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/*
* Copyright 2007 - 2018 ETH Zuerich, CISD and SIS.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package ch.systemsx.cisd.hdf5;
import ch.systemsx.cisd.hdf5.hdf5lib.HDFHelper;
/**
* A class with methods for padding of memory structures.
* <p>
* <i>This is an internal API that should not be expected to be stable between releases!</i>
*
* @author Bernd Rinn
*/
class PaddingUtils
{
private static final int machineWordSize = HDFHelper.getMachineWordSize();
private PaddingUtils()
{
// Cannot be instantiated
}
/**
* Compute the padded <code>offset</code> to have aligned access to variables of
* <code>elementSize</code>, or the size of the machine word, whatever is smaller.
*/
static int padOffset(int offset, int elementSize)
{
if (elementSize > 0)
{
final int actualElementSize = Math.min(elementSize, machineWordSize);
int mod = offset % actualElementSize;
return (mod > 0) ? offset + actualElementSize - mod : offset;
} else
{
return offset;
}
}
/**
* Compute the maximal element size (in bytes). If the maximal element size is larger than the
* size of a machine word on this platform, return the size of a machine word instead.
*/
static int findMaxElementSize(HDF5MemberByteifyer[] byteifyers)
{
int maxElementSize = 0;
for (HDF5MemberByteifyer b : byteifyers)
{
maxElementSize = Math.max(maxElementSize, b.getElementSize());
if (maxElementSize >= machineWordSize)
{
return machineWordSize;
}
}
return maxElementSize;
}
}
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