/*
* Copyright 2000-2015 JetBrains s.r.o.
*
* 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.intellij.formatting;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.util.List;
class ProbablyIncreasingLowerboundAlgorithm<T extends AbstractBlockWrapper> {
private List<T> myBlocks;
private int myLastCalculatedOffset = -1;
private int myLastCalculatedAnswerIndex = -1;
public ProbablyIncreasingLowerboundAlgorithm(@NotNull List<T> blocks) {
myBlocks = blocks;
}
public void reset() {
myLastCalculatedAnswerIndex = -1;
myLastCalculatedOffset = -1;
}
public List<T> getLeftSubList(@Nullable AbstractBlockWrapper block) {
return myBlocks.subList(0, getLeftRespNeighborIndex(block) + 1);
}
public void setBlocksList(List<T> blocks) {
myBlocks = blocks;
reset();
}
@Nullable
public AbstractBlockWrapper getLeftRespNeighbor(@NotNull AbstractBlockWrapper block) {
int index = getLeftRespNeighborIndex(block);
if (index == -1) {
return null;
}
else {
return myBlocks.get(index);
}
}
private int getLeftRespNeighborIndex(@Nullable AbstractBlockWrapper block) {
if (block == null) {
return myBlocks.size() - 1;
}
final int offset = block.getStartOffset();
if (myLastCalculatedOffset != -1) {
if (offset >= myLastCalculatedOffset) {
myLastCalculatedAnswerIndex = calcLeftRespNeighborIndexLinear(myLastCalculatedAnswerIndex, offset);
myLastCalculatedOffset = offset;
return myLastCalculatedAnswerIndex;
}
//Logger.getInstance(ProbablyIncreasingLowerboundAlgorithm.class).error("not very good!");
myLastCalculatedOffset = -1;
}
myLastCalculatedOffset = offset;
return myLastCalculatedAnswerIndex = calcLeftRespNeighborIndex(offset);
}
private int calcLeftRespNeighborIndexLinear(int lastAnswerIndex, int blockOffset) {
int index = lastAnswerIndex;
while (index + 1 < myBlocks.size()) {
if (blockOffset <= myBlocks.get(index + 1).getStartOffset()) {
break;
}
index++;
}
return index;
}
private int calcLeftRespNeighborIndex(final int blockOffset) {
int l = -1, r = myBlocks.size();
while (r - l > 1) {
int m = (l + r) / 2;
if (myBlocks.get(m).getStartOffset() >= blockOffset) {
r = m;
}
else {
l = m;
}
}
return l;
}
}