mirror of
https://github.com/GreemDev/Ryujinx.git
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72 lines
1.7 KiB
C#
72 lines
1.7 KiB
C#
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using Ryujinx.Common.Utilities;
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using System;
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using System.Diagnostics;
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namespace Ryujinx.Graphics.Texture.Astc
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{
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public struct BitStream128
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{
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private Buffer16 _data;
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public int BitsLeft { get; set; }
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public BitStream128(Buffer16 data)
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{
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_data = data;
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BitsLeft = 128;
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}
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public int ReadBits(int bitCount)
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{
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Debug.Assert(bitCount < 32);
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if (bitCount == 0)
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{
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return 0;
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}
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int mask = (1 << bitCount) - 1;
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int value = _data.As<int>() & mask;
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Span<ulong> span = _data.AsSpan<ulong>();
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ulong carry = span[1] << (64 - bitCount);
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span[0] = (span[0] >> bitCount) | carry;
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span[1] >>= bitCount;
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BitsLeft -= bitCount;
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return value;
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}
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public void WriteBits(int value, int bitCount)
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{
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Debug.Assert(bitCount < 32);
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if (bitCount == 0) return;
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ulong maskedValue = (uint)(value & ((1 << bitCount) - 1));
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Span<ulong> span = _data.AsSpan<ulong>();
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if (BitsLeft < 64)
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{
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ulong lowMask = maskedValue << BitsLeft;
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span[0] |= lowMask;
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}
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if (BitsLeft + bitCount > 64)
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{
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if (BitsLeft > 64)
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{
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span[1] |= maskedValue << (BitsLeft - 64);
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}
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else
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{
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span[1] |= maskedValue >> (64 - BitsLeft);
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}
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}
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BitsLeft += bitCount;
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}
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}
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}
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