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merged 1 commit into from
Jan 22, 2024
Merged

Spanify SequentialReader #368

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43 changes: 40 additions & 3 deletions MetadataExtractor.Tests/IO/SequentialReaderTestBase.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -236,15 +236,15 @@ public void GetBytes()
}

[Fact]
public void OverflowBoundsCalculation()
public void GetBytes_OverflowBoundsCalculation()
{
var reader = CreateReader(new byte[10]);
var ex = Assert.Throws<IOException>(() => reader.GetBytes(15));
Assert.Equal("End of data reached.", ex.Message);
}

[Fact]
public void GetBytesEof()
public void GetBytes_Eof()
{
CreateReader(new byte[50]).GetBytes(50);

Expand All @@ -255,8 +255,45 @@ public void GetBytesEof()
Assert.Throws<IOException>(() => CreateReader(new byte[50]).GetBytes(51));
}

#if NET
[Fact]
public void GetByteEof()
public void GetBytes_Span()
{
var bytes = new byte[] { 0, 1, 2, 3, 4, 5 };
for (var i = 0; i < bytes.Length; i++)
{
var reader = CreateReader(bytes);
#pragma warning disable CA2014 // Do not use stackalloc in loops
Span<byte> span = stackalloc byte[i];
#pragma warning restore CA2014 // Do not use stackalloc in loops
reader.GetBytes(span);
Assert.Equal(bytes.Take(i).ToArray(), span.ToArray());
}
}

[Fact]
public void GetBytes_OverflowBoundsCalculation_Span()
{
var reader = CreateReader(new byte[10]);
var ex = Assert.Throws<IOException>(() => reader.GetBytes(stackalloc byte[15]));
Assert.Equal("End of data reached.", ex.Message);
}

[Fact]
public void GetBytes_Eof_Span()
{
CreateReader(new byte[50]).GetBytes(stackalloc byte[50]);

var reader = CreateReader(new byte[50]);
reader.GetBytes(stackalloc byte[25]);
reader.GetBytes(stackalloc byte[25]);

Assert.Throws<IOException>(() => CreateReader(new byte[50]).GetBytes(stackalloc byte[51]));
}
#endif

[Fact]
public void GetByte_Eof()
{
CreateReader(new byte[1]).GetByte();

Expand Down
9 changes: 9 additions & 0 deletions MetadataExtractor/IO/SequentialByteArrayReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,15 @@ public override byte[] GetBytes(int count)
return bytes;
}

public override void GetBytes(Span<byte> bytes)
{
if (_index + bytes.Length > _bytes.Length)
throw new IOException("End of data reached.");

_bytes.AsSpan(_index, bytes.Length).CopyTo(bytes);
_index += bytes.Length;
}

public override void GetBytes(byte[] buffer, int offset, int count)
{
if (_index + count > _bytes.Length)
Expand Down
157 changes: 52 additions & 105 deletions MetadataExtractor/IO/SequentialReader.cs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
// Copyright (c) Drew Noakes and contributors. All Rights Reserved. Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.

using System.Buffers.Binary;

namespace MetadataExtractor.IO
{
/// <summary>Base class for reading sequentially through a sequence of data encoded in a byte stream.</summary>
Expand All @@ -13,13 +15,8 @@ namespace MetadataExtractor.IO
/// <see cref="IsMotorolaByteOrder"/>.
/// </remarks>
/// <author>Drew Noakes https://drewnoakes.com</author>
public abstract class SequentialReader
public abstract class SequentialReader(bool isMotorolaByteOrder)
{
protected SequentialReader(bool isMotorolaByteOrder)
{
IsMotorolaByteOrder = isMotorolaByteOrder;
}

/// <summary>Get and set the byte order of this reader. <c>true</c> by default.</summary>
/// <remarks>
/// <list type="bullet">
Expand All @@ -28,7 +25,7 @@ protected SequentialReader(bool isMotorolaByteOrder)
/// </list>
/// </remarks>
/// <value><c>true</c> for Motorola/big endian, <c>false</c> for Intel/little endian</value>
public bool IsMotorolaByteOrder { get; }
public bool IsMotorolaByteOrder { get; } = isMotorolaByteOrder;

public abstract long Position { get; }

Expand All @@ -40,6 +37,8 @@ protected SequentialReader(bool isMotorolaByteOrder)
/// <exception cref="IOException"/>
public abstract byte[] GetBytes(int count);

public abstract void GetBytes(Span<byte> bytes);

/// <summary>Retrieves bytes, writing them into a caller-provided buffer.</summary>
/// <param name="buffer">The array to write bytes to.</param>
/// <param name="offset">The starting position within <paramref name="buffer"/> to write to.</param>
Expand Down Expand Up @@ -100,139 +99,81 @@ protected SequentialReader(bool isMotorolaByteOrder)
/// <exception cref="IOException"/>
public ushort GetUInt16()
{
if (IsMotorolaByteOrder)
{
// Motorola - MSB first
return (ushort)
(GetByte() << 8 |
GetByte());
}
// Intel ordering - LSB first
return (ushort)
(GetByte() |
GetByte() << 8);
Span<byte> bytes = stackalloc byte[2];

GetBytes(bytes);

return IsMotorolaByteOrder
? BinaryPrimitives.ReadUInt16BigEndian(bytes)
: BinaryPrimitives.ReadUInt16LittleEndian(bytes);
}

/// <summary>Returns a signed 16-bit int calculated from two bytes of data (MSB, LSB).</summary>
/// <returns>the 16 bit int value, between 0x0000 and 0xFFFF</returns>
/// <exception cref="IOException">the buffer does not contain enough bytes to service the request</exception>
public short GetInt16()
{
if (IsMotorolaByteOrder)
{
// Motorola - MSB first
return (short)
(GetByte() << 8 |
GetByte());
}
// Intel ordering - LSB first
return (short)
(GetByte() |
GetByte() << 8);
Span<byte> bytes = stackalloc byte[2];

GetBytes(bytes);

return IsMotorolaByteOrder
? BinaryPrimitives.ReadInt16BigEndian(bytes)
: BinaryPrimitives.ReadInt16LittleEndian(bytes);
}

/// <summary>Get a 32-bit unsigned integer from the buffer, returning it as a long.</summary>
/// <returns>the unsigned 32-bit int value as a long, between 0x00000000 and 0xFFFFFFFF</returns>
/// <exception cref="IOException">the buffer does not contain enough bytes to service the request</exception>
public uint GetUInt32()
{
if (IsMotorolaByteOrder)
{
// Motorola - MSB first (big endian)
return (uint)
(GetByte() << 24 |
GetByte() << 16 |
GetByte() << 8 |
GetByte());
}
// Intel ordering - LSB first (little endian)
return (uint)
(GetByte() |
GetByte() << 8 |
GetByte() << 16 |
GetByte() << 24);
Span<byte> bytes = stackalloc byte[4];

GetBytes(bytes);

return IsMotorolaByteOrder
? BinaryPrimitives.ReadUInt32BigEndian(bytes)
: BinaryPrimitives.ReadUInt32LittleEndian(bytes);
}

/// <summary>Returns a signed 32-bit integer from four bytes of data.</summary>
/// <returns>the signed 32 bit int value, between 0x00000000 and 0xFFFFFFFF</returns>
/// <exception cref="IOException">the buffer does not contain enough bytes to service the request</exception>
public int GetInt32()
{
if (IsMotorolaByteOrder)
{
// Motorola - MSB first (big endian)
return
GetByte() << 24 |
GetByte() << 16 |
GetByte() << 8 |
GetByte();
}
// Intel ordering - LSB first (little endian)
return
GetByte() |
GetByte() << 8 |
GetByte() << 16 |
GetByte() << 24;
Span<byte> bytes = stackalloc byte[4];

GetBytes(bytes);

return IsMotorolaByteOrder
? BinaryPrimitives.ReadInt32BigEndian(bytes)
: BinaryPrimitives.ReadInt32LittleEndian(bytes);
}

/// <summary>Get a signed 64-bit integer from the buffer.</summary>
/// <returns>the 64 bit int value, between 0x0000000000000000 and 0xFFFFFFFFFFFFFFFF</returns>
/// <exception cref="IOException">the buffer does not contain enough bytes to service the request</exception>
public long GetInt64()
{
if (IsMotorolaByteOrder)
{
// Motorola - MSB first
return
(long)GetByte() << 56 |
(long)GetByte() << 48 |
(long)GetByte() << 40 |
(long)GetByte() << 32 |
(long)GetByte() << 24 |
(long)GetByte() << 16 |
(long)GetByte() << 8 |
GetByte();
}
// Intel ordering - LSB first
return
GetByte() |
(long)GetByte() << 8 |
(long)GetByte() << 16 |
(long)GetByte() << 24 |
(long)GetByte() << 32 |
(long)GetByte() << 40 |
(long)GetByte() << 48 |
(long)GetByte() << 56;
Span<byte> bytes = stackalloc byte[8];
GetBytes(bytes);

return IsMotorolaByteOrder
? BinaryPrimitives.ReadInt64BigEndian(bytes)
: BinaryPrimitives.ReadInt64LittleEndian(bytes);
}

/// <summary>Get an unsigned 64-bit integer from the buffer.</summary>
/// <returns>the unsigned 64 bit int value, between 0x0000000000000000 and 0xFFFFFFFFFFFFFFFF</returns>
/// <exception cref="IOException">the buffer does not contain enough bytes to service the request</exception>
public ulong GetUInt64()
{
if (IsMotorolaByteOrder)
{
// Motorola - MSB first
return
(ulong)GetByte() << 56 |
(ulong)GetByte() << 48 |
(ulong)GetByte() << 40 |
(ulong)GetByte() << 32 |
(ulong)GetByte() << 24 |
(ulong)GetByte() << 16 |
(ulong)GetByte() << 8 |
GetByte();
}
// Intel ordering - LSB first
return
GetByte() |
(ulong)GetByte() << 8 |
(ulong)GetByte() << 16 |
(ulong)GetByte() << 24 |
(ulong)GetByte() << 32 |
(ulong)GetByte() << 40 |
(ulong)GetByte() << 48 |
(ulong)GetByte() << 56;
Span<byte> bytes = stackalloc byte[8];
GetBytes(bytes);

return IsMotorolaByteOrder
? BinaryPrimitives.ReadUInt64BigEndian(bytes)
: BinaryPrimitives.ReadUInt64LittleEndian(bytes);
}

#pragma warning restore format
Expand Down Expand Up @@ -271,8 +212,14 @@ public float GetS15Fixed16()
/// <exception cref="IOException"/>
public string GetString(int bytesRequested, Encoding encoding)
{
#if NETSTANDARD2_1
Span<byte> bytes = bytesRequested > 2048 ? new byte[bytesRequested] : stackalloc byte[bytesRequested];
GetBytes(bytes);
return encoding.GetString(bytes);
#else
var bytes = GetBytes(bytesRequested);
return encoding.GetString(bytes, 0, bytes.Length);
#endif
}

public StringValue GetStringValue(int bytesRequested, Encoding? encoding = null)
Expand Down
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