public JpegReadStatusInt DecodeACFirst(JpegBinaryReader stream, float[] zz)
{
if (stream.eobRun > 0)
{
stream.eobRun--;
return(JpegReadStatusInt.GetSuccess());
}
for (int k = spectralStart; k <= spectralEnd; k++)
{
var status = ACTable.Decode(stream);
if (status.Status != Status.Success)
{
return(status);
}
int s = status.Result;
int r = s >> 4;
s &= 15;
if (s != 0)
{
k += r;
status = stream.ReadBits(s);
if (status.Status != Status.Success)
{
return(status);
}
r = status.Result;
s = HuffmanTable.Extend(r, s);
zz[k] = s << successiveLow;
}
else
{
if (r != 15)
{
stream.eobRun = 1 << r;
if (r != 0)
{
status = stream.ReadBits(r);
if (status.Status != Status.Success)
{
return(status);
}
stream.eobRun += status.Result;
}
stream.eobRun--;
break;
}
k += 15;
}
}
return(JpegReadStatusInt.GetSuccess());
}
/// <summary>
/// Generated from text on F-22, F.2.2.1 - Huffman decoding of DC
/// coefficients on ISO DIS 10918-1. Requirements and Guidelines.
/// </summary>
/// <param name="jpegStream">Stream that contains huffman bits</param>
/// <param name="diff">The DC coefficient</param>
/// <returns>The result of the read</returns>
public JpegReadStatusInt decode_dc_coefficient(JpegBinaryReader jpegStream, out float diff)
{
diff = 0;
var status = DCTable.Decode(jpegStream);
if (status.Status != Status.Success)
{
return(status);
}
int t = status.Result;
status = jpegStream.ReadBits(t);
if (status.Status != Status.Success)
{
return(status);
}
diff = HuffmanTable.Extend(status.Result, t);
diff = (previousDC + diff);
previousDC = diff;
return(status);
}
/// <summary>
/// Generated from text on F-23, F.13 - Huffman decoded of AC coefficients
/// on ISO DIS 10918-1. Requirements and Guidelines.
/// </summary>
internal JpegReadStatusInt decode_ac_coefficients(JpegBinaryReader jpegStream, float[] zz)
{
var status = new JpegReadStatusInt();
for (int k = 1; k < 64; k++)
{
status = ACTable.Decode(jpegStream);
if (status.Status != Status.Success)
{
return(status);
}
int s = status.Result;
int r = s >> 4;
s &= 15;
if (s != 0)
{
k += r;
status = jpegStream.ReadBits(s);
if (status.Status != Status.Success)
{
return(status);
}
s = HuffmanTable.Extend(status.Result, s);
zz[k] = s;
}
else
{
if (r != 15)
{
//throw new JPEGMarkerFoundException();
return(status);
}
k += 15;
}
}
return(status);
}
public JpegReadStatusInt DecodeDCFirst(JpegBinaryReader stream, float[] dest)
{
var status = DCTable.Decode(stream);
if (status.Status != Status.Success)
{
return(status); // We reached the end of the stream.
}
int s = status.Result;
status = stream.ReadBits(s);
if (status.Status != Status.Success)
{
return(status);
}
int r = status.Result;
s = HuffmanTable.Extend(r, s);
s = (int)previousDC + s;
previousDC = s;
dest[0] = s << successiveLow;
return(status);
}