Fast comparison of char arrays?
- by StackedCrooked
I'm currently working in a codebase where IPv4 addresses are represented as pointers to u_int8. The equality operator is implemented like this:
bool Ipv4Address::operator==(const u_int8 * inAddress) const
{
return (*(u_int32*) this->myBytes == *(u_int32*) inAddress);
}
This is probably the fasted solution, but it causes the GCC compiler warning:
ipv4address.cpp:65: warning: dereferencing type-punned pointer will break strict-aliasing rules
How can I rewrite the comparison correctly without breaking strict-aliasing rules and without losing performance points?
I have considered using either memcmp or this macro:
#define IS_EQUAL(a, b) \
(a[0] == b[0] && a[1] == b[1] && a[2] == b[2] && a[3] == b[3])
I'm thinking that the macro is the fastest solution.
What do you recommend?
