fmt/pl: add pl_strncasecmp and tests

include/re_fmt.h

@@ -47,6 +47,7 @@ int      pl_strdup(char **dst, const struct pl *src);
 int      pl_dup(struct pl *dst, const struct pl *src);
 int      pl_strcmp(const struct pl *pl, const char *str);
 int      pl_strncmp(const struct pl *pl, const char *str, size_t n);
+int      pl_strncasecmp(const struct pl *pl, const char *str, size_t n);
 int      pl_strcasecmp(const struct pl *pl, const char *str);
 int      pl_cmp(const struct pl *pl1, const struct pl *pl2);
 int      pl_casecmp(const struct pl *pl1, const struct pl *pl2);

src/fmt/pl.c

@@ -558,6 +558,28 @@ int pl_strncmp(const struct pl *pl, const char *str, size_t n)
 }
 
 
+/**
+ * Compare n characters of a pointer-length object with a NULL-terminated
+ * string (case-insensitive)
+ *
+ * @param pl  Pointer-length object
+ * @param str NULL-terminated string
+ * @param n   number of characters that should be compared
+ *
+ * @return 0 if match, otherwise errorcode
+ */
+int pl_strncasecmp(const struct pl *pl, const char *str, size_t n)
+{
+	if (!pl_isset(pl) || !str || !n)
+		return EINVAL;
+
+	if (pl->l < n)
+		return EINVAL;
+
+	return strncasecmp(pl->p, str, n) == 0 ? 0 : EINVAL;
+}
+
+
 /**
  * Compare a pointer-length object with a NULL-terminated string
  * (case-insensitive)

test/fmt.c

@@ -17,6 +17,7 @@
 
 int test_fmt_pl(void)
 {
+	int err;
 	const struct pl pl   = PL("rattarei");
 	const struct pl pl0  = PL("rattarei");
 	const struct pl pl0_ = PL("rAtTaReI");
@@ -94,6 +95,16 @@ int test_fmt_pl(void)
 	if (0 == pl_strcmp(&pl3, str0))
 		goto out;
 
+	/* pl_strncmp() */
+	err = pl_strncmp(&pl, "rat", 3);
+	TEST_ERR(err);
+	err = pl_strncmp(&pl, "RAT", 3);
+	TEST_EQUALS(EINVAL, err);
+
+	/* pl_strncasecmp() */
+	err = pl_strncasecmp(&pl, "RaT", 3);
+	TEST_ERR(err);
+
 	/* pl_strcasecmp() */
 	if (EINVAL != pl_strcasecmp(NULL, NULL))
 		goto out;