lib/index.cc: generalize filter state machine

To match things more complicated than fixed strings, we need states
with multiple out arrows.
This commit is contained in:
David Bremner 2017-06-07 23:11:48 -03:00
parent 4a085a5137
commit 64f81f95a1

View file

@ -159,16 +159,23 @@ filter_filter (GMimeFilter *gmime_filter, char *inbuf, size_t inlen, size_t pres
g_mime_filter_set_size (gmime_filter, inlen, FALSE);
outptr = gmime_filter->outbuf;
next = filter->state;
while (inptr < inend) {
if (*inptr >= states[filter->state].a &&
*inptr <= states[filter->state].b)
{
next = states[filter->state].next_if_match;
}
else
{
next = states[filter->state].next_if_not_match;
}
/* Each state is defined by a contiguous set of rows of the
* state table marked by a common value for '.state'. The
* state numbers must be equal to the index of the first row
* in a given state; thus the loop condition here looks for a
* jump to a first row of a state, which is a real transition
* in the underlying DFA.
*/
do {
if (*inptr >= states[next].a && *inptr <= states[next].b) {
next = states[next].next_if_match;
} else {
next = states[next].next_if_not_match;
}
} while (next != states[next].state);
if (filter->state < filter->first_skipping_state)
*outptr++ = *inptr;