133 lines
3.9 KiB
Dart
133 lines
3.9 KiB
Dart
import 'dart:typed_data';
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import 'package:pointycastle/asn1/asn1_encoding_rule.dart';
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import 'package:pointycastle/asn1/asn1_object.dart';
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import 'package:pointycastle/asn1/asn1_parser.dart';
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import 'package:pointycastle/asn1/asn1_tags.dart';
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import 'package:pointycastle/asn1/asn1_utils.dart';
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import 'package:pointycastle/asn1/unsupported_asn1_encoding_rule_exception.dart';
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///
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/// An ASN1 Octed String object
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///
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class ASN1OctetString extends ASN1Object {
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///
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/// The decoded string value
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///
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Uint8List? octets;
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///
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/// A list of elements. Only set if this ASN1OctetString is constructed, otherwhise null.
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///
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List<ASN1Object>? elements;
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///
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/// Create an [ASN1OctetString] entity with the given [octets].
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///
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ASN1OctetString({this.octets, this.elements, int tag = ASN1Tags.OCTET_STRING})
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: super(tag: tag);
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///
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/// Creates an [ASN1OctetString] entity from the given [encodedBytes].
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///
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ASN1OctetString.fromBytes(Uint8List encodedBytes)
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: super.fromBytes(encodedBytes) {
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if (ASN1Utils.isConstructed(encodedBytes.elementAt(0))) {
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elements = [];
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var parser = ASN1Parser(valueBytes);
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var bytes = <int>[];
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while (parser.hasNext()) {
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var octetString = parser.nextObject() as ASN1OctetString;
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bytes.addAll(octetString.octets!);
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elements!.add(octetString);
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}
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octets = Uint8List.fromList(bytes);
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} else {
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octets = valueBytes;
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}
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}
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///
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/// Encodes this ASN1Object depending on the given [encodingRule]
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///
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/// If no [ASN1EncodingRule] is given, ENCODING_DER will be used.
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///
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/// Supported encoding rules are :
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/// * [ASN1EncodingRule.ENCODING_DER]
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/// * [ASN1EncodingRule.ENCODING_BER_LONG_LENGTH_FORM]
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/// * [ASN1EncodingRule.ENCODING_BER_CONSTRUCTED]
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/// * [ASN1EncodingRule.ENCODING_BER_CONSTRUCTED_INDEFINITE_LENGTH]
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///
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/// Throws an [UnsupportedAsn1EncodingRuleException] if the given [encodingRule] is not supported.
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///
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@override
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Uint8List encode(
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{ASN1EncodingRule encodingRule = ASN1EncodingRule.ENCODING_DER}) {
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switch (encodingRule) {
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case ASN1EncodingRule.ENCODING_DER:
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case ASN1EncodingRule.ENCODING_BER_LONG_LENGTH_FORM:
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valueByteLength = octets!.length;
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valueBytes = octets;
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break;
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case ASN1EncodingRule.ENCODING_BER_CONSTRUCTED:
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case ASN1EncodingRule.ENCODING_BER_CONSTRUCTED_INDEFINITE_LENGTH:
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valueByteLength = 0;
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if (elements == null) {
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elements!.add(ASN1OctetString(octets: octets));
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}
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valueByteLength = _childLength(
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isIndefinite: encodingRule ==
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ASN1EncodingRule.ENCODING_BER_CONSTRUCTED_INDEFINITE_LENGTH);
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valueBytes = Uint8List(valueByteLength!);
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var i = 0;
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for (var obj in elements!) {
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var b = obj.encode();
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valueBytes!.setRange(i, i + b.length, b);
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i += b.length;
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}
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break;
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case ASN1EncodingRule.ENCODING_BER_PADDED:
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throw UnsupportedAsn1EncodingRuleException(encodingRule);
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}
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return super.encode(encodingRule: encodingRule);
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}
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///
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/// Calculate encoded length of all children
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///
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int _childLength({bool isIndefinite = false}) {
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var l = 0;
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for (var obj in elements!) {
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l += obj.encode().length;
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}
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if (isIndefinite) {
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return l + 2;
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}
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return l;
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}
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@override
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String dump({int spaces = 0}) {
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var sb = StringBuffer();
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for (var i = 0; i < spaces; i++) {
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sb.write(' ');
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}
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if (isConstructed!) {
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sb.write('OCTET STRING (${elements!.length} elem)');
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for (var e in elements!) {
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var dump = e.dump(spaces: spaces + dumpIndent);
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sb.write('\n $dump');
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}
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} else {
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sb.write('OCTET STRING (${octets!.length} byte) ');
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for (var o in octets!) {
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var s = o.toRadixString(16).toUpperCase();
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if (s.length == 1) {
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s = '0$s';
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}
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sb.write(s);
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}
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}
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return sb.toString();
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}
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}
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