private CacheArgs(string fileName, ByteOrder byteOrder, string buildString, CacheMetadata metadata)
{
FileName = fileName;
ByteOrder = byteOrder;
BuildString = buildString;
Metadata = metadata;
}
public static CacheArgs FromFile(string fileName)
{
if (fileName == null)
{
throw new ArgumentNullException(nameof(fileName));
}
if (!File.Exists(fileName))
{
throw Exceptions.FileNotFound(fileName);
}
using (var fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
using (var reader = new EndianReader(fs, ByteOrder.LittleEndian))
{
var header = reader.ReadInt32();
if (header == BigHeader)
{
reader.ByteOrder = ByteOrder.BigEndian;
}
else if (header != LittleHeader)
{
throw Exceptions.NotAValidMapFile(fileName);
}
var version = reader.ReadInt32();
int buildAddress;
if (new[] { 5, 7, 609 }.Contains(version)) // Halo1 Xbox, PC, CE
{
buildAddress = 64;
}
else if (version == 8)
{
reader.Seek(36, SeekOrigin.Begin);
version = reader.ReadInt32();
if (version == 0)
{
buildAddress = 288; //Halo2 Xbox
}
else if (version == -1)
{
buildAddress = 300; //Halo2 Vista
}
else
{
throw Exceptions.NotAValidMapFile(fileName);
}
}
else if (reader.ByteOrder == ByteOrder.LittleEndian)
{
buildAddress = 288; //MCC
}
else
{
buildAddress = 284;
}
reader.Seek(buildAddress, SeekOrigin.Begin);
var buildString = reader.ReadNullTerminatedString(32);
System.Diagnostics.Debug.WriteLine($"Found build string {buildString ?? "\\0"}");
return(new CacheArgs(fileName, reader.ByteOrder, buildString, CacheMetadata.FromBuildString(buildString)));
}
}