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-rw-r--r--src/mscorlib/shared/System/Buffers/Utilities.cs35
1 files changed, 35 insertions, 0 deletions
diff --git a/src/mscorlib/shared/System/Buffers/Utilities.cs b/src/mscorlib/shared/System/Buffers/Utilities.cs
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+++ b/src/mscorlib/shared/System/Buffers/Utilities.cs
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+// 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.
+
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+namespace System.Buffers
+{
+ internal static class Utilities
+ {
+ [MethodImpl(MethodImplOptions.AggressiveInlining)]
+ internal static int SelectBucketIndex(int bufferSize)
+ {
+ 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;
+ }
+ }
+}