/// <summary>
/// Tokenizes the GIF image's byte[] into constituent components.
/// </summary>
public static DataStream ParseDataStream(byte[] data)
{
DataStream ds = new DataStream();
using (MemoryStream ms = new MemoryStream(data))
{
using (BinaryReader br = new BinaryReader(ms))
{
ds.Header = VcvjParser.ParseHeader(br.ReadBytes(Header.TotalBlockLength));
ds.LogicalScreen = new LogicalScreen()
{
LogicalScreenDescriptor = VcvjParser.ParseLogicalScreenDescriptor(br.ReadBytes(LogicalScreenDescriptor.TotalBlockLength))
};
if (ds.LogicalScreen.LogicalScreenDescriptor.HasGlobalColorTable)
{
ds.LogicalScreen.GlobalColorTable = VcvjParser.ParseGlobalColorTable(
br.ReadBytes(ds.LogicalScreen.LogicalScreenDescriptor.GlobalColorTableLength)
);
}
while (br.PeekChar() != -1)
{
long currentIndex = br.BaseStream.Position;
byte currentByte = data[currentIndex];
byte?nextByte = currentIndex + 1 < data.Length ? (byte?)data[currentIndex + 1] : (byte?)null;
if (ParserUtils.IsTrailerMarker(currentByte))
{
ds.Trailer = new Trailer(br.ReadByte());
continue;
}
else if (ParserUtils.IsApplicationExtensionBlock(currentByte, nextByte))
{
ApplicationExtension ae = VcvjParser.ParseApplicationExtension(
br.ReadBytes(VcvjParser.GetApplicationExtensionBlockLength(currentIndex, ref data))
);
ds.DataBlocks.Add(ae);
continue;
}
else if (ParserUtils.IsCommentExtensionBlock(currentByte, nextByte))
{
int totalBlockLength = data[currentIndex + 2] + 4;
CommentExtension ce = VcvjParser.ParseCommentExtension(br.ReadBytes(totalBlockLength));
ds.DataBlocks.Add(ce);
continue;
}
else
{
GraphicBlock gb = new GraphicBlock();
if (ParserUtils.IsGraphicControlExtensionBlock(currentByte, nextByte))
{
gb.GraphicControlExtension = VcvjParser.ParseGraphicControlExtension(
br.ReadBytes(8)
);
currentIndex = br.BaseStream.Position;
currentByte = data[currentIndex];
nextByte = data[currentIndex + 1];
}
if (ParserUtils.IsImageDescriptor(currentByte))
{
TableBasedImage tbi = new TableBasedImage()
{
ImageDescriptor = VcvjParser.ParseImageDescriptor(
br.ReadBytes(10)
)
};
if (tbi.ImageDescriptor.LocalColorTableFlag)
{
tbi.LocalColorTable = VcvjParser.ParseLocalColorTable(
br.ReadBytes(tbi.ImageDescriptor.LocalColorTableLength)
);
}
currentIndex = br.BaseStream.Position;
currentByte = data[currentIndex];
nextByte = data[currentIndex + 1];
tbi.ImageData = VcvjParser.ParseImageData(
br.ReadBytes(VcvjParser.GetImageDataBlockLength(currentIndex, ref data))
);
gb.GraphicRenderingBlock = tbi;
ds.DataBlocks.Add(gb);
continue;
}
else if (ParserUtils.IsPlaintextExtension(currentByte, nextByte))
{
//GraphicBlock gb = new GraphicBlock()
//{
//};
}
else if (ParserUtils.IsApplicationExtensionBlock(currentByte, nextByte))
{
ApplicationExtension ae = VcvjParser.ParseApplicationExtension(
br.ReadBytes(VcvjParser.GetApplicationExtensionBlockLength(currentIndex, ref data))
);
ds.DataBlocks.Add(ae);
continue;
}
else if (ParserUtils.IsCommentExtensionBlock(currentByte, nextByte))
{
int totalBlockLength = data[currentIndex + 2] + 4;
CommentExtension ce = VcvjParser.ParseCommentExtension(br.ReadBytes(totalBlockLength));
ds.DataBlocks.Add(ce);
continue;
}
else
{
throw new UnidentifiedBlockException(
string.Format(
"The current byte is {0} and the next one is {1}. Not really sure what to make of this.",
currentByte.ToString(),
String.IsNullOrEmpty(nextByte.ToString()) ? "null" : nextByte.ToString()
)
);
}
}
}
}
}
return(ds);
}
/// <summary>
/// Compiles the parsed tokens/components back into a byte array.
/// </summary>
public void CompileByteArray()
{
List <byte> output = new List <byte>();
output.AddRange(DataStream.Header.Bytes);
output.AddRange(DataStream.LogicalScreen.LogicalScreenDescriptor.Bytes);
if (DataStream.LogicalScreen.GlobalColorTable != null)
{
output.AddRange(DataStream.LogicalScreen.GlobalColorTable.Bytes);
}
foreach (DataBlock db in DataStream.DataBlocks)
{
if (db is GraphicBlock)
{
GraphicBlock gb = (GraphicBlock)db;
if (gb.GraphicControlExtension != null)
{
output.AddRange(gb.GraphicControlExtension.Bytes);
}
if (gb.GraphicRenderingBlock is PlainTextExtension)
{
PlainTextExtension pte = (PlainTextExtension)gb.GraphicRenderingBlock;
output.AddRange(pte.Bytes);
}
else if (gb.GraphicRenderingBlock is TableBasedImage)
{
TableBasedImage tbi = (TableBasedImage)gb.GraphicRenderingBlock;
output.AddRange(tbi.ImageDescriptor.Bytes);
if (tbi.LocalColorTable != null)
{
output.AddRange(tbi.LocalColorTable.Bytes);
}
output.AddRange(tbi.ImageData.Bytes);
}
}
else if (db is SpecialPurposeBlock)
{
SpecialPurposeBlock spb = (SpecialPurposeBlock)db;
if (spb is ApplicationExtension)
{
ApplicationExtension ae = (ApplicationExtension)spb;
output.AddRange(ae.Bytes);
}
else if (spb is CommentExtension)
{
CommentExtension ce = (CommentExtension)spb;
output.AddRange(ce.Bytes);
}
}
}
output.AddRange(DataStream.Trailer.Bytes);
DataStream.Bytes = output.ToArray();
}
