ASCII与BCD互转

//基于查表实现BCD与Ascii之间的转换  
static unsigned char bcd2ascii[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

static unsigned char ascii2bcd1[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
static unsigned char ascii2bcd2[6] = { 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F };
UINT32 ASC2BCD(unsigned char *bcd, const unsigned char *asc, UINT32 len)
{
    unsigned char c = 0;
    unsigned char index = 0;
    unsigned char i = 0;

    len >>= 1;

    for (; i < len; i++) {
        //first BCD  
        if (*asc >= 'A' && *asc <= 'F') {
            index = *asc - 'A';
            c = ascii2bcd2[index] << 4;
        }
        else if (*asc >= '0' && *asc <= '9') {
            index = *asc - '0';
            c = ascii2bcd1[index] << 4;
        }
        asc++;

        //second BCD  
        if (*asc >= 'A' && *asc <= 'F') {
            index = *asc - 'A';
            c |= ascii2bcd2[index];
        }
        else if (*asc >= '0' && *asc <= '9') {
            index = *asc - '0';
            c |= ascii2bcd1[index];
        }
        asc++;

        *bcd++ = c;
    }

    return 0;
}
UINT32 BCD2ASC(unsigned char *asc, const unsigned char *bcd, UINT32 len)
{
    unsigned char c = 0;
    unsigned char i;


    for (i = 0; i < len; i++) {
        //first BCD  
        c = *bcd >> 4;
        *asc++ = bcd2ascii[c];


        //second  
        c = *bcd & 0x0f;
        *asc++ = bcd2ascii[c];
        bcd++;
    }


    return 0;
}