CPLErr VRTWarpedRasterBand::IReadBlock( int nBlockXOff, int nBlockYOff,
void * pImage )
{
CPLErr eErr;
VRTWarpedDataset *poWDS = (VRTWarpedDataset *) poDS;
GDALRasterBlock *poBlock;
poBlock = GetLockedBlockRef( nBlockXOff, nBlockYOff, TRUE );
eErr = poWDS->ProcessBlock( nBlockXOff, nBlockYOff );
if( eErr == CE_None && pImage != poBlock->GetDataRef() )
{
int nDataBytes;
nDataBytes = (GDALGetDataTypeSize(poBlock->GetDataType()) / 8)
* poBlock->GetXSize() * poBlock->GetYSize();
memcpy( pImage, poBlock->GetDataRef(), nDataBytes );
}
poBlock->DropLock();
return eErr;
}
CPLErr VRTWarpedDataset::ProcessBlock( int iBlockX, int iBlockY )
{
if( poWarper == NULL )
return CE_Failure;
const GDALWarpOptions *psWO = poWarper->GetOptions();
/* -------------------------------------------------------------------- */
/* Allocate block of memory large enough to hold all the bands */
/* for this block. */
/* -------------------------------------------------------------------- */
int iBand;
GByte *pabyDstBuffer;
int nDstBufferSize;
int nWordSize = (GDALGetDataTypeSize(psWO->eWorkingDataType) / 8);
// FIXME? : risk of overflow in multiplication if nBlockXSize or nBlockYSize are very large
nDstBufferSize = nBlockXSize * nBlockYSize * psWO->nBandCount * nWordSize;
pabyDstBuffer = (GByte *) VSIMalloc(nDstBufferSize);
if( pabyDstBuffer == NULL )
{
CPLError( CE_Failure, CPLE_OutOfMemory,
"Out of memory allocating %d byte buffer in VRTWarpedDataset::ProcessBlock()",
nDstBufferSize );
return CE_Failure;
}
memset( pabyDstBuffer, 0, nDstBufferSize );
/* -------------------------------------------------------------------- */
/* Process INIT_DEST option to initialize the buffer prior to */
/* warping into it. */
/* NOTE:The following code is 99% similar in gdalwarpoperation.cpp and */
/* vrtwarped.cpp. Be careful to keep it in sync ! */
/* -------------------------------------------------------------------- */
const char *pszInitDest = CSLFetchNameValue( psWO->papszWarpOptions,
"INIT_DEST" );
if( pszInitDest != NULL && !EQUAL(pszInitDest, "") )
{
char **papszInitValues =
CSLTokenizeStringComplex( pszInitDest, ",", FALSE, FALSE );
int nInitCount = CSLCount(papszInitValues);
for( iBand = 0; iBand < psWO->nBandCount; iBand++ )
{
double adfInitRealImag[2];
GByte *pBandData;
int nBandSize = nBlockXSize * nBlockYSize * nWordSize;
const char *pszBandInit = papszInitValues[MIN(iBand,nInitCount-1)];
if( EQUAL(pszBandInit,"NO_DATA")
&& psWO->padfDstNoDataReal != NULL )
{
adfInitRealImag[0] = psWO->padfDstNoDataReal[iBand];
adfInitRealImag[1] = psWO->padfDstNoDataImag[iBand];
}
else
{
CPLStringToComplex( pszBandInit,
adfInitRealImag + 0, adfInitRealImag + 1);
}
pBandData = ((GByte *) pabyDstBuffer) + iBand * nBandSize;
if( psWO->eWorkingDataType == GDT_Byte )
memset( pBandData,
MAX(0,MIN(255,(int)adfInitRealImag[0])),
nBandSize);
else if( adfInitRealImag[0] == 0.0 && adfInitRealImag[1] == 0 )
{
memset( pBandData, 0, nBandSize );
}
else if( adfInitRealImag[1] == 0.0 )
{
GDALCopyWords( &adfInitRealImag, GDT_Float64, 0,
pBandData,psWO->eWorkingDataType,nWordSize,
nBlockXSize * nBlockYSize );
}
else
{
GDALCopyWords( &adfInitRealImag, GDT_CFloat64, 0,
pBandData,psWO->eWorkingDataType,nWordSize,
nBlockXSize * nBlockYSize );
}
}
CSLDestroy( papszInitValues );
}
/* -------------------------------------------------------------------- */
/* Warp into this buffer. */
/* -------------------------------------------------------------------- */
CPLErr eErr;
eErr =
poWarper->WarpRegionToBuffer(
iBlockX * nBlockXSize, iBlockY * nBlockYSize,
nBlockXSize, nBlockYSize,
pabyDstBuffer, psWO->eWorkingDataType );
if( eErr != CE_None )
{
VSIFree( pabyDstBuffer );
return eErr;
}
/* -------------------------------------------------------------------- */
/* Copy out into cache blocks for each band. */
/* -------------------------------------------------------------------- */
for( iBand = 0; iBand < psWO->nBandCount; iBand++ )
{
GDALRasterBand *poBand;
GDALRasterBlock *poBlock;
poBand = GetRasterBand(iBand+1);
poBlock = poBand->GetLockedBlockRef( iBlockX, iBlockY, TRUE );
CPLAssert( poBlock != NULL && poBlock->GetDataRef() != NULL );
GDALCopyWords( pabyDstBuffer + iBand*nBlockXSize*nBlockYSize*nWordSize,
psWO->eWorkingDataType, nWordSize,
poBlock->GetDataRef(),
poBlock->GetDataType(),
GDALGetDataTypeSize(poBlock->GetDataType())/8,
nBlockXSize * nBlockYSize );
poBlock->DropLock();
}
VSIFree( pabyDstBuffer );
return CE_None;
}