1 // Copyright (c) 2019-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5 #ifndef BITCOIN_TEST_UTIL_STR_H
6 #define BITCOIN_TEST_UTIL_STR_H
7
8 #include <string>
9
10 /**
11 * Increment a string. Useful to enumerate all fixed length strings with
12 * characters in [min_char, max_char].
13 */
14 template <typename CharType, size_t StringLength>
15 bool NextString(CharType (&string)[StringLength], CharType min_char, CharType max_char)
16 {
17 for (CharType& elem : string) {
18 bool has_next = elem != max_char;
19 elem = elem < min_char || elem >= max_char ? min_char : CharType(elem + 1);
20 if (has_next) return true;
21 }
22 return false;
23 }
24
25 /**
26 * Iterate over string values and call function for each string without
27 * successive duplicate characters.
28 */
29 template <typename CharType, size_t StringLength, typename Fn>
30 void ForEachNoDup(CharType (&string)[StringLength], CharType min_char, CharType max_char, Fn&& fn) {
31 for (bool has_next = true; has_next; has_next = NextString(string, min_char, max_char)) {
32 int prev = -1;
33 bool skip_string = false;
34 for (CharType c : string) {
35 if (c == prev) skip_string = true;
36 if (skip_string || c < min_char || c > max_char) break;
37 prev = c;
38 }
39 if (!skip_string) fn();
40 }
41 }
42
43 #endif // BITCOIN_TEST_UTIL_STR_H
44