dart 自己寫一個檔案編碼器
阿新 • • 發佈：2018-12-22
// import 'dart:convert';
import 'dart:io';
main() async { var src = File('./lib/convert/source.txt'); var output = File('./lib/convert/output.txt');
var ins = src.openRead(); var encoded = convert(ins, 128); var outs = output.openWrite(); await encoded.pipe(outs); outs.close();
// the second transform. var output2 = File('./lib/convert/output2.txt'); var outs2 = output2.openWrite(); await convert(output.openRead(), -128).pipe(outs2); outs2.close(); }
Stream<List<int>> convert(Stream<List<int>> source, [int key = 128, int base = 256]) async* { await for (var chunk in source) { yield encode(chunk, key, base); } }
List<int> encode(List<int> original, [int key = 128, int base = 256]) { var encoded = List<int>(original.length); for (var i = 0; i < original.length; i++) { encoded[i] = (original[i] + key) % base; } return encoded; }
main() async { var src = File('./lib/convert/source.txt'); var output = File('./lib/convert/output.txt');
var ins = src.openRead(); var encoded = convert(ins, 128); var outs = output.openWrite(); await encoded.pipe(outs); outs.close();
// the second transform. var output2 = File('./lib/convert/output2.txt'); var outs2 = output2.openWrite(); await convert(output.openRead(), -128).pipe(outs2); outs2.close(); }
Stream<List<int>> convert(Stream<List<int>> source, [int key = 128, int base = 256]) async* { await for (var chunk in source) { yield encode(chunk, key, base); } }
List<int> encode(List<int> original, [int key = 128, int base = 256]) { var encoded = List<int>(original.length); for (var i = 0; i < original.length; i++) { encoded[i] = (original[i] + key) % base; } return encoded; }