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ハッシュ計算の最適化とリファクタリング #148

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merged 1 commit into from
Sep 3, 2023
Merged

ハッシュ計算の最適化とリファクタリング #148

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17 changes: 12 additions & 5 deletions Source/Utf8Utility/Utf8Array.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
using System.Runtime.InteropServices;
using System.Text;
using CommunityToolkit.HighPerformance;
using CommunityToolkit.HighPerformance.Helpers;
using Utf8Utility.Helpers;
using Utf8Utility.Text;
#if NET6_0_OR_GREATER
Expand Down Expand Up @@ -116,13 +117,18 @@ public static Utf8Array Empty
/// UTF-8配列が空の場合は<see langword="true"/>、
/// それ以外は<see langword="false"/>を返します。
/// </returns>
[SuppressMessage("Style", "IDE0075:条件式を簡略化する", Justification = "最適化のため")]
public bool IsEmpty
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
#if NET7_0_OR_GREATER

get => _value is null || _value.Length == 0;
#else
// インライン化された場合の最適化のため、三項演算子でtrue/falseを返す。
// https://github.com/dotnet/runtime/issues/4207
[MethodImpl(MethodImplOptions.AggressiveInlining)]
[SuppressMessage("Style", "IDE0075:条件式を簡略化する", Justification = "最適化のため")]
get => (_value is null || _value.Length == 0) ? true : false;
#endif
}

/// <summary>
Expand Down Expand Up @@ -168,7 +174,7 @@ public bool Equals(Utf8Array other)
=> AsSpan().SequenceEqual(other.AsSpan());

/// <inheritdoc/>
public override int GetHashCode() => _value.GetDjb2HashCode();
public override int GetHashCode() => HashCode<byte>.Combine(AsSpan());

/// <inheritdoc/>
public override string ToString() => Encoding.UTF8.GetString(_value);
Expand Down Expand Up @@ -247,7 +253,7 @@ public int GetLength()
while ((int)index <= length)
{
// 最適化の関係でrefローカル変数にしてはいけない。
var value = Unsafe.As<byte, ulong>(ref Unsafe.AddByteOffset(ref _value.DangerousGetReference(), index));
var value = Unsafe.As<byte, ulong>(ref Unsafe.AddByteOffset(ref DangerousGetReference(), index));

var x = ((value >> 6) | (~value >> 7)) & Mask;
count += BitOperations.PopCount(x);
Expand All @@ -259,7 +265,7 @@ public int GetLength()
while ((int)index < ByteCount)
{
// 最適化の関係でrefローカル変数にしてはいけない。
var value = Unsafe.AddByteOffset(ref _value.DangerousGetReference(), index);
var value = Unsafe.AddByteOffset(ref DangerousGetReference(), index);

if ((value & 0xC0) != 0x80)
{
Expand Down Expand Up @@ -353,6 +359,7 @@ public bool IsEmptyOrWhiteSpace()
/// このメソッドは境界チェックを行いません。
/// </summary>
/// <returns>最初の要素への参照を返します。</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public ref byte DangerousGetReference() => ref _value.DangerousGetReference();

/// <summary>
Expand Down
3 changes: 2 additions & 1 deletion Source/Utf8Utility/Utf8ArrayDictionary.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
using System.Runtime.CompilerServices;
using System.Text;
using CommunityToolkit.HighPerformance;
using CommunityToolkit.HighPerformance.Helpers;
using Utf8Utility.Helpers;

namespace Utf8Utility;
Expand Down Expand Up @@ -163,7 +164,7 @@ public ref TValue GetValueRefOrNullRef(Utf8Array key)
public ref TValue GetValueRefOrNullRef(ReadOnlySpan<byte> key)
{
var entries = _entries;
var bucketIndex = GetBucketIndex(key.GetDjb2HashCode());
var bucketIndex = GetBucketIndex(HashCode<byte>.Combine(key));
var i = GetBucket(bucketIndex) - 1;

do
Expand Down