Index: lib/src/hex/encoder.dart |
diff --git a/lib/src/hex/encoder.dart b/lib/src/hex/encoder.dart |
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index 0000000000000000000000000000000000000000..cae55a09afcbe5180ec97fbf7d267ff5421fe61c |
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+++ b/lib/src/hex/encoder.dart |
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+// Copyright (c) 2015, 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. |
+ |
+library convert.hex.encoder; |
+ |
+import 'dart:convert'; |
+ |
+import 'package:charcode/ascii.dart'; |
+ |
+/// The canonical instance of [HexEncoder]. |
+const hexEncoder = const HexEncoder._(); |
+ |
+/// A converter that encodes byte arrays into hexadecimal strings. |
+/// |
+/// This will throw a [RangeError] if the byte array has any digits that don't |
+/// fit in the gamut of a byte. |
+class HexEncoder extends Converter<List<int>, String> { |
+ const HexEncoder._(); |
+ |
+ String convert(List<int> bytes) { |
+ var buffer = new StringBuffer(); |
Lasse Reichstein Nielsen
2015/09/23 08:32:04
Use an Uint8List instead of a StringBuffer. String
nweiz
2015/09/23 22:04:21
Done.
|
+ for (var byte in bytes) { |
+ RangeError.checkValueInInterval(byte, 0, 255); |
+ buffer.writeCharCode(_codeUnitForDigit(byte ~/ 16)); |
+ buffer.writeCharCode(_codeUnitForDigit(byte % 16)); |
+ } |
+ return buffer.toString(); |
+ } |
+ |
+ /// Returns the ASCII/Unicode code unit corresponding to the hexadecimal digit |
+ /// [digit]. |
+ int _codeUnitForDigit(int digit) => digit < 10 ? digit + $0 : digit + $a - 10; |
Lasse Reichstein Nielsen
2015/09/23 08:32:04
Maybe just use "0123456789abcdef".codeUnitAt(digit
nweiz
2015/09/23 22:04:21
Will a memory read really be better than simple ar
Lasse Reichstein Nielsen
2015/09/24 08:07:01
It's not simple arithmetic - there is an unpredict
nweiz
2015/09/24 23:23:42
I'm going to leave this as-is for now. We can come
|
+ |
+ ByteConversionSink startChunkedConversion(Sink<String> sink) => |
+ new _HexEncoderSink(sink); |
+} |
+ |
+/// A sink for chunked hexadecimal encoding. |
+class _HexEncoderSink extends ByteConversionSinkBase { |
+ /// The underlying sink to which decoded byte arrays will be passed. |
+ final Sink<String> _sink; |
+ |
+ _HexEncoderSink(this._sink); |
+ |
+ void add(List<int> chunk) { |
+ _sink.add(hexEncoder.convert(chunk)); |
+ } |
Lasse Reichstein Nielsen
2015/09/23 08:32:04
Consider implementing the addSlice function (and h
nweiz
2015/09/23 22:04:21
Done.
|
+ |
+ void close() { |
+ _sink.close(); |
+ } |
+} |