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#define CHARSET_MAX 41
static const char *
getTok(const char **pp)
{
enum { inAtom, inString, init, inComment };
int state = init;
const char *tokStart = 0;
for (;;) {
switch (**pp) {
case '\0':
return 0;
case ' ':
case '\r':
case '\t':
case '\n':
if (state == inAtom)
return tokStart;
break;
case '(':
if (state == inAtom)
return tokStart;
if (state != inString)
state++;
break;
case ')':
if (state > init)
--state;
else if (state != inString)
return 0;
break;
case ';':
case '/':
case '=':
if (state == inAtom)
return tokStart;
if (state == init)
return (*pp)++;
break;
case '\\':
++*pp;
if (**pp == '\0')
return 0;
break;
case '"':
switch (state) {
case inString:
++*pp;
return tokStart;
case inAtom:
return tokStart;
case init:
tokStart = *pp;
state = inString;
break;
}
break;
default:
if (state == init) {
tokStart = *pp;
state = inAtom;
}
break;
}
++*pp;
}
/* not reached */
}
/* key must be lowercase ASCII */
static int
matchkey(const char *start, const char *end, const char *key)
{
if (!start)
return 0;
for (; start != end; start++, key++)
if (*start != *key && *start != 'A' + (*key - 'a'))
return 0;
return *key == '\0';
}
void
getXMLCharset(const char *buf, char *charset)
{
const char *next, *p;
charset[0] = '\0';
next = buf;
p = getTok(&next);
if (matchkey(p, next, "text"))
strcpy(charset, "us-ascii");
else if (!matchkey(p, next, "application"))
return;
p = getTok(&next);
if (!p || *p != '/')
return;
p = getTok(&next);
if (matchkey(p, next, "xml"))
isXml = 1;
p = getTok(&next);
while (p) {
if (*p == ';') {
p = getTok(&next);
if (matchkey(p, next, "charset")) {
p = getTok(&next);
if (p && *p == '=') {
p = getTok(&next);
if (p) {
char *s = charset;
if (*p == '"') {
while (++p != next - 1) {
if (*p == '\\')
++p;
if (s == charset + CHARSET_MAX - 1) {
charset[0] = '\0';
break;
}
*s++ = *p;
}
*s++ = '\0';
}
else {
if (next - p > CHARSET_MAX - 1)
break;
while (p != next)
*s++ = *p++;
*s = 0;
break;
}
}
}
}
}
else
p = getTok(&next);
}
}
int
main(int argc, char **argv)
{
char buf[CHARSET_MAX];
getXMLCharset(argv[1], buf);
printf("charset = \"%s\"\n", buf);
return 0;
}
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