country: Add simple function to test if a country code is valid

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/database.c

@@ -751,10 +751,6 @@ LOC_EXPORT int loc_database_enumerator_set_country_code(struct loc_database_enum
 		return 0;
 	}
 
-	// Country codes must be two characters
-	if (strlen(country_code) != 2)
-		return -EINVAL;
-
 	// Treat A1, A2, A3 as special country codes,
 	// but perform search for flags instead
 	if (strcmp(country_code, "A1") == 0) {
@@ -768,6 +764,10 @@ LOC_EXPORT int loc_database_enumerator_set_country_code(struct loc_database_enum
 			LOC_NETWORK_FLAG_ANYCAST);
 	}
 
+	// Country codes must be two characters
+	if (!loc_country_code_is_valid(country_code))
+		return -EINVAL;
+
 	for (unsigned int i = 0; i < 3; i++) {
 		enumerator->country_code[i] = country_code[i];
 	}

src/loc/country.h

@@ -38,11 +38,32 @@ int loc_country_cmp(struct loc_country* country1, struct loc_country* country2);
 
 #ifdef LIBLOC_PRIVATE
 
+#include <string.h>
+
 int loc_country_new_from_database_v0(struct loc_ctx* ctx, struct loc_stringpool* pool,
 		struct loc_country** country, const struct loc_database_country_v0* dbobj);
 int loc_country_to_database_v0(struct loc_country* country,
     struct loc_stringpool* pool, struct loc_database_country_v0* dbobj);
 
+static inline int loc_country_code_is_valid(const char* cc) {
+	// It cannot be NULL
+	if (!cc || !*cc)
+		return 0;
+
+	// It must be 2 characters long
+	if (strlen(cc) != 2)
+		return 0;
+
+	// It must only contain A-Z
+	for (unsigned int i = 0; i < 2; i++) {
+		if (cc[i] < 'A' || cc[i] > 'Z')
+			return 0;
+	}
+
+	// Looks valid
+	return 1;
+}
+
 static inline void loc_country_copy_code(char* dst, const char* src) {
     for (unsigned int i = 0; i < 2; i++) {
         dst[i] = src[i];

src/network.c

@@ -23,6 +23,7 @@
 #include <string.h>
 
 #include <loc/libloc.h>
+#include <loc/country.h>
 #include <loc/network.h>
 #include <loc/private.h>
 
@@ -295,8 +296,8 @@ LOC_EXPORT int loc_network_set_country_code(struct loc_network* network, const c
 		return 0;
 	}
 
-	// Country codes must be two characters
-	if (strlen(country_code) != 2)
+	// Check country code
+	if (!loc_country_code_is_valid(country_code))
 		return -EINVAL;
 
 	for (unsigned int i = 0; i < 3; i++) {
@@ -307,8 +308,8 @@ LOC_EXPORT int loc_network_set_country_code(struct loc_network* network, const c
 }
 
 LOC_EXPORT int loc_network_match_country_code(struct loc_network* network, const char* country_code) {
-	// Country codes must be two characters
-	if (strlen(country_code) != 2)
+	// Check country code
+	if (!loc_country_code_is_valid(country_code))
 		return -EINVAL;
 
 	return (network->country_code[0] == country_code[0])

src/test-country.c

@@ -21,6 +21,7 @@
 #include <string.h>
 
 #include <loc/libloc.h>
+#include <loc/country.h>
 #include <loc/database.h>
 #include <loc/network.h>
 #include <loc/writer.h>
@@ -29,6 +30,18 @@ int main(int argc, char** argv) {
 	struct loc_country* country;
 	int err;
 
+	// Check some valid country codes
+	if (!loc_country_code_is_valid("XX")) {
+		fprintf(stderr, "Valid country code detected as invalid: %s\n", "XX");
+		exit(EXIT_FAILURE);
+	}
+
+	// Check some invalid country codes
+	if (loc_country_code_is_valid("X1")) {
+		fprintf(stderr, "Invalid country code detected as valid: %s\n", "X1");
+		exit(EXIT_FAILURE);
+	}
+
 	struct loc_ctx* ctx;
 	err = loc_new(&ctx);
 	if (err < 0)
@@ -41,7 +54,7 @@ int main(int argc, char** argv) {
 		exit(EXIT_FAILURE);
 
 	// Create a country
-	err = loc_writer_add_country(writer, &country, "T1");
+	err = loc_writer_add_country(writer, &country, "XX");
 	if (err) {
 		fprintf(stderr, "Could not create country\n");
 		exit(EXIT_FAILURE);
@@ -49,7 +62,7 @@ int main(int argc, char** argv) {
 
 	// Set name & continent
 	loc_country_set_name(country, "Testistan");
-	loc_country_set_continent_code(country, "XX");
+	loc_country_set_continent_code(country, "YY");
 
 	// Free country
 	loc_country_unref(country);
@@ -84,9 +97,9 @@ int main(int argc, char** argv) {
 	}
 
 	// Lookup an address in the subnet
-	err = loc_database_get_country(db, &country, "T1");
+	err = loc_database_get_country(db, &country, "XX");
 	if (err) {
-		fprintf(stderr, "Could not find country T1\n");
+		fprintf(stderr, "Could not find country XX\n");
 		exit(EXIT_FAILURE);
 	}
 	loc_country_unref(country);