KCodecs

kcodecsbase64.h
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1/* -*- c++ -*-
2 SPDX-FileCopyrightText: 2001-2002 Marc Mutz <mutz@kde.org>
3
4 SPDX-License-Identifier: LGPL-2.0-or-later
5*/
6/**
7 @file
8 This file is part of the API for handling @ref MIME data and
9 defines the @ref Base64 and @ref RFC2047B @ref Codec classes.
10
11 @brief
12 Defines the Base64Codec and Rfc2047BEncodingCodec classes.
13
14 @authors Marc Mutz <mutz@kde.org>
15
16 @glossary @anchor Base64 @anchor base64 @b base64:
17 a binary to text encoding scheme based on @ref RFC1421.
18
19 @glossary @anchor RFC1421 @anchor rfc1421 @b RFC @b 1421:
20 RFC that defines the <a href="http://tools.ietf.org/html/rfc1421">
21 Privacy Enhancement for Internet Electronic Mail: Part I:
22 Message Encryption and Authentication Procedures</a>.
23
24 @glossary @anchor RFC2045 @anchor rfc2045 @b RFC @b 2045:
25 RFC that defines the <a href="http://tools.ietf.org/html/rfc2045">
26 MIME Part One: Format of Internet Message Bodies</a>.
27
28 @glossary @anchor RFC2047 @anchor rfc2047 @b RFC @b 2047:
29 RFC that defines the <a href="http://tools.ietf.org/html/rfc2047">
30 MIME Part Three: Message Header Extensions for Non-ASCII Text</a>.
31
32 @glossary @anchor RFC2047B @anchor rfc2047b @b RFC @b 2047B:
33 Section 4.1 of @ref RFC2047.
34*/
35
36#ifndef KCODECS_BASE64_H
37#define KCODECS_BASE64_H
38
39#include "kcodecs.h"
40
41namespace KCodecs
42{
43/**
44 @brief
45 A class representing the @ref codec for @ref Base64 as specified in
46 @ref RFC2045
47*/
48class Base64Codec : public Codec
49{
50public:
51 /**
52 Constructs a Base64 codec.
53 */
55 : Codec()
56 {
57 }
58
59 /**
60 Destroys the codec.
61 */
62 ~Base64Codec() override
63 {
64 }
65
66 /**
67 @copydoc
68 Codec::name()
69 */
70 const char *name() const override
71 {
72 return "base64";
73 }
74
75 /**
76 @copydoc
77 Codec::maxEncodedSizeFor()
78 */
79 qsizetype maxEncodedSizeFor(qsizetype insize, NewlineType newline) const override
80 {
81 // first, the total number of 4-char packets will be:
82 qsizetype totalNumPackets = (insize + 2) / 3;
83 // now, after every 76/4'th packet there needs to be a linebreak:
84 qsizetype numLineBreaks = totalNumPackets / (76 / 4);
85 // and at the very end, too:
86 ++numLineBreaks;
87 // putting it all together, we have:
88 return 4 * totalNumPackets + (newline == Codec::NewlineCRLF ? 2 : 1) * numLineBreaks;
89 }
90
91 /**
92 @copydoc
93 Codec::maxDecodedSizeFor()
94 */
95 qsizetype maxDecodedSizeFor(qsizetype insize, NewlineType newline = Codec::NewlineLF) const override
96 {
97 // assuming all characters are part of the base64 stream (which
98 // does almost never hold due to required linebreaking; but
99 // additional non-base64 chars don't affect the output size), each
100 // 4-tupel of them becomes a 3-tupel in the decoded octet
101 // stream. So:
102 qsizetype result = ((insize + 3) / 4) * 3;
103 // but all of them may be \n, so
104 if (newline == Codec::NewlineCRLF) {
105 result *= 2; // :-o
106 }
107
108 return result;
109 }
110
111 /**
112 @copydoc
113 Codec::makeEncoder()
114 */
115 Encoder *makeEncoder(NewlineType newline = Codec::NewlineLF) const override;
116
117 /**
118 @copydoc
119 Codec::makeDecoder()
120 */
121 Decoder *makeDecoder(NewlineType newline = Codec::NewlineLF) const override;
122};
123
124/**
125 @brief
126 A class representing the @ref codec for the B encoding as specified
127 in @ref RFC2047B.
128*/
130{
131public:
132 /**
133 Constructs a RFC2047B codec.
134 */
136 : Base64Codec()
137 {
138 }
139
140 /**
141 Destroys the codec.
142 */
144 {
145 }
146
147 /**
148 @copydoc
149 Codec::name()
150 */
151 const char *name() const override
152 {
153 return "b";
154 }
155
156 /**
157 @copydoc
158 Codec::maxEncodedSizeFor()
159 */
160 qsizetype maxEncodedSizeFor(qsizetype insize, NewlineType newline = Codec::NewlineLF) const override
161 {
162 Q_UNUSED(newline);
163 // Each (begun) 3-octet triple becomes a 4 char quartet, so:
164 return ((insize + 2) / 3) * 4;
165 }
166
167 /**
168 @copydoc
169 Codec::maxDecodedSizeFor()
170 */
171 qsizetype maxDecodedSizeFor(qsizetype insize, NewlineType newline = Codec::NewlineLF) const override
172 {
173 Q_UNUSED(newline);
174 // Each 4-char quartet becomes a 3-octet triple, the last one
175 // possibly even less. So:
176 return ((insize + 3) / 4) * 3;
177 }
178
179 /**
180 @copydoc
181 Codec::makeEncoder()
182 */
183 Encoder *makeEncoder(NewlineType newline = Codec::NewlineLF) const override;
184};
185
186} // namespace KCodecs
187
188#endif // KCODECS_BASE64_H
A class representing the codec for Base64 as specified in RFC2045.
const char * name() const override
Decoder * makeDecoder(NewlineType newline=Codec::NewlineLF) const override
Encoder * makeEncoder(NewlineType newline=Codec::NewlineLF) const override
qsizetype maxEncodedSizeFor(qsizetype insize, NewlineType newline) const override
Base64Codec()
Constructs a Base64 codec.
qsizetype maxDecodedSizeFor(qsizetype insize, NewlineType newline=Codec::NewlineLF) const override
~Base64Codec() override
Destroys the codec.
An abstract base class of codecs for common mail transfer encodings.
Stateful CTE decoder class.
Stateful encoder class.
A class representing the codec for the B encoding as specified in RFC2047B.
~Rfc2047BEncodingCodec() override
Destroys the codec.
const char * name() const override
qsizetype maxEncodedSizeFor(qsizetype insize, NewlineType newline=Codec::NewlineLF) const override
qsizetype maxDecodedSizeFor(qsizetype insize, NewlineType newline=Codec::NewlineLF) const override
Encoder * makeEncoder(NewlineType newline=Codec::NewlineLF) const override
Rfc2047BEncodingCodec()
Constructs a RFC2047B codec.
A wrapper class for the most commonly used encoding and decoding algorithms.
Definition kcodecs.cpp:41
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