internal new static async Task <GifExtension> ReadAsync(Stream stream, IEnumerable <GifExtension> controlExtensions)
{
// Note: at this point, the Extension Introducer (0x21) has already been read
int label = stream.ReadByte();
if (label < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
switch (label)
{
case GifGraphicControlExtension.ExtensionLabel:
return(await GifGraphicControlExtension.ReadAsync(stream).ConfigureAwait(false));
case GifCommentExtension.ExtensionLabel:
return(await GifCommentExtension.ReadAsync(stream).ConfigureAwait(false));
case GifPlainTextExtension.ExtensionLabel:
return(await GifPlainTextExtension.ReadAsync(stream, controlExtensions).ConfigureAwait(false));
case GifApplicationExtension.ExtensionLabel:
return(await GifApplicationExtension.ReadAsync(stream).ConfigureAwait(false));
default:
throw GifHelpers.UnknownExtensionTypeException(label);
}
}
internal static async Task <GifExtension> ReadAsync(Stream stream, IEnumerable <GifExtension> controlExtensions)
{
int label = stream.ReadByte();
if (label < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
switch (label)
{
case 254:
return((GifExtension)await GifCommentExtension.ReadAsync(stream).ConfigureAwait(false));
case (int)byte.MaxValue:
return((GifExtension)await GifApplicationExtension.ReadAsync(stream).ConfigureAwait(false));
case 1:
return((GifExtension)await GifPlainTextExtension.ReadAsync(stream, controlExtensions).ConfigureAwait(false));
case 249:
return((GifExtension)await GifGraphicControlExtension.ReadAsync(stream).ConfigureAwait(false));
default:
throw GifHelpers.UnknownExtensionTypeException(label);
}
}
internal static async Task<GifBlock> ReadAsync(Stream stream, IEnumerable<GifExtension> controlExtensions)
{
int blockId = await stream.ReadByteAsync().ConfigureAwait(false);
if (blockId < 0)
throw GifHelpers.UnexpectedEndOfStreamException();
switch (blockId)
{
case GifExtension.ExtensionIntroducer:
return await GifExtension.ReadAsync(stream, controlExtensions).ConfigureAwait(false);
case GifFrame.ImageSeparator:
return await GifFrame.ReadAsync(stream, controlExtensions).ConfigureAwait(false);
case GifTrailer.TrailerByte:
return await GifTrailer.ReadAsync().ConfigureAwait(false);
default:
throw GifHelpers.UnknownBlockTypeException(blockId);
}
}
internal static async Task <GifBlock> ReadAsync(Stream stream, IEnumerable <GifExtension> controlExtensions)
{
int blockId = await stream.ReadByteAsync(new CancellationToken()).ConfigureAwait(false);
if (blockId < 0)
{
throw GifHelpers.UnexpectedEndOfStreamException();
}
switch (blockId)
{
case 33:
return((GifBlock)await GifExtension.ReadAsync(stream, controlExtensions).ConfigureAwait(false));
case 44:
return((GifBlock)await GifFrame.ReadAsync(stream, controlExtensions).ConfigureAwait(false));
case 59:
return((GifBlock)await GifTrailer.ReadAsync().ConfigureAwait(false));
default:
throw GifHelpers.UnknownBlockTypeException(blockId);
}
}
