Protocol Buffer runtime library and 'protoc' plugin

lib/protobuf/runtime/CodedReader.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.
+
+class CodedReader {
+  static final int DEFAULT_RECURSION_LIMIT = 64;
+  static final int DEFAULT_SIZE_LIMIT = 64 << 20;
+
+  int _bufferPos = 0;
+  int _bufferSize = 0;
+  int _bufferSizeAfterLimit = 0;
+  int _currentLimit = -1;
+  int _lastTag = 0;
+  int _recursionDepth = 0;
+  int _recursionLimit;
+  int _sizeLimit;
+  int _totalBytesRetired = 0;
+
+  CodedReader(this._recursionLimit, this._sizeLimit);
+
+  void checkLastTagWas(int value) {
+    if (_lastTag != value) {
+      throw InvalidProtocolBufferException.invalidEndTag();
+    }
+  }
+
+  int getBytesUntilLimit() =>
+      _currentLimit >= 0 ? _currentLimit - (_totalBytesRetired + _bufferPos) :
+      -1;
+
+  abstract bool isAtEnd();
+
+  /**
+   * Restores the limit to a particular absolute position as returned from
+   * [_pushLimit].
+   */
+  void _popLimit(int oldLimit) {
+    _currentLimit = oldLimit;
+  }
+
+  /**
+   * Push a new limit that includes [size] bytes past the current cursor
+   * location. The method returns the current limit (absolute position).
+   */
+  int _pushLimit(int byteLimit) {
+    if (byteLimit < 0) {
+      throw InvalidProtocolBufferException.negativeSize();
+    }
+    if (_currentLimit == -1) _enableReadAhead(byteLimit);
+    byteLimit += _bufferPos;
+    int oldLimit = _currentLimit;
+    if ((oldLimit != -1 && byteLimit > oldLimit) || byteLimit > _sizeLimit) {
+      throw InvalidProtocolBufferException.truncatedMessage();
+    }
+    _currentLimit = byteLimit;
+    return oldLimit;
+  }
+
+  void _enableReadAhead(int numberOfBytes) {}
+
+  void _checkLimit() {
+    if ((_currentLimit != -1 && _bufferPos > _currentLimit) ||
+        _bufferPos > _sizeLimit) {
+      throw InvalidProtocolBufferException.truncatedMessage();
+    }
+  }
+}