彩色图像霍(哈)夫曼编码、解码

/***********************************************************************************************************Huffman.c本演示程序提供了哈夫曼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 <stdlib.h>#include <string.h>#include <time.h>/* 函数原型 */int Huffman_Compression(char * infilename, char * outfilename);int Huffman_Decompression(char * infilename, char * outfilename);/* 内部函数 */unsigned short  generate_code_table ();void          build_code_tree ();void build_initial_heap ();void          compress_image ();void          get_frequency_count ();voidbuild_decomp_tree ();voiddecompress_image ();/* 全局变量 */short           father[512];unsigned short  code[256], heap_length;unsigned long   compress_charcount, file_size, heap[257];unsigned char   code_length[256];long            frequency_count[512];short           decomp_tree[512];FILE            *ifile, *ofile;int total_time;clock_t start, finish;/* 主程序 */void main(){printf("Huffman compression and decompression utility\n");if (1){printf("\nCompress...");start = clock();Huffman_Compression("2.bmp", "3.bmp");//压缩finish = clock();total_time = finish - start;printf("\n耗时： %d毫秒\n", total_time);}else {printf("\nDecompress...");//解压Huffman_Decompression("3.bmp", "4.bmp");}}/*********************************************************************************  Huffman_Compression ()  用Huffman编码压缩指定的文件，并将结果存为新的文件 ********************************************************************************/int Huffman_Compression(char * infilename, char * outfilename){if ((ifile = fopen (infilename, "rb")) != NULL){fseek (ifile, 0L, 2);file_size = (unsigned long) ftell (ifile);//文件的长度fseek (ifile, 0L, 0);get_frequency_count ();//本函数对需要进行压缩的数据进行频率统计build_initial_heap ();build_code_tree ();if (!generate_code_table ()){printf ("ERROR!  Code Value Out of Range. Cannot Compress.\n");return 0;}else{if ((ofile = fopen (outfilename, "wb")) != NULL){fwrite (&file_size, sizeof (file_size), 1, ofile);fwrite (code, 2, 256, ofile);fwrite (code_length, 1, 256, ofile);fseek (ifile, 0L, 0);compress_image ();fclose (ofile);}else{printf("\nERROR: Couldn't create output file %s\n", outfilename);return 0;}}fclose (ifile);}else{printf ("\nERROR:  %s -- File not found!\n", infilename);return 0;}return 1;}/************************************************************************** COMPRESS_IMAGE () 本函数进行数据的压缩操作 **************************************************************************/void compress_image (){   register unsigned int    thebyte = 0;   register short           loop1;   register unsigned short  current_code;   register unsigned long   loop;   unsigned short  current_length, dvalue;   unsigned long   curbyte = 0;   short           curbit = 7;   for (loop = 0L; loop < file_size; loop++)   {      dvalue         = (unsigned short) getc (ifile);      current_code   = code[dvalue];      current_length = (unsigned short) code_length[dvalue];      for (loop1 = current_length-1; loop1 >= 0; --loop1)      {         if ((current_code >> loop1) & 1)            thebyte |= (char) (1 << curbit);         if (--curbit < 0)         {            putc (thebyte, ofile);            thebyte = 0;            curbyte++;            curbit = 7;         }      }   }   putc (thebyte, ofile);   compress_charcount = ++curbyte;}/************************************************************************** GENERATE_CODE_TABLE () 本函数生成压缩码表 **************************************************************************/unsigned short  generate_code_table (){   register unsigned short  loop;   register unsigned short  current_length;   register unsigned short  current_bit;   unsigned short  bitcode;   short           parent;   for (loop = 0; loop < 256; loop++)      if (frequency_count[loop])      {         current_length = bitcode = 0;         current_bit = 1;         parent = father[loop];         while (parent)         {            if (parent < 0)            {               bitcode += current_bit;               parent = -parent;            }            parent = father[parent];            current_bit <<= 1;            current_length++;         }         code[loop] = bitcode;         if (current_length > 16)            return (0);         else            code_length[loop] = (unsigned char) current_length;      }      else         code[loop] = code_length[loop] = 0;   return (1);}/************************************************************************** BUILD_CODE_TREE () 建立压缩编码树 **************************************************************************/void build_code_tree (){   void    reheap ();   register unsigned short  findex;   register unsigned long   heap_value;   while (heap_length != 1)   {      heap_value = heap[1];      heap[1]    = heap[heap_length--];      reheap (1);      findex = heap_length + 255;      frequency_count[findex] = frequency_count[heap[1]] +                                frequency_count[heap_value];      father[heap_value] =  findex;      father[heap[1]]    = -findex;      heap[1]            =  findex;      reheap (1);   }   father[256] = 0;}/************************************************************************** REHEAP () 从当前的堆树结构中建立逻辑堆结构 **************************************************************************/void reheap (heap_entry)unsigned short  heap_entry;{   register unsigned short  index;   register unsigned short  flag = 1;   unsigned long   heap_value;   heap_value = heap[heap_entry];   while ((heap_entry <= (heap_length >> 1)) && (flag))   {      index = heap_entry << 1;      if (index < heap_length)         if (frequency_count[heap[index]] >= frequency_count[heap[index+1]])            index++;      if (frequency_count[heap_value] < frequency_count[heap[index]]) flag--;      else      {         heap[heap_entry] = heap[index];         heap_entry       = index;      }   }   heap[heap_entry] = heap_value;}/************************************************************************** BUILD_INITIAL_HEAP () 本函数从初始的频率统计数据中建立堆结构 **************************************************************************/void build_initial_heap (){   void    reheap ();//从当前的堆树结构中建立逻辑堆结构   register unsigned short  loop;   heap_length = 0;   for (loop = 0; loop < 256; loop++)      if (frequency_count[loop])         heap[++heap_length] = (unsigned long) loop;   for (loop = heap_length; loop > 0; loop--)      reheap (loop);}/************************************************************************** GET_FREQUENCY_COUNT () 本函数对需要进行压缩的数据进行频率统计 **************************************************************************/void get_frequency_count (){register unsigned long  loop;//如某个变量使用过于频繁，可能把变量放在 寄存器 更合适    for (loop = 0; loop < file_size; loop++)      frequency_count[getc (ifile)]++;//getc (ifile)从文件指针指向的文件读入一个字符}/************************************************************************** Huffman_Decompression () 本函数进行Huffman解码 **************************************************************************/int  Huffman_Decompression(char * infilename, char * outfilename){if ((ifile = fopen (infilename, "rb")) != NULL){fread (&file_size, sizeof (file_size), 1, ifile);fread (code, 2, 256, ifile);fread (code_length, 1, 256, ifile);build_decomp_tree ();if ((ofile = fopen (outfilename, "wb")) != NULL){decompress_image();fclose (ofile);}else{printf ("\nERROR:  Couldn't create output file %s\n", outfilename);return 0;}fclose (ifile);}else{printf ("\nERROR:  %s -- File not found!\n", infilename);return 0;}return 1;}/************************************************************************** BUILD_DECOMP_TREE () 创建解压缩树 **************************************************************************/void  build_decomp_tree (){   register unsigned short  loop1;   register unsigned short  current_index;   unsigned short  loop;   unsigned short  current_node = 1;   decomp_tree[1] = 1;   for (loop = 0; loop < 256; loop++)   {      if (code_length[loop])      { current_index = 1; for (loop1 = code_length[loop] - 1; loop1 > 0; loop1--) {    current_index = (decomp_tree[current_index] << 1) +    ((code[loop] >> loop1) & 1);    if (!(decomp_tree[current_index]))       decomp_tree[current_index] = ++current_node; } decomp_tree[(decomp_tree[current_index] << 1) +   (code[loop] & 1)] = -loop;      }   }}/************************************************************************** DECOMPRESS_IMAGE () 进行解压缩操作 **************************************************************************/void  decompress_image (){   register unsigned short  cindex = 1;   register char            curchar;   register short           bitshift;   unsigned long  charcount = 0L;   while (charcount < file_size)   {      curchar = (char) getc (ifile);      for (bitshift = 7; bitshift >= 0; --bitshift)      { cindex = (cindex << 1) + ((curchar >> bitshift) & 1); if (decomp_tree[cindex] <= 0) {    putc ((int) (-decomp_tree[cindex]), ofile);    if ((++charcount) == file_size)               bitshift = 0;            else               cindex = 1; } else    cindex = decomp_tree[cindex];      }   }}

注：此程序是针对彩色图像进行的编解码

把2.bmp压缩成3.bmp.但3.bmp打不开，

把3.bmp解压到4.bmp，即原来的2.bmp