Add utility classes for SegmentTemplate/SegmentList refactor.

A step towards supporting SegmentTemplate style MPDs.

library/src/main/java/com/google/android/exoplayer/dash/mpd/RangedUri.java

+/*
+ * 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 com.google.android.exoplayer.dash.mpd;
+
+import com.google.android.exoplayer.util.Assertions;
+
+import android.net.Uri;
+
+/**
+ * Defines a range of data located at a {@link 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 -1 to indicate that the range is unbounded.
+   */
+  public final long length;
+
+  // The {@link Uri} is stored internally in two parts, {@link #baseUri} and {@link uriString}.
+  // This helps optimize memory usage in the same way that DASH manifests allow many URLs to be
+  // expressed concisely in the form of a single BaseURL and many relative paths. Note that this
+  // optimization relies on the same {@code Uri} being passed as the {@link #baseUri} to many
+  // instances of this class.
+  private final Uri baseUri;
+  private final String stringUri;
+
+  /**
+   * Constructs an ranged uri.
+   * <p>
+   * The uri is built according to the following rules:
+   * <ul>
+   * <li>If {@code baseUri} is null or if {@code stringUri} is absolute, then {@code baseUri} is
+   * ignored and the url consists solely of {@code stringUri}.
+   * <li>If {@code stringUri} is null, then the url consists solely of {@code baseUrl}.
+   * <li>Otherwise, the url consists of the concatenation of {@code baseUri} and {@code stringUri}.
+   * </ul>
+   *
+   * @param baseUri An uri that can form the base of the uri defined by the instance.
+   * @param stringUri A relative or absolute uri in string form.
+   * @param start The (zero based) index of the first byte of the range.
+   * @param length The length of the range, or -1 to indicate that the range is unbounded.
+   */
+  public RangedUri(Uri baseUri, String stringUri, long start, long length) {
+    Assertions.checkArgument(baseUri != null || stringUri != null);
+    this.baseUri = baseUri;
+    this.stringUri = stringUri;
+    this.start = start;
+    this.length = length;
+  }
+
+  /**
+   * Returns the {@link Uri} represented by the instance.
+   *
+   * @return The {@link Uri} represented by the instance.
+   */
+  public Uri getUri() {
+    if (stringUri == null) {
+      return baseUri;
+    }
+    Uri uri = Uri.parse(stringUri);
+    if (!uri.isAbsolute() && baseUri != null) {
+      uri = Uri.withAppendedPath(baseUri, stringUri);
+    }
+    return uri;
+  }
+
+}

library/src/main/java/com/google/android/exoplayer/dash/mpd/UrlTemplate.java

+/*
+ * 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 com.google.android.exoplayer.dash.mpd;
+
+/**
+ * A template from which URLs can be built.
+ * <p>
+ * URLs are built according to the substitution rules defined in ISO/IEC 23009-1:2014 5.3.9.4.4.
+ */
+public final class UrlTemplate {
+
+  private static final String REPRESENTATION = "RepresentationID";
+  private static final String NUMBER = "Number";
+  private static final String BANDWIDTH = "Bandwidth";
+  private static final String TIME = "Time";
+  private static final String ESCAPED_DOLLAR = "$$";
+  private static final String DEFAULT_FORMAT_TAG = "%01d";
+
+  private static final int REPRESENTATION_ID = 1;
+  private static final int NUMBER_ID = 2;
+  private static final int BANDWIDTH_ID = 3;
+  private static final int TIME_ID = 4;
+
+  private final String[] urlPieces;
+  private final int[] identifiers;
+  private final String[] identifierFormatTags;
+  private final int identifierCount;
+
+  /**
+   * Compile an instance from the provided template string.
+   *
+   * @param template The template.
+   * @return The compiled instance.
+   * @throws IllegalArgumentException If the template string is malformed.
+   */
+  public static UrlTemplate compile(String template) {
+    // These arrays are sizes assuming each of the four possible identifiers will be present at
+    // most once in the template, which seems like a reasonable assumption.
+    String[] urlPieces = new String[5];
+    int[] identifiers = new int[4];
+    String[] identifierFormatTags = new String[4];
+    int identifierCount = parseTemplate(template, urlPieces, identifiers, identifierFormatTags);
+    return new UrlTemplate(urlPieces, identifiers, identifierFormatTags, identifierCount);
+  }
+
+  /**
+   * Internal constructor. Use {@link #compile(String)} to build instances of this class.
+   */
+  private UrlTemplate(String[] urlPieces, int[] identifiers, String[] identifierFormatTags,
+      int identifierCount) {
+    this.urlPieces = urlPieces;
+    this.identifiers = identifiers;
+    this.identifierFormatTags = identifierFormatTags;
+    this.identifierCount = identifierCount;
+  }
+
+  /**
+   * Constructs a Uri from the template, substituting in the provided arguments.
+   * <p>
+   * Arguments whose corresponding identifiers are not present in the template will be ignored.
+   *
+   * @param representationId The representation identifier.
+   * @param segmentNumber The segment number.
+   * @param bandwidth The bandwidth.
+   * @param time The time as specified by the segment timeline.
+   * @return The built Uri.
+   */
+  public String buildUri(String representationId, int segmentNumber, int bandwidth, long time) {
+    StringBuilder builder = new StringBuilder();
+    for (int i = 0; i < identifierCount; i++) {
+      builder.append(urlPieces[i]);
+      if (identifiers[i] == REPRESENTATION_ID) {
+        builder.append(representationId);
+      } else if (identifiers[i] == NUMBER_ID) {
+        builder.append(String.format(identifierFormatTags[i], segmentNumber));
+      } else if (identifiers[i] == BANDWIDTH_ID) {
+        builder.append(String.format(identifierFormatTags[i], bandwidth));
+      } else if (identifiers[i] == TIME_ID) {
+        builder.append(String.format(identifierFormatTags[i], time));
+      }
+    }
+    builder.append(urlPieces[identifierCount]);
+    return builder.toString();
+  }
+
+  /**
+   * Parses {@code template}, placing the decomposed components into the provided arrays.
+   * <p>
+   * If the return value is N, {@code urlPieces} will contain (N+1) strings that must be
+   * interleaved with N arguments in order to construct a url. The N identifiers that correspond to
+   * the required arguments, together with the tags that define their required formatting, are
+   * returned in {@code identifiers} and {@code identifierFormatTags} respectively.
+   *
+   * @param template The template to parse.
+   * @param urlPieces A holder for pieces of url parsed from the template.
+   * @param identifiers A holder for identifiers parsed from the template.
+   * @param identifierFormatTags A holder for format tags corresponding to the parsed identifiers.
+   * @return The number of identifiers in the template url.
+   * @throws IllegalArgumentException If the template string is malformed.
+   */
+  private static int parseTemplate(String template, String[] urlPieces, int[] identifiers,
+      String[] identifierFormatTags) {
+    urlPieces[0] = "";
+    int templateIndex = 0;
+    int identifierCount = 0;
+    while (templateIndex < template.length()) {
+      int dollarIndex = template.indexOf("$", templateIndex);
+      if (dollarIndex == -1) {
+        urlPieces[identifierCount] += template.substring(templateIndex);
+        templateIndex = template.length();
+      } else if (dollarIndex != templateIndex) {
+        urlPieces[identifierCount] += template.substring(templateIndex, dollarIndex);
+        templateIndex = dollarIndex;
+      } else if (template.startsWith(ESCAPED_DOLLAR, templateIndex)) {
+        urlPieces[identifierCount] += "$";
+        templateIndex += 2;
+      } else {
+        int secondIndex = template.indexOf("$", templateIndex + 1);
+        String identifier = template.substring(templateIndex + 1, secondIndex);
+        if (identifier.equals(REPRESENTATION)) {
+          identifiers[identifierCount] = REPRESENTATION_ID;
+        } else {
+          int formatTagIndex = identifier.indexOf("%0");
+          String formatTag = DEFAULT_FORMAT_TAG;
+          if (formatTagIndex != -1) {
+            formatTag = identifier.substring(formatTagIndex);
+            if (!formatTag.endsWith("d")) {
+              formatTag += "d";
+            }
+            identifier = identifier.substring(0, formatTagIndex);
+          }
+          if (identifier.equals(NUMBER)) {
+            identifiers[identifierCount] = NUMBER_ID;
+          } else if (identifier.equals(BANDWIDTH)) {
+            identifiers[identifierCount] = BANDWIDTH_ID;
+          } else if (identifier.equals(TIME)) {
+            identifiers[identifierCount] = TIME_ID;
+          } else {
+            throw new IllegalArgumentException("Invalid template: " + template);
+          }
+          identifierFormatTags[identifierCount] = formatTag;
+        }
+        identifierCount++;
+        urlPieces[identifierCount] = "";
+        templateIndex = secondIndex + 1;
+      }
+    }
+    return identifierCount;
+  }
+
+}

library/src/main/java/com/google/android/exoplayer/parser/webm/EbmlEventHandler.java

@@ -103,6 +103,7 @@ import java.nio.ByteBuffer;
    * <li>{@link EbmlReader#readBytes(NonBlockingInputStream, ByteBuffer, int)}.
    * <li>{@link EbmlReader#skipBytes(NonBlockingInputStream, int)}.
    * <li>{@link EbmlReader#getBytesRead()}.
+   * </ul>
    *
    * @param id The integer ID of this element
    * @param elementOffsetBytes The byte offset where this element starts