blob: deb490660837c8542c056501f11ce83b25ef4213 [file] [log] [blame]
// Copyright (c) 2016, 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.
import 'dart:convert';
import 'dart:typed_data';
import 'charcodes.dart';
/// The canonical instance of [ChunkedCodingEncoder].
const chunkedCodingEncoder = ChunkedCodingEncoder._();
/// The chunk indicating that the chunked message has finished.
final _doneChunk = Uint8List.fromList([$0, $cr, $lf, $cr, $lf]);
/// A converter that encodes byte arrays into chunks with size tags.
class ChunkedCodingEncoder extends Converter<List<int>, List<int>> {
const ChunkedCodingEncoder._();
List<int> convert(List<int> input) =>
_convert(input, 0, input.length, isLast: true);
ByteConversionSink startChunkedConversion(Sink<List<int>> sink) =>
/// A conversion sink for the chunked transfer encoding.
class _Sink extends ByteConversionSinkBase {
/// The underlying sink to which encoded byte arrays will be passed.
final Sink<List<int>> _sink;
void add(List<int> chunk) {
_sink.add(_convert(chunk, 0, chunk.length));
void addSlice(List<int> chunk, int start, int end, bool isLast) {
RangeError.checkValidRange(start, end, chunk.length);
_sink.add(_convert(chunk, start, end, isLast: isLast));
if (isLast) _sink.close();
void close() {
/// Returns a new list a chunked transfer encoding header followed by the slice
/// of [bytes] from [start] to [end].
/// If [isLast] is `true`, this adds the footer that indicates that the chunked
/// message is complete.
List<int> _convert(List<int> bytes, int start, int end, {bool isLast = false}) {
if (end == start) return isLast ? _doneChunk : const [];
final size = end - start;
final sizeInHex = size.toRadixString(16);
final footerSize = isLast ? _doneChunk.length : 0;
// Add 4 for the CRLF sequences that follow the size header and the bytes.
final list = Uint8List(sizeInHex.length + 4 + size + footerSize);
list.setRange(0, sizeInHex.length, sizeInHex.codeUnits);
var cursor = sizeInHex.length;
list[cursor++] = $cr;
list[cursor++] = $lf;
list.setRange(cursor, cursor + end - start, bytes, start);
cursor += end - start;
list[cursor++] = $cr;
list[cursor++] = $lf;
if (isLast) {
list.setRange(list.length - footerSize, list.length, _doneChunk);
return list;