CPLErr USGSDEMRasterBand::IReadBlock( CPL_UNUSED int nBlockXOff,
CPL_UNUSED int nBlockYOff,
void * pImage )
{
/* int bad = FALSE; */
USGSDEMDataset *poGDS = reinterpret_cast<USGSDEMDataset *>( poDS );
/* -------------------------------------------------------------------- */
/* Initialize image buffer to nodata value. */
/* -------------------------------------------------------------------- */
for( int k = GetXSize() * GetYSize() - 1; k >= 0; k-- )
{
if( GetRasterDataType() == GDT_Int16 )
reinterpret_cast<GInt16 *>( pImage )[k] = USGSDEM_NODATA;
else
reinterpret_cast<float *>( pImage )[k] = USGSDEM_NODATA;
}
/* -------------------------------------------------------------------- */
/* Seek to data. */
/* -------------------------------------------------------------------- */
CPL_IGNORE_RET_VAL(VSIFSeekL(poGDS->fp, poGDS->nDataStartOffset, 0));
double dfYMin = poGDS->adfGeoTransform[3]
+ (GetYSize()-0.5) * poGDS->adfGeoTransform[5];
/* -------------------------------------------------------------------- */
/* Read all the profiles into the image buffer. */
/* -------------------------------------------------------------------- */
Buffer sBuffer;
sBuffer.max_size = 32768;
sBuffer.buffer
= reinterpret_cast<char *>( CPLMalloc( sBuffer.max_size + 1 ) );
sBuffer.fp = poGDS->fp;
sBuffer.buffer_size = 0;
sBuffer.cur_index = 0;
for( int i = 0; i < GetXSize(); i++)
{
int bSuccess;
const int nRowNumber = USGSDEMReadIntFromBuffer(&sBuffer, &bSuccess);
if( nRowNumber != 1 )
CPLDebug("USGSDEM", "i = %d, nRowNumber = %d", i, nRowNumber);
if( bSuccess )
{
const int nColNumber = USGSDEMReadIntFromBuffer(&sBuffer, &bSuccess);
if( nColNumber != i + 1 )
{
CPLDebug("USGSDEM", "i = %d, nColNumber = %d", i, nColNumber);
}
}
const int nCPoints = (bSuccess) ? USGSDEMReadIntFromBuffer(&sBuffer, &bSuccess) : 0;
#ifdef DEBUG_VERBOSE
CPLDebug("USGSDEM", "i = %d, nCPoints = %d", i, nCPoints);
#endif
if( bSuccess )
{
const int nNumberOfCols = USGSDEMReadIntFromBuffer(&sBuffer, &bSuccess);
if( nNumberOfCols != 1 )
{
CPLDebug("USGSDEM", "i = %d, nNumberOfCols = %d", i, nNumberOfCols);
}
}
// x-start
if( bSuccess )
/* dxStart = */ USGSDEMReadDoubleFromBuffer(&sBuffer, 24, &bSuccess);
double dyStart = (bSuccess) ? USGSDEMReadDoubleFromBuffer(&sBuffer, 24, &bSuccess) : 0;
const double dfElevOffset = (bSuccess) ? USGSDEMReadDoubleFromBuffer(&sBuffer, 24, &bSuccess) : 0;
// min z value
if( bSuccess )
/* djunk = */ USGSDEMReadDoubleFromBuffer(&sBuffer, 24, &bSuccess);
// max z value
if( bSuccess )
/* djunk = */ USGSDEMReadDoubleFromBuffer(&sBuffer, 24, &bSuccess);
if( !bSuccess )
{
CPLFree(sBuffer.buffer);
return CE_Failure;
}
if( STARTS_WITH_CI(poGDS->pszProjection, "GEOGCS") )
dyStart = dyStart / 3600.0;
double dygap = (dfYMin - dyStart)/poGDS->adfGeoTransform[5]+ 0.5;
if( dygap <= INT_MIN || dygap >= INT_MAX || !CPLIsFinite(dygap) )
{
CPLFree(sBuffer.buffer);
return CE_Failure;
}
int lygap = static_cast<int>(dygap);
if( nCPoints <= 0 )
continue;
if( lygap > INT_MAX - nCPoints )
lygap = INT_MAX - nCPoints;
for (int j=lygap; j < (nCPoints + lygap); j++)
{
const int iY = GetYSize() - j - 1;
const int nElev = USGSDEMReadIntFromBuffer(&sBuffer, &bSuccess);
#ifdef DEBUG_VERBOSE
CPLDebug("USGSDEM", " j - lygap = %d, nElev = %d", j - lygap, nElev);
#endif
if( !bSuccess )
{
CPLFree(sBuffer.buffer);
return CE_Failure;
}
if (iY < 0 || iY >= GetYSize() ) {
/* bad = TRUE; */
} else if( nElev == USGSDEM_NODATA )
/* leave in output buffer as nodata */;
else
{
const float fComputedElev =
static_cast<float>(nElev * poGDS->fVRes + dfElevOffset);
if( GetRasterDataType() == GDT_Int16 )
{
GUInt16 nVal = ( fComputedElev < -32768 ) ? -32768 :
( fComputedElev > 32767 ) ? 32767 :
static_cast<GInt16>( fComputedElev );
reinterpret_cast<GInt16 *>( pImage )[i + iY*GetXSize()]
= nVal;
}
else
{
reinterpret_cast<float *>( pImage )[i + iY*GetXSize()]
= fComputedElev;
}
}
}
if( poGDS->nDataStartOffset == 1024 )
{
// Seek to the next 1024 byte boundary.
// Some files have 'junk' profile values after the valid/declared ones
vsi_l_offset nCurPos = USGSDEMGetCurrentFilePos(&sBuffer);
vsi_l_offset nNewPos = (nCurPos + 1023) / 1024 * 1024;
if( nNewPos > nCurPos )
{
USGSDEMSetCurrentFilePos(&sBuffer, nNewPos);
}
}
}
CPLFree(sBuffer.buffer);
return CE_None;
}
CPLErr USGSDEMRasterBand::IReadBlock( CPL_UNUSED int nBlockXOff,
CPL_UNUSED int nBlockYOff,
void * pImage )
{
double dfYMin;
/* int bad = FALSE; */
USGSDEMDataset *poGDS = (USGSDEMDataset *) poDS;
/* -------------------------------------------------------------------- */
/* Initialize image buffer to nodata value. */
/* -------------------------------------------------------------------- */
for( int k = GetXSize() * GetYSize() - 1; k >= 0; k-- )
{
if( GetRasterDataType() == GDT_Int16 )
((GInt16 *) pImage)[k] = USGSDEM_NODATA;
else
((float *) pImage)[k] = USGSDEM_NODATA;
}
/* -------------------------------------------------------------------- */
/* Seek to data. */
/* -------------------------------------------------------------------- */
VSIFSeekL(poGDS->fp, poGDS->nDataStartOffset, 0);
dfYMin = poGDS->adfGeoTransform[3]
+ (GetYSize()-0.5) * poGDS->adfGeoTransform[5];
/* -------------------------------------------------------------------- */
/* Read all the profiles into the image buffer. */
/* -------------------------------------------------------------------- */
Buffer sBuffer;
sBuffer.max_size = 32768;
sBuffer.buffer = (char*) CPLMalloc(sBuffer.max_size + 1);
sBuffer.fp = poGDS->fp;
sBuffer.buffer_size = 0;
sBuffer.cur_index = 0;
for( int i = 0; i < GetXSize(); i++)
{
int /* njunk, */ nCPoints, lygap;
double /* djunk, dxStart, */ dyStart, dfElevOffset;
/* njunk = */ USGSDEMReadIntFromBuffer(&sBuffer);
/* njunk = */ USGSDEMReadIntFromBuffer(&sBuffer);
nCPoints = USGSDEMReadIntFromBuffer(&sBuffer);
/* njunk = */ USGSDEMReadIntFromBuffer(&sBuffer);
/* dxStart = */ USGSDEMReadDoubleFromBuffer(&sBuffer, 24);
dyStart = USGSDEMReadDoubleFromBuffer(&sBuffer, 24);
dfElevOffset = USGSDEMReadDoubleFromBuffer(&sBuffer, 24);
/* djunk = */ USGSDEMReadDoubleFromBuffer(&sBuffer, 24);
/* djunk = */ USGSDEMReadDoubleFromBuffer(&sBuffer, 24);
if( EQUALN(poGDS->pszProjection,"GEOGCS",6) )
dyStart = dyStart / 3600.0;
lygap = (int)((dfYMin - dyStart)/poGDS->adfGeoTransform[5]+ 0.5);
for (int j=lygap; j < (nCPoints+(int)lygap); j++)
{
int iY = GetYSize() - j - 1;
int nElev;
int bSuccess;
nElev = USGSDEMReadIntFromBuffer(&sBuffer, &bSuccess);
if( !bSuccess )
{
CPLFree(sBuffer.buffer);
return CE_Failure;
}
if (iY < 0 || iY >= GetYSize() ) {
/* bad = TRUE; */
} else if( nElev == USGSDEM_NODATA )
/* leave in output buffer as nodata */;
else
{
float fComputedElev =
(float)(nElev * poGDS->fVRes + dfElevOffset);
if( GetRasterDataType() == GDT_Int16 )
{
((GInt16 *) pImage)[i + iY*GetXSize()] =
(GInt16) fComputedElev;
}
else
{
((float *) pImage)[i + iY*GetXSize()] = fComputedElev;
}
}
}
}
CPLFree(sBuffer.buffer);
return CE_None;
}