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pkg/dev_compiler/tool/input_sdk/lib/io/bytes_builder.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;
-
-/**
- * Builds a list of bytes, allowing bytes and lists of bytes to be added at the
- * end.
- *
- * Used to efficiently collect bytes and lists of bytes.
- */
-abstract class BytesBuilder {
-  /**
-   * Construct a new empty [BytesBuilder].
-   *
-   * If [copy] is true, the data is always copied when added to the list. If
-   * it [copy] is false, the data is only copied if needed. That means that if
-   * the lists are changed after added to the [BytesBuilder], it may effect the
-   * output. Default is `true`.
-   */
-  factory BytesBuilder({bool copy: true}) {
-    if (copy) {
-      return new _CopyingBytesBuilder();
-    } else {
-      return new _BytesBuilder();
-    }
-  }
-
-  /**
-   * Appends [bytes] to the current contents of the builder.
-   *
-   * Each value of [bytes] will be bit-representation truncated to the range
-   * 0 .. 255.
-   */
-  void add(List<int> bytes);
-
-  /**
-   * Append [byte] to the current contents of the builder.
-   *
-   * The [byte] will be bit-representation truncated to the range 0 .. 255.
-   */
-  void addByte(int byte);
-
-  /**
-   * Returns the contents of `this` and clears `this`.
-   *
-   * The list returned is a view of the internal buffer, limited to the
-   * [length].
-   */
-  List<int> takeBytes();
-
-  /**
-   * Returns a copy of the current contents of the builder.
-   *
-   * Leaves the contents of the builder intact.
-   */
-  List<int> toBytes();
-
-  /**
-   * The number of bytes in the builder.
-   */
-  int get length;
-
-  /**
-   * Returns `true` if the buffer is empty.
-   */
-  bool get isEmpty;
-
-  /**
-   * Returns `true` if the buffer is not empty.
-   */
-  bool get isNotEmpty;
-
-  /**
-   * Clear the contents of the builder.
-   */
-  void clear();
-}
-
-
-class _CopyingBytesBuilder implements BytesBuilder {
-  // Start with 1024 bytes.
-  static const int _INIT_SIZE = 1024;
-
-  int _length = 0;
-  Uint8List _buffer;
-
-  void add(List<int> bytes) {
-    int bytesLength = bytes.length;
-    if (bytesLength == 0) return;
-    int required = _length + bytesLength;
-    if (_buffer == null) {
-      int size = _pow2roundup(required);
-      size = max(size, _INIT_SIZE);
-      _buffer = new Uint8List(size);
-    } else if (_buffer.length < required) {
-      // We will create a list in the range of 2-4 times larger than
-      // required.
-      int size = _pow2roundup(required) * 2;
-      var newBuffer = new Uint8List(size);
-      newBuffer.setRange(0, _buffer.length, _buffer);
-      _buffer = newBuffer;
-    }
-    assert(_buffer.length >= required);
-    if (bytes is Uint8List) {
-      _buffer.setRange(_length, required, bytes);
-    } else {
-      for (int i = 0; i < bytesLength; i++) {
-        _buffer[_length + i] = bytes[i];
-      }
-    }
-    _length = required;
-  }
-
-  void addByte(int byte) { add([byte]); }
-
-  List<int> takeBytes() {
-    if (_buffer == null) return new Uint8List(0);
-    var buffer = new Uint8List.view(_buffer.buffer, 0, _length);
-    clear();
-    return buffer;
-  }
-
-  List<int> toBytes() {
-    if (_buffer == null) return new Uint8List(0);
-    return new Uint8List.fromList(
-        new Uint8List.view(_buffer.buffer, 0, _length));
-  }
-
-  int get length => _length;
-
-  bool get isEmpty => _length == 0;
-
-  bool get isNotEmpty => _length != 0;
-
-  void clear() {
-    _length = 0;
-    _buffer = null;
-  }
-
-  int _pow2roundup(int x) {
-    --x;
-    x |= x >> 1;
-    x |= x >> 2;
-    x |= x >> 4;
-    x |= x >> 8;
-    x |= x >> 16;
-    return x + 1;
-  }
-}
-
-
-class _BytesBuilder implements BytesBuilder {
-  int _length = 0;
-  final _chunks = <List<int>>[];
-
-  void add(List<int> bytes) {
-    if (bytes is! Uint8List) {
-      bytes = new Uint8List.fromList(bytes);
-    }
-    _chunks.add(bytes);
-    _length += bytes.length;
-  }
-
-  void addByte(int byte) { add([byte]); }
-
-  List<int> takeBytes() {
-    if (_chunks.length == 0) return new Uint8List(0);
-    if (_chunks.length == 1) {
-      var buffer = _chunks.single;
-      clear();
-      return buffer;
-    }
-    var buffer = new Uint8List(_length);
-    int offset = 0;
-    for (var chunk in _chunks) {
-      buffer.setRange(offset, offset + chunk.length, chunk);
-      offset += chunk.length;
-    }
-    clear();
-    return buffer;
-  }
-
-  List<int> toBytes() {
-    if (_chunks.length == 0) return new Uint8List(0);
-    var buffer = new Uint8List(_length);
-    int offset = 0;
-    for (var chunk in _chunks) {
-      buffer.setRange(offset, offset + chunk.length, chunk);
-      offset += chunk.length;
-    }
-    return buffer;
-  }
-
-  int get length => _length;
-
-  bool get isEmpty => _length == 0;
-
-  bool get isNotEmpty => _length != 0;
-
-  void clear() {
-    _length = 0;
-    _chunks.clear();
-  }
-}