+
+
+/*
+ * Finds first occurrence of str in buf. buf is not a C string but a
+ * byte array of length buflen. str is a null-terminated C string.
+ * find_str() does not modify buf but passes back a non-const char *
+ * pointer so that the caller can modify it.
+ */
+char *
+find_str (const char buf[], size_t buflen, const char *str) {
+ const size_t len = strlen (str);
+ size_t i;
+
+ for (i = 0; i + len <= buflen; ++i, ++buf) {
+ if (! memcmp (buf, str, len)) return (char *) buf;
+ }
+
+ return NULL;
+}
+
+
+/*
+ * Finds last occurrence of str in buf. buf is not a C string but a
+ * byte array of length buflen. str is a null-terminated C string.
+ * find_str() does not modify buf but passes back a non-const char *
+ * pointer so that the caller can modify it.
+ */
+char *
+rfind_str (const char buf[], size_t buflen, const char *str) {
+ const size_t len = strlen (str);
+ size_t i;
+
+ for (i = 0, buf += buflen - len; i + len <= buflen; ++i, --buf) {
+ if (! memcmp (buf, str, len)) return (char *) buf;
+ }
+
+ return NULL;
+}