static int
expand_rule(jsgf_t * grammar, jsgf_rule_t * rule, int rule_entry,
int rule_exit)
{
jsgf_rule_stack_t *rule_stack_entry;
jsgf_rhs_t *rhs;
/* Push this rule onto the stack */
rule_stack_entry =
(jsgf_rule_stack_t *) ckd_calloc(1, sizeof(jsgf_rule_stack_t));
rule_stack_entry->rule = rule;
rule_stack_entry->entry = rule_entry;
grammar->rulestack = glist_add_ptr(grammar->rulestack,
rule_stack_entry);
for (rhs = rule->rhs; rhs; rhs = rhs->alt) {
int lastnode;
lastnode = expand_rhs(grammar, rule, rhs, rule_entry, rule_exit);
if (lastnode == NO_NODE) {
return NO_NODE;
}
else if (lastnode == RECURSIVE_NODE) {
/* The rhs ended with right-recursion, i.e. a transition to
an earlier state. Nothing needs to happen at this level. */
;
}
else if (rule_exit == NO_NODE) {
/* If this rule doesn't have an exit state yet, use the exit
state of its first right-hand-side.
All other right-hand-sides will use this exit state. */
assert(lastnode >= 0);
rule_exit = lastnode;
}
}
/* If no exit-state was created, use the entry-state. */
if (rule_exit == NO_NODE) {
rule_exit = rule_entry;
}
/* Pop this rule from the rule stack */
ckd_free(gnode_ptr(grammar->rulestack));
grammar->rulestack = gnode_free(grammar->rulestack, NULL);
return rule_exit;
}
static int
expand_rule(jsgf_t *grammar, jsgf_rule_t *rule)
{
jsgf_rhs_t *rhs;
float norm;
/* Push this rule onto the stack */
grammar->rulestack = glist_add_ptr(grammar->rulestack, rule);
/* Normalize weights for all alternatives exiting rule->entry */
norm = 0;
for (rhs = rule->rhs; rhs; rhs = rhs->alt) {
if (rhs->atoms) {
jsgf_atom_t *atom = gnode_ptr(rhs->atoms);
norm += atom->weight;
}
}
rule->entry = grammar->nstate++;
rule->exit = grammar->nstate++;
if (norm == 0) norm = 1;
for (rhs = rule->rhs; rhs; rhs = rhs->alt) {
int lastnode;
if (rhs->atoms) {
jsgf_atom_t *atom = gnode_ptr(rhs->atoms);
atom->weight /= norm;
}
lastnode = expand_rhs(grammar, rule, rhs);
if (lastnode == -1) {
return -1;
}
else {
jsgf_add_link(grammar, NULL, lastnode, rule->exit);
}
}
/* Pop this rule from the rule stack */
grammar->rulestack = gnode_free(grammar->rulestack, NULL);
return rule->exit;
}
