content: /*
   * Copyright (C) 2014 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 android.util;
  
  import static com.android.internal.util.Preconditions.*;
  
  import android.hardware.camera2.utils.HashCodeHelpers;
  
  /**
   * Immutable class for describing the range of two numeric values.
   * <p>
   * A range (or "interval") defines the inclusive boundaries around a contiguous span of
   * values of some {@link Comparable} type; for example,
   * "integers from 1 to 100 inclusive."
   * </p>
   * <p>
   * All ranges are bounded, and the left side of the range is always {@code <=}
   * the right side of the range.
   * </p>
   *
   * <p>Although the implementation itself is immutable, there is no restriction that objects
   * stored must also be immutable. If mutable objects are stored here, then the range
   * effectively becomes mutable. </p>
   */
  public final class Range<T extends Comparable<? super T>> {
      /**
       * Create a new immutable range.
       *
       * <p>
       * The endpoints are {@code [lower, upper]}; that
       * is the range is bounded. {@code lower} must be {@link Comparable#compareTo lesser or equal}
       * to {@code upper}.
       * </p>
       *
       * @param lower The lower endpoint (inclusive)
       * @param upper The upper endpoint (inclusive)
       *
       * @throws NullPointerException if {@code lower} or {@code upper} is {@code null}
       */
      public Range(final T lower, final T upper) {
          mLower = checkNotNull(lower, "lower must not be null");
          mUpper = checkNotNull(upper, "upper must not be null");
  
          if (lower.compareTo(upper) > 0) {
              throw new IllegalArgumentException("lower must be less than or equal to upper");
          }
      }
  
      /**
       * Create a new immutable range, with the argument types inferred.
       *
       * <p>
       * The endpoints are {@code [lower, upper]}; that
       * is the range is bounded. {@code lower} must be {@link Comparable#compareTo lesser or equal}
       * to {@code upper}.
       * </p>
       *
       * @param lower The lower endpoint (inclusive)
       * @param upper The upper endpoint (inclusive)
       *
       * @throws NullPointerException if {@code lower} or {@code upper} is {@code null}
       */
      public static <T extends Comparable<? super T>> Range<T> create(final T lower, final T upper) {
          return new Range<T>(lower, upper);
      }
  
      /**
       * Get the lower endpoint.
       *
       * @return a non-{@code null} {@code T} reference
       */
      public T getLower() {
          return mLower;
      }
  
      /**
       * Get the upper endpoint.
       *
       * @return a non-{@code null} {@code T} reference
       */
      public T getUpper() {
          return mUpper;
      }
  
      /**
       * Checks if the {@code value} is within the bounds of this range.
       *
       * <p>A value is considered to be within this range if it's {@code >=}
       * the lower endpoint <i>and</i> {@code <=} the upper endpoint (using the {@link Comparable}
       * interface.)</p>
       *
       * @param value a non-{@code null} {@code T} reference
       * @return {@code true} if the value is within this inclusive range, {@code false} otherwise
       *
       * @throws NullPointerException if {@code value} was {@code null}
       */
      public boolean contains(T value) {
          checkNotNull(value, "value must not be null");
  
          boolean gteLower = value.compareTo(mLower) >= 0;
          boolean lteUpper  = value.compareTo(mUpper) <= 0;
  
          return gteLower && lteUpper;
      }
  
      /**
       * Checks if another {@code range} is within the bounds of this range.
       *
       * <p>A range is considered to be within this range if both of its endpoints
       * are within this range.</p>
       *
       * @param range a non-{@code null} {@code T} reference
       * @return {@code true} if the range is within this inclusive range, {@code false} otherwise
       *
       * @throws NullPointerException if {@code range} was {@code null}
       */
      public boolean contains(Range<T> range) {
          checkNotNull(range, "value must not be null");
  
          boolean gteLower = range.mLower.compareTo(mLower) >= 0;
          boolean lteUpper = range.mUpper.compareTo(mUpper) <= 0;
  
          return gteLower && lteUpper;
      }
  
      /**
       * Compare two ranges for equality.
       *
       * <p>A range is considered equal if and only if both the lower and upper endpoints
       * are also equal.</p>
       *
       * @return {@code true} if the ranges are equal, {@code false} otherwise
       */
      @Override
      public boolean equals(Object obj) {
          if (obj == null) {
              return false;
          } else if (this == obj) {
              return true;
          } else if (obj instanceof Range) {
              @SuppressWarnings("rawtypes")
              Range other = (Range) obj;
              return mLower.equals(other.mLower) && mUpper.equals(other.mUpper);
          }
          return false;
      }
  
      /**
       * Clamps {@code value} to this range.
       *
       * <p>If the value is within this range, it is returned.  Otherwise, if it
       * is {@code <} than the lower endpoint, the lower endpoint is returned,
       * else the upper endpoint is returned. Comparisons are performed using the
       * {@link Comparable} interface.</p>
       *
       * @param value a non-{@code null} {@code T} reference
       * @return {@code value} clamped to this range.
       */
      public T clamp(T value) {
          checkNotNull(value, "value must not be null");
  
          if (value.compareTo(mLower) < 0) {
              return mLower;
          } else if (value.compareTo(mUpper) > 0) {
              return mUpper;
          } else {
              return value;
          }
      }
  
      /**
       * Returns the intersection of this range and another {@code range}.
       * <p>
       * E.g. if a {@code <} b {@code <} c {@code <} d, the
       * intersection of [a, c] and [b, d] ranges is [b, c].
       * As the endpoints are object references, there is no guarantee
       * which specific endpoint reference is used from the input ranges:</p>
       * <p>
       * E.g. if a {@code ==} a' {@code <} b {@code <} c, the
       * intersection of [a, b] and [a', c] ranges could be either
       * [a, b] or ['a, b], where [a, b] could be either the exact
       * input range, or a newly created range with the same endpoints.</p>
       *
       * @param range a non-{@code null} {@code Range<T>} reference
       * @return the intersection of this range and the other range.
       *
       * @throws NullPointerException if {@code range} was {@code null}
       * @throws IllegalArgumentException if the ranges are disjoint.
       */
      public Range<T> intersect(Range<T> range) {
          checkNotNull(range, "range must not be null");
  
          int cmpLower = range.mLower.compareTo(mLower);
          int cmpUpper = range.mUpper.compareTo(mUpper);
  
          if (cmpLower <= 0 && cmpUpper >= 0) {
              // range includes this
              return this;
          } else if (cmpLower >= 0 && cmpUpper <= 0) {
              // this inludes range
              return range;
          } else {
              return Range.create(
                      cmpLower <= 0 ? mLower : range.mLower,
                      cmpUpper >= 0 ? mUpper : range.mUpper);
          }
      }
  
      /**
       * Returns the intersection of this range and the inclusive range
       * specified by {@code [lower, upper]}.
       * <p>
       * See {@link #intersect(Range)} for more details.</p>
       *
       * @param lower a non-{@code null} {@code T} reference
       * @param upper a non-{@code null} {@code T} reference
       * @return the intersection of this range and the other range
       *
       * @throws NullPointerException if {@code lower} or {@code upper} was {@code null}
       * @throws IllegalArgumentException if the ranges are disjoint.
       */
      public Range<T> intersect(T lower, T upper) {
          checkNotNull(lower, "lower must not be null");
          checkNotNull(upper, "upper must not be null");
  
          int cmpLower = lower.compareTo(mLower);
          int cmpUpper = upper.compareTo(mUpper);
  
          if (cmpLower <= 0 && cmpUpper >= 0) {
              // [lower, upper] includes this
              return this;
          } else {
              return Range.create(
                      cmpLower <= 0 ? mLower : lower,
                      cmpUpper >= 0 ? mUpper : upper);
          }
      }
  
      /**
       * Returns the smallest range that includes this range and
       * another {@code range}.
       * <p>
       * E.g. if a {@code <} b {@code <} c {@code <} d, the
       * extension of [a, c] and [b, d] ranges is [a, d].
       * As the endpoints are object references, there is no guarantee
       * which specific endpoint reference is used from the input ranges:</p>
       * <p>
       * E.g. if a {@code ==} a' {@code <} b {@code <} c, the
       * extension of [a, b] and [a', c] ranges could be either
       * [a, c] or ['a, c], where ['a, c] could be either the exact
       * input range, or a newly created range with the same endpoints.</p>
       *
       * @param range a non-{@code null} {@code Range<T>} reference
       * @return the extension of this range and the other range.
       *
       * @throws NullPointerException if {@code range} was {@code null}
       */
      public Range<T> extend(Range<T> range) {
          checkNotNull(range, "range must not be null");
  
          int cmpLower = range.mLower.compareTo(mLower);
          int cmpUpper = range.mUpper.compareTo(mUpper);
  
          if (cmpLower <= 0 && cmpUpper >= 0) {
              // other includes this
              return range;
          } else if (cmpLower >= 0 && cmpUpper <= 0) {
              // this inludes other
              return this;
          } else {
              return Range.create(
                      cmpLower >= 0 ? mLower : range.mLower,
                      cmpUpper <= 0 ? mUpper : range.mUpper);
          }
      }
  
      /**
       * Returns the smallest range that includes this range and
       * the inclusive range specified by {@code [lower, upper]}.
       * <p>
       * See {@link #extend(Range)} for more details.</p>
       *
       * @param lower a non-{@code null} {@code T} reference
       * @param upper a non-{@code null} {@code T} reference
       * @return the extension of this range and the other range.
       *
       * @throws NullPointerException if {@code lower} or {@code
       *                              upper} was {@code null}
       */
      public Range<T> extend(T lower, T upper) {
          checkNotNull(lower, "lower must not be null");
          checkNotNull(upper, "upper must not be null");
  
          int cmpLower = lower.compareTo(mLower);
          int cmpUpper = upper.compareTo(mUpper);
  
          if (cmpLower >= 0 && cmpUpper <= 0) {
              // this inludes other
              return this;
          } else {
              return Range.create(
                      cmpLower >= 0 ? mLower : lower,
                      cmpUpper <= 0 ? mUpper : upper);
          }
      }
  
      /**
       * Returns the smallest range that includes this range and
       * the {@code value}.
       * <p>
       * See {@link #extend(Range)} for more details, as this method is
       * equivalent to {@code extend(Range.create(value, value))}.</p>
       *
       * @param value a non-{@code null} {@code T} reference
       * @return the extension of this range and the value.
       *
       * @throws NullPointerException if {@code value} was {@code null}
       */
      public Range<T> extend(T value) {
          checkNotNull(value, "value must not be null");
          return extend(value, value);
      }
  
      /**
       * Return the range as a string representation {@code "[lower, upper]"}.
       *
       * @return string representation of the range
       */
      @Override
      public String toString() {
          return String.format("[%s, %s]", mLower, mUpper);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public int hashCode() {
          return HashCodeHelpers.hashCodeGeneric(mLower, mUpper);
      }
  
      private final T mLower;
      private final T mUpper;
  };
  