Add CompressSave, with Chinese instructions in READMEs

2025-12-09 05:33:37 +08:00 · 2022-09-14 17:34:15 +08:00
parent 8117ee7659
commit c49378412e
37 changed files with 11924 additions and 94 deletions
--- a/CompressSave/LZ4Wrap/DoubleBuffer.cs
+++ b/CompressSave/LZ4Wrap/DoubleBuffer.cs
@@ -0,0 +1,131 @@
+using System;
+using System.Threading;
+
+namespace CompressSave.LZ4Wrap;
+
+public class ByteSpan
+{
+    public byte[] Buffer { get; private set; }
+    //public int Start;
+    public int Length;
+    public int Capacity;
+    public int IdleCapacity => Capacity - Length;
+    public int Position;
+
+    public ByteSpan(byte[] buffer)
+    {
+        Buffer = buffer;
+        Capacity = Buffer.Length;
+    }
+    public void Clear()
+    {
+        Length = 0;
+        Position = 0;
+    }
+    public int Write(byte[] src, int offset, int count)
+    {
+        int writeLen = Math.Min(Capacity - Length, count);
+        Array.Copy(src, offset, Buffer, Length, writeLen);
+        Length += writeLen;
+        return writeLen;
+    }
+
+    public int Read(byte[] dst, int offset, int count)
+    {
+        count = Math.Min(Length - Position, count);
+        Array.Copy(Buffer, Position, dst, offset, count);
+        Position += count;
+        return count;
+    }
+
+    public static implicit operator byte[](ByteSpan bs) => bs.Buffer;
+}
+
+public struct ReadOnlySpan
+{
+    public readonly int Length;
+    public readonly byte[] Buffer;
+    public int Position;
+
+    public ReadOnlySpan(byte[] buffer, int length)
+    {
+        Buffer = buffer;
+        Length = length;
+        Position = 0;
+    }
+
+    public int Read(byte[] dst, int offset, int count)
+    {
+        count = Math.Min(Length - Position, count);
+        Array.Copy(Buffer, Position, dst, offset, count);
+        Position += count;
+        return count;
+    }
+
+    public static implicit operator byte[](ReadOnlySpan s) => s.Buffer;
+}
+
+public class DoubleBuffer
+{
+    public const int MB = 1024 * 1024;
+
+    public ByteSpan writeBuffer;
+    public ByteSpan readBuffer;
+    private ByteSpan midBuffer;
+    private Action onReadBufferReady;
+
+    Semaphore readEnd = new Semaphore(1, 1);
+    Semaphore writeEnd = new Semaphore(0, 1);
+
+    public DoubleBuffer(byte[] readBuffer, byte[] writeBuffer, Action onReadBufferReady)
+    {
+        this.onReadBufferReady = onReadBufferReady;
+        this.midBuffer = new ByteSpan(readBuffer);
+        this.writeBuffer = new ByteSpan(writeBuffer);
+    }
+
+    public ByteSpan ReadBegin()
+    {
+        writeEnd.WaitOne();
+        return readBuffer;
+    }
+
+    public void ReadEnd()
+    {
+        readBuffer.Clear();
+        midBuffer = readBuffer;
+        readBuffer = null;
+        readEnd.Release();
+    }
+    /// <summary>
+    /// swap current write buffer to read and wait a new write buffer
+    /// </summary>
+    /// <returns> write buffer </returns>
+    public ByteSpan SwapBuffer(bool triggerEvent = true)
+    {
+        var write = SwapBegin();
+        SwapEnd();
+        onReadBufferReady?.Invoke();
+        return write;
+    }
+
+    public void WaitReadEnd()
+    {
+        readEnd.WaitOne();
+        readEnd.Release();
+    }
+
+    public ByteSpan SwapBegin()
+    {
+        readEnd.WaitOne();
+        readBuffer = writeBuffer;
+        writeBuffer = midBuffer;
+        midBuffer = null;
+        return writeBuffer;
+    }
+
+    public void SwapEnd()
+    {
+        writeEnd.Release();
+    }
+}