Improper argument types result in Undefined Behavior

[vpetrigo]

Hello,

There is an issue with argument types for the whole set of CRC functions. For example, the following input buffer would result in the improper CRC calculation:

    const uint8_t buffer[] = {0xb0, 0, 0, 0, 0, 0, 0};

    expect = 0x1a;
    EXPECT_EQ(crc8_lsb((const char *)buffer, sizeof(buffer)), expect);

On my machine the test fails with the following issue:

failed: Expect:3f == Actual:1a

The issue with signed characters that current interface expects: 0xb0 is -80 as char. Thus, this code leads to negative array index access:

crc = crc8tab_lsb[crc ^ *buf++];
// On the veriy first step crc ^ *buf = -80