sdk/lib/_internal/compiler/implementation/scanner/byte_array_scanner.dart

// Copyright (c) 2011, 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.

/**
 * Scanner that reads from a byte array and creates tokens that points
 * to the same array.
 */
class ByteArrayScanner extends ArrayBasedScanner<ByteString> {
  final List<int> bytes;

  ByteArrayScanner(List<int> this.bytes, [bool includeComments = false])
    : super(includeComments);

  int nextByte() => byteAt(++byteOffset);

  int peek() => byteAt(byteOffset + 1);

  int byteAt(int index) => bytes[index];

  AsciiString asciiString(int start, int offset) {
    return AsciiString.of(bytes, start, byteOffset - start + offset);
  }

  Utf8String utf8String(int start, int offset) {
    return Utf8String.of(bytes, start, byteOffset - start + offset + 1);
  }

  void appendByteStringToken(PrecedenceInfo info, ByteString value) {
    tail.next = new ByteStringToken(info, value, tokenStart);
    tail = tail.next;
  }

  // This method should be equivalent to the one in super. However,
  // this is a *HOT* method and Dart VM performs better if it is easy
  // to inline.
  int advance() => bytes[++byteOffset];
}