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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
// SPDX-License-Identifier: NONE
/*
* This is part of the libb64 project, and has been placed in the public domain.
* For details, see http://sourceforge.net/projects/libb64
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "base64.h"
static const int CHARS_PER_LINE = 72;
static const char *ENCODING =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
void base64_init_encodestate(struct base64_encodestate *state_in)
{
state_in->step = step_A;
state_in->result = 0;
state_in->stepcount = 0;
}
char base64_encode_value(char value_in)
{
if (value_in > 63)
return '=';
return ENCODING[(int)value_in];
}
int base64_encode_block(const char *plaintext_in, int length_in, char *code_out,
struct base64_encodestate *state_in)
{
const char *plainchar = plaintext_in;
const char *const plaintextend = plaintext_in + length_in;
char *codechar = code_out;
char result;
char fragment;
result = state_in->result;
switch (state_in->step) {
while (1) {
case step_A:
if (plainchar == plaintextend) {
state_in->result = result;
state_in->step = step_A;
return codechar - code_out;
}
fragment = *plainchar++;
result = (fragment & 0x0fc) >> 2;
*codechar++ = base64_encode_value(result);
result = (fragment & 0x003) << 4;
/* fall through */
case step_B:
if (plainchar == plaintextend) {
state_in->result = result;
state_in->step = step_B;
return codechar - code_out;
}
fragment = *plainchar++;
result |= (fragment & 0x0f0) >> 4;
*codechar++ = base64_encode_value(result);
result = (fragment & 0x00f) << 2;
/* fall through */
case step_C:
if (plainchar == plaintextend) {
state_in->result = result;
state_in->step = step_C;
return codechar - code_out;
}
fragment = *plainchar++;
result |= (fragment & 0x0c0) >> 6;
*codechar++ = base64_encode_value(result);
result = (fragment & 0x03f) >> 0;
*codechar++ = base64_encode_value(result);
++(state_in->stepcount);
if (state_in->stepcount == CHARS_PER_LINE/4) {
*codechar++ = '\n';
state_in->stepcount = 0;
}
}
}
/* control should not reach here */
return codechar - code_out;
}
int base64_encode_blockend(char *code_out, struct base64_encodestate *state_in)
{
char *codechar = code_out;
switch (state_in->step) {
case step_B:
*codechar++ = base64_encode_value(state_in->result);
*codechar++ = '=';
*codechar++ = '=';
break;
case step_C:
*codechar++ = base64_encode_value(state_in->result);
*codechar++ = '=';
break;
case step_A:
break;
}
*codechar++ = '\n';
return codechar - code_out;
}
signed char base64_decode_value(signed char value_in)
{
static const signed char decoding[] = {
62, -1, -1, -1, 63, 52, 53, 54,
55, 56, 57, 58, 59, 60, 61, -1,
-1, -1, -2, -1, -1, -1, 0, 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,
-1, -1, -1, -1, -1, -1, 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
};
value_in -= 43;
if (value_in < 0 || value_in >= 80)
return -1;
return decoding[(int)value_in];
}
void base64_init_decodestate(struct base64_decodestate *state_in)
{
state_in->step = step_a;
state_in->plainchar = 0;
}
int base64_decode_block(const char *code_in, int length_in, char *plaintext_out,
struct base64_decodestate *state_in)
{
const char *codec = code_in;
char *plainc = plaintext_out;
signed char fragmt;
*plainc = state_in->plainchar;
switch (state_in->step) {
while (1) {
case step_a:
do {
if (codec == code_in+length_in) {
state_in->step = step_a;
state_in->plainchar = *plainc;
return plainc - plaintext_out;
}
fragmt = base64_decode_value(*codec++);
} while (fragmt < 0);
*plainc = (fragmt & 0x03f) << 2;
/* fall through */
case step_b:
do {
if (codec == code_in+length_in) {
state_in->step = step_b;
state_in->plainchar = *plainc;
return plainc - plaintext_out;
}
fragmt = base64_decode_value(*codec++);
} while (fragmt < 0);
*plainc++ |= (fragmt & 0x030) >> 4;
*plainc = (fragmt & 0x00f) << 4;
/* fall through */
case step_c:
do {
if (codec == code_in+length_in) {
state_in->step = step_c;
state_in->plainchar = *plainc;
return plainc - plaintext_out;
}
fragmt = base64_decode_value(*codec++);
} while (fragmt < 0);
*plainc++ |= (fragmt & 0x03c) >> 2;
*plainc = (fragmt & 0x003) << 6;
/* fall through */
case step_d:
do {
if (codec == code_in+length_in) {
state_in->step = step_d;
state_in->plainchar = *plainc;
return plainc - plaintext_out;
}
fragmt = base64_decode_value(*codec++);
} while (fragmt < 0);
*plainc++ |= (fragmt & 0x03f);
}
}
/* control should not reach here */
return plainc - plaintext_out;
}
|
