/*******************************************************************************
* Copyright 2014 Analog Devices, Inc.
*
* 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 com.analog.lyric.benchmarking.utils.doublespace;
import java.security.InvalidParameterException;
import java.util.Iterator;
class StrideIndexer implements Indexer
{
final int _finish;
final int _start;
final int _stride;
public StrideIndexer(int just)
{
this(just, 1, just);
}
public StrideIndexer(int start, int finish)
{
this(start, (int) Math.signum(finish - start), finish);
}
public StrideIndexer(int start, int stride, int finish)
{
final boolean positive = finish >= start;
if (positive && stride < 1 || !positive && stride > -1)
{
throw new InvalidParameterException("Sign of stride does not suit start and finish values.");
}
if (start < 0 || finish < 0)
{
throw new InvalidParameterException("Start and finish values must be non-negative.");
}
_start = start;
_stride = stride;
_finish = finish;
}
@Override
public int getCardinality()
{
return (_finish - _start) / _stride + 1;
}
@Override
public int getNth(int i)
{
final int proposal = _start + i * _stride;
if (_stride >= 0)
{
if (proposal <= _finish)
{
return proposal;
}
}
else
{
if (proposal >= _finish)
{
return proposal;
}
}
throw new IllegalArgumentException();
}
@Override
public Iterator<Integer> iterator()
{
return new StrideIndexerIterator();
}
private class StrideIndexerIterator implements Iterator<Integer>
{
private int _current = -1;
@Override
public boolean hasNext()
{
int proposal;
if (_current == -1)
{
proposal = _start;
}
else
{
proposal = _current + _stride;
}
if (_stride > 0)
{
if (proposal <= _finish)
{
return true;
}
}
else
{
if (proposal >= _finish)
{
return true;
}
}
return false;
}
@Override
public Integer next()
{
int proposal;
if (_current == -1)
{
proposal = _start;
}
else
{
proposal = _current + _stride;
}
if (_stride > 0)
{
if (proposal <= _finish)
{
_current = proposal;
}
}
else
{
if (proposal >= _finish)
{
_current = proposal;
}
}
return _current;
}
@Override
public void remove()
{
throw new UnsupportedOperationException();
}
}
}