Class Matcher

java/com/google/re2j/Matcher.java:41–608

A stateful iterator that interprets a regex Pattern on a specific input. Its interface mimics the JDK 1.4.2 java.util.regex.Matcher. Conceptually, a Matcher consists of four parts: A compiled regular expression Pattern, set at construction and fixed for the life

 * @author rsc@google.com (Russ Cox)
 */
public final class Matcher {
  // The pattern being matched.
  private final Pattern pattern;

  // The group indexes, in [start, end) pairs.  Zeroth pair is overall match.
  private final int[] groups;

  private final Map<String, Integer> namedGroups;

  // The number of submatches (groups) in the pattern.
  private final int groupCount;

  // The number of instructions in the pattern.
  private final int numberOfInstructions;

  private MatcherInput matcherInput;

  // The input length in UTF16 codes.
  private int inputLength;

  // The append position: where the next append should start.
  private int appendPos;

  // Is there a current match?
  private boolean hasMatch;

  // Have we found the submatches (groups) of the current match?
  // group[0], group[1] are set regardless.
  private boolean hasGroups;

  // The anchor flag to use when repeating the match to find subgroups.
  private int anchorFlag;

  private Matcher(Pattern pattern) {
    if (pattern == null) {
      throw new NullPointerException("pattern is null");
    }
    this.pattern = pattern;
    RE2 re2 = pattern.re2();
    groupCount = re2.numberOfCapturingGroups();
    groups = new int[2 + 2 * groupCount];
    namedGroups = re2.namedGroups;
    numberOfInstructions = re2.numberOfInstructions();
  }

  /** Creates a new {@code Matcher} with the given pattern and input. */
  Matcher(Pattern pattern, CharSequence input) {
    this(pattern);
    reset(input);
  }

  Matcher(Pattern pattern, MatcherInput input) {
    this(pattern);
    reset(input);
  }

  /** Returns the {@code Pattern} associated with this {@code Matcher}. */
  public Pattern pattern() {