BizHawk/BizHawk.Client.Common/SharpCompress/Buffers/Utilities.cs

38 lines
1.3 KiB
C#

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
#if NETCORE
using System.Diagnostics;
using System.Runtime.CompilerServices;
namespace SharpCompress.Buffers
{
internal static class Utilities
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal static int SelectBucketIndex(int bufferSize)
{
Debug.Assert(bufferSize > 0);
uint bitsRemaining = ((uint)bufferSize - 1) >> 4;
int poolIndex = 0;
if (bitsRemaining > 0xFFFF) { bitsRemaining >>= 16; poolIndex = 16; }
if (bitsRemaining > 0xFF) { bitsRemaining >>= 8; poolIndex += 8; }
if (bitsRemaining > 0xF) { bitsRemaining >>= 4; poolIndex += 4; }
if (bitsRemaining > 0x3) { bitsRemaining >>= 2; poolIndex += 2; }
if (bitsRemaining > 0x1) { bitsRemaining >>= 1; poolIndex += 1; }
return poolIndex + (int)bitsRemaining;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal static int GetMaxSizeForBucket(int binIndex)
{
int maxSize = 16 << binIndex;
Debug.Assert(maxSize >= 0);
return maxSize;
}
}
}
#endif