[misc] add regexp engine

* From https://github.com/kokke/tiny-regex-c

src/re.h

@@ -0,0 +1,65 @@
+/*
+ *
+ * Mini regex-module inspired by Rob Pike's regex code described in:
+ *
+ * http://www.cs.princeton.edu/courses/archive/spr09/cos333/beautiful.html
+ *
+ *
+ *
+ * Supports:
+ * ---------
+ *   '.'        Dot, matches any character
+ *   '^'        Start anchor, matches beginning of string
+ *   '$'        End anchor, matches end of string
+ *   '*'        Asterisk, match zero or more (greedy)
+ *   '+'        Plus, match one or more (greedy)
+ *   '?'        Question, match zero or one (non-greedy)
+ *   '[abc]'    Character class, match if one of {'a', 'b', 'c'}
+ *   '[^abc]'   Inverted class, match if NOT one of {'a', 'b', 'c'} -- NOTE: feature is currently broken!
+ *   '[a-zA-Z]' Character ranges, the character set of the ranges { a-z | A-Z }
+ *   '\s'       Whitespace, \t \f \r \n \v and spaces
+ *   '\S'       Non-whitespace
+ *   '\w'       Alphanumeric, [a-zA-Z0-9_]
+ *   '\W'       Non-alphanumeric
+ *   '\d'       Digits, [0-9]
+ *   '\D'       Non-digits
+ *
+ *
+ */
+
+#ifndef _TINY_REGEX_C
+#define _TINY_REGEX_C
+
+
+#ifndef RE_DOT_MATCHES_NEWLINE
+/* Define to 0 if you DON'T want '.' to match '\r' + '\n' */
+#define RE_DOT_MATCHES_NEWLINE 1
+#endif
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+
+
+/* Typedef'd pointer to get abstract datatype. */
+typedef struct regex_t* re_t;
+
+
+/* Compile regex string pattern to a regex_t-array. */
+re_t re_compile(const char* pattern);
+
+
+/* Find matches of the compiled pattern inside text. */
+int re_matchp(re_t pattern, const char* text, int* matchlength);
+
+
+/* Find matches of the txt pattern inside text (will compile automatically first). */
+int re_match(const char* pattern, const char* text, int* matchlength);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ifndef _TINY_REGEX_C */