internal static string readRecordFilename(Stream s, Arc_V3_Header header, ArcRecordHeader recordHeader)
{
BinaryReader reader = new BinaryReader(s);
s.Seek(header.recordTableOffset + header.recordTableSize + recordHeader.stringEntryOffset, SeekOrigin.Begin);
return(Encoding.ASCII.GetString(reader.ReadBytes(recordHeader.stringEntryLength)));
}
public static Dictionary <string, byte[]> read(string filepath)
{
using (FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read))
{
// Check on the file header
Arc_V3_Header header = (Arc_V3_Header)Program.readStructure(typeof(Arc_V3_Header), fs, null);
if (header.magic != 0x435241 || header.version != 0x3)
{
throw new Exception("I don't understand this ARC format!");
}
// Read out the records table
var recordsTable = readRecordHeadersTable(fs, header.recordTableOffset + header.recordTableSize + header.stringTableSize, header.numberOfFileEntries);
// Read out the contents of each "record" and return them in a map associated with their filename
var arcContents = new Dictionary <string, byte[]>();
foreach (var recordHeader in recordsTable)
{
string filename = readRecordFilename(fs, header, recordHeader);
byte[] contents = readRecord(fs, header, recordHeader);
arcContents[filename] = contents;
}
return(arcContents);
}
}
internal static byte[] readRecord(Stream s, Arc_V3_Header header, ArcRecordHeader recordHeader)
{
BinaryReader reader = new BinaryReader(s);
s.Seek(recordHeader.fileOffset, SeekOrigin.Begin);
// If the file contents isn't compressed, just read and return the contents now
if (recordHeader.entryType == 1 && recordHeader.compressedSize == recordHeader.decompressedSize)
{
return(reader.ReadBytes(recordHeader.decompressedSize));
}
// The file content is compressed...
MemoryStream contentsStream = new MemoryStream();
BinaryWriter contentWriter = new BinaryWriter(contentsStream);
for (int partCursor = 0; partCursor < recordHeader.fileParts; partCursor++)
{
// Goto the beginning of the file part
// Magic number "12" is the size of the ArcFilePart on disk
s.Seek(header.recordTableOffset + (recordHeader.firstPartIndex + partCursor) * 12, SeekOrigin.Begin);
// Read out the file part header
var partHeader = (ArcFilePartHeader)Program.readStructure(typeof(ArcFilePartHeader), s, null);
// Read out the part content
s.Seek(partHeader.offset, SeekOrigin.Begin);
byte[] contentBytes = reader.ReadBytes(partHeader.compressedSize);
// If the content isn't compressed, just write it out
if (partHeader.compressedSize == partHeader.decompressedSize)
{
contentWriter.Write(contentBytes);
continue;
}
// If the content *is* compressed, decompress before writing it out
byte[] decompressedBytes = LZ4.LZ4Codec.Decode(contentBytes, 0, contentBytes.Length, partHeader.decompressedSize);
contentWriter.Write(decompressedBytes);
}
return(contentsStream.GetBuffer());
}
