fec.cpp

2/3 FEC编码的另一种方法,即采用模拟硬件移位寄存器的方式,速度比较快。

#include <stdio.h>
#include "iostream.h"

main()
{
//	int code_in,j;
//	int code_out[15];
//	int mid[15];

	int input,proc;
	int i,a,b,c,d,e,err,temp,ecc=0;
	proc=1;
	a=b=c=d=e=0;
	cout<<"请输入信息(0~0x3ff):";
	cin>>input;
	//FEC ENCODE*******************************************************
    for(i=0;i<10;i++)
	{
      temp=e^((input&proc)>>i);
	  e=temp^d;
	  d=c;
	  c=temp^b;
	  b=a;
	  a=temp;
	  proc<<=1;
	}
	cout<<"进行编码后输出为:";
	if(a)input|=16384;
	if(b)input|=8192;
	if(c)input|=4096;
	if(d)input|=2048;
	if(e)input|=1024;
	for(proc=16384,i=0;i<15;i++)
	{
		if(input&proc)cout<<"1";else cout<<"0";
		proc>>=1;
	}
	//FEC DECODE*******************************************************
/*	for (i=0;i<15;i++)
	{ 
		code_out[i]=0;
		mid[i]=0;
	}
	code_in=0;
	i=0;j=0;a=0;
	
	/*int check_out[5];
	int errorflag,matchbit,matchflag,comparebit;
	
	int check[5]={0x765,0x9AF,0x135E,0x21D9,0x43B2};  /*the check array*/
	/* int check[5]={000011101100101b,    */
	/*	             000100110101111b,    */
	/*      	     001001101011110b,    */
	/*	             010000111011001b,    */
	/*	             100001110110010b }   */
	
	/*printf("\n输入接受端收到的原始数据（16进制）:");
	scanf("%x",&code_in);    /*input the data received at the receiver*/
	
	/*a=code_in;
	/*for (i=0;i<15;i++)      /*change the data received into bits*/
	/*{ 
		code_out[i]=a&1;
		a=a>>1;
	}
	
	
	for(i=0;i<5;i++)        /*caculate the cheksum*/
	/*{  
		a=code_in&check[i];
		for(j=0;j<15;j++)    /*get every bit of a */
/*		{
			mid[j]=a&1;
			a=a>>1;
		}
		check_out[i]=mid[0];
		for(j=1;j<15;j++)
			check_out[i]=check_out[i]^mid[j]; /*add the bits in mode 2*/
/*	}
	
	
	i=0; errorflag=0;
	do 
	{
		if (check_out[i]==1) { errorflag=1; i=5;}
		else i++;
	}
	while (i<5);     /* check if the check is all 0 */
	
/*	if (errorflag==1)
	{   i=0;  matchbit=100;      /* look for the same line*/
/*	do  
	{ 
		j=0; matchflag=1;
		do 
		{ 
			comparebit=(check[j]>>i)&1; /* get the [j][i] bit of the array*/
/*			if (check_out[j]!=comparebit) 
			{
				j=5;matchflag=0;
			}                /*not coincident,jump out at once*/
/*			else j++;
		} 
		while (j<5);
	       
		if (matchflag==1) 
		{
			matchbit=i;i=15;
		}               /*if found,jump out at once*/
/*	       else i++;
	}
	while (i<15);
	
	if (matchbit<=14)
	{
		code_out[matchbit]=code_out[matchbit]^1;    /*correct the error bit*/
/*		printf("第%d位数据出错!\n",matchbit+1);
	}
	else printf("错误但不可纠!\n");
	
	}
	else printf("传输正确或错误不可检!\n");
	
	printf("还原的信息比特为:");
	for (i=9;i>=0;i--)                     /*only print the information bits*/
/*		printf("%d",code_out[i]);*/
	a=b=c=d=e=0;
	cout<<endl<<"请输入接收的信息:";
	cin>>input;temp=0;proc=1;
	for(proc=1,i=0;i<15;i++)
	{
		//err=(a^1)&(b^1)&(c)&(d)&(e^1);
		//if(i<15){temp=(e^err^((input&proc)>>i));proc<<=1;}
		//else {temp=e^err^0;}
		//if(err)input^=(err<<(i-15));
		      temp=e^((input&proc)>>i);
			  e=temp^d;
			  d=c;
			  c=temp^b;
			  b=a;
			  a=temp;
			  proc<<=1;

	}
	if(a)ecc|=16;
	if(b)ecc|=8;
	if(c)ecc|=4;
	if(d)ecc|=2;
	if(e)ecc|=1;
	proc=1;
    if(ecc)
	{
		if(ecc<15)input^=(proc<<(ecc-1));else cout<<"不可纠正错误";
    }
	//proc=1;
	//ecc=(a<<4)|(b<<3)|(c<<2)|(d<<1)|e;
	//if(ecc!=0)input^=(proc<<(ecc-1));
	cout<<"译码后输出信息为:";
	cout<<' '<<' '<<' '<<' '<<' ';
	for(proc=512,i=0;i<10;i++)
	{
		if(input&proc)cout<<"1";else cout<<"0";
		proc>>=1;
	}
	cout<<endl;
	cout<<a<<b<<c<<d<<e;
	return 1;
}