Add missing files from previous commit

sdk/lib/io/string_transformer.dart

+// Copyright (c) 2013, 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.
+
+part of dart.io;
+
+/**
+ * Stream transformer that can decode a stream of bytes into a stream of
+ * strings using [encoding].
+ *
+ * Invalid or forbidden byte-sequences will not produce errors, but will instead
+ * insert [replacementChar] in the decoded strings.
+ */
+class StringDecoder implements StreamTransformer<List<int>, String> {
+  var _decoder;
+
+  /**
+   * Create a new [StringDecoder] with an optional [encoding] and
+   * [replacementChar].
+   */
+  StringDecoder([Encoding encoding = Encoding.UTF_8, int replacementChar]) {
+    switch (encoding) {
+      case Encoding.UTF_8:
+        if (replacementChar == null) {
+          replacementChar = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT;
+        }
+        _decoder = new Utf8DecoderTransformer(replacementChar);
+        break;
+      case Encoding.ASCII:
+        if (replacementChar == null) {
+          replacementChar = '?'.charCodeAt(0);
+        } else if (replacementChar > 127) {
+          throw new ArgumentError("Invalid replacement character for ASCII");
+        }
+        _decoder = new _AsciiDecoder(replacementChar);
+        break;
+      case Encoding.ISO_8859_1:
+        if (replacementChar == null) {
+          replacementChar = '?'.charCodeAt(0);
+        } else if (replacementChar > 255) {
+          throw new ArgumentError(
+              "Invalid replacement character for ISO_8859_1");
+        }
+        _decoder = new _Latin1Decoder(replacementChar);
+        break;
+      case Encoding.SYSTEM:
+        if (Platform.operatingSystem == "windows") {
+          _decoder = new _WindowsCodePageDecoder();
+        } else {
+          if (replacementChar != null) {
+            // TODO(ajohnsen): Handle replacement character.
+            throw new UnsupportedError(
+                "Replacement character is not supported for SYSTEM encoding");
+          }
+          _decoder = new Utf8DecoderTransformer();
+        }
+        break;
+      default:
+        throw new ArgumentError("Unsupported encoding '$encoding'");
+    }
+  }
+
+  Stream<String> bind(Stream<List<int>> stream) => _decoder.bind(stream);
+}
+
+
+/**
+ * Stream transformer that can encode a stream of strings info a stream of
+ * bytes using [encoding].
+ *
+ * Strings that cannot be represented in the given encoding will result in an
+ * error and a close event on the stream.
+ */
+class StringEncoder implements StreamTransformer<String, List<int>> {
+  var _encoder;
+
+  /**
+   * Create a new [StringDecoder] with an optional [encoding] and
+   * [replacementChar].
+   */
+  StringEncoder([Encoding encoding = Encoding.UTF_8]) {
+    switch (encoding) {
+      case Encoding.UTF_8:
+        _encoder = new Utf8EncoderTransformer();
+        break;
+      case Encoding.ASCII:
+        _encoder = new _AsciiEncoder();
+        break;
+      case Encoding.ISO_8859_1:
+        _encoder = new _Latin1Encoder();
+        break;
+      case Encoding.SYSTEM:
+        if (Platform.operatingSystem == "windows") {
+          _encoder = new _WindowsCodePageEncoder();
+        } else {
+          _encoder = new Utf8EncoderTransformer();
+        }
+        break;
+      default:
+        throw new ArgumentError("Unsupported encoding '$encoding'");
+    }
+  }
+
+  Stream<List<int>> bind(Stream<String> stream) => _encoder.bind(stream);
+}
+
+
+// Utility function to synchronously decode a list of bytes.
+String _decodeString(List<int> bytes, [Encoding encoding = Encoding.UTF_8]) {
+  if (bytes.length == 0) return "";
+  var string;
+  var controller = new StreamController();
+  controller.stream
+    .transform(new StringDecoder(encoding))
+    .listen((data) => string = data);
+  controller.add(bytes);
+  controller.close();
+  assert(string != null);
+  return string;
+}
+
+
+// Utility function to synchronously encode a String.
+// Will throw an exception if the encoding is invalid.
+List<int> _encodeString(String string, [Encoding encoding = Encoding.UTF_8]) {
+  if (string.length == 0) return [];
+  var bytes;
+  var controller = new StreamController();
+  controller.stream
+    .transform(new StringEncoder(encoding))
+    .listen((data) => bytes = data);
+  controller.add(string);
+  controller.close();
+  assert(bytes != null);
+  return bytes;
+}
+
+
+class LineTransformer implements StreamTransformer<String, String> {
+  const int _LF = 10;
+  const int _CR = 13;
+
+  final StringBuffer _buffer = new StringBuffer();
+
+  StreamSubscription<String> _subscription;
+  StreamController<String> _controller;
+  String _carry;
+
+  Stream<String> bind(Stream<String> stream) {
+    _controller = new StreamController<String>(
+        onPauseStateChange: _pauseChanged,
+        onSubscriptionStateChange: _subscriptionChanged);
+
+    void handle(String data, bool isClosing) {
+      if (_carry != null) {
+        data = _carry.concat(data);
+        _carry = null;
+      }
+      int startPos = 0;
+      int pos = 0;
+      while (pos < data.length) {
+        int skip = 0;
+        int char = data.charCodeAt(pos);
+        if (char == _LF) {
+          skip = 1;
+        } else if (char == _CR) {
+          skip = 1;
+          if (pos + 1 < data.length) {
+            if (data.charCodeAt(pos + 1) == _LF) {
+              skip = 2;
+            }
+          } else if (!isClosing) {
+            _carry = data.substring(startPos);
+            return;
+          }
+        }
+        if (skip > 0) {
+          _buffer.add(data.substring(startPos, pos));
+          _controller.add(_buffer.toString());
+          _buffer.clear();
+          startPos = pos = pos + skip;
+        } else {
+          pos++;
+        }
+      }
+      if (pos != startPos) {
+        // Add remaining
+        _buffer.add(data.substring(startPos, pos));
+      }
+      if (isClosing && !_buffer.isEmpty) {
+        _controller.add(_buffer.toString());
+        _buffer.clear();
+      }
+    }
+
+    _subscription = stream.listen(
+        (data) => handle(data, false),
+        onDone: () {
+          // Handle remaining data (mainly _carry).
+          handle("", true);
+          _controller.close();
+        },
+        onError: _controller.signalError);
+    return _controller.stream;
+  }
+
+  void _pauseChanged() {
+    if (_controller.isPaused) {
+      _subscription.pause();
+    } else {
+      _subscription.resume();
+    }
+  }
+
+  void _subscriptionChanged() {
+    if (!_controller.hasSubscribers) {
+      _subscription.cancel();
+    }
+  }
+}
+
+
+class _SingleByteDecoder implements StreamTransformer<List<int>, String> {
+  StreamSubscription<List<int>> _subscription;
+  StreamController<String> _controller;
+  final int _replacementChar;
+
+  _SingleByteDecoder(this._replacementChar);
+
+  Stream<String> bind(Stream<List<int>> stream) {
+    _controller = new StreamController<String>(
+        onPauseStateChange: _pauseChanged,
+        onSubscriptionStateChange: _subscriptionChanged);
+    _subscription = stream.listen(
+        (data) {
+          var buffer = new List<int>.fixedLength(data.length);
+          for (int i = 0; i < data.length; i++) {
+            int char = _decodeByte(data[i]);
+            if (char < 0) char = _replacementChar;
+            buffer[i] = char;
+          }
+          _controller.add(new String.fromCharCodes(buffer));
+        },
+        onDone: _controller.close,
+        onError: _controller.signalError);
+    return _controller.stream;
+  }
+
+  int _decodeByte(int byte);
+
+  void _pauseChanged() {
+    if (_controller.isPaused) {
+      _subscription.pause();
+    } else {
+      _subscription.resume();
+    }
+  }
+
+  void _subscriptionChanged() {
+    if (!_controller.hasSubscribers) {
+      _subscription.cancel();
+    }
+  }
+}
+
+
+// Utility class for decoding ascii data delivered as a stream of
+// bytes.
+class _AsciiDecoder extends _SingleByteDecoder {
+  _AsciiDecoder(int replacementChar) : super(replacementChar);
+
+  int _decodeByte(int byte) => ((byte & 0x7f) == byte) ? byte : -1;
+}
+
+
+// Utility class for decoding Latin-1 data delivered as a stream of
+// bytes.
+class _Latin1Decoder extends _SingleByteDecoder {
+  _Latin1Decoder(int replacementChar) : super(replacementChar);
+
+  int _decodeByte(int byte) => ((byte & 0xFF) == byte) ? byte : -1;
+}
+
+
+class _SingleByteEncoder implements StreamTransformer<String, List<int>> {
+  StreamSubscription<String> _subscription;
+  StreamController<List<int>> _controller;
+
+  Stream<List<int>> bind(Stream<String> stream) {
+    _controller = new StreamController<List<int>>(
+        onPauseStateChange: _pauseChanged,
+        onSubscriptionStateChange: _subscriptionChanged);
+    _subscription = stream.listen(
+        (string) {
+          var bytes = _encode(string);
+          if (bytes == null) {
+            _controller.signalError(new FormatException(
+                "Invalid character for encoding"));
+            _controller.close();
+            _subscription.cancel();
+          } else {
+            _controller.add(bytes);
+          }
+        },
+        onDone: _controller.close,
+        onError: _controller.signalError);
+    return _controller.stream;
+  }
+
+  List<int> _encode(String string);
+
+  void _pauseChanged() {
+    if (_controller.isPaused) {
+      _subscription.pause();
+    } else {
+      _subscription.resume();
+    }
+  }
+
+  void _subscriptionChanged() {
+    if (!_controller.hasSubscribers) {
+      _subscription.cancel();
+    }
+  }
+}
+
+
+// Utility class for encoding a string into an ASCII byte stream.
+class _AsciiEncoder extends _SingleByteEncoder {
+  List<int> _encode(String string) {
+    var bytes = string.charCodes;
+    for (var byte in bytes) {
+      if (byte > 127) return null;
+    }
+    return bytes;
+  }
+}
+
+
+// Utility class for encoding a string into a Latin1 byte stream.
+class _Latin1Encoder extends _SingleByteEncoder {
+  List<int> _encode(String string) {
+    var bytes = string.charCodes;
+    for (var byte in bytes) {
+      if (byte > 255) return null;
+    }
+    return bytes;
+  }
+}
+
+
+// Utility class for encoding a string into a current windows
+// code page byte list.
+// Implemented on top of a _SingleByteEncoder, even though it's not really a
+// single byte encoder, to avoid copying boilerplate.
+class _WindowsCodePageEncoder extends _SingleByteEncoder {
+  List<int> _encode(String string) => _encodeString(string);
+
+  external static List<int> _encodeString(String string);
+}
+
+
+// Utility class for decoding Windows current code page data delivered
+// as a stream of bytes.
+class _WindowsCodePageDecoder implements StreamTransformer<List<int>, String> {
+  StreamSubscription<List<int>> _subscription;
+  StreamController<String> _controller;
+
+  Stream<String> bind(Stream<List<int>> stream) {
+    _controller = new StreamController<String>(
+        onPauseStateChange: _pauseChanged,
+        onSubscriptionStateChange: _subscriptionChanged);
+    _subscription = stream.listen(
+        (data) {
+          _controller.add(_decodeBytes(data));
+        },
+        onDone: _controller.close,
+        onError: _controller.signalError);
+    return _controller.stream;
+  }
+
+  external static String _decodeBytes(List<int> bytes);
+
+  void _pauseChanged() {
+    if (_controller.isPaused) {
+      _subscription.pause();
+    } else {
+      _subscription.resume();
+    }
+  }
+
+  void _subscriptionChanged() {
+    if (!_controller.hasSubscribers) {
+      _subscription.cancel();
+    }
+  }
+}