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/******************************************************************************
* $Id: gdalchecksum.cpp 33715 2016-03-13 08:52:06Z goatbar $
*
* Project: GDAL
* Purpose: Compute simple checksum for a region of image data.
* Author: Frank Warmerdam, warmerdam@pobox.com
*
******************************************************************************
* Copyright (c) 2003, Frank Warmerdam
* Copyright (c) 2007-2008, Even Rouault <even dot rouault at mines-paris dot org>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
****************************************************************************/
#include "gdal_alg.h"
#include "cpl_conv.h"
CPL_CVSID("$Id: gdalchecksum.cpp 33715 2016-03-13 08:52:06Z goatbar $");
/************************************************************************/
/* GDALChecksumImage() */
/************************************************************************/
/**
* Compute checksum for image region.
*
* Computes a 16bit (0-65535) checksum from a region of raster data on a GDAL
* supported band. Floating point data is converted to 32bit integer
* so decimal portions of such raster data will not affect the checksum.
* Real and Imaginary components of complex bands influence the result.
*
* @param hBand the raster band to read from.
* @param nXOff pixel offset of window to read.
* @param nYOff line offset of window to read.
* @param nXSize pixel size of window to read.
* @param nYSize line size of window to read.
*
* @return Checksum value.
*/
int CPL_STDCALL
GDALChecksumImage( GDALRasterBandH hBand,
int nXOff, int nYOff, int nXSize, int nYSize )
{
VALIDATE_POINTER1( hBand, "GDALChecksumImage", 0 );
const static int anPrimes[11] =
{ 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43 };
int iLine, i, nChecksum = 0, iPrime = 0, nCount;
GDALDataType eDataType = GDALGetRasterDataType( hBand );
int bComplex = GDALDataTypeIsComplex( eDataType );
if (eDataType == GDT_Float32 || eDataType == GDT_Float64 ||
eDataType == GDT_CFloat32 || eDataType == GDT_CFloat64)
{
double* padfLineData;
GDALDataType eDstDataType = (bComplex) ? GDT_CFloat64 : GDT_Float64;
padfLineData = (double *) VSI_MALLOC2_VERBOSE(nXSize, sizeof(double) * 2);
if (padfLineData == NULL)
{
return 0;
}
for( iLine = nYOff; iLine < nYOff + nYSize; iLine++ )
{
if (GDALRasterIO( hBand, GF_Read, nXOff, iLine, nXSize, 1,
padfLineData, nXSize, 1, eDstDataType, 0, 0 ) != CE_None)
{
CPLError( CE_Failure, CPLE_FileIO,
"Checksum value couldn't be computed due to I/O read error.\n");
break;
}
nCount = (bComplex) ? nXSize * 2 : nXSize;
for( i = 0; i < nCount; i++ )
{
double dfVal = padfLineData[i];
int nVal;
if (CPLIsNan(dfVal) || CPLIsInf(dfVal))
{
/* Most compilers seem to cast NaN or Inf to 0x80000000. */
/* but VC7 is an exception. So we force the result */
/* of such a cast */
nVal = 0x80000000;
}
else
{
/* Standard behaviour of GDALCopyWords when converting */
/* from floating point to Int32 */
dfVal += 0.5;
if( dfVal < -2147483647.0 )
nVal = -2147483647;
else if( dfVal > 2147483647 )
nVal = 2147483647;
else
nVal = (GInt32) floor(dfVal);
}
nChecksum += (nVal % anPrimes[iPrime++]);
if( iPrime > 10 )
iPrime = 0;
nChecksum &= 0xffff;
}
}
CPLFree(padfLineData);
}
else
{
int *panLineData;
GDALDataType eDstDataType = (bComplex) ? GDT_CInt32 : GDT_Int32;
panLineData = (GInt32 *) VSI_MALLOC2_VERBOSE(nXSize, sizeof(GInt32) * 2);
if (panLineData == NULL)
{
return 0;
}
for( iLine = nYOff; iLine < nYOff + nYSize; iLine++ )
{
if (GDALRasterIO( hBand, GF_Read, nXOff, iLine, nXSize, 1,
panLineData, nXSize, 1, eDstDataType, 0, 0 ) != CE_None)
{
CPLError( CE_Failure, CPLE_FileIO,
"Checksum value could not be computed due to I/O "
"read error.\n");
break;
}
nCount = (bComplex) ? nXSize * 2 : nXSize;
for( i = 0; i < nCount; i++ )
{
nChecksum += (panLineData[i] % anPrimes[iPrime++]);
if( iPrime > 10 )
iPrime = 0;
nChecksum &= 0xffff;
}
}
CPLFree( panLineData );
}
return nChecksum;
}
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