用哈夫曼树实现压缩解压.docx

1、用哈夫曼树实现压缩解压用哈夫曼树实现压缩解压程序是用 VC+ 编译完成的，可以完成对任意文件的压缩解压 （为 方便寻找，压缩出的文件与待压缩文件在同一文件夹中） ，但压缩文 件夹还不可以， 另外该程序还能打印出压缩时所建立的哈夫曼树及哈 夫曼编码。源代码如下：#include #include #include #include typedef struct nodelong w;short p,l,r;htnode,*htnp;typedef struct huffman_codeunsigned char len;unsigned char *codestr;hufcode;typedef

2、 char *huffmancode;int initial_files(char *source_filename,FILE *inp,char *obj_filename,FILE *outp);char *create_filename(char *source_filename,char* obj_filename);int compress(char *source_filename,char *obj_filename);long frequency_data(FILE *in,long fre);int search_set(htnp ht,int n,int *s1, int

3、*s2);int create_hftree(long w,int n,htnode ht);int encode_hftree(htnp htp,int n,hufcode hc);unsigned char chars_to_bits(const unsigned char chars8);int write_compress_file(FILE *in,FILE *out,htnp ht,hufcode hc,char* source_filename,long source_filesize);int decompress(char *source_filename,char *obj

4、_filename);void get_mini_huffmantree(FILE* in,short mini_ht2);int write_decompress_file(FILE *in,FILE* mini_ht2,long bits_pos,long obj_filesize);int d_initial_files(char *source_filename,FILE *obj_filename,FILE *outp);main()int s;char filename10;system(color 3F);printf(*n);printf( *n);printf( * 1.ou

5、t,short*inp,char菜单：压缩*n);*n);退出printf( * 0. *n);printf( *n);scanf(%d,&s);while(s!=0)getchar();switch(s)case 1:puts(请输入待压缩文件路径：);gets(filename);compress(filename,NULL);break;case 2:puts(请输入待解压文件路径：);gets(filename);decompress(filename,NULL); break;default :printf( 指令错误！请重新输入指令： n);puts( );printf(*n);p

6、rintf( * 菜单： *n);printf( * 1.压缩 *n);printf( * 2. -解压缩 - *n);printf( * 0.退出 *n);printf(*n);scanf(%d,&s);int initial_files(char *source_filename,FILE *inp,char *obj_filename,FILE *outp)if(fopen(source_filename,rb)=NULL)return -1;if(obj_filename=NULL)if(obj_filename=(char*)malloc(256*sizeof(char)=NULL)

7、return -1; create_filename(source_filename,obj_filename);if(strcmp(source_filename,obj_filename)=0)return -1;printf( 待 压 缩 文 件 :%s, 压 缩件:sn,source_file name,obj_file name);if(*outp=fopen(obj_filename,wb)=NULL)return -1;if(*inp=fopen(source_filename,rb)=NULL)return -1;free(obj_filename);return 0;char

8、 *create_filename(char *source_filename,char* obj_filename) char *temp; if(temp=strrchr(source_filename,.)=NULL)strcpy(obj_filename,source_filename); strcat(obj_filename,.zip);elsestrncpy(obj_filename,source_filename,temp-source_filename);obj_filenametemp-source_filename=0;strcat(obj_filename,.zip);

9、return obj_filename;int compress(char *source_filename,char *obj_filename)FILE *in,*out;char ch;int error_code,i,j;float compress_rate;hufcode hc256;htnode ht256*2-1;long frequency256,source_filesize,obj_filesize=0;error_code=initial_files(source_filename,&in,obj_filename,&out);if(error_code!=0)puts

10、(文件打开失败！请重新输入文件路径：);return error_code;source_filesize=frequency_data(in,frequency); printf( 文件大小 %ld 字节 n,source_filesize); error_code=create_hftree(frequency,256,ht); if(error_code!=0)puts(”建立哈夫曼树失败！);return error_code;error_code=encode_hftree(ht,256,hc);if(error_code!=0)puts(建立哈夫曼编码失败！ ”)；return e

11、rror_code;for(i=0；i256；i+) obj_filesize+=frequencyi*hci.len；obj_filesize=obj_filesize%8=0?obj_filesize/8:obj_filesize/8+1；for(i=0；i256-1；i+)obj_filesize+=2*sizeof(short)； obj_filesize+=strlen(source_filename)+1；obj_filesize+=sizeof(long);obj_filesize+=sizeof(unsigned int);compress_rate=(float)obj_fi

12、lesize/source_filesize;printf( 压 缩 文 件 大 小 :%ld 字 节 , 压 缩 比例:.2lf%n,obj_filesize,compress_rate*100);error_code=write_compress_file(in,out,ht,hc,source_filename,source_filesize);if(error_code!=0)puts(写入文件失败！);return error_code;puts(压缩完成!);puts( );puts(”是否打印该文件中字符对应的huffman树及编码？ ”)；puts( Please input

13、Y OR N);doscanf(%s,&ch);switch(ch)case Y:puts(”以下是哈夫曼树：”)；for(i=256;i0)printf(%-10d%-10d%-10d%-10d%-10dn,i,hti.w,hti.p,hti.l,hti .r)；puts(”以下是哈夫曼编码：”)；for(i=0；i256；i+)if(frequencyi=0)i+；elseprintf(%dt,frequencyi)；for(j=0；jhci.len；j+)printf( %d,hci.codestrj)；printf(n)；break； case N: break;default :n)

14、;printf( 指令错误！请重新输入指令： while(ch!=Y&ch!=N); fclose(in);fclose(out); for(i=0;i256;i+)free(hci.codestr);return 0;long frequency_data(FILE *in,long frequency)int i,read_len;unsigned char buf256;long filesize;for(i=0;i256;i+)frequencyi=0;fseek(in,0L,SEEK_SET);read_len=256;while(read_len=256)read_len=frea

15、d(buf,1,256,in);for(i=0;iread_len;i+)frequency*(buf+i)+;for(i=0,filesize=0;i256;i+)filesize+=frequencyi;return filesize;int search_set(htnp ht,int n,int *s1, int *s2)int i,x;long minValue = 1000000,min = 0;for(x=0;xn;x+)if(htx.p=-1) break;for(i=0;in;i+)if(hti.p=-1 & hti.w minValue)minValue = hti.w;m

16、in=i;*s1 = min;minValue = 1000000,min = 0;for(i=0;in;i+)if(hti.p=-1 & hti.w minValue & i != *s1)minValue = hti.w;min=i;*s2 = min;return 1;int create_hftree(long w,int n,htnode ht)int m,i,s1,s2;if (n1) return -1;m=2*n-1;if (ht=NULL) return -1;for(i=0;in;i+)hti.w=wi;hti.p=hti.l=hti.r=-1;for(;im;i+)hti

17、.w=hti.p=hti.l=hti.r=-1;for(i=n;im;i+)search_set(ht,i,&s1,&s2);hts1.p = hts2.p = i;hti.l = s1;hti.r = s2;hti.w = hts1.w + hts2.w;return 0;int encode_hftree(htnp htp,int n,hufcode hc) int i,j,p,codelen;*code=(unsignedunsigned char char*)malloc(n*sizeof(unsigned char);if (code=NULL) return -1;for(i=0;

18、in;i+)for(p=i,codelen=0;p!=2*n-2;p=htpp.p,codelen+) codecodelen=(htphtpp.p.l=p?0:1);charif(hci.codestr=(unsigned*)malloc(codelen)*sizeof(unsigned char)=NULL)return -1;hci.len=codelen;for(j=0;jcodelen;j+)hci.codestrj=codecodelen-j-1;free(code);return 0; unsigned char chars_to_bits(const unsigned char

19、 chars8) int i;unsigned char bits=0; bits|=chars0;for(i=1;i8;+i) bits=1; bits|=charsi;return bits;int write_compress_file(FILE *in,FILE *out,htnp ht,hufcode hc,char* source_filename,long source_filesize)unsigned int i,read_counter,write_counter,zip_head=0xFFFFFFFF;unsigned charwrite_char_counter,cod

20、e_char_counter,copy_char_counter,read_buf256,write_buf256,write_chars8,filename_size=strlen(source _filename);hufcode *cur_hufcode;fseek(in,0L,SEEK_SET);fseek(out,0L,SEEK_SET); fwrite(&zip_head,sizeof(unsigned int),1,out); fwrite(&filename_size,sizeof(unsigned char),1,out); fwrite(source_filename,si

21、zeof(char),filename_size,out); fwrite(&source_filesize,sizeof(long),1,out);for(i=256;i256*2-1;i+)fwrite(&(hti.l),sizeof(hti.l),1,out); fwrite(&(hti.r),sizeof(hti.r),1,out);write_counter=write_char_counter=0;read_counter=256;while(read_counter=256) read_counter=fread(read_buf,1,256,in); for(i=0;ilen)

22、copy_char_counter= (8-write_char_counter cur_hufcode-len-code_char_counter ?cur_hufcode-len-code_char_counter : 8-write_char_counter);memcpy(write_chars+write_char_counter,cur_hufcode-codestr+code_char_counter,copy_char_counter);write_char_counter+=copy_char_counter;code_char_counter+=copy_char_coun

23、ter; if(write_char_counter=8)write_char_counter=0;write_bufwrite_counter+=chars_to_bits(write_chars);if(write_counter=256)fwrite(write_buf,1,256,out);write_counter=0;fwrite(write_buf,1,write_counter,out);if(write_char_counter!=0)write_char_counter=chars_to_bits(write_chars); fwrite(&write_char_count

24、er,1,1,out);return 0;void get_mini_huffmantree(FILE* in,short mini_ht2)int i;for(i=0;i=1)cur_pos=(read_bufread_counter&convert_bit)=0?mini_htcur_pos0 :mini_htcur_pos1);if(cur_pos256)write_bufwrite_counter=(unsignedchar)cur_pos;if(+write_counter=256)fwrite(write_buf,1,256,out);write_counter=0;cur_pos

25、=256*2-2;if(+cur_size=obj_filesize)break;fwrite(write_buf,1,write_counter,out);return 0;int decompress(char *source_filename,char *obj_filename)interror_code;FILE*in,*out;shortmini_ht256*2-12;longobj_filesize;error_code=d_initial_files(source_filename,&in,obj_filename,&out);if(error_code!=0)puts(”打开文件失败！请重新输入文件路径：)；return error_code;fread(&obj_filesize,sizeof(long),1,in);printf( 解压文件大小 :%ld 字节 n,obj_filesize);get_mini_huffmantree(in,mini_ht);error_code=write_decompress_file(in,out,mini_ht,ftell(in),obj_filesize);if(error_code!=0)puts(”解压缩失败！ ”)；return e