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Use spans to improve performance in StreamExts.

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Also avoid ReadBytes calls that allocate a buffer by either updating the stream position (if not interested in the bytes), by reusing an input buffer (if interested in the bytes), or using a stackalloc buffer to avoid the allocation (for small reads).
This commit is contained in:
RoosterDragon
2023-09-19 18:10:09 +01:00
committed by Gustas
parent b3ee3551ca
commit 5d91b678bb
20 changed files with 153 additions and 92 deletions
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106
OpenRA.Game/StreamExts.cs
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@@ -20,10 +20,23 @@ namespace OpenRA
{
public static class StreamExts
{
public static void ReadBytes(this Stream s, Span<byte> dest)
{
while (dest.Length > 0)
{
var bytesRead = s.Read(dest);
if (bytesRead == 0)
throw new EndOfStreamException();
dest = dest[bytesRead..];
}
}
public static byte[] ReadBytes(this Stream s, int count)
{
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count), "Non-negative number required.");
var buffer = new byte[count];
s.ReadBytes(buffer, 0, count);
return buffer;
@@ -33,10 +46,11 @@ namespace OpenRA
{
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count), "Non-negative number required.");
while (count > 0)
{
int bytesRead;
if ((bytesRead = s.Read(buffer, offset, count)) == 0)
var bytesRead = s.Read(buffer, offset, count);
if (bytesRead == 0)
throw new EndOfStreamException();
offset += bytesRead;
count -= bytesRead;
@@ -48,6 +62,7 @@ namespace OpenRA
var b = s.ReadByte();
if (b == -1)
return -1;
s.Seek(-1, SeekOrigin.Current);
return (byte)b;
}
@@ -57,52 +72,85 @@ namespace OpenRA
var b = s.ReadByte();
if (b == -1)
throw new EndOfStreamException();
return (byte)b;
}
public static ushort ReadUInt16(this Stream s)
{
return (ushort)(s.ReadUInt8() | s.ReadUInt8() << 8);
Span<byte> buffer = stackalloc byte[2];
s.ReadBytes(buffer);
return BitConverter.ToUInt16(buffer);
}
public static short ReadInt16(this Stream s)
{
return (short)(s.ReadUInt8() | s.ReadUInt8() << 8);
Span<byte> buffer = stackalloc byte[2];
s.ReadBytes(buffer);
return BitConverter.ToInt16(buffer);
}
public static uint ReadUInt32(this Stream s)
{
return (uint)(s.ReadUInt8() | s.ReadUInt8() << 8 | s.ReadUInt8() << 16 | s.ReadUInt8() << 24);
Span<byte> buffer = stackalloc byte[4];
s.ReadBytes(buffer);
return BitConverter.ToUInt32(buffer);
}
public static int ReadInt32(this Stream s)
{
return s.ReadUInt8() | s.ReadUInt8() << 8 | s.ReadUInt8() << 16 | s.ReadUInt8() << 24;
Span<byte> buffer = stackalloc byte[4];
s.ReadBytes(buffer);
return BitConverter.ToInt32(buffer);
}
public static void Write(this Stream s, int value)
{
s.WriteArray(BitConverter.GetBytes(value));
Span<byte> buffer = stackalloc byte[4];
BitConverter.TryWriteBytes(buffer, value);
s.Write(buffer);
}
public static void Write(this Stream s, long value)
{
Span<byte> buffer = stackalloc byte[8];
BitConverter.TryWriteBytes(buffer, value);
s.Write(buffer);
}
public static void Write(this Stream s, ulong value)
{
Span<byte> buffer = stackalloc byte[8];
BitConverter.TryWriteBytes(buffer, value);
s.Write(buffer);
}
public static void Write(this Stream s, float value)
{
s.WriteArray(BitConverter.GetBytes(value));
Span<byte> buffer = stackalloc byte[4];
BitConverter.TryWriteBytes(buffer, value);
s.Write(buffer);
}
public static float ReadFloat(this Stream s)
public static float ReadSingle(this Stream s)
{
return BitConverter.ToSingle(s.ReadBytes(4), 0);
Span<byte> buffer = stackalloc byte[4];
s.ReadBytes(buffer);
return BitConverter.ToSingle(buffer);
}
public static double ReadDouble(this Stream s)
{
return BitConverter.ToDouble(s.ReadBytes(8), 0);
Span<byte> buffer = stackalloc byte[8];
s.ReadBytes(buffer);
return BitConverter.ToDouble(buffer);
}
public static string ReadASCII(this Stream s, int length)
{
return new string(Encoding.ASCII.GetChars(s.ReadBytes(length)));
Span<byte> buffer = length < 128 ? stackalloc byte[length] : new byte[length];
s.ReadBytes(buffer);
return Encoding.ASCII.GetString(buffer);
}
public static string ReadASCIIZ(this Stream s)
@@ -111,7 +159,12 @@ namespace OpenRA
byte b;
while ((b = s.ReadUInt8()) != 0)
bytes.Add(b);
return new string(Encoding.ASCII.GetChars(bytes.ToArray()));
#if NET5_0_OR_GREATER
return Encoding.ASCII.GetString(System.Runtime.InteropServices.CollectionsMarshal.AsSpan(bytes));
#else
return Encoding.ASCII.GetString(bytes.ToArray());
#endif
}
public static string ReadAllText(this Stream s)
@@ -133,17 +186,11 @@ namespace OpenRA
int count;
while ((count = s.Read(buffer, 0, buffer.Length)) > 0)
bytes.AddRange(buffer.Take(count));
return bytes.ToArray();
}
}
// Note: renamed from Write() to avoid being aliased by
// System.IO.Stream.Write(System.ReadOnlySpan) (which is not implemented in Mono)
public static void WriteArray(this Stream s, byte[] data)
{
s.Write(data, 0, data.Length);
}
public static IEnumerable<string> ReadAllLines(this Stream s)
{
string line;
@@ -210,19 +257,24 @@ namespace OpenRA
}
}
// The string is assumed to be length-prefixed, as written by WriteString()
public static string ReadString(this Stream s, Encoding encoding, int maxLength)
/// <summary>
/// The string is assumed to be length-prefixed, as written by <see cref="WriteLengthPrefixedString"/>.
/// </summary>
public static string ReadLengthPrefixedString(this Stream s, Encoding encoding, int maxLength)
{
var length = s.ReadInt32();
if (length > maxLength)
throw new InvalidOperationException($"The length of the string ({length}) is longer than the maximum allowed ({maxLength}).");
return encoding.GetString(s.ReadBytes(length));
Span<byte> buffer = length < 128 ? stackalloc byte[length] : new byte[length];
s.ReadBytes(buffer);
return encoding.GetString(buffer);
}
// Writes a length-prefixed string using the specified encoding and returns
// the number of bytes written.
public static int WriteString(this Stream s, Encoding encoding, string text)
/// <summary>
/// Writes a length-prefixed string using the specified encoding and returns the number of bytes written.
/// </summary>
public static int WriteLengthPrefixedString(this Stream s, Encoding encoding, string text)
{
byte[] bytes;
@@ -232,7 +284,7 @@ namespace OpenRA
bytes = Array.Empty<byte>();
s.Write(bytes.Length);
s.WriteArray(bytes);
s.Write(bytes);
return 4 + bytes.Length;
}