Adds BufferReader and BufferWriter. Updates UOP handling. (#101)

Projects/Server/Buffers/BufferReaderExtensions.cs

@@ -0,0 +1,181 @@
+// Copyright (c) Harry Pierson. All rights reserved.
+// Licensed under the MIT license.
+// See LICENSE file in the project root for full license information.
+
+using System.Buffers.Binary;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace System.Buffers
+{
+  public static class BufferReaderExtensions
+  {
+    private static unsafe bool TryRead<T>(ref this BufferReader<byte> reader, out T value)
+      where T : unmanaged
+    {
+      ReadOnlySpan<byte> span = reader.UnreadSpan;
+      if (span.Length < sizeof(T)) return TryReadMultisegment(ref reader, out value);
+
+      value = Unsafe.ReadUnaligned<T>(ref MemoryMarshal.GetReference(span));
+      reader.Advance(sizeof(T));
+      return true;
+    }
+
+    private static unsafe bool TryReadMultisegment<T>(ref BufferReader<byte> reader, out T value)
+      where T : unmanaged
+    {
+      Debug.Assert(reader.UnreadSpan.Length < sizeof(T), "reader.UnreadSpan.Length < sizeof(T)");
+
+      // Not enough data in the current segment, try to peek for the data we need.
+      T buffer = default;
+      Span<byte> tempSpan = new Span<byte>(&buffer, sizeof(T));
+
+      if (!reader.TryCopyTo(tempSpan))
+      {
+        value = default;
+        return false;
+      }
+
+      value = Unsafe.ReadUnaligned<T>(ref MemoryMarshal.GetReference(tempSpan));
+      reader.Advance(sizeof(T));
+      return true;
+    }
+
+    public static bool TryRead(ref this BufferReader<byte> reader, out sbyte value)
+    {
+      if (TryRead(ref reader, out byte byteValue))
+      {
+        value = unchecked((sbyte)byteValue);
+        return true;
+      }
+
+      value = default;
+      return false;
+    }
+
+    public static bool TryReadLittleEndian(ref this BufferReader<byte> reader, out short value) =>
+      BitConverter.IsLittleEndian ? reader.TryRead(out value) : TryReadReverseEndianness(ref reader, out value);
+
+    public static bool TryReadBigEndian(ref this BufferReader<byte> reader, out short value) =>
+      !BitConverter.IsLittleEndian ? reader.TryRead(out value) : TryReadReverseEndianness(ref reader, out value);
+
+    private static bool TryReadReverseEndianness(ref BufferReader<byte> reader, out short value)
+    {
+      if (reader.TryRead(out value))
+      {
+        value = BinaryPrimitives.ReverseEndianness(value);
+        return true;
+      }
+
+      return false;
+    }
+
+    public static bool TryReadLittleEndian(ref this BufferReader<byte> reader, out ushort value)
+    {
+      if (TryReadLittleEndian(ref reader, out short signedvalue))
+      {
+        value = unchecked((ushort)signedvalue);
+        return true;
+      }
+
+      value = default;
+      return false;
+    }
+
+    public static bool TryReadBigEndian(ref this BufferReader<byte> reader, out ushort value)
+    {
+      if (TryReadBigEndian(ref reader, out short signedvalue))
+      {
+        value = unchecked((ushort)signedvalue);
+        return true;
+      }
+
+      value = default;
+      return false;
+    }
+
+    public static bool TryReadLittleEndian(ref this BufferReader<byte> reader, out int value) =>
+      BitConverter.IsLittleEndian ? reader.TryRead(out value) : TryReadReverseEndianness(ref reader, out value);
+
+    public static bool TryReadBigEndian(ref this BufferReader<byte> reader, out int value) =>
+      !BitConverter.IsLittleEndian ? reader.TryRead(out value) : TryReadReverseEndianness(ref reader, out value);
+
+    private static bool TryReadReverseEndianness(ref BufferReader<byte> reader, out int value)
+    {
+      if (reader.TryRead(out value))
+      {
+        value = BinaryPrimitives.ReverseEndianness(value);
+        return true;
+      }
+
+      return false;
+    }
+
+    public static bool TryReadLittleEndian(ref this BufferReader<byte> reader, out uint value)
+    {
+      if (TryReadLittleEndian(ref reader, out int signedvalue))
+      {
+        value = unchecked((uint)signedvalue);
+        return true;
+      }
+
+      value = default;
+      return false;
+    }
+
+    public static bool TryReadBigEndian(ref this BufferReader<byte> reader, out uint value)
+    {
+      if (TryReadBigEndian(ref reader, out int signedvalue))
+      {
+        value = unchecked((uint)signedvalue);
+        return true;
+      }
+
+      value = default;
+      return false;
+    }
+
+    public static bool TryReadLittleEndian(ref this BufferReader<byte> reader, out long value) =>
+      BitConverter.IsLittleEndian ? reader.TryRead(out value) : TryReadReverseEndianness(ref reader, out value);
+
+    public static bool TryReadBigEndian(ref this BufferReader<byte> reader, out long value) =>
+      !BitConverter.IsLittleEndian ? reader.TryRead(out value) : TryReadReverseEndianness(ref reader, out value);
+
+    private static bool TryReadReverseEndianness(ref BufferReader<byte> reader, out long value)
+    {
+      if (reader.TryRead(out value))
+      {
+        value = BinaryPrimitives.ReverseEndianness(value);
+        return true;
+      }
+
+      return false;
+    }
+
+
+    public static bool TryReadLittleEndian(ref this BufferReader<byte> reader, out ulong value)
+    {
+      if (TryReadLittleEndian(ref reader, out long signedvalue))
+      {
+        value = unchecked((ulong)signedvalue);
+        return true;
+      }
+
+      value = default;
+      return false;
+    }
+
+    public static bool TryReadBigEndian(ref this BufferReader<byte> reader, out ulong value)
+    {
+      if (TryReadBigEndian(ref reader, out long signedvalue))
+      {
+        value = unchecked((ulong)signedvalue);
+        return true;
+      }
+
+      value = default;
+      return false;
+    }
+  }
+}