std::hash< Guid > Struct Reference

#include <Guid.h>

Collaboration diagram for std::hash< Guid >:

Public Member Functions
size_t	operator() (const Guid &g) const noexcept

Detailed Description

Definition at line 280 of file Guid.h.

Member Function Documentation

operator()()

size_t std::hash< Guid >::operator() ( const Guid &  g ) const

inlinenoexcept

Definition at line 281 of file Guid.h.

                                                     {
         // Treat the Guid as a 16-byte array for hashing.
         // Checking the memory layout is contiguous and test for padding at compile time.
         static_assert(sizeof(Guid) == (sizeof(unsigned int) + sizeof(unsigned short)
                + sizeof(unsigned short) + sizeof(std::array<unsigned char,8>)));
         const unsigned char* bytes = reinterpret_cast<const unsigned char*>(&g);
         size_t hash_value = 0;
         // Simple hash combiner: FNV-1a inspired for 128-bit data
         constexpr size_t fnv_prime = sizeof(size_t) == 8 ? 0x100000001b3ULL : 0x01000193U;
         constexpr size_t fnv_offset = sizeof(size_t) == 8 ? 0xcbf29ce484222325ULL : 0x811c9dc5U;
         hash_value = fnv_offset;
         for (size_t i = 0; i < sizeof(Guid); ++i) {
             hash_value ^= static_cast<size_t>(bytes[i]);
             hash_value *= fnv_prime;
         }
         return hash_value;
     }

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The documentation for this struct was generated from the following file:

• Guid.h