/// <summary>
/// Decompresses the specified data.
/// </summary>
/// <param name="data">The compressed byte array.</param>
/// <param name="pos">The starting position into the byte array.</param>
/// <param name="Length">The number of compressed bytes to decompress.</param>
/// <returns>An uncompressed byte array</returns>
public static byte[] Decompress(byte[] data, int pos, int Length)
{
byte[] compressedData = new byte[Length];
Array.Copy(data, pos + 50, compressedData, 0, Length);
using (MemoryStream ms = new MemoryStream(compressedData))
{
Inflater inflater = new Inflater(false);
using (InflaterInputStream zIn = new InflaterInputStream(ms, inflater))
{
using (MemoryStream out1 = new MemoryStream())
{
int c;
try
{
while ((c = zIn.ReadByte()) != -1)
out1.WriteByte((byte)c);
return out1.ToArray();
}
catch (IOException e)
{
throw new RecordFormatException(e.ToString());
}
}
}
}
}
private void ReadScanlines(MemoryStream dataStream, byte[] pixels, IColorReader colorReader, PngColorTypeInformation colorTypeInformation)
{
dataStream.Position = 0;
int scanlineLength = CalculateScanlineLength(colorTypeInformation);
int scanlineStep = CalculateScanlineStep(colorTypeInformation);
byte[] lastScanline = new byte[scanlineLength];
byte[] currScanline = new byte[scanlineLength];
byte a = 0;
byte b = 0;
byte c = 0;
int row = 0, filter = 0, column = -1;
using (InflaterInputStream compressedStream = new InflaterInputStream(dataStream))
{
int readByte = 0;
while ((readByte = compressedStream.ReadByte()) >= 0)
{
if (column == -1)
{
filter = readByte;
column++;
}
else
{
currScanline[column] = (byte)readByte;
if (column >= scanlineStep)
{
a = currScanline[column - scanlineStep];
c = lastScanline[column - scanlineStep];
}
else
{
a = 0;
c = 0;
}
b = lastScanline[column];
if (filter == 1)
{
currScanline[column] = (byte)(currScanline[column] + a);
}
else if (filter == 2)
{
currScanline[column] = (byte)(currScanline[column] + b);
}
else if (filter == 3)
{
currScanline[column] = (byte)(currScanline[column] + (byte)Math.Floor((a + b) / 2d));
}
else if (filter == 4)
{
currScanline[column] = (byte)(currScanline[column] + PaethPredicator(a, b, c));
}
column++;
if (column == scanlineLength)
{
colorReader.ReadScanline(currScanline, pixels, _header);
column = -1;
row++;
Extensions.Swap(ref currScanline, ref lastScanline);
}
}
}
}
}
private Object GetObjectLoose(string aId)
{
var path = Path.Combine(iFolderObjects.FullName, aId.Substring(0, 2), aId.Substring(2, 38));
try
{
var file = File.OpenRead(path);
using (var inflater = new InflaterInputStream(file))
{
int offset = 0;
byte[] header = new byte[100];
while (true)
{
int b = inflater.ReadByte();
if (b == 0)
{
break;
}
if (offset >= 100)
{
throw (new GitException("Illegal object header " + aId));
}
header[offset++] = (byte)b;
}
string[] parts = ASCIIEncoding.ASCII.GetString(header, 0, offset).Split(new char[] { ' ' });
if (parts.Length != 2)
{
throw (new GitException("Illegal object header " + aId));
}
int length;
if (!int.TryParse(parts[1], out length))
{
throw (new GitException("Illegal object length " + aId));
}
byte[] bytes = new byte[length];
inflater.Read(bytes, 0, length);
switch (parts[0])
{
case "commit":
return (new Object(EObjectType.Commit, bytes));
case "tag":
return (new Object(EObjectType.Tag, bytes));
case "tree":
return (new Object(EObjectType.Tree, bytes));
case "blob":
return (new Object(EObjectType.Blob, bytes));
default:
throw (new GitException("Unrecognised object type " + aId));
}
}
}
catch (FileNotFoundException)
{
return (null);
}
}
Tuple<PackObjectType, byte[]> readLooseObject(FileInfo objectFi)
{
ObjectId objId = ObjectId.Parse(objectFi.Directory.Name + objectFi.Name);
var sha = SHA1.Create();
string tag;
byte[] objectContents;
using (var fs = objectFi.OpenRead())
{
//TODO: apply some not-invented-here syndrom by reimplmenting inflate
using (var inflater = new InflaterInputStream(fs))
{
int? spaceNdx = null;
int headerBytesRead = 0;
byte[] headerBytes = new byte[30]; //should be enough for a 64-bit size
while (true)
{
int b = inflater.ReadByte();
if (b == -1)
throw new Exception("Unexpected EOF");
headerBytes[headerBytesRead] = (byte)b;
if (b == ' ')
spaceNdx = headerBytesRead;
headerBytesRead++;
if (b == 0)
break;
if (headerBytesRead == headerBytes.Length)
throw new Exception("Header too big.");
}
if (!spaceNdx.HasValue)
throw new Exception("Did not find space.");
//split the string along the space to get the object type and size and size
tag = Encoding.ASCII.GetString(headerBytes, 0, spaceNdx.Value);
string sizeStr = Encoding.ASCII.GetString(headerBytes, spaceNdx.Value + 1, headerBytesRead - spaceNdx.Value - 2);
int objectSize = int.Parse(sizeStr, NumberStyles.None, CultureInfo.InvariantCulture);
objectContents = new byte[objectSize];
if (inflater.Read(objectContents, 0, objectSize) != objectSize)
throw new Exception("Short read.");
sha.TransformBlock(headerBytes, 0, headerBytesRead, null, 0);
}
}
sha.TransformFinalBlock(objectContents, 0, objectContents.Length);
if (!objId.Equals(new ObjectId(sha.Hash)))
throw new Exception("Hash is not right!");
PackObjectType objType;
switch (tag)
{
case "blob":
objType = PackObjectType.Blob;
break;
case "commit":
objType = PackObjectType.Commit;
break;
case "tree":
objType = PackObjectType.Tree;
break;
case "tag":
objType = PackObjectType.Tag;
break;
default:
throw new Exception("Unrecognized object type: " + tag);
}
return new Tuple<PackObjectType, byte[]>(objType, objectContents);
}
/// <summary>
/// Decompresses the specified data.
/// </summary>
/// <param name="data">The compressed byte array.</param>
/// <param name="pos">The starting position into the byte array.</param>
/// <param name="Length">The number of compressed bytes to decompress.</param>
/// <returns>An uncompressed byte array</returns>
public static byte[] Decompress(byte[] data, int pos, int Length)
{
byte[] compressedData = new byte[Length];
Array.Copy(data, pos + 50, compressedData, 0, Length);
Stream compressedInputStream = new MemoryStream(compressedData);
InflaterInputStream inflaterInputStream = new InflaterInputStream(compressedInputStream);
MemoryStream out1 = new MemoryStream();
int c;
try
{
while ((c = inflaterInputStream.ReadByte()) != -1)
out1.WriteByte((byte)c);
}
catch (IOException e)
{
throw new RecordFormatException(e.ToString());
}
return out1.ToArray();
}
