Function getBitfieldTypeFromArgument

src/bitops.cpp:455–479

This helper function for BITFIELD parses a bitfield type in the form * where sign is 'u' or 'i' for unsigned and signed, and * the bits is a value between 1 and 64. However 64 bits unsigned integers * are reported as an error because of current limitations of Redis protocol * to return unsigned integer values greater than INT64_MAX. * * On error C_ERR is returned and an error is

 *
 * On error C_ERR is returned and an error is sent to the client. */
int getBitfieldTypeFromArgument(client *c, robj *o, int *sign, int *bits) {
    char *p = szFromObj(o);
    const char *err = "Invalid bitfield type. Use something like i16 u8. Note that u64 is not supported but i64 is.";
    long long llbits;

    if (p[0] == 'i') {
        *sign = 1;
    } else if (p[0] == 'u') {
        *sign = 0;
    } else {
        addReplyError(c,err);
        return C_ERR;
    }

    if ((string2ll(p+1,strlen(p+1),&llbits)) == 0 ||
        llbits < 1 ||
        (*sign == 1 && llbits > 64) ||
        (*sign == 0 && llbits > 63))
    {
        addReplyError(c,err);
        return C_ERR;
    }
    *bits = llbits;
    return C_OK;
}

/* This is an helper function for commands implementations that need to write
 * bits to a string object. The command creates or pad with zeroes the string