public static GifContainer Parse(Stream fs)
{
GifContainer ret = new GifContainer();
{
ret.Header.Read(fs);
ret.LogicalScreen.Read(fs);
int findex = 0;
//lookahead
while (true)
{
var b = fs.ReadByte();
fs.Position--;
if (b == 0x3b)
{
break;
}
if (b == 0x21)
{
b = fs.ReadByte();
var b2 = fs.ReadByte();
fs.Position -= 2;;
if (b2 == 0xf9)
{
ret.Data.Add(GraphicControlExtension.Read(fs));
}
else
if (b2 == 0xff)
{
ret.Data.Add(GifApplicationExtension.Read(fs));
}
else
if (b2 == 0xfe)
{
ret.Data.Add(GifCommentBlock.Read(fs));
}
else
{
throw new GifParsingException("unknown header: " + b.ToString("X2") + b2.ToString("X2") + ", shift: " + fs.Position);
}
}
else
if (b == 0x2c)
{
var r = GifRenderBlock.Read(fs);
ret.Data.Add(r);
r.FrameIndex = findex++;
}
else
{
throw new GifParsingException("unknown header: " + b.ToString("X2") + ", shift: " + fs.Position);
}
}
}
ret.UpdateInfo();
return(ret);
}
public static GifCommentBlock Read(Stream s)
{
GifCommentBlock ret = new GifCommentBlock();
ret.Shift = s.Position;
s.ReadByte();
s.ReadByte();
var b = s.ReadByte();
while (b != 0)
{
var bb = new byte[b];
s.Read(bb, 0, b);
b = s.ReadByte();
}
return(ret);
}
