16进制字符串到十进制的转换

SUINT64 HexToUINT64(const char* strSrc)
{
SUINT64 sum = 0;

for(int i = 0; i<(int)strlen(strSrc); i++)
{
int nDecNum;
switch(strSrc[i])
{
case 'a':
case 'A': nDecNum = 10; break;
case 'b':
case 'B': nDecNum = 11; break;
case 'c':
case 'C': nDecNum = 12; break;
case 'd':
case 'D': nDecNum = 13; break;
case 'e':
case 'E': nDecNum = 14; break;
case 'f':
case 'F': nDecNum = 15; break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9': nDecNum = strSrc[i] - '0'; break;
default: return 0;
}
sum = sum*16+nDecNum;
}

return sum;
}