bool ieJpegDecoder::ParseScanHeader()
// Read the start of a scan (everything through the SOS marker).
// Return true if find SOS, false if find EOI.
{
// Process markers until SOS or EOI
int c = ParseTables();
if (c == M_ERROR) return false;
switch (c) {
case M_SOS:
return GetSOS();
case M_EOI:
iScanNumber = 0;
return true;
default:
return false;
}
}
// parse and load a DXF file
// currently pretty limited, but knows enough to handle 3DFACEs and LINEs
bool DXFRenderer::Load(wxInputStream& stream)
{
Clear();
wxTextInputStream text(stream);
wxString line1, line2;
while (stream.CanRead())
{
GetLines(text, line1, line2);
if (line1 == "999") // comment
continue;
else if (line1 == "0" && line2 == "SECTION")
{
GetLines(text, line1, line2);
if (line1 == "2")
{
if (line2 == "HEADER")
{
if (!ParseHeader(stream))
return false;
}
else if (line2 == "TABLES")
{
if (!ParseTables(stream))
return false;
}
else if (line2 == "ENTITIES")
{
if (!ParseEntities(stream))
return false;
}
}
}
}
NormalizeEntities();
m_loaded = true;
return true;
}
ieResult ieJpegDecoder::ParseHeaders()
// Initialize and read the file header (everything through the SOF marker).
{
// Demand an SOI marker at the start of the file --- otherwise it's
// probably not a JPEG file at all. If the user interface wants to support
// nonstandard headers in front of the SOI, it must skip over them itself
// before calling jpeg_decompress().
if (GetWord() != 0xFFD8) return IE_E_CORRUPTEDFILE;
// OK, process SOI
GetSOI();
// Process markers until SOF
int c = ParseTables();
bArithCoding = false;
bLosslessDPCM = false;
bProgressive = false;
switch (c) {
case M_ERROR:
return IE_E_CORRUPTEDFILE;
case M_SOF0: // Baseline sequential Huffman
case M_SOF1: // Extended sequential Huffman
break;
case M_SOF2: // Progressive Huffman
bProgressive = true;
break;
case M_SOF5: // Differential sequential Huffman
bLosslessDPCM = true;
break;
case M_SOF6: // Differential progressive Huffman
bProgressive = true;
bLosslessDPCM = true;
break;
case M_SOF9: // Extended sequential arithmetic
bArithCoding = true;
break;
case M_SOF10: // Progressive arithmetic
bArithCoding = true;
bProgressive = true;
break;
case M_SOF13: // Differential sequential arithmetic
bArithCoding = true;
bLosslessDPCM = true;
break;
case M_SOF14: // Differential progressive arithmetic
bProgressive = true;
bArithCoding = true;
bLosslessDPCM = true;
break;
//case M_SOF3: // Spatial Huffman
//case M_SOF7: // Differential spatial Huffman
//case M_JPG: // Reserved for JPEG extensions
//case M_SOF11: // Spatial arithmetic
//case M_SOF15: // Differential lossless, arithmetic
//case M_EOI: // No image data?
default:
return IE_E_UNSUPSUBFORMAT;
}
if (!GetSOF(c)) return IE_E_CORRUPTEDFILE;
iScanNumber = 0;
// Figure out what colorspace we have:
// (too bad the JPEG committee didn't provide a real way to specify this)
if (eColorSpace == ieColorSpace::Count) switch (nComps) {
case 1:
eColorSpace = ieColorSpace::L;
break;
case 3:
if ((aComps[0].iId == 1) && (aComps[1].iId == 2) && (aComps[2].iId == 3))
eColorSpace = ieColorSpace::YCbCr;
else if ((aComps[0].iId == 82) && (aComps[1].iId == 71) && (aComps[2].iId == 66))
eColorSpace = ieColorSpace::RGB;
else
eColorSpace = ieColorSpace::YCbCr;
break;
case 4:
if ((aComps[0].iId == 67) && (aComps[1].iId == 77) && (aComps[2].iId == 89) && (aComps[3].iId == 75))
eColorSpace = ieColorSpace::CMYL; // Adobe CMYK
else
eColorSpace = ieColorSpace::CMYK;
break;
}
// Compute maximum sampling factors; check factor validity
iMaxXSamp = 1;
iMaxYSamp = 1;
for (int ci = 0; ci < nComps; ci++) {
jdCompInfo &co = aComps[ci];
if ( (co.iXSamp <= 0) || (co.iXSamp > IE_JPEG_MAX_SAMP) ||
(co.iYSamp <= 0) || (co.iYSamp > IE_JPEG_MAX_SAMP) )
return IE_E_CORRUPTEDFILE;
if (co.iXSamp > iMaxXSamp) iMaxXSamp = co.iXSamp;
if (co.iYSamp > iMaxYSamp) iMaxYSamp = co.iYSamp;
}
// Compute logical dimensions of components
nXRes = ie_RoundUp(nRealXRes, iMaxXSamp * DCTSIZE);
nYRes = ie_RoundUp(nRealYRes, iMaxYSamp * DCTSIZE);
return IE_S_OK;
}
