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 <regex>
  17
  18 #include <cassert>
  19 #include <string>
  20
  21 int main(int, char**) {
  22   char str1[] = "\na";
  23   auto str1_scnd = str1 + 1;
  24
  25   // Assert that match_prev_avail disables match_not_bol and this matches
  26   assert(std::regex_match(str1 + 1, str1 + 2, std::regex("^a"),
  27                      std::regex_constants::match_not_bol |
  28                          std::regex_constants::match_prev_avail));
  29   // Manually passing match_prev_avail defines that --str1 is a valid position
  30   assert(std::regex_match(str1_scnd, std::regex("a"),
  31                      std::regex_constants::match_not_bol |
  32                          std::regex_constants::match_prev_avail));
  33
  34   //Assert that match_prev_avail disables match_not_bow and this matches
  35   assert(std::regex_search(str1, std::regex("\\ba")));
  36   assert(std::regex_match(str1 + 1, str1 + 2, std::regex("\\ba\\b"),
  37                      std::regex_constants::match_not_bow |
  38                          std::regex_constants::match_prev_avail));
  39   assert(std::regex_search(str1_scnd, std::regex("\\ba"),
  40                       std::regex_constants::match_not_bow |
  41                           std::regex_constants::match_prev_avail));
  42
  43   //Assert that match_prev_avail disables both match_not_bow and match_not_bol
  44   assert(std::regex_match(str1 + 1, str1 + 2, std::regex("^a"),
  45                      std::regex_constants::match_not_bol |
  46                          std::regex_constants::match_not_bow |
  47                          std::regex_constants::match_prev_avail));
  48   assert(std::regex_match(str1_scnd, std::regex("\\ba"),
  49                      std::regex_constants::match_not_bol |
  50                          std::regex_constants::match_not_bow |
  51                          std::regex_constants::match_prev_avail));
  52
  53   // pr 42199
  54   std::string S = " cd";
  55   std::string::iterator Start = S.begin() + 1;
  56   std::string::iterator End = S.end();
  57   assert(std::regex_search(Start, End, std::regex("^cd")));
  58
  59   assert(!std::regex_search(Start, End, std::regex("^cd"),
  60             std::regex_constants::match_not_bol));
  61   assert(!std::regex_search(Start, End, std::regex(".*\\bcd\\b"),
  62             std::regex_constants::match_not_bow));
  63   assert(!std::regex_search(Start, End, std::regex("^cd"),
  64             std::regex_constants::match_not_bol |
  65             std::regex_constants::match_not_bow));
  66   assert(!std::regex_search(Start, End, std::regex(".*\\bcd\\b"),
  67             std::regex_constants::match_not_bol |
  68             std::regex_constants::match_not_bow));
  69
  70   assert(std::regex_search(Start, End, std::regex("^cd"),
  71             std::regex_constants::match_prev_avail));
  72
  73   assert(std::regex_search(Start, End, std::regex("^cd"),
  74             std::regex_constants::match_not_bol |
  75             std::regex_constants::match_prev_avail));
  76   assert(std::regex_search(Start, End, std::regex("^cd"),
  77             std::regex_constants::match_not_bow |
  78             std::regex_constants::match_prev_avail));
  79   assert(std::regex_match(Start, End, std::regex("\\bcd\\b"),
  80             std::regex_constants::match_not_bol |
  81             std::regex_constants::match_not_bow |
  82             std::regex_constants::match_prev_avail));
  83   return 0;
  84 }