minmea: add minmea_talker_id()

minmea.c

@@ -259,6 +259,19 @@ end:
     return result;
 }
 
+bool minmea_talker_id(char talker[3], const char *sentence)
+{
+    char type[6];
+    if (!minmea_scan(sentence, "t", type))
+        return false;
+
+    talker[0] = type[0];
+    talker[1] = type[1];
+    talker[2] = '\0';
+
+    return true;
+}
+
 enum minmea_sentence_id minmea_sentence_id(const char *sentence)
 {
     if (!minmea_check(sentence))

minmea.h

@@ -92,6 +92,11 @@ struct minmea_sentence_gsa {
  */
 bool minmea_check(const char *sentence);
 
+/**
+ * Determine talker identifier.
+ */
+bool minmea_talker_id(char talker[3], const char *sentence);
+
 /**
  * Determine sentence identifier.
  */

tests.c

@@ -382,7 +382,7 @@ START_TEST(test_minmea_usage1)
     const char *sentences[] = {
         "$GPRMC,081836,A,3751.65,S,14507.36,E,000.0,360.0,130998,011.3,E*62",
         "$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47",
-        "$GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39",
+        "$GNGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1",
         NULL,
     };
 
@@ -407,6 +407,11 @@ START_TEST(test_minmea_usage1)
             default: {
             } break;
         }
+
+        char talker[3];
+        char expected[3] = { (*sentence)[1], (*sentence)[2], '\0' };
+        ck_assert(minmea_talker_id(talker, *sentence) == true);
+        ck_assert_str_eq(talker, expected);
     }
 }
 END_TEST