internal static GifApplicationExtension ReadApplication(Stream stream)
{
var ext = new GifApplicationExtension();
ext.Read(stream);
return(ext);
}
internal static GifExtension ReadExtension(Stream stream, IEnumerable <GifExtension> controlExtensions, bool metadataOnly)
{
// Note: at this point, the Extension Introducer (0x21) has already been read
var label = stream.ReadByte();
if (label < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
return(label switch
{
GifGraphicControlExtension.ExtensionLabel => (GifExtension)GifGraphicControlExtension.ReadGraphicsControl(stream),
GifCommentExtension.ExtensionLabel => GifCommentExtension.ReadComment(stream),
GifPlainTextExtension.ExtensionLabel => GifPlainTextExtension.ReadPlainText(stream, controlExtensions, metadataOnly),
GifApplicationExtension.ExtensionLabel => GifApplicationExtension.ReadApplication(stream),
_ => throw GifHelpers.UnknownExtensionTypeException(label)
});
public static ushort GetRepeatCount(GifApplicationExtension ext)
{
return(ext.Data?.Length >= 3 ? BitConverter.ToUInt16(ext.Data, 1) : (ushort)1);
}
public static bool IsNetscapeExtension(GifApplicationExtension ext)
{
return(ext.ApplicationIdentifier == "NETSCAPE" &&
Encoding.ASCII.GetString(ext.AuthenticationCode ?? Array.Empty <byte>()) == "2.0");
}
