C++ 哈弗曼编码的实现与反编码

#include<iostream> #include<stdlib.h> #include<string.h> using namespace std; typedef struct{ int weight; int parent,lchild,rchild; int asc; }HTNode,*HuffmanTree; //定义赫夫曼存储结构 struct node{ int ASCII; int n; }; struct node a[127]; struct node w[127]; //一些全局变量 int count; HTNode H_T[250]; char ** HC; char filename[20]; //函数声明 void menu1(); //菜单1 HuffmanTree HeapSort(HuffmanTree HT,int length); //堆排序 void MinHeapify(HuffmanTree HT, int k,int len); //调整成一个小顶堆 void buildMinHeap(HuffmanTree HT,int len); //建一个小顶堆 void swap(HTNode &t1,HTNode &t2); //交换两结构体 void savefile(); //把输入的英文文章保存到文件 void loadfile(); //从文件中读取文章 HuffmanTree CreateHuffman(HuffmanTree &HT,struct node *w,int n); //建立赫夫曼数并存入文件 void BianMa(HuffmanTree HT,int n ); //字符编码 void BianMa_all(HuffmanTree HT,char**HC,char *filename); //整篇文章编码 int loadfile2(); //从文件读入文章 void JieMa(); //解码 //主函数 void main() { char s; while(s!='0') { system("cls"); cout<<"/n/n/n"; cout<<"/t/t/t/t赫夫曼编码/译码器"<<endl<<endl<<endl<<endl<<endl; cout<<"/t/t/t/t 1.编码"<<endl<<endl<<endl<<endl; cout<<"/t/t/t/t 2.译码"<<endl<<endl<<endl<<endl; cout<<"/t/t/t/t 0.退出"<<endl<<endl<<endl<<endl; cout<<"/t请输入0—2进行选择，按回车确认"; cin>>s; switch(s) { case '1': menu1(); break; case '2': { system("cls"); JieMa(); system("pause"); break; } } } } //菜单1 void menu1(){ char s; int i; int a; char c; char fpname[20]="article.txt"; HuffmanTree HT; while(s!='0'){ system("cls"); cout<<"/n/t/t/t/t编码界面"; cout<<"/n/n/n/t/t/t/t1.输入英文文章"<<endl; cout<<"/n/n/t/t/t/t2.从文件中读入文章"<<endl; cout<<"/n/n/t/t/t/t0.返回上一层"<<endl; cout<<"/n/t请输入0—2进行选择，按回车确认"; cin>>s; switch(s){ case'1': system("cls"); savefile(); loadfile(); CreateHuffman(HT,w,count); BianMa(HT,count); BianMa_all(HT,HC,fpname); system("cls"); cout<<"出现字符种类共计："; cout<<count<<endl; for(i=1;i<=count;i++) { a=HT[i].asc; c=(char)a; cout<<"________________________________________________________________________________"<<endl; cout<<"/t/t/t字符："; cout<<c<<endl; cout<<"/t/t/tASCII码："; cout<<a<<endl; cout<<"/t/t/t频数："; cout<<HT[i].weight<<endl; cout<<"/t/t/t赫夫曼编码："; cout<<HC[i]<<endl; } cout<<"________________________________________________________________________________"; cout<<"/n/t/t整篇文章的编码已存入文件“赫夫曼编码.txt”"<<endl; system("pause"); break; case'2': system("cls"); if(loadfile2()) { system("pause"); return;} CreateHuffman(HT,w,count); BianMa(HT,count); BianMa_all(HT,HC,filename); system("cls"); cout<<"出现字符种类共计："; cout<<count<<endl; for(i=1;i<=count;i++) { a=HT[i].asc; c=(char)a; cout<<"________________________________________________________________________________"<<endl; cout<<"/t/t/t字符："; cout<<c<<endl; cout<<"/t/t/tASCII码："; cout<<a<<endl; cout<<"/t/t/t频数："; cout<<HT[i].weight<<endl; cout<<"/t/t/t赫夫曼编码："; cout<<HC[i]<<endl; } cout<<"________________________________________________________________________________"; cout<<"/n/t/t整篇文章的编码已存入文件“赫夫曼编码.txt”"<<endl; system("pause"); break; } } } //交换结构体 void swap(HTNode &t1,HTNode &t2) { HTNode m; m = t1; t1 = t2; t2 = m; } //从键盘输入文章并保存 void savefile(){ FILE *fp; char article; if((fp=fopen("article.txt","w"))==NULL){ printf("打开文件不成功！"); exit(0); } cout<<"请输入英文文章,以#结束:"; getchar(); article=getchar(); while(article!='#'){ fputc(article,fp); article=getchar(); } fclose(fp); } //从文件读取文章，并统计字符出现频数 void loadfile(){ FILE *fp; char ch; int i,k,j=0; count=0; for(i=0;i<=127;i++) //把所有字符的ascii码存在数组 { a[i].ASCII=i; a[i].n=0; } if((fp=fopen("article.txt","r"))==NULL){ printf("打开文件不成功！"); exit(0); } ch=fgetc(fp); k=(int)ch; a[k].n++; while(!feof(fp)){ ch=fgetc(fp); k=(int)ch; a[k].n++; } fclose(fp); for(i=0;i<=127;i++) //统计字符种类总数 { ch=(char)i; if(a[i].n){ count++; } } for(i=0;i<=127;i++) { for(;j<count;) { if(a[i].n) { w[j].n=a[i].n; w[j].ASCII=a[i].ASCII; j++; break; } else break; } } } //调整为小顶堆 void MinHeapify(HuffmanTree HT, int k,int len) { int left=k*2; int right=k*2+1; int large; int l=len; large = k; if (left<=l&&HT[left].weight<HT[large].weight) large = left; if (right<=l&& HT[right].weight<HT[large].weight) large=right; if (large!=k) { swap(HT[k],HT[large]); MinHeapify(HT,large,l); } } //建立小顶堆 void buildMinHeap(HuffmanTree HT,int len) { int i; for (i=len/2;i>=1;i--) { MinHeapify(HT,i,len); } } //堆排序 HuffmanTree HeapSort(HuffmanTree HT,int length) { int i; int l=length; buildMinHeap(HT,length); for (i=length;i>= 2;i--) { swap(HT[1],HT[i]); length--; MinHeapify(HT,1,length); } return HT; } //建立赫夫曼数 HuffmanTree CreateHuffman(HuffmanTree &HT,struct node *w,int n) { int i,m,s1,s2,k1,k2,j,x,a; FILE *fp,*fp2; if(n<=1) return HT; m=2*n-1; HT=(HuffmanTree)malloc((m+1)*sizeof(HTNode));//0不用 for(i=1,j=0;i<=n;i++,j++) { HT[i].asc=w[j].ASCII; HT[i].weight=w[j].n; HT[i].parent=0; HT[i].lchild=0; HT[i].rchild=0; } for(;i<=m;i++) { a=250+i; HT[i].asc=a;//父亲节点的asc可以是大于127的任意值 HT[i].weight=0; HT[i].parent=0; HT[i].lchild=0; HT[i].rchild=0; } for(i=1;i<=n;i++){ H_T[i].asc=HT[i].asc; H_T[i].parent=HT[i].parent; H_T[i].lchild=HT[i].lchild; H_T[i].rchild=HT[i].rchild; H_T[i].weight=HT[i].weight; } for(i=n+1,x=n;i<=m;i++,x--) { HeapSort(H_T,x); k1=H_T[x].asc; k2=H_T[x-1].asc; for(j=1;j<=127;j++) { if(HT[j].asc==k1) { s1=j;break;} } for(j=1;j<=127;j++) { if(HT[j].asc==k2) { s2=j;break;} } HT[s2].parent=i; HT[s1].parent=i; HT[i].lchild=s1; HT[i].rchild=s2; HT[i].weight=HT[s1].weight+HT[s2].weight; H_T[x-1].asc=HT[i].asc; H_T[x-1].lchild=HT[i].lchild; H_T[x-1].parent=HT[i].parent; H_T[x-1].rchild=HT[i].rchild; H_T[x-1].weight=HT[i].weight; } if((fp2=fopen("count.txt","w"))==NULL) //保存赫夫曼树 { cout<<"文件打开不成功！"<<endl; exit(0); } fputc(count,fp2); if((fp=fopen("HuffmanTree.dat","wb"))==NULL) { cout<<"文件打开不成功！"<<endl; exit(0); } for(i=1;i<=(2*count-1);i++){ fwrite(&HT[i],sizeof(HTNode),1,fp); } fclose(fp); fclose(fp2); return HT; } //逆向编码 void BianMa(HuffmanTree HT,int n){ char *cd,temp; int c,f,i,j,len,p,q; cd=(char *)malloc(n*sizeof(char)); HC=(char * *)malloc(n*sizeof(char*)); for(i=1;i<=n;i++){ for(c=i,f=HT[i].parent,j=0;f!=0;c=f,f=HT[f].parent,j++) { if(HT[f].lchild==c) cd[j]='0'; else cd[j]='1'; if(HT[f].parent==0) cd[j+1]='/0'; } len=strlen(cd); for(p=0,q=len-1;p<=q;p++,q--) { temp=cd[q]; cd[q]=cd[p]; cd[p]=temp; } cd[len]='/0'; HC[i]=(char*)malloc((len+10)*sizeof(char)); strcpy(HC[i],cd); } } //整篇文章编码，并存入文件 void BianMa_all(HuffmanTree HT,char**HC,char *filename){ char ch; int k,i; FILE *fp,*fp2; char code[100]; if((fp=fopen(filename,"r"))==NULL){ printf("打开文件不成功！"); exit(0); } if((fp2=fopen("赫夫曼编码.txt","w"))==NULL){ printf("打开文件不成功！"); exit(0); } ch=fgetc(fp); k=(int)ch; while(!feof(fp)) { for(i=1;i<=count;i++) { if(k==HT[i].asc) strcpy(code,HC[i]); } fputs(code,fp2); ch=fgetc(fp); k=(int)ch; } fclose(fp); fclose(fp2); } void JieMa(){ int i,k,a,t,n=0; FILE *fp1,*fp2,*fp3; char ch,c; HuffmanTree ht; if((fp3=fopen("count.txt","r"))==NULL) //从文件读出字符总数 { printf("打开文件不成功！"); exit(0); } n=fgetc(fp3); ht=(HuffmanTree)malloc(2*n*sizeof(HTNode)); if((fp1=fopen("赫夫曼编码.txt","r"))==NULL) { printf("打开文件不成功！"); exit(0); } if((fp2=fopen("HuffmanTree.dat","rb"))==NULL) { cout<<"文件打开不成功！"<<endl; exit(0); } for(i=1;i<=2*n-1;i++) fread(&ht[i],sizeof(HTNode),1,fp2); for(i=1;i<=2*n-1;i++) { if(ht[i].parent==0){t=k=i;break;} } ch=fgetc(fp1); while(!feof(fp1)){ if(ch=='0') { k=ht[k].lchild; if(ht[k].lchild==0) {a=ht[k].asc; c=(char)a; printf("%c",c);; k=t; } } if(ch=='1') { k=ht[k].rchild; if(ht[k].lchild==0) { a=ht[k].asc; c=(char)a; printf("%c",c); k=t; } } ch=fgetc(fp1); } fclose(fp1); fclose(fp2); } //读取文件中的文章，可自己选择文件 int loadfile2(){ FILE *fp; char ch; int i,k,j=0; count=0; for(i=0;i<=127;i++) { a[i].ASCII=i; a[i].n=0; } cout<<"/n/n/n/t/t/t请输入你要打开的文件名："; cin>>filename; if((fp=fopen(filename,"r"))==NULL){ printf("打开文件不成功！"); return 1; } ch=fgetc(fp); k=(int)ch; a[k].n++; while(!feof(fp)){ ch=fgetc(fp); k=(int)ch; a[k].n++; } fclose(fp); for(i=0;i<=127;i++){ ch=(char)i; if(a[i].n){ count++; } } for(i=0;i<=127;i++) { for(;j<count;) { if(a[i].n) { w[j].n=a[i].n; w[j].ASCII=a[i].ASCII; j++; break; } else break; } } return 0; }