int SDTSRasterReader::GetBlock( int nXOffset, int nYOffset, void * pData )
{
DDFRecord *poRecord = NULL;
int nBytesPerValue;
int iTry;
CPLAssert( nXOffset == 0 );
/* -------------------------------------------------------------------- */
/* Analyse the datatype. */
/* -------------------------------------------------------------------- */
CPLAssert( EQUAL(szFMT,"BI16") || EQUAL(szFMT,"BFP32") );
if( EQUAL(szFMT,"BI16") )
nBytesPerValue = 2;
else
nBytesPerValue = 4;
for(iTry=0;iTry<2;iTry++)
{
/* -------------------------------------------------------------------- */
/* Read through till we find the desired record. */
/* -------------------------------------------------------------------- */
CPLErrorReset();
while( (poRecord = oDDFModule.ReadRecord()) != NULL )
{
if( poRecord->GetIntSubfield( "CELL", 0, "ROWI", 0 )
== nYOffset + nYStart )
{
break;
}
}
if( CPLGetLastErrorType() == CE_Failure )
return FALSE;
/* -------------------------------------------------------------------- */
/* If we didn't get what we needed just start over. */
/* -------------------------------------------------------------------- */
if( poRecord == NULL )
{
if (iTry == 0)
oDDFModule.Rewind();
else
{
CPLError( CE_Failure, CPLE_AppDefined,
"Cannot read scanline %d. Raster access failed.\n",
nYOffset );
return FALSE;
}
}
else
{
break;
}
}
/* -------------------------------------------------------------------- */
/* Validate the records size. Does it represent exactly one */
/* scanline? */
/* -------------------------------------------------------------------- */
DDFField *poCVLS;
poCVLS = poRecord->FindField( "CVLS" );
if( poCVLS == NULL )
return FALSE;
if( poCVLS->GetRepeatCount() != nXSize )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Cell record is %d long, but we expected %d, the number\n"
"of pixels in a scanline. Raster access failed.\n",
poCVLS->GetRepeatCount(), nXSize );
return FALSE;
}
/* -------------------------------------------------------------------- */
/* Does the CVLS field consist of exactly 1 B(16) field? */
/* -------------------------------------------------------------------- */
if( poCVLS->GetDataSize() < nBytesPerValue * nXSize
|| poCVLS->GetDataSize() > nBytesPerValue * nXSize + 1 )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Cell record is not of expected format. Raster access "
"failed.\n" );
return FALSE;
}
/* -------------------------------------------------------------------- */
/* Copy the data to the application buffer, and byte swap if */
/* required. */
/* -------------------------------------------------------------------- */
memcpy( pData, poCVLS->GetData(), nXSize * nBytesPerValue );
#ifdef CPL_LSB
if( nBytesPerValue == 2 )
{
for( int i = 0; i < nXSize; i++ )
{
((GInt16 *) pData)[i] = CPL_MSBWORD16(((GInt16 *) pData)[i]);
}
}
else
{
for( int i = 0; i < nXSize; i++ )
{
CPL_MSBPTR32( ((GByte *)pData) + i*4 );
}
}
#endif
return TRUE;
}
GDALDataset *SGIDataset::Create( const char * pszFilename,
int nXSize, int nYSize, int nBands,
GDALDataType eType, CPL_UNUSED char **papszOptions )
{
if( eType != GDT_Byte )
{
CPLError( CE_Failure, CPLE_AppDefined,
"Attempt to create SGI dataset with an illegal\n"
"data type (%s), only Byte supported by the format.\n",
GDALGetDataTypeName(eType) );
return NULL;
}
/* -------------------------------------------------------------------- */
/* Open the file for output. */
/* -------------------------------------------------------------------- */
VSILFILE *fp = VSIFOpenL( pszFilename, "w" );
if( fp == NULL )
{
CPLError( CE_Failure, CPLE_OpenFailed,
"Failed to create file '%s': %s",
pszFilename, VSIStrerror( errno ) );
return NULL;
}
/* -------------------------------------------------------------------- */
/* Prepare and write 512 byte header. */
/* -------------------------------------------------------------------- */
GByte abyHeader[512];
GInt16 nShortValue;
GInt32 nIntValue;
memset( abyHeader, 0, 512 );
abyHeader[0] = 1;
abyHeader[1] = 218;
abyHeader[2] = 1; // RLE
abyHeader[3] = 1; // 8bit
if( nBands == 1 )
nShortValue = CPL_MSBWORD16(2);
else
nShortValue = CPL_MSBWORD16(3);
memcpy( abyHeader + 4, &nShortValue, 2 );
nShortValue = CPL_MSBWORD16(nXSize);
memcpy( abyHeader + 6, &nShortValue, 2 );
nShortValue = CPL_MSBWORD16(nYSize);
memcpy( abyHeader + 8, &nShortValue, 2 );
nShortValue = CPL_MSBWORD16(nBands);
memcpy( abyHeader + 10, &nShortValue, 2 );
nIntValue = CPL_MSBWORD32(0);
memcpy( abyHeader + 12, &nIntValue, 4 );
nIntValue = CPL_MSBWORD32(255);
memcpy( abyHeader + 16, &nIntValue, 4 );
VSIFWriteL( abyHeader, 1, 512, fp );
/* -------------------------------------------------------------------- */
/* Create our RLE compressed zero-ed dummy line. */
/* -------------------------------------------------------------------- */
GByte *pabyRLELine;
GInt32 nRLEBytes = 0;
int nPixelsRemaining = nXSize;
pabyRLELine = (GByte *) CPLMalloc((nXSize/127) * 2 + 4);
while( nPixelsRemaining > 0 )
{
pabyRLELine[nRLEBytes] = (GByte) MIN(127,nPixelsRemaining);
pabyRLELine[nRLEBytes+1] = 0;
nPixelsRemaining -= pabyRLELine[nRLEBytes];
nRLEBytes += 2;
}
/* -------------------------------------------------------------------- */
/* Prepare and write RLE offset/size tables with everything */
/* zeroed indicating dummy lines. */
/* -------------------------------------------------------------------- */
int i;
int nTableLen = nYSize * nBands;
GInt32 nDummyRLEOffset = 512 + 4 * nTableLen * 2;
CPL_MSBPTR32( &nRLEBytes );
CPL_MSBPTR32( &nDummyRLEOffset );
for( i = 0; i < nTableLen; i++ )
VSIFWriteL( &nDummyRLEOffset, 1, 4, fp );
for( i = 0; i < nTableLen; i++ )
VSIFWriteL( &nRLEBytes, 1, 4, fp );
/* -------------------------------------------------------------------- */
/* write the dummy RLE blank line. */
/* -------------------------------------------------------------------- */
CPL_MSBPTR32( &nRLEBytes );
if( (GInt32) VSIFWriteL( pabyRLELine, 1, nRLEBytes, fp ) != nRLEBytes )
{
CPLError( CE_Failure, CPLE_FileIO,
"Failure writing SGI file '%s'.\n%s",
pszFilename,
VSIStrerror( errno ) );
return NULL;
}
VSIFCloseL( fp );
CPLFree( pabyRLELine );
return (GDALDataset*) GDALOpen( pszFilename, GA_Update );
}