diff --git a/shared-infrastructure b/shared-infrastructure index 48e73f455f..25f5653105 160000 --- a/shared-infrastructure +++ b/shared-infrastructure @@ -1 +1 @@ -Subproject commit 48e73f455f15eafefbe3175efc7433e5f277e506 +Subproject commit 25f56531057293e9f1fa8e070b2f780a0c3d7e0c diff --git a/src/ImageSharp/Common/Helpers/Numerics.cs b/src/ImageSharp/Common/Helpers/Numerics.cs index e8ba6dde61..37d2a943cc 100644 --- a/src/ImageSharp/Common/Helpers/Numerics.cs +++ b/src/ImageSharp/Common/Helpers/Numerics.cs @@ -23,6 +23,25 @@ namespace SixLabors.ImageSharp private const int ShuffleAlphaControl = 0b_11_11_11_11; #endif +#if !SUPPORTS_BITOPERATIONS + private static ReadOnlySpan BitCountLut => new byte[] + { + 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, + 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, + }; +#endif + /// /// Determine the Greatest CommonDivisor (GCD) of two numbers. /// @@ -832,10 +851,24 @@ namespace SixLabors.ImageSharp /// Unsigned integer to store /// Minimum number of bits needed to store given value [MethodImpl(MethodImplOptions.AggressiveInlining)] - public static int MinimumBitsToStore(uint number) + public static int MinimumBitsToStore16(uint number) { +#if SUPPORTS_BITOPERATIONS const int bitInUnsignedInteger = sizeof(uint) * 8; return bitInUnsignedInteger - BitOperations.LeadingZeroCount(number); +#else + int bt; + if (number < 0x100) + { + bt = BitCountLut[(int)number]; + } + else + { + bt = 8 + BitCountLut[(int)(number >> 8)]; + } + + return bt; +#endif } } } diff --git a/src/ImageSharp/Formats/Jpeg/Components/Encoder/HuffmanScanEncoder.cs b/src/ImageSharp/Formats/Jpeg/Components/Encoder/HuffmanScanEncoder.cs index 28eefadc7d..8f133f0deb 100644 --- a/src/ImageSharp/Formats/Jpeg/Components/Encoder/HuffmanScanEncoder.cs +++ b/src/ImageSharp/Formats/Jpeg/Components/Encoder/HuffmanScanEncoder.cs @@ -371,7 +371,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Encoder b = value - 1; } - uint bt = (uint)Numerics.MinimumBitsToStore((uint)a); + uint bt = (uint)Numerics.MinimumBitsToStore16((uint)a); this.EmitHuff(index, (int)((uint)(runLength << 4) | bt)); if (bt > 0)