private static void BlockDecompress(Stream stream, byte[] outData)
{
while (stream.Position < stream.Length)
{
var header = BinaryHelpers.ReadStruct <CIPHeader>(stream);
if (header.Magic != 0x55441122)
{
throw new InvalidDataException($"Invalid magic! Expected 0x55441122, got 0x{header.Magic:X8}");
}
var data = new byte[header.CSize - 24];
var decompressed = new byte[header.USize];
if (stream.Read(data, 0, data.Length) != data.Length)
{
throw new InvalidDataException($"Failed to read {data.Length} bytes from stream");
}
Compression.Decompress(data, decompressed);
Array.ConstrainedCopy(
decompressed,
0,
outData,
header.UPos,
decompressed.Length);
}
}
private static void WriteBlocksInternal(List <CompressedBlock> blocksSorted, BinaryWriter bw)
{
foreach (var compressedBlock in blocksSorted)
{
var cbh = new CIPHeader();
cbh.Magic = 0x55441122;
cbh.CPos = compressedBlock.CPos;
cbh.USize = compressedBlock.DataRaw.Length;
cbh.CSize = 24 + compressedBlock.DataComp.Length;
cbh.UPos = compressedBlock.UPos;
BinaryHelpers.WriteStruct(bw, cbh);
bw.Write(compressedBlock.DataComp);
}
}
/// <summary>
/// Reads a compressed-in-place file. This involves reading a header and then
/// proceeding to a shared routine for decompression.
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
public static byte[] ReadBlockFile(Stream stream)
{
var br = new BinaryReader(stream);
var fileHeader = BinaryHelpers.ReadStruct <CIPFileHeader>(br);
if (fileHeader.Magic != 0x66113388)
{
throw new InvalidDataException("Invalid header");
}
var data = new byte[fileHeader.USize];
BlockDecompress(stream, data);
return(data);
}
/// <summary>
/// Writes a compressed-in-place file. Compresses the input data as blocks,
/// then writes a header followed by the blocks.
/// </summary>
/// <param name="stream"></param>
/// <param name="data"></param>
/// <param name="blockSize"></param>
public static void WriteBlockFile(Stream stream, IEnumerable <byte> data, int blockSize = 32768)
{
if ((blockSize & (blockSize - 1)) != 0)
{
throw new ArgumentException("blockSize must be a power of two!");
}
var blocksSorted = BlockCompress(data, blockSize);
using (var bw = new BinaryWriter(stream))
{
var header = new CIPFileHeader();
header.Magic = 0x66113388;
header.CSize = blocksSorted.Sum(b => b.DataComp.Length + 24);
header.USize = blocksSorted.Sum(b => b.DataRaw.Length);
header.Unknown = 0;
BinaryHelpers.WriteStruct(bw, header);
WriteBlocksInternal(blocksSorted, bw);
}
}
