src/main/java/com/android/apksig/internal/util/InclusiveIntRange.java

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * 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.android.apksig.internal.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * Inclusive interval of integers.
 */
public class InclusiveIntRange {
    private final int min;
    private final int max;

    private InclusiveIntRange(int min, int max) {
        this.min = min;
        this.max = max;
    }

    public int getMin() {
        return min;
    }

    public int getMax() {
        return max;
    }

    public static InclusiveIntRange fromTo(int min, int max) {
        return new InclusiveIntRange(min, max);
    }

    public static InclusiveIntRange from(int min) {
        return new InclusiveIntRange(min, Integer.MAX_VALUE);
    }

    public List<InclusiveIntRange> getValuesNotIn(
            List<InclusiveIntRange> sortedNonOverlappingRanges) {
        if (sortedNonOverlappingRanges.isEmpty()) {
            return Collections.singletonList(this);
        }

        int testValue = min;
        List<InclusiveIntRange> result = null;
        for (InclusiveIntRange range : sortedNonOverlappingRanges) {
            int rangeMax = range.max;
            if (testValue > rangeMax) {
                continue;
            }
            int rangeMin = range.min;
            if (testValue < range.min) {
                if (result == null) {
                    result = new ArrayList<>();
                }
                result.add(fromTo(testValue, rangeMin - 1));
            }
            if (rangeMax >= max) {
                return (result != null) ? result : Collections.emptyList();
            }
            testValue = rangeMax + 1;
        }
        if (testValue <= max) {
            if (result == null) {
                result = new ArrayList<>(1);
            }
            result.add(fromTo(testValue, max));
        }
        return (result != null) ? result : Collections.emptyList();
    }

    @Override
    public String toString() {
        return "[" + min + ", " + ((max < Integer.MAX_VALUE) ? (max + "]") : "\u221e)");
    }
}