Move scanner into pkg/front_end/lib/src/scanner.

pkg/analyzer/lib/src/dart/scanner/reader.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.src.dart.scanner.reader;
 
+import 'package:front_end/src/scanner/reader.dart';
+
+export 'package:front_end/src/scanner/reader.dart' show CharacterReader;
+
 /**
  * A [CharacterReader] that reads a range of characters from another character
  * reader.
  */
 class CharacterRangeReader extends CharacterReader {
   /**
    * The reader from which the characters are actually being read.
    */
   final CharacterReader baseReader;
 
@@ skipping 33 matching lines @@
   @override
   int peek() {
     if (baseReader.offset + 1 >= endIndex) {
       return -1;
     }
     return baseReader.peek();
   }
 }
 
 /**
- * An object used by the scanner to read the characters to be scanned.
- */
-abstract class CharacterReader {
-  /**
-   * The current offset relative to the beginning of the source. Return the
-   * initial offset if the scanner has not yet scanned the source code, and one
-   * (1) past the end of the source code if the entire source code has been
-   * scanned.
-   */
-  int get offset;
-
-  /**
-   * Set the current offset relative to the beginning of the source to the given
-   * [offset]. The new offset must be between the initial offset and one (1)
-   * past the end of the source code.
-   */
-  void set offset(int offset);
-
-  /**
-   * Advance the current position and return the character at the new current
-   * position.
-   */
-  int advance();
-
-  /**
-   * Return the substring of the source code between the [start] offset and the
-   * modified current position. The current position is modified by adding the
-   * [endDelta], which is the number of characters after the current location to
-   * be included in the string, or the number of characters before the current
-   * location to be excluded if the offset is negative.
-   */
-  String getString(int start, int endDelta);
-
-  /**
-   * Return the character at the current position without changing the current
-   * position.
-   */
-  int peek();
-}
-
-/**
  * A [CharacterReader] that reads characters from a character sequence.
  */
 class CharSequenceReader implements CharacterReader {
   /**
    * The sequence from which characters will be read.
    */
   final String _sequence;
 
   /**
    * The number of characters in the string.
@@ skipping 67 matching lines @@
 
   @override
   void set offset(int offset) {
     super.offset = offset - _offsetDelta;
   }
 
   @override
   String getString(int start, int endDelta) =>
       super.getString(start - _offsetDelta, endDelta);
 }