#if BITS <= 12

  #define TABLE_SIZE 5021

#endif



/* 函数原型 */

int LZW_Compression(char *in_filename, char *out_filename);

int LZW_Decompression(char *in_filename, char *out_filename);



/* 内部函数 */

int find_match(int hash_prefix,unsigned int hash_character);

char *decode_string(unsigned char *buffer,unsigned int code);

unsigned int input_code(FILE *input);

void output_code(FILE *output,unsigned int code);



/* 全局变量，编码/解码使用的内存缓冲区 */

int *code_value;                  /* This is the code value array        */

unsigned int *prefix_code;        /* This array holds the prefix codes   */

unsigned char *append_character;  /* This array holds the appended chars */

unsigned char decode_stack[4000]; /* This array holds the decoded string */





/* 主程序 */

void main(int argc, char *argv[])

{

	printf("LZW compression and decompression utility\n");



	if (4 != argc) 

	{

		printf("\nUsage : lzw -c|d sourcefilename targetfilename\n");

		exit(0);

	}



	if (! strcmp(argv[1], "-c"))

		LZW_Compression(argv[2], argv[3]);

	else if (! strcmp(argv[1], "-d"))

		LZW_Decompression(argv[2], argv[3]);

	else

		printf("\nUnknow command.\n");

}



/**************************************************************************************************

	LZW_Compression()



  本函数用LZW算法压缩指定的文件，并将结构存储到新的文件中                                     

***************************************************************************************************/

int LZW_Compression(char *in_filename, char *out_filename)

{

  unsigned int next_code;

  unsigned int character;

  unsigned int string_code;

  unsigned int index;

  int i;

  FILE *input;

  FILE *output;



  /* allocate memory for compression */

  code_value=malloc(TABLE_SIZE*sizeof(unsigned int));

  prefix_code=malloc(TABLE_SIZE*sizeof(unsigned int));

  append_character=malloc(TABLE_SIZE*sizeof(unsigned char));

  if (code_value==NULL || prefix_code==NULL || append_character==NULL)

  {

    printf("Fatal error allocating table space!\n");

    return 0;

  }



  /* open files */

  input=fopen(in_filename,"rb");

  output=fopen(out_filename,"wb");

  if (input==NULL || output==NULL)

  {

    printf("Fatal error opening files.\n");

    return 0;

  };



  /* compressing... */



  next_code=256;              /* Next code is the next available string code*/

  for (i=0;i<TABLE_SIZE;i++)  /* Clear out the string table before starting */

    code_value[i]=-1;



  i=0;

  printf("Compressing...\n");

  string_code=getc(input);    /* Get the first code                         */

/*

** This is the main loop where it all happens.  This loop runs util all of

** the input has been exhausted.  Note that it stops adding codes to the

** table after all of the possible codes have been defined.

*/

  while ((character=getc(input)) != (unsigned)EOF)

  {

    if (++i==1000)                         /* Print a * every 1000    */

    {                                      /* input characters.  This */

      i=0;                                 /* is just a pacifier.     */

      printf(".");

    }

    index=find_match(string_code,character);/* See if the string is in */

    if (code_value[index] != -1)            /* the table.  If it is,   */

      string_code=code_value[index];        /* get the code value.  If */

    else                                    /* the string is not in the*/

    {                                       /* table, try to add it.   */

      if (next_code <= MAX_CODE)

      {

        code_value[index]=next_code++;

        prefix_code[index]=string_code;

        append_character[index]=character;

      }

      output_code(output,string_code);  /* When a string is found  */

      string_code=character;            /* that is not in the table*/

    }                                   /* I output the last string*/

  }                                     /* after adding the new one*/

/*

** End of the main loop.

*/

  output_code(output,string_code); /* Output the last code               */

  output_code(output,MAX_VALUE);   /* Output the end of buffer code      */

  output_code(output,0);           /* This code flushes the output buffer*/

  printf("\n");



  /* cleanup... */

  fclose(input);

  fclose(output);



  free(code_value);

  free(prefix_code);

  free(append_character);



  return 1;

}

[/code]

laolaoliu2002 2008-02-27

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/***********************************************************************************************************

	LZW.c



本演示程序提供了LZW编码法的压缩和解压缩函数，并实现了对图象

文件的压缩和解压缩

**********************************************************************************************************/



#include <stdio.h>

#include <string.h>

#include <stdlib.h>



#define BITS 12                   /* Setting the number of bits to 12, 13*/

#define HASHING_SHIFT BITS-8      /* or 14 affects several constants.    */

#define MAX_VALUE (1 << BITS) - 1 /* Note that MS-DOS machines need to   */

#define MAX_CODE MAX_VALUE - 1    /* compile their code in large model if*/

                                  /* 14 bits are selected.               */

#if BITS == 14

  #define TABLE_SIZE 18041        /* The string table size needs to be a */

#endif                            /* prime number that is somewhat larger*/

#if BITS == 13                    /* than 2**BITS.                       */

  #define TABLE_SIZE 9029

#endif

#if BITS <= 12

  #define TABLE_SIZE 5021

#endif



/* 函数原型 */

int LZW_Compression(char *in_filename, char *out_filename);

int LZW_Decompression(char *in_filename, char *out_filename);



/* 内部函数 */

int find_match(int hash_prefix,unsigned int hash_character);

char *decode_string(unsigned char *buffer,unsigned int code);

unsigned int input_code(FILE *input);

void output_code(FILE *output,unsigned int code);



/* 全局变量，编码/解码使用的内存缓冲区 */

int *code_value;                  /* This is the code value array        */

unsigned int *prefix_code;        /* This array holds the prefix codes   */

unsigned char *append_character;  /* This array holds the appended chars */

unsigned char decode_stack[4000]; /* This array holds the decoded string */





/* 主程序 */

void main(int argc, char *argv[])

{

	printf("LZW compression and decompression utility\n");



	if (4 != argc) 

	{

		printf("\nUsage : lzw -c|d sourcefilename targetfilename\n");

		exit(0);

	}



	if (! strcmp(argv[1], "-c"))

		LZW_Compression(argv[2], argv[3]);

	else if (! strcmp(argv[1], "-d"))

		LZW_Decompression(argv[2], argv[3]);

	else

		printf("\nUnknow command.\n");

}



/**************************************************************************************************

	LZW_Compression()



  本函数用LZW算法压缩指定的文件，并将结构存储到新的文件中                                     

***************************************************************************************************/

int LZW_Compression(char *in_filename, char *out_filename)

{

  unsigned int next_code;

  unsigned int character;

  unsigned int string_code;

  unsigned int index;

  int i;

  FILE *input;

  FILE *output;



  /* allocate memory for compression */

  code_value=malloc(TABLE_SIZE*sizeof(unsigned int));

  prefix_code=malloc(TABLE_SIZE*sizeof(unsigned int));

  append_character=malloc(TABLE_SIZE*sizeof(unsigned char));

  if (code_value==NULL || prefix_code==NULL || append_character==NULL)

  {

    printf("Fatal error allocating table space!\n");

    return 0;

  }



  /* open files */

  input=fopen(in_filename,"rb");

  output=fopen(out_filename,"wb");

  if (input==NULL || output==NULL)

  {

    printf("Fatal error opening files.\n");

    return 0;

  };



  /* compressing... */



  next_code=256;              /* Next code is the next available string code*/

  for (i=0;i<TABLE_SIZE;i++)  /* Clear out the string table before starting */

    code_value[i]=-1;



  i=0;

  printf("Compressing...\n");

  string_code=getc(input);    /* Get the first code                         */

/*

** This is the main loop where it all happens.  This loop runs util all of

** the input has been exhausted.  Note that it stops adding codes to the

** table after all of the possible codes have been defined.

*/

  while ((character=getc(input)) != (unsigned)EOF)

  {

    if (++i==1000)                         /* Print a * every 1000    */

    {                                      /* input characters.  This */

      i=0;                                 /* is just a pacifier.     */

      printf(".");

    }

    index=find_match(string_code,character);/* See if the string is in */

    if (code_value[index] != -1)            /* the table.  If it is,   */

      string_code=code_value[index];        /* get the code value.  If */

    else                                    /* the string is not in the*/

    {                                       /* table, try to add it.   */

      if (next_code <= MAX_CODE)

      {

        code_value[index]=next_code++;

        prefix_code[index]=string_code;

        append_character[index]=character;

      }

      output_code(output,string_code);  /* When a string is found  */

      string_code=character;            /* that is not in the table*/

    }                                   /* I output the last string*/

  }                                     /* after adding the new one*/

/*

** End of the main loop.

*/

  output_code(output,string_code); /* Output the last code               */

  output_code(output,MAX_VALUE);   /* Output the end of buffer code      */

  output_code(output,0);           /* This code flushes the output buffer*/

  printf("\n");



  /* cleanup... */

  fclose(input);

  fclose(output);



  free(code_value);

  free(prefix_code);

  free(append_character);



  return 1;

}

laolaoliu2002 2008-02-27

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http://www.programsalon.com/downloads75/sourcecode/zip/detail277344.html

sexisnothing 2008-02-27

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同志们！

sexisnothing 2008-02-26

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网上有一些源码 windows下的很多移植性很差

无心人 2008-02-22

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下载7z源代码研究

但不知道7z是不是LZW编码

求 LZ78 & LZW 压缩算法源码

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