GARbro-mirror/ArcFormats/Unity/AssetReader.cs

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//! \file AssetReader.cs
//! \date Wed Apr 05 13:28:33 2017
//! \brief Unity asset reader class.
//
// Copyright (C) 2017 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//
using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using GameRes.Utility;
namespace GameRes.Formats.Unity
{
/// <summary>
/// AssetReader provides access to a serialized stream of Unity assets.
/// </summary>
internal sealed class AssetReader : IDisposable
{
IBinaryStream m_input;
int m_format;
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public Stream Source { get { return m_input.AsStream; } }
public int Format { get { return m_format; } }
public long Position {
get { return m_input.Position; }
set { m_input.Position = value; }
}
public AssetReader (Stream input, string name) : this (BinaryStream.FromStream (input, name))
{
}
public AssetReader (IBinaryStream input)
{
m_input = input;
SetupReaders (0, false);
}
public Action Align;
public Func<ushort> ReadUInt16;
public Func<short> ReadInt16;
public Func<uint> ReadUInt32;
public Func<int> ReadInt32;
public Func<long> ReadInt64;
public Func<long> ReadId;
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public void SetupReaders (Asset asset)
{
SetupReaders (asset.Format, asset.IsLittleEndian);
}
/// <summary>
/// Setup reader endianness accordingly.
/// </summary>
public void SetupReaders (int format, bool is_little_endian)
{
m_format = format;
if (is_little_endian)
{
ReadUInt16 = () => m_input.ReadUInt16();
ReadUInt32 = () => m_input.ReadUInt32();
ReadInt16 = () => m_input.ReadInt16();
ReadInt32 = () => m_input.ReadInt32();
ReadInt64 = () => m_input.ReadInt64();
}
else
{
ReadUInt16 = () => Binary.BigEndian (m_input.ReadUInt16());
ReadUInt32 = () => Binary.BigEndian (m_input.ReadUInt32());
ReadInt16 = () => Binary.BigEndian (m_input.ReadInt16());
ReadInt32 = () => Binary.BigEndian (m_input.ReadInt32());
ReadInt64 = () => Binary.BigEndian (m_input.ReadInt64());
}
if (m_format >= 14 || m_format == 9)
{
Align = () => {
long pos = m_input.Position;
if (0 != (pos & 3))
m_input.Position = (pos + 3) & ~3L;
};
}
else
{
Align = () => {};
}
if (m_format >= 14)
ReadId = ReadInt64;
else
ReadId = () => ReadInt32();
}
/// <summary>
/// Set asset ID length. If <paramref name="long_id"/> is <c>true</c> IDs are 64-bit, otherwise 32-bit.
/// </summary>
public void SetupReadId (bool long_ids)
{
if (long_ids)
ReadId = ReadInt64;
else
ReadId = () => ReadInt32();
}
/// <summary>
/// Read bytes into specified buffer.
/// </summary>
public int Read (byte[] buffer, int offset, int count)
{
return m_input.Read (buffer, offset, count);
}
/// <summary>
/// Read null-terminated UTF8 string.
/// </summary>
public string ReadCString ()
{
return m_input.ReadCString (Encoding.UTF8);
}
/// <summary>
/// Read UTF8 string prefixed with length.
/// </summary>
public string ReadString ()
{
int length = ReadInt32();
if (0 == length)
return string.Empty;
var bytes = ReadBytes (length);
return Encoding.UTF8.GetString (bytes);
}
/// <summary>
/// Read <paramref name="length"/> bytes from stream and return them in a byte array.
/// May return less than <paramref name="length"/> bytes if end of file was encountered.
/// </summary>
public byte[] ReadBytes (int length)
{
return m_input.ReadBytes (length);
}
/// <summary>
/// Read unsigned 8-bits byte from a stream.
/// </summary>
public byte ReadByte ()
{
return m_input.ReadUInt8();
}
/// <summary>
/// Read byte and interpret is as a bool value, non-zero resulting in <c>true</c>.
/// </summary>
public bool ReadBool ()
{
return ReadByte() != 0;
}
[StructLayout(LayoutKind.Explicit)]
struct Union
{
[FieldOffset (0)]
public uint u;
[FieldOffset(0)]
public float f;
}
/// <summary>
/// Read float value from a stream.
/// </summary>
public float ReadFloat ()
{
var buf = new Union();
buf.u = ReadUInt32();
return buf.f;
}
bool _disposed = false;
public void Dispose ()
{
if (!_disposed)
{
m_input.Dispose();
_disposed = true;
}
GC.SuppressFinalize (this);
}
}
}