#include <stdint.h>

  // FNV1a c++11 constexpr compile time hash functions, 32 and 64 bit
  // str should be a null terminated string literal, value should be left out 
  // e.g hash_32_fnv1a_const("example")

  constexpr uint32_t val_32_const = 2166136261;
  constexpr uint32_t prime_32_const = 16777619;
  constexpr uint64_t val_64_const = 0xcbf29ce484222325;
  constexpr uint64_t prime_64_const = 0x100000001b3;

  inline constexpr uint32_t hash_32_fnv1a_const(const char* const str, const uint32_t value = val_32_const) noexcept {
      return (str[0] == '\0') ? value : hash_32_fnv1a_const(&str[1], (value ^ uint32_t(str[0])) * prime_32_const);
  }

  inline constexpr uint64_t hash_64_fnv1a_const(const char* const str, const uint64_t value = val_64_const) noexcept {
      return (str[0] == '\0') ? value : hash_64_fnv1a_const(&str[1], (value ^ uint64_t(str[0])) * prime_64_const);
  }