1 files changed, 269 insertions, 0 deletions
diff --git a/Ryujinx.Graphics.Texture/Astc/IntegerEncoded.cs b/Ryujinx.Graphics.Texture/Astc/IntegerEncoded.cs
new file mode 100644
index 00000000..5aa610e7
--- /dev/null
+++ b/Ryujinx.Graphics.Texture/Astc/IntegerEncoded.cs
@@ -0,0 +1,269 @@
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Ryujinx.Graphics.Texture.Astc
+{
+    public struct IntegerEncoded
+    {
+        public enum EIntegerEncoding
+        {
+            JustBits,
+            Quint,
+            Trit
+        }
+
+        EIntegerEncoding _encoding;
+        public int NumberBits { get; private set; }
+        public int BitValue   { get; private set; }
+        public int TritValue  { get; private set; }
+        public int QuintValue { get; private set; }
+
+        public IntegerEncoded(EIntegerEncoding encoding, int numBits)
+        {
+            _encoding  = encoding;
+            NumberBits = numBits;
+            BitValue   = 0;
+            TritValue  = 0;
+            QuintValue = 0;
+        }
+
+        public bool MatchesEncoding(IntegerEncoded other)
+        {
+            return _encoding == other._encoding && NumberBits == other.NumberBits;
+        }
+
+        public EIntegerEncoding GetEncoding()
+        {
+            return _encoding;
+        }
+
+        public int GetBitLength(int numberVals)
+        {
+            int totalBits = NumberBits * numberVals;
+            if (_encoding == EIntegerEncoding.Trit)
+            {
+                totalBits += (numberVals * 8 + 4) / 5;
+            }
+            else if (_encoding == EIntegerEncoding.Quint)
+            {
+                totalBits += (numberVals * 7 + 2) / 3;
+            }
+            return totalBits;
+        }
+
+        public static IntegerEncoded CreateEncoding(int maxVal)
+        {
+            while (maxVal > 0)
+            {
+                int check = maxVal + 1;
+
+                // Is maxVal a power of two?
+                if ((check & (check - 1)) == 0)
+                {
+                    return new IntegerEncoded(EIntegerEncoding.JustBits, BitArrayStream.PopCnt(maxVal));
+                }
+
+                // Is maxVal of the type 3*2^n - 1?
+                if ((check % 3 == 0) && ((check / 3) & ((check / 3) - 1)) == 0)
+                {
+                    return new IntegerEncoded(EIntegerEncoding.Trit, BitArrayStream.PopCnt(check / 3 - 1));
+                }
+
+                // Is maxVal of the type 5*2^n - 1?
+                if ((check % 5 == 0) && ((check / 5) & ((check / 5) - 1)) == 0)
+                {
+                    return new IntegerEncoded(EIntegerEncoding.Quint, BitArrayStream.PopCnt(check / 5 - 1));
+                }
+
+                // Apparently it can't be represented with a bounded integer sequence...
+                // just iterate.
+                maxVal--;
+            }
+
+            return new IntegerEncoded(EIntegerEncoding.JustBits, 0);
+        }
+
+        public static void DecodeTritBlock(
+            BitArrayStream       bitStream,
+            List<IntegerEncoded> listIntegerEncoded,
+            int                  numberBitsPerValue)
+        {
+            // Implement the algorithm in section C.2.12
+            int[] m = new int[5];
+            int[] t = new int[5];
+            int T;
+
+            // Read the trit encoded block according to
+            // table C.2.14
+            m[0] = bitStream.ReadBits(numberBitsPerValue);
+            T    = bitStream.ReadBits(2);
+            m[1] = bitStream.ReadBits(numberBitsPerValue);
+            T   |= bitStream.ReadBits(2) << 2;
+            m[2] = bitStream.ReadBits(numberBitsPerValue);
+            T   |= bitStream.ReadBits(1) << 4;
+            m[3] = bitStream.ReadBits(numberBitsPerValue);
+            T   |= bitStream.ReadBits(2) << 5;
+            m[4] = bitStream.ReadBits(numberBitsPerValue);
+            T   |= bitStream.ReadBits(1) << 7;
+
+            int c = 0;
+
+            BitArrayStream tb = new BitArrayStream(new BitArray(new int[] { T }));
+            if (tb.ReadBits(2, 4) == 7)
+            {
+                c    = (tb.ReadBits(5, 7) << 2) | tb.ReadBits(0, 1);
+                t[4] = t[3] = 2;
+            }
+            else
+            {
+                c = tb.ReadBits(0, 4);
+                if (tb.ReadBits(5, 6) == 3)
+                {
+                    t[4] = 2;
+                    t[3] = tb.ReadBit(7);
+                }
+                else
+                {
+                    t[4] = tb.ReadBit(7);
+                    t[3] = tb.ReadBits(5, 6);
+                }
+            }
+
+            BitArrayStream cb = new BitArrayStream(new BitArray(new int[] { c }));
+            if (cb.ReadBits(0, 1) == 3)
+            {
+                t[2] = 2;
+                t[1] = cb.ReadBit(4);
+                t[0] = (cb.ReadBit(3) << 1) | (cb.ReadBit(2) & ~cb.ReadBit(3));
+            }
+            else if (cb.ReadBits(2, 3) == 3)
+            {
+                t[2] = 2;
+                t[1] = 2;
+                t[0] = cb.ReadBits(0, 1);
+            }
+            else
+            {
+                t[2] = cb.ReadBit(4);
+                t[1] = cb.ReadBits(2, 3);
+                t[0] = (cb.ReadBit(1) << 1) | (cb.ReadBit(0) & ~cb.ReadBit(1));
+            }
+
+            for (int i = 0; i < 5; i++)
+            {
+                IntegerEncoded intEncoded = new IntegerEncoded(EIntegerEncoding.Trit, numberBitsPerValue)
+                {
+                    BitValue  = m[i],
+                    TritValue = t[i]
+                };
+                listIntegerEncoded.Add(intEncoded);
+            }
+        }
+
+        public static void DecodeQuintBlock(
+            BitArrayStream       bitStream,
+            List<IntegerEncoded> listIntegerEncoded,
+            int                  numberBitsPerValue)
+        {
+            // Implement the algorithm in section C.2.12
+            int[] m = new int[3];
+            int[] qa = new int[3];
+            int q;
+
+            // Read the trit encoded block according to
+            // table C.2.15
+            m[0] = bitStream.ReadBits(numberBitsPerValue);
+            q    = bitStream.ReadBits(3);
+            m[1] = bitStream.ReadBits(numberBitsPerValue);
+            q   |= bitStream.ReadBits(2) << 3;
+            m[2] = bitStream.ReadBits(numberBitsPerValue);
+            q   |= bitStream.ReadBits(2) << 5;
+
+            BitArrayStream qb = new BitArrayStream(new BitArray(new int[] { q }));
+            if (qb.ReadBits(1, 2) == 3 && qb.ReadBits(5, 6) == 0)
+            {
+                qa[0] = qa[1] = 4;
+                qa[2] = (qb.ReadBit(0) << 2) | ((qb.ReadBit(4) & ~qb.ReadBit(0)) << 1) | (qb.ReadBit(3) & ~qb.ReadBit(0));
+            }
+            else
+            {
+                int c = 0;
+                if (qb.ReadBits(1, 2) == 3)
+                {
+                    qa[2] = 4;
+                    c    = (qb.ReadBits(3, 4) << 3) | ((~qb.ReadBits(5, 6) & 3) << 1) | qb.ReadBit(0);
+                }
+                else
+                {
+                    qa[2] = qb.ReadBits(5, 6);
+                    c    = qb.ReadBits(0, 4);
+                }
+
+                BitArrayStream cb = new BitArrayStream(new BitArray(new int[] { c }));
+                if (cb.ReadBits(0, 2) == 5)
+                {
+                    qa[1] = 4;
+                    qa[0] = cb.ReadBits(3, 4);
+                }
+                else
+                {
+                    qa[1] = cb.ReadBits(3, 4);
+                    qa[0] = cb.ReadBits(0, 2);
+                }
+            }
+
+            for (int i = 0; i < 3; i++)
+            {
+                IntegerEncoded intEncoded = new IntegerEncoded(EIntegerEncoding.Quint, numberBitsPerValue)
+                {
+                    BitValue   = m[i],
+                    QuintValue = qa[i]
+                };
+                listIntegerEncoded.Add(intEncoded);
+            }
+        }
+
+        public static void DecodeIntegerSequence(
+            List<IntegerEncoded> decodeIntegerSequence,
+            BitArrayStream       bitStream,
+            int                  maxRange,
+            int                  numberValues)
+        {
+            // Determine encoding parameters
+            IntegerEncoded intEncoded = CreateEncoding(maxRange);
+
+            // Start decoding
+            int numberValuesDecoded = 0;
+            while (numberValuesDecoded < numberValues)
+            {
+                switch (intEncoded.GetEncoding())
+                {
+                    case EIntegerEncoding.Quint:
+                    {
+                        DecodeQuintBlock(bitStream, decodeIntegerSequence, intEncoded.NumberBits);
+                        numberValuesDecoded += 3;
+
+                        break;
+                    }
+
+                    case EIntegerEncoding.Trit:
+                    {
+                        DecodeTritBlock(bitStream, decodeIntegerSequence, intEncoded.NumberBits);
+                        numberValuesDecoded += 5;
+
+                        break;
+                    }
+
+                    case EIntegerEncoding.JustBits:
+                    {
+                        intEncoded.BitValue = bitStream.ReadBits(intEncoded.NumberBits);
+                        decodeIntegerSequence.Add(intEncoded);
+                        numberValuesDecoded++;
+
+                        break;
+                    }
+                }
+            }
+        }
+    }
+}