算术编码用c语言实现.docx

算术编码用c语言实现?(2010-07-07 23:43:59)转载标签：?杂谈描述：在source1.dat文件中有100个数据，其中，0的概率为1/8,1的概率为7/8.用算术编码进行压缩。程序如下：//============================================================================// Name????????: suanshcoding.cpp// Author??????: 朗月清风// Version?????:1.0// Copyright???: All rights Reserved by 2010// Description : 从source1.dat文件中读取信息,即100个0、1码，完成算术编码，并给//???????????????出了译码及验证。// Department??:upc//============================================================================#includestdio.h#includemath.h#define max 100void main(){?FILE *fp;?int i=0;?int n;?long double high;//上限?long double low;//下限?long double d;//间距?long double buf[max]; //大数组，暂存读取的数据?long double decode[max]; //存解码后的结果?int code[55];??//编码结果?long double temp;?long double hx;//总信息量?long double tp;//从区间取数?long double x=0.0; //存恢复的小数?long double line;//解码时判断准线//?char ch;??if((fp=fopen(f:\\source1.dat,r))==NULL)?{??printf(open erro!\n);??//exit(0);?}?else?{?while (!feof(fp))?{??fscanf(fp,%lf,temp);??buf[i]=temp;????//?printf(%d--%lf\n,i,buf[i]);??i++;?}?}?//for(i=0;imax;i++)?//?printf(%1f\n,buf[i]);?double p0=1.0/8;//0的概率?double p1=7.0/8; //1的概率?low=0.0;?high=1.0;?d=1.0;?for(i=0;imax;i++)?{??if(buf[i]==1.0)??{???low+=d*p0;???d=high-low;??}??else if(buf[i]==0.0)??{???high=low+d*p0;???d=high-low;??}?}?hx=max*(1.0/8*log(8)/log(2)+7.0/8*log(8.0/7)/log(2));?// 计算总共传递的信息?printf(总共传递的信息量%f\n,hx);?n=(int)hx+1;?//需编码位数?printf(至少需要%d位编码\n,n);?printf(下限是：%.17f下限是：%.17f\n,low,high);tp=(low+high)/2.0;//取区间的中点编码printf(\n选取的小数为：%.17f\n,tp);?for(int j=0;jn;j++)?{??tp=tp*2;??if(tp1.0)??{???tp=tp-1;???code[j]=1;??}??else???code[j]=0;?}?printf(编码为：\n);//输出编码?for(i=0;in;i++)?{??printf(%d,code[i]);??x+=code[i]*pow(2,(-i-1));?}??printf(\n恢复的小数为：%.17f,x);??if((xlow)(xhigh))//判断恢复的是否成功???printf(\n恢复的小数仍在允许区间，成功！\n);?low=0.0;?high=1.0;?d=1.0;?line=1.0/8;?for(i=0;imax;i++)?{??if(xline)??{???decode[i]=1.0;???low+=d*p0;??}??else??{???decode[i]=0.0;???high=low+d*p0;??//?d=high-low;??}??d=high-low;??line=low+d*p0;?}?printf(原始输入数据：\n);?fo