void PLPGMDecoder::readPgmHeader
( PGMHEADER * pPgmHead, // Pointer to PGM header structure
PLDataSource * pDataSrc
)
{
int current = 0;
// bool HeaderComplete = false;
// Read type
m_LastByte = ReadByte (pDataSrc);
if (m_LastByte!=0x50) // ASCII P
raiseError (PL_ERRFORMAT_UNKNOWN,
"PGM decoder: Is not the correct identifier P5 or P2.");
m_LastByte = ReadByte (pDataSrc);
if (m_LastByte==0x32) // ASCII 2
pPgmHead->ImageType = PGM_P2;
else if (m_LastByte==0x35) // ASCII 5
pPgmHead->ImageType = PGM_P5;
else
raiseError (PL_ERRFORMAT_UNKNOWN,
"PGM decoder: Is not the correct identifier P5 or P2.");
m_LastByte = ReadByte (pDataSrc);
// Search for the with, height and Max gray value
while (current<3)
{
if (m_LastByte==0x23) // # Starts a comment
skipComment(pDataSrc);
else if ((m_LastByte>=0x30)&&(m_LastByte<=0x39)) // A digit
switch (current)
{
case 0: // looking for the width
{
pPgmHead->ImageWidth = readASCIIDecimal(pDataSrc);
current++;
}
break;
case 1: // looking for the height
{
pPgmHead->ImageHeight = readASCIIDecimal(pDataSrc);
current++;
}
break;
case 2: // looking for the max gray value
{
pPgmHead->MaxGrayValue = readASCIIDecimal(pDataSrc);
if ((pPgmHead->MaxGrayValue>255)||(pPgmHead->MaxGrayValue<=0))
pPgmHead->MaxGrayValue=255;
current++;
}
break;
default:
continue;
}
else
skipPgmASCIISeparators(pDataSrc);
}
}
void PLPPMDecoder::readPpmHeader(PPMHEADER *pPpmHead, PLDataSource *pDataSrc) {
int current = 0;
bool HeaderComplete = false;
// Read type
m_LastByte = ReadByte(pDataSrc);
if(m_LastByte != 'P')
raiseError(PL_ERRFORMAT_UNKNOWN,"PPM decoder: Is not the correct identifier P3 or P6.");
m_LastByte = ReadByte(pDataSrc);
switch(m_LastByte) {
case '3':
pPpmHead->ImageType = PPM_P3;
break;
case '6':
pPpmHead->ImageType = PPM_P6;
break;
default:
raiseError(PL_ERRFORMAT_UNKNOWN,"PPM decoder: Is not the correct identifier P3 or P6.");
}
m_LastByte = ReadByte(pDataSrc);
// Search for the width, height and Max sample value
while(current<3) {
if(m_LastByte == '#') // # Starts a comment
skipComment(pDataSrc);
else if(m_LastByte >='0' && m_LastByte <= '9') // A digit
switch(current) {
case 0: // looking for the width
{
pPpmHead->ImageWidth = readASCIIDecimal(pDataSrc);
current++;
}
break;
case 1: // looking for the height
{
pPpmHead->ImageHeight = readASCIIDecimal(pDataSrc);
current++;
}
break;
case 2: // looking for the sample value (max = 255)
{
pPpmHead->MaxSampleValue = readASCIIDecimal(pDataSrc);
if(pPpmHead->MaxSampleValue > 255 || pPpmHead->MaxSampleValue <= 0)
pPpmHead->MaxSampleValue = 255;
current++;
}
break;
default:
continue;
}
else
skipPpmASCIISeparators(pDataSrc);
}
}
PLPixel32 PLPPMDecoder::readASCIIPixel32( int MaxSampleValue, PLDataSource *pDataSrc) {
skipPpmASCIISeparators(pDataSrc);
PLBYTE r = readASCIIDecimal(pDataSrc);
skipPpmASCIISeparators(pDataSrc);
PLBYTE g = readASCIIDecimal(pDataSrc);
skipPpmASCIISeparators(pDataSrc);
PLBYTE b = readASCIIDecimal(pDataSrc);
if(MaxSampleValue != 255) {
r = (r * 255) / MaxSampleValue;
g = (g * 255) / MaxSampleValue;
b = (b * 255) / MaxSampleValue;
}
PLPixel32 Dest;
Dest.Set(r, g, b, 0);
return Dest;
}
PLBYTE PLPGMDecoder::readASCIIPixel8
( int MaxGrayValue,
PLDataSource * pDataSrc
)
{
PLBYTE Dest;
int Value;
skipPgmASCIISeparators(pDataSrc);
m_UseLastByte = true;
Value = readASCIIDecimal(pDataSrc);
Dest = (PLBYTE)((Value*255)/MaxGrayValue);
return Dest;
}
