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A compile-time Bernstein hash example using constexpr (c++11 or above).
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#include <cstddef> | |
#include <iostream> | |
constexpr std::size_t bernstein_hash(char const *s, std::size_t size, std::size_t value = 5381) { | |
return size ? bernstein_hash(s + 1, size - 1, 33 * value + *s) : value; | |
} | |
struct symbol { | |
std::size_t const len; | |
std::size_t const hash; | |
char const * const str; | |
template<std::size_t N> | |
constexpr symbol(char const (&s)[N]) noexcept : len{N - 1}, hash{bernstein_hash(s, len)}, str{s} {} | |
}; | |
int main() { | |
symbol name("Bernstein"); | |
std::cout << name.str << std::endl; | |
std::cout << name.hash << std::endl; | |
return 0; | |
} |
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