C语言版的16进制与字符串互转函数

/*
// C prototype : void StrToHex(BYTE *pbDest, BYTE *pbSrc, int nLen)
// parameter(s): [OUT] pbDest - 输出缓冲区
// [IN] pbSrc - 字符串
// [IN] nLen - 16进制数的字节数(字符串的长度/2)
// return value:
// remarks : 将字符串转化为16进制数
*/
void StrToHex(BYTE *pbDest, BYTE *pbSrc, int nLen)
{
char h1,h2;
BYTE s1,s2;
int i;

for (i=0; i<nLen; i++)
{
h1 = pbSrc[2*i];
h2 = pbSrc[2*i+1];

s1 = toupper(h1) - 0x30;
if (s1 > 9)
s1 -= 7;

s2 = toupper(h2) - 0x30;
if (s2 > 9)
s2 -= 7;

pbDest[i] = s1*16 + s2;
}
}

/*
// C prototype : void HexToStr(BYTE *pbDest, BYTE *pbSrc, int nLen)
// parameter(s): [OUT] pbDest - 存放目标字符串
// [IN] pbSrc - 输入16进制数的起始地址
// [IN] nLen - 16进制数的字节数
// return value:
// remarks : 将16进制数转化为字符串
*/
void HexToStr(BYTE *pbDest, BYTE *pbSrc, int nLen)
{
char ddl,ddh;
int i;

for (i=0; i<nLen; i++)
{
ddh = 48 + pbSrc[i] / 16;
ddl = 48 + pbSrc[i] % 16;
if (ddh > 57) ddh = ddh + 7;
if (ddl > 57) ddl = ddl + 7;
pbDest[i*2] = ddh;
pbDest[i*2+1] = ddl;
}

pbDest[nLen*2] = '\0';
}