huff.c

该程序可以用来实现huffman的编码译码功能

#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>
#define NULL 0
#define OK 1
#define ERROR 0
#define OVERFLOW -2
#define MAX_NUM 1000
#define MAX 100


typedef struct{
    unsigned int   weight;
    unsigned int   parent,lc,rc;
}HTNode,*HuffmanTree;         /*动态分配数组存储Huffman树*/

typedef int Status;
typedef char **HuffmanCode;   /*动态分配数组存储Huffman编码表*/
typedef struct Huffman{
    HuffmanTree HT;
    char        *c;
    int         ln;
    HuffmanCode HC;
}Huffman;


void Select(HuffmanTree HT,int end,int *s1,int *s2)
{
  int i;
  int min1=MAX_NUM;
  int min2;
  for (i=1;i<=end;i++)
  {
    if (HT[i].parent==0&&HT[i].weight<min1)
    {
      *s1=i;
      min1=HT[i].weight;
    }
  }
  min2=MAX_NUM;
  for(i=1;i<=end;i++)
  {
    if(HT[i].parent==0&&(*s1!=i)&&min2>HT[i].weight)
    {
      *s2=i;
      min2=HT[i].weight;
    }
  }
}

Huffman HuffmanCoding(Huffman Hfm)
{
  int i,n,m,s1,s2,start;
  int c,f;
  char *cd;
  n=Hfm.ln;
  if(n<=1)  return Hfm;
  m=2*n-1;
  for(i=n+1;i<=m;++i)    /*建立Huffman树*/
  {
    Select(Hfm.HT,i-1,&s1,&s2);
    Hfm.HT[s1].parent=i;
    Hfm.HT[s2].parent=i;
    Hfm.HT[i].lc=s1;
    Hfm.HT[i].rc=s2;
    Hfm.HT[i].weight=Hfm.HT[s1].weight+Hfm.HT[s2].weight;
  }
  Hfm.HC=(HuffmanCode)malloc((n+1)*sizeof(char *));  /*分配n个字符编码的头指针向量*/
  cd=(char *)malloc(n*sizeof(char));  /*分配求编码的工作空间*/
  cd[n-1]='\0';    /*编码结束符*/
  for(i=1;i<=n;++i)   /*逐个字符求Huffman编码*/
  {
    start=n-1;    /*编码结束符位置*/
    for(c=i,f=Hfm.HT[i].parent;f!=0;c=f,f=Hfm.HT[f].parent) /*从叶子到根逆向求编码*/
    {
      if(c==Hfm.HT[f].lc)  cd[--start]='0';
      else cd[--start]='1';
    }
    Hfm.HC[i]=(char *)malloc((n-start)*sizeof(char)); /*为第i个字符编码分配空间*/
    strcpy(Hfm.HC[i],&cd[start]);    /*从cd复制编码（串）到HC*/
  }
  free(cd);
  return Hfm;
}

Huffman InitHuffman(Huffman Hfm)
{
    int i,n;
    clrscr();
    printf("The chars and weights will be saved in the file \"hfmTree\"\n");
    printf("Please input the number of the chars: ");
    scanf("%d",&n);
    Hfm.HT=(HuffmanTree)malloc((2*n)*sizeof(HTNode));
    Hfm.c=(char *)malloc((n+1)*sizeof(char));
    printf("Please input the char: ");
    for(i=1;i<=n;i++)
      scanf("%s",&Hfm.c[i]);
    printf("Please input the weight of the char: ");
    for(i=1;i<=n;i++)
      scanf("%d",&Hfm.HT[i].weight);
    for(i=1;i<=n;i++)
    {
      Hfm.HT[i].parent=0;
      Hfm.HT[i].lc=0;
      Hfm.HT[i].rc=0;
    }
    for(;i<=2*n-1;++i)
    {
      Hfm.HT[i].weight=0;
      Hfm.HT[i].parent=0;
      Hfm.HT[i].lc=0;
      Hfm.HT[i].rc=0;
    }
    Hfm.ln=n;
    return Hfm;
}

Huffman RebuildHuffman(Huffman Hfm)
{
  int n,i;
  FILE *fp;
  fp=fopen("hfmTree","wt");
  Hfm=InitHuffman(Hfm);
  fprintf(fp,"%d\n",Hfm.ln);
  for(i=1;i<=Hfm.ln;i++)
  fprintf(fp,"%c %d",Hfm.c[i],Hfm.HT[i].weight);
  rewind(fp);
  fclose(fp);
  Hfm=HuffmanCoding(Hfm);
  return Hfm;
}

void Encoding(Huffman Hfm)
{
  int i=0,j=0,n;
  char ch[MAX];
  FILE *fp,*ffp;
  n=Hfm.ln;
  printf("\n\n*******************Encoding************************\n\n");
  if((ffp=fopen("ToBeTran","rt"))==NULL)
  {
    printf("\nPlease input the sentence: ");
    scanf("%s",&ch);
    printf("\n");
    fp=fopen("CodeFile","wt+");
  }
  else
  {
    fscanf(ffp,"%s",ch);
    fclose(ffp);
  }
  while(ch[j])
    {
      for(i=1;i<=n;i++)
    if(ch[j]==Hfm.c[i])
    {
      printf("%s",Hfm.HC[i]);
      fprintf(fp,"%s",Hfm.HC[i]);
      break;
    }
     j++;
   }
   rewind(fp);
   fclose(fp);
}

void Decoding(Huffman Hfm)
{
  HuffmanTree p;
  int i,n;
  int j=0;
  char d[50];
  FILE *fp;
  n=Hfm.ln;
  printf("\n\n******************Decoding************************\n\n");
  if((fp=fopen("CodeFile","rt"))==NULL)
  {
    printf("Please input the code:");
    scanf("%s",&d);
  }
  else
  {
    fscanf(fp,"%s",d);
    fclose(fp);
  }
  printf("\nThe file is : ");
  fp=fopen("TextFile","wt+");
  while(d[j])
  {
    p=&Hfm.HT[2*n-1];
    while(p->lc||p->rc)
    {
      if(d[j]=='0')
      { i=p->lc;  p=&Hfm.HT[i]; }
      else
      { i=p->rc;  p=&Hfm.HT[i]; }
      j++;
    }
    printf("%c",Hfm.c[i]);
    fprintf(fp,"%c",Hfm.c[i]);
  }
  fclose(fp);
}

Huffman InputHuffman(Huffman Hfm)
{
  int n,i;
  FILE *fp;
  fp=fopen("hfmTree","rt");
  if(fp==NULL)
  {
    Hfm=InitHuffman(Hfm);
    fp=fopen("hfmTree","wt");
    fprintf(fp,"%d\n",Hfm.ln);
    for(i=1;i<=Hfm.ln;i++)
      fprintf(fp,"%c%d",Hfm.c[i],Hfm.HT[i].weight);
    rewind(fp);
  }
  else
  {
    fscanf(fp,"%d\n",&n);
    Hfm.c=(char *)malloc((n+1)*sizeof(char));
    Hfm.HT=(HuffmanTree)malloc((2*n)*sizeof(HTNode));
    for(i=1;i<=n;i++)
      fscanf(fp,"%c%d",&Hfm.c[i],&Hfm.HT[i].weight);
    for(i=1;i<=n;i++)
    {
      Hfm.HT[i].parent=0;
      Hfm.HT[i].lc=0;
      Hfm.HT[i].rc=0;
    }
    for(;i<=2*n-1;++i)
    {
      Hfm.HT[i].weight=0;
      Hfm.HT[i].parent=0;
      Hfm.HT[i].lc=0;
      Hfm.HT[i].rc=0;
    }
    Hfm.ln=n;
  }
  fclose(fp);
  Hfm=HuffmanCoding(Hfm);
  return Hfm;
}


void OutputHuffman(Huffman Hfm)
{
  int i,n;
  n=Hfm.ln;
  printf("\n\n******************Output the code of the chars****************\n\n");
  for(i=1;i<=n;i++)
  {
     printf("\n");
     printf("Char: %c\t",Hfm.c[i]);
     printf("Weight: %d\t",Hfm.HT[i].weight);
     printf("Code: ");
     puts(Hfm.HC[i]);
  }
}


int main()
{
  struct Huffman Hfm;
  char choice;
  Hfm=InputHuffman(Hfm);
  while(choice!='q')
  {
    clrscr();
    printf("\n\n\n*************************************\n\n");
    printf("E. Code:\n\n");
    printf("D. Translate:\n\n");
    printf("P. Output   bianma code :\n\n");
    printf("R. rebuild Huffman tree:\n\n");
    printf("Q. exit\n\n");
    printf("\n************************************\n\n");
    printf("Please enter your choice: ");
    scanf("%c",&choice);
    switch(choice)
    {
      case 'e':
      case 'E':
       clrscr();
       Encoding(Hfm);
       printf("\nPlease enter anykey to continue!\n");
       getch(); break;
      case 'd':
      case 'D':
       clrscr();
       Decoding(Hfm);
       printf("\nPlease enter anykey to continue!\n");
       getch(); break;
      case 'p':
      case 'P':
       clrscr();
       OutputHuffman(Hfm);
       printf("\nPlease enter anykey to continue!\n");
       getch(); break;
      case 'r':
      case 'R':
       clrscr();
       Hfm=RebuildHuffman(Hfm);
       printf("\nInitial!\n");
       getch(); break;
      case 'q':
      case 'Q':
        break;
        default:
        printf(" Your choice is wrong!\n Please enter anykey to choice again!\n");
        getch(); break;
    }
  }
  return 0;
}