libcxx/test/std/re/re.const/re.matchflag/match_prev_avail.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <regex>
  10
  11 // match_prev_avail:
  12 //     --first is a valid iterator position. When this flag is set the flags
  13 //     match_not_bol and match_not_bow shall be ignored by the regular
  14 //     expression algorithms (30.11) and iterators (30.12)
  15
  16 #include <cassert>
  17 #include <regex>
  18 using namespace std;
  19
  20 int main(int, char**) {
  21   char str1[] = "\na";
  22   auto str1_scnd = str1 + 1;
  23   // Assert that match_prev_avail disables match_not_bol and this matches
  24   assert(regex_match(str1 + 1, str1 + 2, regex("^a"),
  25                      regex_constants::match_not_bol |
  26                          regex_constants::match_prev_avail));
  27   // Manually passing match_prev_avail defines that --str1 is a valid position
  28   assert(regex_match(str1_scnd, regex("a"),
  29                      regex_constants::match_not_bol |
  30                          regex_constants::match_prev_avail));
  31
  32   //Assert that match_prev_avail disables match_not_bow and this matches
  33   assert(regex_search(str1, regex("\\ba")));
  34   assert(regex_match(str1 + 1, str1 + 2, regex("\\ba\\b"),
  35                      regex_constants::match_not_bow |
  36                          regex_constants::match_prev_avail));
  37   assert(regex_search(str1_scnd, regex("\\ba"),
  38                       regex_constants::match_not_bow |
  39                           regex_constants::match_prev_avail));
  40
  41   //Assert that match_prev_avail disables both match_not_bow and match_not_bol
  42   assert(regex_match(str1 + 1, str1 + 2, regex("^a"),
  43                      regex_constants::match_not_bol |
  44                          regex_constants::match_not_bow |
  45                          regex_constants::match_prev_avail));
  46   assert(regex_match(str1_scnd, regex("\\ba"),
  47                      regex_constants::match_not_bol |
  48                          regex_constants::match_not_bow |
  49                          regex_constants::match_prev_avail));
  50
  51   // pr 42199
  52   string S = " cd";
  53   string::iterator Start = S.begin() + 1;
  54   string::iterator End = S.end();
  55   assert(regex_search(Start, End, regex("^cd")));
  56
  57   assert(
  58       !regex_search(Start, End, regex("^cd"), regex_constants::match_not_bol));
  59   assert(!regex_search(Start, End, regex(".*\\bcd\\b"),
  60                        regex_constants::match_not_bow));
  61   assert(!regex_search(Start, End, regex("^cd"),
  62                        regex_constants::match_not_bol |
  63                            regex_constants::match_not_bow));
  64   assert(!regex_search(Start, End, regex(".*\\bcd\\b"),
  65                        regex_constants::match_not_bol |
  66                            regex_constants::match_not_bow));
  67
  68   assert(regex_search(Start, End, regex("^cd"),
  69                       regex_constants::match_prev_avail));
  70
  71   assert(regex_search(Start, End, regex("^cd"),
  72                       regex_constants::match_not_bol |
  73                           regex_constants::match_prev_avail));
  74   assert(regex_search(Start, End, regex("^cd"),
  75                       regex_constants::match_not_bow |
  76                           regex_constants::match_prev_avail));
  77   assert(regex_match(Start, End, regex("\\bcd\\b"),
  78                      regex_constants::match_not_bol |
  79                          regex_constants::match_not_bow |
  80                          regex_constants::match_prev_avail));
  81   return 0;
  82 }