2 files changed, 22 insertions(+), 0 deletions(-)

M generator.c
M generator.h

@@ 28,6 28,21 @@ static struct dtmf_gen_key dtmf_gen_keys[] = {
 };
 
 int
+dtmf_gen_key_exist(char key) {
+	char key_norm;
+	struct dtmf_gen_key *k;
+
+	key_norm = isalpha(key) ? tolower(key) : key;
+
+	for (k = dtmf_gen_keys; k->key != '\0'; k++) {
+		if (k->key == key_norm) {
+			return 1;
+		}
+	}
+	return 0;
+}
+
+int
 dtmf_gen_get_freqs(double *fst, double *snd, char key) {
 	assert(fst != NULL && snd != NULL);
 

@@ 12,6 12,13 @@ struct dtmf_gen_key {
 };
 
 /*
+ * Checks if `key` is present in `dtmf_gen_keys`
+ *
+ * Returns 1 if found, 0 otherwise.
+ */
+int dtmf_gen_key_exist(char key);
+
+/*
  * Retrieves the two frequencies assigned to the given `key`.
  *
  * The search is case-insensitive for letters.