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kaitai_struct_csharp_runtime
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Detect system endianness when reading values 

The BitConverter functions use the endianness of
the current system to convert bytes into values.
So when reading LE data on LE system it should not
change, but on a BE system it must be reversed.
This commit is contained in:
Daniel Walder 2016-07-19 22:23:08 +10:00
parent 72e01779ad
commit 3122ca220a
1 changed files with 38 additions and 44 deletions
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82
KaitaiStream.cs
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@ -12,7 +12,7 @@ namespace Kaitai
public partial class KaitaiStream : BinaryReader
{
#region Constructors
public KaitaiStream(Stream stream) : base(stream)
{
@ -70,7 +70,31 @@ namespace Kaitai
/// <returns></returns>
public byte[] ReadBytes(long count)
{
return base.ReadBytes((int) count);
return base.ReadBytes((int)count);
}
/// <summary>
/// Read bytes from the stream in little endian format and convert them to the endianness of the current platform
/// </summary>
/// <param name="count">The number of bytes to read</param>
/// <returns>An array of bytes that matches the endianness of the current platform</returns>
protected byte[] ReadBytesNormalisedLittleEndian(int count)
{
var bytes = ReadBytes(count);
if (!BitConverter.IsLittleEndian) Array.Reverse(bytes);
return bytes;
}
/// <summary>
/// Read bytes from the stream in big endian format and convert them to the endianness of the current platform
/// </summary>
/// <param name="count">The number of bytes to read</param>
/// <returns>An array of bytes that matches the endianness of the current platform</returns>
protected byte[] ReadBytesNormalisedBigEndian(int count)
{
var bytes = ReadBytes(count);
if (BitConverter.IsLittleEndian) Array.Reverse(bytes);
return bytes;
}
/// <summary>
@ -97,7 +121,7 @@ namespace Kaitai
/// <returns></returns>
public ushort ReadU2le()
{
return ReadUInt16();
return BitConverter.ToUInt16(ReadBytesNormalisedLittleEndian(2), 0);
}
/// <summary>
@ -106,7 +130,7 @@ namespace Kaitai
/// <returns></returns>
public short ReadS2le()
{
return ReadInt16();
return BitConverter.ToInt16(ReadBytesNormalisedLittleEndian(2), 0);
}
/// <summary>
@ -115,7 +139,7 @@ namespace Kaitai
/// <returns></returns>
public uint ReadU4le()
{
return ReadUInt32();
return BitConverter.ToUInt32(ReadBytesNormalisedLittleEndian(4), 0);
}
/// <summary>
@ -124,7 +148,7 @@ namespace Kaitai
/// <returns></returns>
public int ReadS4le()
{
return ReadInt32();
return BitConverter.ToInt32(ReadBytesNormalisedLittleEndian(4), 0);
}
/// <summary>
@ -133,7 +157,7 @@ namespace Kaitai
/// <returns></returns>
public ulong ReadU8le()
{
return ReadUInt64();
return BitConverter.ToUInt64(ReadBytesNormalisedLittleEndian(8), 0);
}
/// <summary>
@ -142,7 +166,7 @@ namespace Kaitai
/// <returns></returns>
public long ReadS8le()
{
return ReadInt64();
return BitConverter.ToInt64(ReadBytesNormalisedLittleEndian(8), 0);
}
/// <summary>
@ -151,9 +175,7 @@ namespace Kaitai
/// <returns></returns>
public ushort ReadU2be()
{
var b1 = ReadByte();
var b2 = ReadByte();
return (ushort) ((b1 << 8) + (b2 << 0));
return BitConverter.ToUInt16(ReadBytesNormalisedBigEndian(2), 0);
}
/// <summary>
@ -162,9 +184,7 @@ namespace Kaitai
/// <returns></returns>
public short ReadS2be()
{
var b1 = ReadByte();
var b2 = ReadByte();
return (short) ((b1 << 8) + (b2 << 0));
return BitConverter.ToInt16(ReadBytesNormalisedBigEndian(2), 0);
}
/// <summary>
@ -173,11 +193,7 @@ namespace Kaitai
/// <returns></returns>
public uint ReadU4be()
{
var b1 = ReadByte();
var b2 = ReadByte();
var b3 = ReadByte();
var b4 = ReadByte();
return (uint) ((b1 << 24) + (b2 << 16) + (b3 << 8) + (b4 << 0));
return BitConverter.ToUInt32(ReadBytesNormalisedBigEndian(4), 0);
}
/// <summary>
@ -186,11 +202,7 @@ namespace Kaitai
/// <returns></returns>
public int ReadS4be()
{
var b1 = ReadByte();
var b2 = ReadByte();
var b3 = ReadByte();
var b4 = ReadByte();
return (b1 << 24) + (b2 << 16) + (b3 << 8) + (b4 << 0);
return BitConverter.ToInt32(ReadBytesNormalisedBigEndian(4), 0);
}
/// <summary>
@ -199,16 +211,7 @@ namespace Kaitai
/// <returns></returns>
public ulong ReadU8be()
{
byte[] buffer = ReadBytes(8);
return (ulong) (
( buffer[0] << 56) + // high byte
( buffer[1] << 48) +
( buffer[2] << 40) +
( buffer[3] << 32) + // ^ high word
( buffer[4] << 24) + // v low word
( buffer[5] << 16) +
( buffer[6] << 8) +
( buffer[7] << 0) ); // low byte
return BitConverter.ToUInt64(ReadBytesNormalisedBigEndian(8), 0);
}
/// <summary>
@ -217,16 +220,7 @@ namespace Kaitai
/// <returns></returns>
public long ReadS8be()
{
byte[] buffer = ReadBytes(8);
return (Int64) (
( buffer[0] << 56) + // high byte
( buffer[1] << 48) +
( buffer[2] << 40) +
( buffer[3] << 32) + // ^ high word
( buffer[4] << 24) + // v low word
( buffer[5] << 16) +
( buffer[6] << 8) +
( buffer[7] << 0) ); // low byte
return BitConverter.ToInt64(ReadBytesNormalisedBigEndian(8), 0);
}
/// <summary>