7e8da23e453bddc43227879aff83ea71c1d594de
[claws.git] / src / common / quoted-printable.c
1 /*
2  * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client
3  * Copyright (C) 1999-2003 Hiroyuki Yamamoto
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18  */
19
20 #include <glib.h>
21 #include <ctype.h>
22
23 static gboolean get_hex_value(guchar *out, gchar c1, gchar c2);
24 static void get_hex_str(gchar *out, guchar ch);
25
26 #define MAX_LINELEN     76
27
28 #define IS_LBREAK(p) \
29         (*(p) == '\0' || *(p) == '\n' || (*(p) == '\r' && *((p) + 1) == '\n'))
30
31 #define SOFT_LBREAK_IF_REQUIRED(n)                                      \
32         if (len + (n) > MAX_LINELEN ||                                  \
33             (len + (n) == MAX_LINELEN && (!IS_LBREAK(inp + 1)))) {      \
34                 *outp++ = '=';                                          \
35                 *outp++ = '\n';                                         \
36                 len = 0;                                                \
37         }
38
39 void qp_encode_line(gchar *out, const guchar *in)
40 {
41         const guchar *inp = in;
42         gchar *outp = out;
43         guchar ch;
44         gint len = 0;
45
46         while (*inp != '\0') {
47                 ch = *inp;
48
49                 if (IS_LBREAK(inp)) {
50                         *outp++ = '\n';
51                         len = 0;
52                         if (*inp == '\r')
53                                 inp++;
54                         inp++;
55                 } else if (ch == '\t' || ch == ' ') {
56                         if (IS_LBREAK(inp + 1)) {
57                                 SOFT_LBREAK_IF_REQUIRED(3);
58                                 *outp++ = '=';
59                                 get_hex_str(outp, ch);
60                                 outp += 2;
61                                 len += 3;
62                                 inp++;
63                         } else {
64                                 SOFT_LBREAK_IF_REQUIRED(1);
65                                 *outp++ = *inp++;
66                                 len++;
67                         }
68                 } else if ((ch >= 33 && ch <= 60) || (ch >= 62 && ch <= 126)) {
69                         SOFT_LBREAK_IF_REQUIRED(1);
70                         *outp++ = *inp++;
71                         len++;
72                 } else {
73                         SOFT_LBREAK_IF_REQUIRED(3);
74                         *outp++ = '=';
75                         get_hex_str(outp, ch);
76                         outp += 2;
77                         len += 3;
78                         inp++;
79                 }
80         }
81
82         if (len > 0)
83                 *outp++ = '\n';
84
85         *outp = '\0';
86 }
87
88 gint qp_decode_line(gchar *str)
89 {
90         gchar *inp = str, *outp = str;
91
92         while (*inp != '\0') {
93                 if (*inp == '=') {
94                         if (inp[1] && inp[2] &&
95                             get_hex_value(outp, inp[1], inp[2]) == TRUE) {
96                                 inp += 3;
97                         } else if (inp[1] == '\0' || isspace(inp[1])) {
98                                 /* soft line break */
99                                 break;
100                         } else {
101                                 /* broken QP string */
102                                 *outp = *inp++;
103                         }
104                 } else {
105                         *outp = *inp++;
106                 }
107                 outp++;
108         }
109
110         *outp = '\0';
111
112         return outp - str;
113 }
114
115 gint qp_decode_q_encoding(guchar *out, const gchar *in, gint inlen)
116 {
117         const gchar *inp = in;
118         guchar *outp = out;
119
120         if (inlen < 0)
121                 inlen = G_MAXINT;
122
123         while (inp - in < inlen && *inp != '\0') {
124                 if (*inp == '=' && inp + 3 - in <= inlen) {
125                         if (get_hex_value(outp, inp[1], inp[2]) == TRUE) {
126                                 inp += 3;
127                         } else {
128                                 *outp = *inp++;
129                         }
130                 } else if (*inp == '_') {
131                         *outp = ' ';
132                         inp++;
133                 } else {
134                         *outp = *inp++;
135                 }
136                 outp++;
137         }
138
139         *outp = '\0';
140
141         return outp - out;
142 }
143
144 gint qp_get_q_encoding_len(const guchar *str)
145 {
146         const guchar *inp = str;
147         gint len = 0;
148
149         while (*inp != '\0') {
150                 if (*inp == 0x20)
151                         len++;
152                 else if (*inp == '=' || *inp == '?' || *inp == '_' ||
153                          *inp < 32 || *inp > 127 || isspace(*inp))
154                         len += 3;
155                 else
156                         len++;
157
158                 inp++;
159         }
160
161         return len;
162 }
163
164 void qp_q_encode(gchar *out, const guchar *in)
165 {
166         const guchar *inp = in;
167         gchar *outp = out;
168
169         while (*inp != '\0') {
170                 if (*inp == 0x20)
171                         *outp++ = '_';
172                 else if (*inp == '=' || *inp == '?' || *inp == '_' ||
173                          *inp < 32 || *inp > 127 || isspace(*inp)) {
174                         *outp++ = '=';
175                         get_hex_str(outp, *inp);
176                         outp += 2;
177                 } else
178                         *outp++ = *inp;
179
180                 inp++;
181         }
182
183         *outp = '\0';
184 }
185
186 #define HEX_TO_INT(val, hex)                    \
187 {                                               \
188         gchar c = hex;                          \
189                                                 \
190         if ('0' <= c && c <= '9') {             \
191                 val = c - '0';                  \
192         } else if ('a' <= c && c <= 'f') {      \
193                 val = c - 'a' + 10;             \
194         } else if ('A' <= c && c <= 'F') {      \
195                 val = c - 'A' + 10;             \
196         } else {                                \
197                 val = -1;                       \
198         }                                       \
199 }
200
201 static gboolean get_hex_value(guchar *out, gchar c1, gchar c2)
202 {
203         gint hi, lo;
204
205         HEX_TO_INT(hi, c1);
206         HEX_TO_INT(lo, c2);
207
208         if (hi == -1 || lo == -1)
209                 return FALSE;
210
211         *out = (hi << 4) + lo;
212         return TRUE;
213 }
214
215 #define INT_TO_HEX(hex, val)            \
216 {                                       \
217         if ((val) < 10)                 \
218                 hex = '0' + (val);      \
219         else                            \
220                 hex = 'A' + (val) - 10; \
221 }
222
223 static void get_hex_str(gchar *out, guchar ch)
224 {
225         gchar hex;
226
227         INT_TO_HEX(hex, ch >> 4);
228         *out++ = hex;
229         INT_TO_HEX(hex, ch & 0x0f);
230         *out++ = hex;
231 }