content: /*
   * 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.google.android.exoplayer2.source.dash.manifest;
  
  import android.net.Uri;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.util.UriUtil;
  
  /**
   * Defines a range of data located at a reference uri.
   */
  public final class RangedUri {
  
    /**
     * The (zero based) index of the first byte of the range.
     */
    public final long start;
  
    /**
     * The length of the range, or {@link C#LENGTH_UNSET} to indicate that the range is unbounded.
     */
    public final long length;
  
    private final String referenceUri;
  
    private int hashCode;
  
    /**
     * Constructs an ranged uri.
     *
     * @param referenceUri The reference uri.
     * @param start The (zero based) index of the first byte of the range.
     * @param length The length of the range, or {@link C#LENGTH_UNSET} to indicate that the range is
     *     unbounded.
     */
    public RangedUri(String referenceUri, long start, long length) {
      this.referenceUri = referenceUri == null ? "" : referenceUri;
      this.start = start;
      this.length = length;
    }
  
    /**
     * Returns the resolved {@link Uri} represented by the instance.
     *
     * @param baseUri The base Uri.
     * @return The {@link Uri} represented by the instance.
     */
    public Uri resolveUri(String baseUri) {
      return UriUtil.resolveToUri(baseUri, referenceUri);
    }
  
    /**
     * Returns the resolved uri represented by the instance as a string.
     *
     * @param baseUri The base Uri.
     * @return The uri represented by the instance.
     */
    public String resolveUriString(String baseUri) {
      return UriUtil.resolve(baseUri, referenceUri);
    }
  
    /**
     * Attempts to merge this {@link RangedUri} with another and an optional common base uri.
     * <p>
     * A merge is successful if both instances define the same {@link Uri} after resolution with the
     * base uri, and if one starts the byte after the other ends, forming a contiguous region with
     * no overlap.
     * <p>
     * If {@code other} is null then the merge is considered unsuccessful, and null is returned.
     *
     * @param other The {@link RangedUri} to merge.
     * @param baseUri The optional base Uri.
     * @return The merged {@link RangedUri} if the merge was successful. Null otherwise.
     */
    public RangedUri attemptMerge(RangedUri other, String baseUri) {
      final String resolvedUri = resolveUriString(baseUri);
      if (other == null || !resolvedUri.equals(other.resolveUriString(baseUri))) {
        return null;
      } else if (length != C.LENGTH_UNSET && start + length == other.start) {
        return new RangedUri(resolvedUri, start,
            other.length == C.LENGTH_UNSET ? C.LENGTH_UNSET : length + other.length);
      } else if (other.length != C.LENGTH_UNSET && other.start + other.length == start) {
        return new RangedUri(resolvedUri, other.start,
            length == C.LENGTH_UNSET ? C.LENGTH_UNSET : other.length + length);
      } else {
        return null;
      }
    }
  
    @Override
    public int hashCode() {
      if (hashCode == 0) {
        int result = 17;
        result = 31 * result + (int) start;
        result = 31 * result + (int) length;
        result = 31 * result + referenceUri.hashCode();
        hashCode = result;
      }
      return hashCode;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }
      if (obj == null || getClass() != obj.getClass()) {
        return false;
      }
      RangedUri other = (RangedUri) obj;
      return this.start == other.start
          && this.length == other.length
          && referenceUri.equals(other.referenceUri);
    }
  
  }
  