C语言十六进制数据同字符串的相互转换

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使用函数如下:

#include <string>  
#include <iostream>  
#include <cctype>  
#include <algorithm>  

/* 
入口参数：pSrc  源十六进制数据 
出口参数：dest  存放运算结果 
    返回：true  转换成功 
          false 失败 
*/  
bool Hex2String(unsigned char *pSrc,std::string &dest,int nL)  
{  
    char buf[256];  

    memset((char *)buf,0,sizeof(buf));  

    unsigned char hb;  
    unsigned char lb;  

    for(int i=0;i<nL;i++)  
    {  
        hb=(pSrc[i]&0xf0)>>4;  

        if( hb>=0 && hb<=9 )  
            hb += 0x30;  
        else if( hb>=10 &&hb <=15 )  
            hb = hb -10 + 'A';  
        else  
            return false;  

        lb = pSrc[i]&0x0f;  
        if( lb>=0 && lb<=9 )  
            lb += 0x30;  
        else if( lb>=10 && lb<=15 )  
            lb = lb - 10 + 'A';  
        else  
            return false;  

        buf[i*2]   = hb;  
        buf[i*2+1] = lb;  
    }  
    dest = buf;  
    return true;  
}  

/* 
入口参数：src  源字符串 
出口参数：dest  存放运算结果 
    返回：true  转换成功 
          false 失败 
*/  
bool String2Hex(std::string &src,unsigned char *dest)  
{  
    unsigned char hb;  
    unsigned char lb;  

    if(src.size()%2!=0)  
        return false;  

    transform(src.begin(), src.end(), src.begin(), toupper);  

    for(int i=0, j=0;i<src.size();i++)  
    {  
        hb=src[i];  
        if( hb>='A' && hb<='F' )  
            hb = hb - 'A' + 10;  
        else if( hb>='0' && hb<='9' )  
            hb = hb - '0';  
        else  
            return false;  

        i++;  
        lb=src[i];  
        if( lb>='A' && lb<='F' )  
            lb = lb - 'A' + 10;  
        else if( lb>='0' && lb<='9' )  
            lb = lb - '0';  
        else  
            return false;  

        dest[j++]=(hb<<4)|(lb);  
    }  
    return true;  
}  

//下面是使用举例，在VisualStudio2008+SP1中调试通过  
int _tmain(int argc, _TCHAR* argv[])  
{  
    unsigned char srcB[]={0x12,0x34,0x56,0x78,0x90,0xab,0xbc,0xcd,0xde,0xef};  

    std::string strDest;  

    Hex2String(srcB,strDest,sizeof(srcB));  
    std::cout<<"HexToString:"<<strDest<<std::endl;  

    if(String2Hex(strDest,srcB))  
        std::cout<<"StringToHex:Success!"<<std::endl;  
    else  
        std::cout<<"StringToHex:Failed!"<<std::endl;  

    return 0;  
}