stream.dart
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/*
* Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// ignore_for_file: omit_local_variable_types
part of pdf;
class PdfStream {
static const int precision = 5;
static const int _grow = 65536;
Uint8List _stream = Uint8List(_grow);
int _offset = 0;
void _ensureCapacity(int size) {
if (_stream.length - _offset >= size) {
return;
}
final int newSize = math.max(_offset + size + _grow, _offset * 2);
final Uint8List newBuffer = Uint8List(newSize);
newBuffer.setAll(0, _stream);
_stream = newBuffer;
}
void putByte(int s) {
_ensureCapacity(1);
_stream[_offset++] = s;
}
void putBytes(List<int> s) {
_ensureCapacity(s.length);
_stream.setAll(_offset, s);
_offset += s.length;
}
void putStream(PdfStream s) {
putBytes(s._stream);
}
int get offset => _offset;
Uint8List output() => _stream.sublist(0, _offset);
void putString(String s) {
for (int codeUnit in s.codeUnits) {
if (codeUnit <= 0x7f) {
putByte(codeUnit);
} else {
putByte(0x20);
}
}
}
void putNum(double d) {
assert(d != double.infinity);
putString(d.toStringAsFixed(precision));
}
void putNumList(List<double> d) {
putString(d.map((double v) {
assert(v != double.infinity);
return v.toStringAsFixed(precision);
}).join(' '));
}
/// Escape special characters
/// \ddd Character code ddd (octal)
void putTextBytes(List<int> s) {
for (int c in s) {
switch (c) {
case 0x0a: // \n Line feed (LF)
putByte(0x5c);
putByte(0x6e);
break;
case 0x0d: // \r Carriage return (CR)
putByte(0x5c);
putByte(0x72);
break;
case 0x09: // \t Horizontal tab (HT)
putByte(0x5c);
putByte(0x74);
break;
case 0x08: // \b Backspace (BS)
putByte(0x5c);
putByte(0x62);
break;
case 0x0c: // \f Form feed (FF)
putByte(0x5c);
putByte(0x66);
break;
case 0x28: // \( Left parenthesis
putByte(0x5c);
putByte(0x28);
break;
case 0x29: // \) Right parenthesis
putByte(0x5c);
putByte(0x29);
break;
case 0x5c: // \\ Backslash
putByte(0x5c);
putByte(0x5c);
break;
default:
putByte(c);
}
}
}
}