codeprocess.cpp

(15,11)BCH编码和译码c语言程序

// codeprocess.cpp : Defines the entry point for the console application.
//
//

//#include "stdafx.h"
#include "stdio.h"

short compress(char *);
short encode(short);
short decode(short);
short decoder(short);
int main(int argc, char* argv[])
{
//	int i;
	short data,endata,endata1,dedata;
	int i,input,output;
	char temp[30];
	
//  	for(;;)
	{
	short temp1=0,temp2=0;
	///////////////////---解交织----/////////////////
	printf("plese input data .....\n");
    scanf("%d",&input);

	for (i=0;i<15;i++)
		{
			if ((input>>(2*i))&0x01)
				temp1|=(0x01<<i);
			if ((input>>(2*i+1))&0x01)
				temp2|=(0x01<<i);
		}
	 printf("%d\n",temp1);
	 printf("%d\n",temp2);

	  //temp=deinterleave(input);
//	  endata=encode(data);//调用编码函数
	  endata1=decoder(temp1);//调用解码函数
	  printf("The result of decoding is.....%d\n",endata1);
	  endata=decoder(temp2);
	  printf("The result of decoding is.....%d\n",endata);

	  output =(((int) endata1<<15)|(int)endata);
	  ///////////////	
	  for (i=0;i<30;i++)//接收码扩展
		{
			if ((output>>i)&0x01)
				temp[i]='1';
			else
				temp[i]='0';		   
		}
	  ///////////////////////////////////
	}
		return 0;
}

short compress (char *x)//压缩函数
{
	short temp = 0;
	int i;
	for (i=0;i<16;i++)
	{
		if (x[i]=='1')
			temp|=(((0x8000)>>(15-i))&0xffff);
	}
	return temp;	
}


short encode(short receive_data)//BCH编码
{
	char temp[16];
	int j;
	short endata;
	for (j=0;j<11;j++)
		{
			if ((receive_data>>j)&0x01)
				temp[j]='1';
			else
				temp[j]='0';		   
		}
	if (((temp[0]+temp[1]+temp[2]+temp[3]+temp[5]+temp[7]+temp[8])%2)&0x01)
		temp[11]='1';
	else
		temp[11]='0';
	if (((temp[1]+temp[2]+temp[3]+temp[4]+temp[6]+temp[8]+temp[9])%2)&0x01)
		temp[12]='1';
	else
		temp[12]='0';
	if (((temp[2]+temp[3]+temp[4]+temp[5]+temp[7]+temp[9]+temp[10])%2)&0x01)
	    temp[13]='1';
	else
	    temp[13]='0';
	if(((temp[0]+temp[1]+temp[2]+temp[4]+temp[6]+temp[7]+temp[10])%2)&0x01)
	    temp[14]='1';
	else
	    temp[14]='0';
    endata = compress(temp);
	return endata;
}

short decode (short receive_code)//BCH译码
{
	short exp,correct_code,syndrome = 0;
	char temp[16];
	int j;
	temp[15]=0;
	static char coef_table[15] ={9,13,15,14,7,10,5,11,12,6,3,8,4,2,1};//域元素的二进制表
	for (j=0;j<15;j++)//接收码扩展
		{
			if ((receive_code>>j)&0x01)
				temp[j]='1';
			else
				temp[j]='0';		   
		}
	for (j=0;j<15;j++)//计算伴随式s=r(a)
		{
			if (temp[j]=='1')
			{
				syndrome^=coef_table[j];
			}
		}
	//printf("syndrome=%d\n",syndrome);
	if (syndrome!=0)
		{
			for (j=0;j<15;j++)//伴随式的指数
				{
					if(syndrome==coef_table[j])
						exp=j;
				}
			printf("The wrong bit is %d\n",exp+1);
			for (j=1;j<=15;j++)
				{	
					if (temp[exp]=='1')
						temp[exp]='0';
					else temp[exp]='1';
				}
			correct_code = compress(temp);
			printf("The correct code is %d\n",correct_code);
		}
	else
		{
			correct_code = receive_code;
			printf("The code is write!!\n");
		}
	return correct_code;
}

short decoder (short receive_code)//BCH译码
{
	short exp,syndrome = 0;
	char temp[16];
	int j;
	temp[15]=0;
	static char coef_table[15] ={9,13,15,14,7,10,5,11,12,6,3,8,4,2,1};//域元素的二进制表
/*	for (j=0;j<15;j++)//接收码扩展
		{
			if ((receive_code>>j)&0x01)
				temp[j]='1';
			else
				temp[j]='0';		   
		}
*/
	for (j=0;j<15;j++)//计算伴随式s=r(a)
		{
			if (((receive_code>>j)&0x01))
			{
				syndrome^=coef_table[j];
			}
		}
	//printf("syndrome=%d\n",syndrome);
	if (syndrome!=0)
		{
			for (j=0;j<15;j++)//伴随式的指数
				{
					if(syndrome==coef_table[j])
						exp=j;
				}
			printf("The wrong bit is %d\n",exp+1);
/*			for (j=1;j<=15;j++)
				{	
					if (temp[exp]=='1')
						temp[exp]='0';
					else temp[exp]='1';
				}
			correct_code = compress(temp);
*/
            receive_code=receive_code^(0x01<<exp);
			printf("The correct code is %d\n",receive_code);
		}
	else
		{
			printf("The code is write!!\n");
		}
	return receive_code;
}