- [Core] Remove K4os.Compression.LZ4

2023-11-11 20:12:16 +04:00
parent 740b8725b2
commit 5e5b6d1105
7 changed files with 165 additions and 84 deletions
--- a/AssetStudio/LZ4/LZ4Utils.cs
+++ b/AssetStudio/LZ4/LZ4Utils.cs
@@ -0,0 +1,143 @@
+using System;
+
+namespace AssetStudio.LZ4;
+public static class LZ4
+{
+    public static int Decompress(ReadOnlySpan<byte> cmp, Span<byte> dec)
+    {
+        int cmpPos = 0;
+        int decPos = 0;
+
+        // ReSharper disable once VariableHidesOuterVariable
+        int GetLength(int length, ReadOnlySpan<byte> cmp)
+        {
+            byte sum;
+
+            if (length == 0xf)
+            {
+                do
+                {
+                    length += sum = cmp[cmpPos++];
+                } while (sum == 0xff);
+            }
+
+            return length;
+        }
+
+        do
+        {
+            byte token = cmp[cmpPos++];
+
+            int encCount = (token >> 0) & 0xf;
+            int litCount = (token >> 4) & 0xf;
+
+            //Copy literal chunk
+            litCount = GetLength(litCount, cmp);
+
+            cmp.Slice(cmpPos, litCount).CopyTo(dec.Slice(decPos));
+
+            cmpPos += litCount;
+            decPos += litCount;
+
+            if (cmpPos >= cmp.Length)
+            {
+                break;
+            }
+
+            //Copy compressed chunk
+            int back = cmp[cmpPos++] << 0 |
+                       cmp[cmpPos++] << 8;
+
+            encCount = GetLength(encCount, cmp) + 4;
+
+            int encPos = decPos - back;
+
+            if (encCount <= back)
+            {
+                dec.Slice(encPos, encCount).CopyTo(dec.Slice(decPos));
+
+                decPos += encCount;
+            }
+            else
+            {
+                while (encCount-- > 0)
+                {
+                    dec[decPos++] = dec[encPos++];
+                }
+            }
+        } while (cmpPos < cmp.Length &&
+                 decPos < dec.Length);
+
+        return decPos;
+    }
+}
+public static class LZ4Inv
+{
+    public static int Decompress(ReadOnlySpan<byte> cmp, Span<byte> dec)
+    {
+        int cmpPos = 0;
+        int decPos = 0;
+
+        // ReSharper disable once VariableHidesOuterVariable
+        int GetLength(int length, ReadOnlySpan<byte> cmp)
+        {
+            byte sum;
+
+            if (length == 0xf)
+            {
+                do
+                {
+                    length += sum = cmp[cmpPos++];
+                } while (sum == 0xff);
+            }
+
+            return length;
+        }
+
+        do
+        {
+            byte token = cmp[cmpPos++];
+
+            int encCount = (token >> 4) & 0xf;
+            int litCount = (token >> 0) & 0xf;
+
+            //Copy literal chunk
+            litCount = GetLength(litCount, cmp);
+
+            cmp.Slice(cmpPos, litCount).CopyTo(dec.Slice(decPos));
+
+            cmpPos += litCount;
+            decPos += litCount;
+
+            if (cmpPos >= cmp.Length)
+            {
+                break;
+            }
+
+            //Copy compressed chunk
+            int back = cmp[cmpPos++] << 8 |
+                       cmp[cmpPos++] << 0;
+
+            encCount = GetLength(encCount, cmp) + 4;
+
+            int encPos = decPos - back;
+
+            if (encCount <= back)
+            {
+                dec.Slice(encPos, encCount).CopyTo(dec.Slice(decPos));
+
+                decPos += encCount;
+            }
+            else
+            {
+                while (encCount-- > 0)
+                {
+                    dec[decPos++] = dec[encPos++];
+                }
+            }
+        } while (cmpPos < cmp.Length &&
+                 decPos < dec.Length);
+
+        return decPos;
+    }
+}