private static void Decode(Stream stream, ShpOffset[] offsets, int width, int height,
byte[][] frames, byte[] src, ref int recdepth)
{
if (recdepth > frames.Length)
{
throw new NotImplementedException("Format 40/20 frames contain infinite loop!");
}
for (uint i = 0; i < frames.Length; i++)
{
byte[] frame = new byte[width * height];
byte[] refframe = null;
ShpOffset curoff = offsets[i + 0];
ShpOffset nxtoff = offsets[i + 1];
int srclen = (int)(nxtoff.Offset - curoff.Offset);
stream.Read(src, 0, srclen);
switch (curoff.OffsetFormat)
{
// Format 20
case 0x20:
refframe = frames[i - 1];
goto do_format40;
// Format 40
case 0x40:
int j = Array.FindIndex(offsets, o => o.Offset == curoff.Ref);
if (j < 0)
{
throw new IndexOutOfRangeException("Invalid frame reference!");
}
refframe = frames[j];
do_format40:
if (refframe == null)
{
recdepth++;
Decode(stream, offsets, width, height, frames, src, ref recdepth);
recdepth--;
}
Format40.Decode(src, srclen, frame, refframe);
break;
// Format 80
case 0x80:
Format80.Decode(src, 0, frame, 0, srclen);
break;
// Invalid format
default:
throw new NotImplementedException("Invalid format!");
}
frames[i] = frame;
}
}
void Decompress(ImageHeader h)
{
// No extra work is required for empty frames
if (h.Size.Width == 0 || h.Size.Height == 0)
{
return;
}
if (recurseDepth > imageCount)
{
throw new InvalidDataException("Format20/40 headers contain infinite loop");
}
switch (h.Format)
{
case Format.Format20:
case Format.Format40:
{
if (h.RefImage.Data == null)
{
++recurseDepth;
Decompress(h.RefImage);
--recurseDepth;
}
h.Data = CopyImageData(h.RefImage.Data);
Format40.DecodeInto(shpBytes, h.Data, (int)(h.FileOffset - shpBytesFileOffset));
break;
}
case Format.Format80:
{
var imageBytes = new byte[Size.Width * Size.Height];
Format80.DecodeInto(shpBytes, imageBytes, (int)(h.FileOffset - shpBytesFileOffset));
h.Data = imageBytes;
break;
}
default:
throw new InvalidDataException();
}
}
