C语言16进制与ASCII字符相互转换

typedef unsigned char uint8_t;
char data[64];
 
uint8_t *hex_to_ascii(uint8_t *str, uint32_t len)
{
    uint8_t *hex_buf = str;
    for (int i = 0; i < len; i++)
    {
        sprintf(&data[i * 2], "%02X", hex_buf[i]);
    }
    return (uint8_t *)data;
}

typedef unsigned char uint8_t;
char data[64];
uint8_t *ascii_to_hex(char *str, uint32_t len)
{
    char *str_buf = str;
    uint8_t *hex = (uint8_t *)data;
    uint8_t data_buf[len];
    for (int i = 0; i < len; i++)
    {
        sscanf(str_buf, "%02x", (int *)&data_buf[i]);
        str_buf += 2;
    }
    memcpy(hex, data_buf, len);
    return hex;
}

typedef unsigned char uint8_t;
char data[64];
uint8_t *Char_to_Hex(char *str,uint32_t len)
{
    char *hex_buf = str;
    uint8_t *hex = (uint8_t *)data;
    for (int i = 0; i < len; i++)
    {
        if ((hex_buf[i] >= '0') && (hex_buf[i] <= '9'))        //0x30--0x39
            hex_buf[i] += 0x30;
        else if ((hex_buf[i] >= 'a') && (hex_buf[i] <= 'z'))   //0x61--0x66
            hex_buf[i] += 0x61;
        else if ((hex_buf[i] >= 'A') && (hex_buf[i] <= 'Z'))   //0x41--0x46
            hex_buf[i] += 0x41;
        else
            hex_buf[i] += 0xff;
    }
    memcpy(hex, hex_buf, len);
 
    return hex;
}

typedef unsigned char uint8_t;
char data[64];
uint8_t *Hex_to_Char(char *str,uint32_t len)
{
    char *hex_buf = str;
    uint8_t *hex = (uint8_t *)data;
    for (int i = 0; i < len; i++)
    {
		if ((hex_buf[i] >= 0x30) && (hex_buf[i] <= 0x39))      //0--9
			hex_buf[i] -= 0x30;
		else if ((hex_buf[i] >= 0x41) && (hex_buf[i] <= 0x46)) //A--Z
			hex_buf[i] -= 0x37;
		else if ((hex_buf[i] >= 0x61) && (hex_buf[i] <= 0x66)) //a--z
			hex_buf[i] -= 0x57;
		else
			hex_buf[i] = 0xff;
    }
    memcpy(hex, hex_buf, len);
 
    return hex;
}