feat: (str) str_find, str_pos

lib/inc/str.h

@@ -3,6 +3,7 @@
 
 #include <stdbool.h>
 #include <stddef.h>
+#include <sys/types.h>
 
 /* represents a string, where length and capacity are stored alongside the string data. */
 typedef struct
@@ -25,5 +26,7 @@ bool str_starts_with (const str_t *str, const char *find); /* check if a str_t s
 bool str_starts_with_len (const str_t *str, const char *find, size_t len); /* check if a str_t string starts with a cstring of given length. */
 bool str_ends_with (const str_t *str, const char *find); /* check if a str_t string ends with a cstring. */
 bool str_ends_with_len (const str_t *str, const char *find, size_t len); /* check if a str_t string ends with a cstring of given length. */
+char *str_find (const str_t *str, const char *find); /* find a substring in a str_t string as a pointer. */
+ssize_t str_pos (const str_t *str, const char *find); /* find the index of a substring in a str_t string. */
 
 #endif // CUTILS_STR_H_

lib/str.c

@@ -208,3 +208,38 @@ str_ends_with_len (const str_t *str, const char *find, size_t len)
 {
     return strcmp (str->str + str->len - len, find) == 0;
 }
+
+/**
+ * find a substring in a str_t string. a pointer to the beginning of the
+ * substring is returned.
+ *
+ * @param   str: the str_t string to search in
+ * @param   find: the cstring to search for
+ *
+ * @return  beginning of found substring as pointer, or NULL if not found
+ */
+inline char *
+str_find (const str_t *str, const char *find)
+{
+    return strstr (str->str, find);
+}
+
+/**
+ * find a substring in a str_t string. the starting index of the substring is
+ * returned.
+ *
+ * @param   str: the str_t string to search in
+ * @param   find: the cstring to search for
+ *
+ * @return  beginning of found substring as string index, or -1 if not found
+ */
+ssize_t
+str_pos (const str_t *str, const char *find)
+{
+    char *pos;
+
+    pos = str_find (str, find);
+    if (pos)
+        return pos - str->str;
+    return -1;
+}

test/main.c

@@ -95,6 +95,11 @@ test_str (void)
     test_add (&group, test_assert (!str_starts_with (&str, "foo")), "str_starts_with false");
     test_add (&group, test_assert (str_ends_with (&str, "elit.")), "str_ends_with true");
     test_add (&group, test_assert (!str_ends_with (&str, "bar")), "str_ends_with false");
+
+    test_add (&group, test_assert (str_find (&str, "ipsum") == str.str + 6), "str_find success");
+    test_add (&group, test_assert (str_find (&str, "foo") == NULL), "str_find failure");
+    test_add (&group, test_assert (str_pos (&str, "ipsum") == 6), "str_pos success");
+    test_add (&group, test_assert (str_pos (&str, "foo") == -1), "str_pos failure");
     str_free (&str);
 
     return test_group_get_results (&group);