/*
* Licensed to GraphHopper GmbH under one or more contributor
* license agreements. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*
* GraphHopper GmbH licenses this file to you 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.graphhopper.routing.util;
/**
* Encapsulates a bit-encoded value.
* <p>
*
* @author Nop
*/
public class EncodedValue {
protected final long shift;
protected final long mask;
protected final double factor;
protected final long defaultValue;
private final String name;
private final long maxValue;
private final boolean allowZero;
private final int bits;
/**
* Define a bit-encoded value
* <p>
*
* @param name Description for debugging
* @param shift bit index of this value
* @param bits number of bits reserved
* @param factor scaling factor for stored values
* @param defaultValue default value
* @param maxValue default maximum value
*/
public EncodedValue(String name, int shift, int bits, double factor, long defaultValue, int maxValue) {
this(name, shift, bits, factor, defaultValue, maxValue, true);
}
public EncodedValue(String name, int shift, int bits, double factor, long defaultValue, int maxValue, boolean allowZero) {
this.name = name;
this.shift = shift;
this.factor = factor;
this.defaultValue = defaultValue;
this.bits = bits;
long tmpMask = (1L << bits) - 1;
this.maxValue = Math.min(maxValue, Math.round(tmpMask * factor));
if (maxValue > this.maxValue)
throw new IllegalStateException(name + " -> maxValue " + maxValue + " is too large for " + bits + " bits");
double factorDivision = maxValue / factor;
if (factorDivision != (int) factorDivision) {
throw new IllegalStateException("MaxValue needs to be divisible by factor without remainder");
}
mask = tmpMask << shift;
this.allowZero = allowZero;
}
protected void checkValue(long value) {
if (value > maxValue)
throw new IllegalArgumentException(name + " value too large for encoding: " + value + ", maxValue:" + maxValue);
if (value < 0)
throw new IllegalArgumentException("negative " + name + " value not allowed! " + value);
if (!allowZero && value == 0)
throw new IllegalArgumentException("zero " + name + " value not allowed! " + value);
}
public long setValue(long flags, long value) {
// scale value
value = Math.round(value / factor);
checkValue((long) (value * factor));
value <<= shift;
// clear value bits
flags &= ~mask;
// set value
return flags | value;
}
public String getName() {
return name;
}
public long getValue(long flags) {
// find value
flags &= mask;
flags >>>= shift;
return Math.round(flags * factor);
}
public int getBits() {
return bits;
}
public double getFactor() {
return factor;
}
public long setDefaultValue(long flags) {
return setValue(flags, defaultValue);
}
public long getMaxValue() {
return maxValue;
}
/**
* Swap the contents controlled by this value encoder with the given value.
* <p>
*
* @return the new flags
*/
public long swap(long flags, EncodedValue otherEncoder) {
long otherValue = otherEncoder.getValue(flags);
flags = otherEncoder.setValue(flags, getValue(flags));
return setValue(flags, otherValue);
}
}