Hash.h

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#pragma once
#include <cstddef>
#include <cstdint>
 
namespace cdc {
namespace core {
namespace hash {

static constexpr uint32_t FNV1A_32_OFFSET_BASIS = 0x811C9DC5u;  // 2166136261
static constexpr uint32_t FNV1A_32_PRIME        = 0x01000193u;  // 16777619

inline void fnv1a_mix_byte(uint32_t& hash, uint8_t value) {
    hash ^= value;
    hash *= FNV1A_32_PRIME;
}

inline void fnv1a_mix_u32(uint32_t& hash, uint32_t value) {
    hash ^= value;
    hash *= FNV1A_32_PRIME;
}

inline uint32_t fnv1a_32(const uint8_t* data, size_t len) {
    uint32_t hash = FNV1A_32_OFFSET_BASIS;
    for (size_t i = 0; i < len; i++) {
        fnv1a_mix_byte(hash, data[i]);
    }
    return hash;
}
 
}  // namespace hash
}  // namespace core
}  // namespace cdc