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1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 part of dart.io; | 5 part of dart.io; |
6 | 6 |
7 /** | 7 /** |
8 * Builds a list of bytes, allowing bytes and lists of bytes to be added at the | 8 * Builds a list of bytes, allowing bytes and lists of bytes to be added at the |
9 * end. | 9 * end. |
10 * | 10 * |
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76 * Clear the contents of the builder. | 76 * Clear the contents of the builder. |
77 */ | 77 */ |
78 void clear(); | 78 void clear(); |
79 } | 79 } |
80 | 80 |
81 | 81 |
82 class _CopyingBytesBuilder implements BytesBuilder { | 82 class _CopyingBytesBuilder implements BytesBuilder { |
83 // Start with 1024 bytes. | 83 // Start with 1024 bytes. |
84 static const int _INIT_SIZE = 1024; | 84 static const int _INIT_SIZE = 1024; |
85 | 85 |
86 static final _emptyList = new Uint8List(0); | |
87 | |
88 int _length = 0; | 86 int _length = 0; |
89 Uint8List _buffer; | 87 Uint8List _buffer; |
90 | 88 |
91 _CopyingBytesBuilder([int initialCapacity = 0]) | |
92 : _buffer = (initialCapacity <= 0) | |
93 ? _emptyList | |
94 : new Uint8List(_pow2roundup(initialCapacity)); | |
95 | |
96 void add(List<int> bytes) { | 89 void add(List<int> bytes) { |
97 int bytesLength = bytes.length; | 90 int bytesLength = bytes.length; |
98 if (bytesLength == 0) return; | 91 if (bytesLength == 0) return; |
99 int required = _length + bytesLength; | 92 int required = _length + bytesLength; |
100 if (_buffer.length < required) { | 93 if (_buffer == null) { |
101 _grow(required); | 94 int size = _pow2roundup(required); |
| 95 size = max(size, _INIT_SIZE); |
| 96 _buffer = new Uint8List(size); |
| 97 } else if (_buffer.length < required) { |
| 98 // We will create a list in the range of 2-4 times larger than |
| 99 // required. |
| 100 int size = _pow2roundup(required) * 2; |
| 101 var newBuffer = new Uint8List(size); |
| 102 newBuffer.setRange(0, _buffer.length, _buffer); |
| 103 _buffer = newBuffer; |
102 } | 104 } |
103 assert(_buffer.length >= required); | 105 assert(_buffer.length >= required); |
104 if (bytes is Uint8List) { | 106 if (bytes is Uint8List) { |
105 _buffer.setRange(_length, required, bytes); | 107 _buffer.setRange(_length, required, bytes); |
106 } else { | 108 } else { |
107 for (int i = 0; i < bytesLength; i++) { | 109 for (int i = 0; i < bytesLength; i++) { |
108 _buffer[_length + i] = bytes[i]; | 110 _buffer[_length + i] = bytes[i]; |
109 } | 111 } |
110 } | 112 } |
111 _length = required; | 113 _length = required; |
112 } | 114 } |
113 | 115 |
114 void addByte(int byte) { | 116 void addByte(int byte) { add([byte]); } |
115 if (_buffer.length == _length) { | |
116 // The grow algorithm always at least doubles. | |
117 // If we added one to _length it would quadruple unnecessarily. | |
118 _grow(_length); | |
119 } | |
120 assert(_buffer.length > _length); | |
121 _buffer[_length] = byte; | |
122 _length++; | |
123 } | |
124 | |
125 void _grow(int required) { | |
126 // We will create a list in the range of 2-4 times larger than | |
127 // required. | |
128 int newSize = required * 2; | |
129 if (newSize < _INIT_SIZE) { | |
130 newSize = _INIT_SIZE; | |
131 } else { | |
132 newSize = _pow2roundup(newSize); | |
133 } | |
134 var newBuffer = new Uint8List(newSize); | |
135 newBuffer.setRange(0, _buffer.length, _buffer); | |
136 _buffer = newBuffer; | |
137 } | |
138 | 117 |
139 List<int> takeBytes() { | 118 List<int> takeBytes() { |
140 if (_length == 0) return _emptyList; | 119 if (_buffer == null) return new Uint8List(0); |
141 var buffer = new Uint8List.view(_buffer.buffer, 0, _length); | 120 var buffer = new Uint8List.view(_buffer.buffer, 0, _length); |
142 clear(); | 121 clear(); |
143 return buffer; | 122 return buffer; |
144 } | 123 } |
145 | 124 |
146 List<int> toBytes() { | 125 List<int> toBytes() { |
147 if (_length == 0) return _emptyList; | 126 if (_buffer == null) return new Uint8List(0); |
148 return new Uint8List.fromList( | 127 return new Uint8List.fromList( |
149 new Uint8List.view(_buffer.buffer, 0, _length)); | 128 new Uint8List.view(_buffer.buffer, 0, _length)); |
150 } | 129 } |
151 | 130 |
152 int get length => _length; | 131 int get length => _length; |
153 | 132 |
154 bool get isEmpty => _length == 0; | 133 bool get isEmpty => _length == 0; |
155 | 134 |
156 bool get isNotEmpty => _length != 0; | 135 bool get isNotEmpty => _length != 0; |
157 | 136 |
158 void clear() { | 137 void clear() { |
159 _length = 0; | 138 _length = 0; |
160 _buffer = _emptyList; | 139 _buffer = null; |
161 } | 140 } |
162 | 141 |
163 static int _pow2roundup(int x) { | 142 int _pow2roundup(int x) { |
164 assert(x > 0); | |
165 --x; | 143 --x; |
166 x |= x >> 1; | 144 x |= x >> 1; |
167 x |= x >> 2; | 145 x |= x >> 2; |
168 x |= x >> 4; | 146 x |= x >> 4; |
169 x |= x >> 8; | 147 x |= x >> 8; |
170 x |= x >> 16; | 148 x |= x >> 16; |
171 return x + 1; | 149 return x + 1; |
172 } | 150 } |
173 } | 151 } |
174 | 152 |
175 | 153 |
176 class _BytesBuilder implements BytesBuilder { | 154 class _BytesBuilder implements BytesBuilder { |
177 int _length = 0; | 155 int _length = 0; |
178 final List<Uint8List> _chunks = []; | 156 final List<Uint8List> _chunks = []; |
179 | 157 |
180 void add(List<int> bytes) { | 158 void add(List<int> bytes) { |
181 Uint8List typedBytes; | 159 Uint8List typedBytes; |
182 if (bytes is Uint8List) { | 160 if (bytes is Uint8List) { |
183 typedBytes = bytes; | 161 typedBytes = bytes; |
184 } else { | 162 } else { |
185 typedBytes = new Uint8List.fromList(bytes); | 163 typedBytes = new Uint8List.fromList(bytes); |
186 } | 164 } |
187 _chunks.add(typedBytes); | 165 _chunks.add(typedBytes); |
188 _length += typedBytes.length; | 166 _length += typedBytes.length; |
189 } | 167 } |
190 | 168 |
191 void addByte(int byte) { | 169 void addByte(int byte) { add([byte]); } |
192 _chunks.add(new Uint8List(1)..[0] = byte); | |
193 _length++; | |
194 } | |
195 | 170 |
196 List<int> takeBytes() { | 171 List<int> takeBytes() { |
197 if (_length == 0) return _CopyingBytesBuilder._emptyList; | 172 if (_chunks.length == 0) return new Uint8List(0); |
198 if (_chunks.length == 1) { | 173 if (_chunks.length == 1) { |
199 var buffer = _chunks[0]; | 174 var buffer = _chunks.single; |
200 clear(); | 175 clear(); |
201 return buffer; | 176 return buffer; |
202 } | 177 } |
203 var buffer = new Uint8List(_length); | 178 var buffer = new Uint8List(_length); |
204 int offset = 0; | 179 int offset = 0; |
205 for (var chunk in _chunks) { | 180 for (var chunk in _chunks) { |
206 buffer.setRange(offset, offset + chunk.length, chunk); | 181 buffer.setRange(offset, offset + chunk.length, chunk); |
207 offset += chunk.length; | 182 offset += chunk.length; |
208 } | 183 } |
209 clear(); | 184 clear(); |
210 return buffer; | 185 return buffer; |
211 } | 186 } |
212 | 187 |
213 List<int> toBytes() { | 188 List<int> toBytes() { |
214 if (_length == 0) return _CopyingBytesBuilder._emptyList; | 189 if (_chunks.length == 0) return new Uint8List(0); |
215 var buffer = new Uint8List(_length); | 190 var buffer = new Uint8List(_length); |
216 int offset = 0; | 191 int offset = 0; |
217 for (var chunk in _chunks) { | 192 for (var chunk in _chunks) { |
218 buffer.setRange(offset, offset + chunk.length, chunk); | 193 buffer.setRange(offset, offset + chunk.length, chunk); |
219 offset += chunk.length; | 194 offset += chunk.length; |
220 } | 195 } |
221 return buffer; | 196 return buffer; |
222 } | 197 } |
223 | 198 |
224 int get length => _length; | 199 int get length => _length; |
225 | 200 |
226 bool get isEmpty => _length == 0; | 201 bool get isEmpty => _length == 0; |
227 | 202 |
228 bool get isNotEmpty => _length != 0; | 203 bool get isNotEmpty => _length != 0; |
229 | 204 |
230 void clear() { | 205 void clear() { |
231 _length = 0; | 206 _length = 0; |
232 _chunks.clear(); | 207 _chunks.clear(); |
233 } | 208 } |
234 } | 209 } |
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