src/lib.c: Add strsjoin() with tests

1 files changed, 104 insertions, 0 deletions

diff --git a/src/lib.c b/src/lib.c
index 39a462b..3c017d8 100644
--- a/src/lib.c
+++ b/src/lib.c
@@ -597,6 +597,109 @@ static void test_strjoin(void) {
 }
 #endif
 
+static char *strsjoin(const char *const strs[]) {
+	size_t size = sizeof('\0');
+	for (size_t i = 0; strs[i]; i++) {
+		const size_t curr_len = strnlen(strs[i], SIZE_MAX);
+		if (SIZE_MAX - size < curr_len) {
+			errno = EOVERFLOW;
+			logerr("strsjoin()", strerror(errno), __LINE__);
+			return NULL;
+		}
+		if (SIZE_MAX == i) {
+			errno = EOVERFLOW;
+			logerr("strsjoin()", strerror(errno), __LINE__);
+			return NULL;
+		}
+		size += curr_len;
+	}
+
+	char *const s = malloc(size);
+	if (!s) {
+		logerrl("malloc(", size, ")", strerror(errno), __LINE__);
+		return NULL;
+	}
+	*s = '\0';
+
+	// "i" can't overflow now, as it was already checked above
+	for (size_t i = 0; strs[i]; i++) {
+		strcat(s, strs[i]);
+	}
+
+	return s;
+}
+
+#ifdef TEST
+static void test_strsjoin(void) {
+	test_start("test_strsjoin");
+	{
+		testing("joining empty strings");
+		char *const s = strsjoin((const char *const [])
+			{ "", "", NULL });
+		assert(s);
+		assert(strcmp(s, "") == 0);
+		free(s);
+		test_ok();
+	}
+	{
+		testing("joining empty strs array");
+		char *const s = strsjoin((const char *const [])
+			{ NULL });
+		assert(s);
+		assert(strcmp(s, "") == 0);
+		free(s);
+		test_ok();
+	}
+	{
+		testing("first string is empty");
+		char *const s = strsjoin((const char *const [])
+			{ "", "second not empty", NULL });
+		assert(s);
+		assert(strcmp(s, "second not empty") == 0);
+		free(s);
+		test_ok();
+	}
+	{
+		testing("third string is empty");
+		char *const s = strsjoin((const char *const [])
+			{ "first not empty", "second not empty", "", NULL });
+		assert(s);
+		assert(strcmp(s, "first not emptysecond not empty") == 0);
+		free(s);
+		test_ok();
+	}
+	{
+		testing("four non-empty strings");
+		char *const s = strsjoin((const char *const [])
+			{ "abc", "def", "ghi", "jkl", NULL });
+		assert(s);
+		assert(strcmp(s, "abcdefghijkl") == 0);
+		free(s);
+		test_ok();
+	}
+	{
+		testing("example usage: with file names");
+		char *const s = strsjoin((const char *const [])
+			{ "../repository.git", "/description", NULL });
+		assert(s);
+		assert(strcmp(s, "../repository.git/description") == 0);
+		free(s);
+		test_ok();
+	}
+	{
+		testing("example usage: with file name parts");
+		char *const s = strsjoin((const char *const []){
+			"/tmp/gistatic.ABCDEF", "/", "project",
+			"-", "main", NULL
+		});
+		assert(s);
+		assert(strcmp(s, "/tmp/gistatic.ABCDEF/project-main") == 0);
+		free(s);
+		test_ok();
+	}
+}
+#endif
+
 static char *formatted_date(const time_t time_sec) {
 	const struct tm *const time_utc = gmtime(&time_sec);
 	if (!time_utc) {
@@ -2058,6 +2161,7 @@ void unit_tests_gistatic(void) {
 	test_underscore();
 	test_remove_suffix();
 	test_strjoin();
+	test_strsjoin();
 	test_formatted_date();
 	test_max();
 	test_escape_html();