xref: /freebsd/contrib/expat/xmlwf/xmlmime.c (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 /*
2                             __  __            _
3                          ___\ \/ /_ __   __ _| |_
4                         / _ \\  /| '_ \ / _` | __|
5                        |  __//  \| |_) | (_| | |_
6                         \___/_/\_\ .__/ \__,_|\__|
7                                  |_| XML parser
8 
9    Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
10    Copyright (c) 2002      Fred L. Drake, Jr. <fdrake@users.sourceforge.net>
11    Copyright (c) 2016-2018 Sebastian Pipping <sebastian@pipping.org>
12    Copyright (c) 2018      Marco Maggi <marco.maggi-ipsu@poste.it>
13    Licensed under the MIT license:
14 
15    Permission is  hereby granted,  free of charge,  to any  person obtaining
16    a  copy  of  this  software   and  associated  documentation  files  (the
17    "Software"),  to  deal in  the  Software  without restriction,  including
18    without  limitation the  rights  to use,  copy,  modify, merge,  publish,
19    distribute, sublicense, and/or sell copies of the Software, and to permit
20    persons  to whom  the Software  is  furnished to  do so,  subject to  the
21    following conditions:
22 
23    The above copyright  notice and this permission notice  shall be included
24    in all copies or substantial portions of the Software.
25 
26    THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
27    EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
28    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
29    NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
30    DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
31    OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
32    USE OR OTHER DEALINGS IN THE SOFTWARE.
33 */
34 
35 #include <string.h>
36 #include "xmlmime.h"
37 
38 static const char *
39 getTok(const char **pp) {
40   /* inComment means one level of nesting; inComment+1 means two levels etc */
41   enum { inAtom, inString, init, inComment };
42   int state = init;
43   const char *tokStart = 0;
44   for (;;) {
45     switch (**pp) {
46     case '\0':
47       if (state == inAtom)
48         return tokStart;
49       return 0;
50     case ' ':
51     case '\r':
52     case '\t':
53     case '\n':
54       if (state == inAtom)
55         return tokStart;
56       break;
57     case '(':
58       if (state == inAtom)
59         return tokStart;
60       if (state != inString)
61         state++;
62       break;
63     case ')':
64       if (state > init)
65         --state;
66       else if (state != inString)
67         return 0;
68       break;
69     case ';':
70     case '/':
71     case '=':
72       if (state == inAtom)
73         return tokStart;
74       if (state == init)
75         return (*pp)++;
76       break;
77     case '\\':
78       ++*pp;
79       if (**pp == '\0')
80         return 0;
81       break;
82     case '"':
83       switch (state) {
84       case inString:
85         ++*pp;
86         return tokStart;
87       case inAtom:
88         return tokStart;
89       case init:
90         tokStart = *pp;
91         state = inString;
92         break;
93       }
94       break;
95     default:
96       if (state == init) {
97         tokStart = *pp;
98         state = inAtom;
99       }
100       break;
101     }
102     ++*pp;
103   }
104   /* not reached */
105 }
106 
107 /* key must be lowercase ASCII */
108 
109 static int
110 matchkey(const char *start, const char *end, const char *key) {
111   if (! start)
112     return 0;
113   for (; start != end; start++, key++)
114     if (*start != *key && *start != 'A' + (*key - 'a'))
115       return 0;
116   return *key == '\0';
117 }
118 
119 void
120 getXMLCharset(const char *buf, char *charset) {
121   const char *next, *p;
122 
123   charset[0] = '\0';
124   next = buf;
125   p = getTok(&next);
126   if (matchkey(p, next, "text"))
127     strcpy(charset, "us-ascii");
128   else if (! matchkey(p, next, "application"))
129     return;
130   p = getTok(&next);
131   if (! p || *p != '/')
132     return;
133   p = getTok(&next);
134   /* BEGIN disabled code */
135   if (0) {
136     if (! matchkey(p, next, "xml") && charset[0] == '\0')
137       return;
138   }
139   /* END disabled code */
140   p = getTok(&next);
141   while (p) {
142     if (*p == ';') {
143       p = getTok(&next);
144       if (matchkey(p, next, "charset")) {
145         p = getTok(&next);
146         if (p && *p == '=') {
147           p = getTok(&next);
148           if (p) {
149             char *s = charset;
150             if (*p == '"') {
151               while (++p != next - 1) {
152                 if (*p == '\\')
153                   ++p;
154                 if (s == charset + CHARSET_MAX - 1) {
155                   charset[0] = '\0';
156                   break;
157                 }
158                 *s++ = *p;
159               }
160               *s++ = '\0';
161             } else {
162               if (next - p > CHARSET_MAX - 1)
163                 break;
164               while (p != next)
165                 *s++ = *p++;
166               *s = 0;
167               break;
168             }
169           }
170         }
171         break;
172       }
173     } else
174       p = getTok(&next);
175   }
176 }
177 
178 #ifdef TEST
179 
180 #  include <stdio.h>
181 
182 int
183 main(int argc, char *argv[]) {
184   char buf[CHARSET_MAX];
185   if (argc <= 1)
186     return 1;
187   printf("%s\n", argv[1]);
188   getXMLCharset(argv[1], buf);
189   printf("charset=\"%s\"\n", buf);
190   return 0;
191 }
192 
193 #endif /* TEST */
194