1/*
2                            __  __            _
3                         ___\ \/ /_ __   __ _| |_
4                        / _ \\  /| '_ \ / _` | __|
5                       |  __//  \| |_) | (_| | |_
6                        \___/_/\_\ .__/ \__,_|\__|
7                                 |_| XML parser
8
9   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
10   Copyright (c) 2000-2017 Expat development team
11   Licensed under the MIT license:
12
13   Permission is  hereby granted,  free of charge,  to any  person obtaining
14   a  copy  of  this  software   and  associated  documentation  files  (the
15   "Software"),  to  deal in  the  Software  without restriction,  including
16   without  limitation the  rights  to use,  copy,  modify, merge,  publish,
17   distribute, sublicense, and/or sell copies of the Software, and to permit
18   persons  to whom  the Software  is  furnished to  do so,  subject to  the
19   following conditions:
20
21   The above copyright  notice and this permission notice  shall be included
22   in all copies or substantial portions of the Software.
23
24   THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
25   EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
26   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
27   NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
28   DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
29   OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
30   USE OR OTHER DEALINGS IN THE SOFTWARE.
31*/
32
33#include <string.h>
34#include "xmlmime.h"
35
36static const char *
37getTok(const char **pp) {
38  /* inComment means one level of nesting; inComment+1 means two levels etc */
39  enum { inAtom, inString, init, inComment };
40  int state = init;
41  const char *tokStart = 0;
42  for (;;) {
43    switch (**pp) {
44    case '\0':
45      if (state == inAtom)
46        return tokStart;
47      return 0;
48    case ' ':
49    case '\r':
50    case '\t':
51    case '\n':
52      if (state == inAtom)
53        return tokStart;
54      break;
55    case '(':
56      if (state == inAtom)
57        return tokStart;
58      if (state != inString)
59        state++;
60      break;
61    case ')':
62      if (state > init)
63        --state;
64      else if (state != inString)
65        return 0;
66      break;
67    case ';':
68    case '/':
69    case '=':
70      if (state == inAtom)
71        return tokStart;
72      if (state == init)
73        return (*pp)++;
74      break;
75    case '\\':
76      ++*pp;
77      if (**pp == '\0')
78        return 0;
79      break;
80    case '"':
81      switch (state) {
82      case inString:
83        ++*pp;
84        return tokStart;
85      case inAtom:
86        return tokStart;
87      case init:
88        tokStart = *pp;
89        state = inString;
90        break;
91      }
92      break;
93    default:
94      if (state == init) {
95        tokStart = *pp;
96        state = inAtom;
97      }
98      break;
99    }
100    ++*pp;
101  }
102  /* not reached */
103}
104
105/* key must be lowercase ASCII */
106
107static int
108matchkey(const char *start, const char *end, const char *key) {
109  if (! start)
110    return 0;
111  for (; start != end; start++, key++)
112    if (*start != *key && *start != 'A' + (*key - 'a'))
113      return 0;
114  return *key == '\0';
115}
116
117void
118getXMLCharset(const char *buf, char *charset) {
119  const char *next, *p;
120
121  charset[0] = '\0';
122  next = buf;
123  p = getTok(&next);
124  if (matchkey(p, next, "text"))
125    strcpy(charset, "us-ascii");
126  else if (! matchkey(p, next, "application"))
127    return;
128  p = getTok(&next);
129  if (! p || *p != '/')
130    return;
131  p = getTok(&next);
132  /* BEGIN disabled code */
133  if (0) {
134    if (! matchkey(p, next, "xml") && charset[0] == '\0')
135      return;
136  }
137  /* END disabled code */
138  p = getTok(&next);
139  while (p) {
140    if (*p == ';') {
141      p = getTok(&next);
142      if (matchkey(p, next, "charset")) {
143        p = getTok(&next);
144        if (p && *p == '=') {
145          p = getTok(&next);
146          if (p) {
147            char *s = charset;
148            if (*p == '"') {
149              while (++p != next - 1) {
150                if (*p == '\\')
151                  ++p;
152                if (s == charset + CHARSET_MAX - 1) {
153                  charset[0] = '\0';
154                  break;
155                }
156                *s++ = *p;
157              }
158              *s++ = '\0';
159            } else {
160              if (next - p > CHARSET_MAX - 1)
161                break;
162              while (p != next)
163                *s++ = *p++;
164              *s = 0;
165              break;
166            }
167          }
168        }
169        break;
170      }
171    } else
172      p = getTok(&next);
173  }
174}
175
176#ifdef TEST
177
178#  include <stdio.h>
179
180int
181main(int argc, char *argv[]) {
182  char buf[CHARSET_MAX];
183  if (argc <= 1)
184    return 1;
185  printf("%s\n", argv[1]);
186  getXMLCharset(argv[1], buf);
187  printf("charset=\"%s\"\n", buf);
188  return 0;
189}
190
191#endif /* TEST */
192