86 lines
2.5 KiB
C++
86 lines
2.5 KiB
C++
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/***
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Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.
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File: auFNV1Utils.hpp
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Date: 2022-3-23
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File: fnv1.hpp
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Date: 2021-6-10
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Author: Reece
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***/
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#pragma once
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#include "auTypeUtils.hpp"
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// Note: we're too early for AuroraEnv.hpp w/ AuroraEnums
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#if defined(AURORA_IS_32BIT)
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#define _AU_FNV1_32 1
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#else
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#define _AU_FNV1_32 0
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#endif
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constexpr AuUInt64 kFnv1MagicVal64 = 0xcbf29ce484222325;
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constexpr AuUInt64 kFnv1MagicPrime64 = 0x100000001b3;
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constexpr AuUInt32 kFnv1MagicVal32 = 0x811c9dc5;
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constexpr AuUInt32 kFnv1MagicPrime32 = 0x01000193;
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constexpr auto kFnv1MagicValPlatform = _AU_FNV1_32 ? kFnv1MagicVal32 : kFnv1MagicVal64;
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constexpr auto kFnv1MagicPrimePlatform = _AU_FNV1_32 ? kFnv1MagicPrime32 : kFnv1MagicPrime64;
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inline constexpr AuUInt64 AuFnv1a64(const char *const str, const AuUInt64 value = kFnv1MagicVal64) noexcept
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{
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return (str[0] == '\0') ? value : AuFnv1a64(&str[1], (value ^ AuUInt64(str[0])) * kFnv1MagicPrime64);
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}
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inline constexpr AuUInt32 AuFnv1aTrunc(const char *const str) noexcept
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{
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return static_cast<AuUInt32>(AuFnv1a64(str));
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}
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inline constexpr AuUInt32 AuFnv1a32(const char *const str, const AuUInt32 value = kFnv1MagicVal32) noexcept
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{
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return (str[0] == '\0') ? value : AuFnv1a32(&str[1], (value ^ AuUInt32(str[0])) * kFnv1MagicPrime32);
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}
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inline constexpr AuUInt AuFnv1aType(const char *type, AuUInt size, AuUInt index, const AuUInt value) noexcept
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{
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return (index == size) ? value : AuFnv1aType(type + 1, size, index + 1, (value ^ AuUInt(*type) * kFnv1MagicPrimePlatform));
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}
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template <class T>
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inline constexpr AuUInt AuFnv1aType(const T &type, const AuUInt value = kFnv1MagicValPlatform) noexcept
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{
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return AuFnv1aType(((const char *)&type) + 1, sizeof(T), 1, (value ^ AuUInt(*(const char *)&type) * kFnv1MagicPrimePlatform));
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}
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inline constexpr auto AuFnv1a(const char *const str) noexcept
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{
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return _AU_FNV1_32 ? AuFnv1a32(str) : AuFnv1a64(str);
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}
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inline AuUInt32 AuFnv1a32Runtime(const void *base, AuUInt length) noexcept
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{
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AuUInt32 result {kFnv1MagicVal32};
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AuUInt i {};
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for (; i < length; i++)
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{
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result ^= AuUInt(AuReadU8(base, i)) * kFnv1MagicPrime32;
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}
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return result;
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}
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inline AuUInt64 AuFnv1a64Runtime(const void *base, AuUInt length) noexcept
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{
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AuUInt64 result {kFnv1MagicVal64};
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AuUInt i {};
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for (; i < length; i++)
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{
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result ^= AuUInt64(AuReadU8(base, i)) * kFnv1MagicPrime64;
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}
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return result;
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}
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#undef _AU_FNV1_32
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