public static long FindChunk(Stream stream, string chunk)
{
long found_offset = -1;
var file = new ArcView.Reader(stream);
try
{
char[] buf = new char[4];
file.BaseStream.Position = 8;
while (-1 != file.PeekChar())
{
long chunk_offset = file.BaseStream.Position;
uint chunk_size = Binary.BigEndian(file.ReadUInt32());
if (4 != file.Read(buf, 0, 4))
{
break;
}
if (chunk.SequenceEqual(buf))
{
found_offset = chunk_offset;
break;
}
file.BaseStream.Position += chunk_size + 4;
}
}
catch
{
// ignore errors
}
finally
{
file.Dispose();
}
return(found_offset);
}
public override ImageMetaData ReadMetaData(Stream stream)
{
if (0xff != stream.ReadByte() || 0xd8 != stream.ReadByte())
{
return(null);
}
using (var file = new ArcView.Reader(stream))
{
while (-1 != file.PeekChar())
{
ushort marker = Binary.BigEndian(file.ReadUInt16());
if ((marker & 0xff00) != 0xff00)
{
break;
}
int length = Binary.BigEndian(file.ReadUInt16());
if ((marker & 0x00f0) == 0xc0 && marker != 0xffc4)
{
if (length < 8)
{
break;
}
int bits = file.ReadByte();
uint height = Binary.BigEndian(file.ReadUInt16());
uint width = Binary.BigEndian(file.ReadUInt16());
int components = file.ReadByte();
return(new ImageMetaData {
Width = width,
Height = height,
BPP = bits * components,
});
}
file.BaseStream.Seek(length - 2, SeekOrigin.Current);
}
return(null);
}
}
public override ImageMetaData ReadMetaData(Stream stream)
{
if (0xff != stream.ReadByte() || 0xd8 != stream.ReadByte())
return null;
using (var file = new ArcView.Reader (stream))
{
while (-1 != file.PeekChar())
{
ushort marker = Binary.BigEndian (file.ReadUInt16());
if ((marker & 0xff00) != 0xff00)
break;
int length = Binary.BigEndian (file.ReadUInt16());
if ((marker & 0x00f0) == 0xc0 && marker != 0xffc4)
{
if (length < 8)
break;
int bits = file.ReadByte();
uint height = Binary.BigEndian (file.ReadUInt16());
uint width = Binary.BigEndian (file.ReadUInt16());
int components = file.ReadByte();
return new ImageMetaData {
Width = width,
Height = height,
BPP = bits * components,
};
}
file.BaseStream.Seek (length-2, SeekOrigin.Current);
}
return null;
}
}