[Feature] Add rspamd_memrchr utility function

src/libutil/str_util.c

@@ -1881,3 +1881,18 @@ rspamd_urls_cmp (gconstpointer a, gconstpointer b)
 
 	return r == 0;
 }
+
+const void *
+rspamd_memrchr (const void *m, gint c, gsize len)
+{
+	const guint8 *p = m;
+	gsize i;
+
+	for (i = len; i > 0; i --) {
+		if (p[i - 1] == c) {
+			return p + i - 1;
+		}
+	}
+
+	return NULL;
+}

src/libutil/str_util.h

@@ -310,4 +310,13 @@ gboolean rspamd_urls_cmp (gconstpointer a, gconstpointer b);
 
 extern const guchar lc_map[256];
 
+/**
+ * Search for the last occurrence of character `c` in memory block of size `len`
+ * @param m
+ * @param c
+ * @param len
+ * @return pointer to the last occurrence or NULL
+ */
+const void *rspamd_memrchr (const void *m, gint c, gsize len);
+
 #endif /* SRC_LIBUTIL_STR_UTIL_H_ */