summary refs log tree commit diff
path: root/crypto/src/asn1/ConstructedOctetStream.cs
blob: d005f9fe70b6dac9a022ecbf78cfb468acdd4c03 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
using System;
using System.IO;

using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.IO;

namespace Org.BouncyCastle.Asn1
{
	internal class ConstructedOctetStream
		: BaseInputStream
	{
		private readonly Asn1StreamParser m_parser;

		private bool m_first = true;
		private Stream m_currentStream;

		internal ConstructedOctetStream(Asn1StreamParser parser)
		{
			m_parser = parser;
		}

		public override int Read(byte[] buffer, int offset, int count)
		{
			Streams.ValidateBufferArguments(buffer, offset, count);

#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
			return Read(buffer.AsSpan(offset, count));
#else
			if (count < 1)
                return 0;

			if (m_currentStream == null)
			{
				if (!m_first)
					return 0;

                Asn1OctetStringParser next = GetNextParser();
                if (next == null)
                    return 0;

				m_first = false;
				m_currentStream = next.GetOctetStream();
			}

			int totalRead = 0;

			for (;;)
			{
				int numRead = m_currentStream.Read(buffer, offset + totalRead, count - totalRead);

				if (numRead > 0)
				{
					totalRead += numRead;

					if (totalRead == count)
						return totalRead;
				}
				else
				{
                    Asn1OctetStringParser next = GetNextParser();
                    if (next == null)
					{
						m_currentStream = null;
						return totalRead;
					}

					m_currentStream = next.GetOctetStream();
				}
			}
#endif
		}

#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
		public override int Read(Span<byte> buffer)
		{
			if (buffer.IsEmpty)
                return 0;

			if (m_currentStream == null)
			{
				if (!m_first)
					return 0;

                Asn1OctetStringParser next = GetNextParser();
                if (next == null)
                    return 0;

				m_first = false;
				m_currentStream = next.GetOctetStream();
			}

			int totalRead = 0;

			for (;;)
			{
				int numRead = m_currentStream.Read(buffer[totalRead..]);

				if (numRead > 0)
				{
					totalRead += numRead;

					if (totalRead == buffer.Length)
						return totalRead;
				}
				else
				{
                    Asn1OctetStringParser next = GetNextParser();
                    if (next == null)
					{
						m_currentStream = null;
						return totalRead;
					}

					m_currentStream = next.GetOctetStream();
				}
			}
		}
#endif

		public override int ReadByte()
		{
			if (m_currentStream == null)
			{
				if (!m_first)
					return -1;

                Asn1OctetStringParser next = GetNextParser();
                if (next == null)
					return -1;

				m_first = false;
				m_currentStream = next.GetOctetStream();
			}

			for (;;)
			{
				int b = m_currentStream.ReadByte();

				if (b >= 0)
					return b;

                Asn1OctetStringParser next = GetNextParser();
                if (next == null)
				{
					m_currentStream = null;
					return -1;
				}

				m_currentStream = next.GetOctetStream();
			}
		}

        private Asn1OctetStringParser GetNextParser()
        {
            IAsn1Convertible asn1Obj = m_parser.ReadObject();
            if (asn1Obj == null)
                return null;

            if (asn1Obj is Asn1OctetStringParser)
                return (Asn1OctetStringParser)asn1Obj;

            throw new IOException("unknown object encountered: " + Platform.GetTypeName(asn1Obj));
        }
	}
}