static struct rx_node *_term(struct parse_sp *ps)
{
struct rx_node *n;
switch (ps->type) {
case 0:
if (!(n = _node(ps->mem, CHARSET, NULL, NULL))) {
stack;
return NULL;
}
dm_bit_copy(n->charset, ps->charset);
_rx_get_token(ps); /* match charset */
break;
case '(':
_rx_get_token(ps); /* match '(' */
n = _or_term(ps);
if (ps->type != ')') {
log_error("missing ')' in regular expression");
return 0;
}
_rx_get_token(ps); /* match ')' */
break;
default:
n = 0;
}
return n;
}
struct rx_node *rx_parse_tok(struct dm_pool *mem,
const char *begin, const char *end)
{
struct rx_node *r;
struct parse_sp *ps = dm_pool_zalloc(mem, sizeof(*ps));
if (!ps)
return_NULL;
ps->mem = mem;
if (!(ps->charset = dm_bitset_create(mem, 256))) {
log_error("Regex charset allocation failed");
dm_pool_free(mem, ps);
return NULL;
}
ps->cursor = begin;
ps->rx_end = end;
_rx_get_token(ps); /* load the first token */
if (!(r = _or_term(ps))) {
log_error("Parse error in regex");
dm_pool_free(mem, ps);
return NULL;
}
if (!(r = _optimise(mem, r))) {
log_error("Regex optimisation error");
dm_pool_free(mem, ps);
return NULL;
}
return r;
}
static struct rx_node *_or_term(struct parse_sp *ps)
{
struct rx_node *l, *r, *n;
if (!(l = _cat_term(ps)))
return NULL;
if (ps->type != '|')
return l;
_rx_get_token(ps); /* match '|' */
if (!(r = _or_term(ps))) {
log_error("Badly formed 'or' expression");
return NULL;
}
if (!(n = _node(ps->mem, OR, l, r)))
stack;
return n;
}
