1//
2// Base32Decoder.cpp
3//
4// Library: Foundation
5// Package: Streams
6// Module: Base32
7//
8// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
9// and Contributors.
10//
11// SPDX-License-Identifier: BSL-1.0
12//
13
14
15#include "Poco/Base32Decoder.h"
16#include "Poco/Base32Encoder.h"
17#include "Poco/Exception.h"
18#include "Poco/Mutex.h"
19#include <cstring>
20
21
22namespace Poco {
23
24
25unsigned char Base32DecoderBuf::IN_ENCODING[256];
26bool Base32DecoderBuf::IN_ENCODING_INIT = false;
27
28
29namespace
30{
31 static FastMutex mutex;
32}
33
34
35Base32DecoderBuf::Base32DecoderBuf(std::istream& istr):
36 _groupLength(0),
37 _groupIndex(0),
38 _buf(*istr.rdbuf())
39{
40 FastMutex::ScopedLock lock(mutex);
41 if (!IN_ENCODING_INIT)
42 {
43 for (unsigned i = 0; i < sizeof(IN_ENCODING); i++)
44 {
45 IN_ENCODING[i] = 0xFF;
46 }
47 for (unsigned i = 0; i < sizeof(Base32EncoderBuf::OUT_ENCODING); i++)
48 {
49 IN_ENCODING[Base32EncoderBuf::OUT_ENCODING[i]] = i;
50 }
51 IN_ENCODING[static_cast<unsigned char>('=')] = '\0';
52 IN_ENCODING_INIT = true;
53 }
54}
55
56
57Base32DecoderBuf::~Base32DecoderBuf()
58{
59}
60
61
62int Base32DecoderBuf::readFromDevice()
63{
64 if (_groupIndex < _groupLength)
65 {
66 return _group[_groupIndex++];
67 }
68 else
69 {
70 unsigned char buffer[8];
71 std::memset(buffer, '=', sizeof(buffer));
72 int c;
73
74 // per RFC-4648, Section 6, permissible block lengths are:
75 // 2, 4, 5, 7, and 8 bytes. Any other length is malformed.
76 //
77 do {
78 if ((c = readOne()) == -1) return -1;
79 buffer[0] = (unsigned char) c;
80 if (IN_ENCODING[buffer[0]] == 0xFF) throw DataFormatException();
81 if ((c = readOne()) == -1) throw DataFormatException();
82 buffer[1] = (unsigned char) c;
83 if (IN_ENCODING[buffer[1]] == 0xFF) throw DataFormatException();
84 if ((c = readOne()) == -1) break;
85 buffer[2] = (unsigned char) c;
86 if (IN_ENCODING[buffer[2]] == 0xFF) throw DataFormatException();
87 if ((c = readOne()) == -1) throw DataFormatException();
88 buffer[3] = (unsigned char) c;
89 if (IN_ENCODING[buffer[3]] == 0xFF) throw DataFormatException();
90 if ((c = readOne()) == -1) break;
91 buffer[4] = (unsigned char) c;
92 if (IN_ENCODING[buffer[4]] == 0xFF) throw DataFormatException();
93 if ((c = readOne()) == -1) break;
94 buffer[5] = (unsigned char) c;
95 if (IN_ENCODING[buffer[5]] == 0xFF) throw DataFormatException();
96 if ((c = readOne()) == -1) throw DataFormatException();
97 buffer[6] = (unsigned char) c;
98 if (IN_ENCODING[buffer[6]] == 0xFF) throw DataFormatException();
99 if ((c = readOne()) == -1) break;
100 buffer[7] = (unsigned char) c;
101 if (IN_ENCODING[buffer[7]] == 0xFF) throw DataFormatException();
102 } while (false);
103
104 _group[0] = (IN_ENCODING[buffer[0]] << 3) | (IN_ENCODING[buffer[1]] >> 2);
105 _group[1] = ((IN_ENCODING[buffer[1]] & 0x03) << 6) | (IN_ENCODING[buffer[2]] << 1) | (IN_ENCODING[buffer[3]] >> 4);
106 _group[2] = ((IN_ENCODING[buffer[3]] & 0x0F) << 4) | (IN_ENCODING[buffer[4]] >> 1);
107 _group[3] = ((IN_ENCODING[buffer[4]] & 0x01) << 7) | (IN_ENCODING[buffer[5]] << 2) | (IN_ENCODING[buffer[6]] >> 3);
108 _group[4] = ((IN_ENCODING[buffer[6]] & 0x07) << 5) | IN_ENCODING[buffer[7]];
109
110 if (buffer[2] == '=')
111 _groupLength = 1;
112 else if (buffer[4] == '=')
113 _groupLength = 2;
114 else if (buffer[5] == '=')
115 _groupLength = 3;
116 else if (buffer[7] == '=')
117 _groupLength = 4;
118 else
119 _groupLength = 5;
120 _groupIndex = 1;
121 return _group[0];
122 }
123}
124
125
126int Base32DecoderBuf::readOne()
127{
128 int ch = _buf.sbumpc();
129 return ch;
130}
131
132
133Base32DecoderIOS::Base32DecoderIOS(std::istream& istr): _buf(istr)
134{
135 poco_ios_init(&_buf);
136}
137
138
139Base32DecoderIOS::~Base32DecoderIOS()
140{
141}
142
143
144Base32DecoderBuf* Base32DecoderIOS::rdbuf()
145{
146 return &_buf;
147}
148
149
150Base32Decoder::Base32Decoder(std::istream& istr): Base32DecoderIOS(istr), std::istream(&_buf)
151{
152}
153
154
155Base32Decoder::~Base32Decoder()
156{
157}
158
159
160} // namespace Poco
161