libstdc++-v3/testsuite/20_util/from_chars/3.cc

   1 // Copyright (C) 2020-2024 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do run { target c++14 } }
  19
  20 #include <charconv>
  21 #include <string>
  22 #include <testsuite_hooks.h>
  23
  24 #ifdef DEBUG
  25 #include <stdio.h>
  26 #endif
  27
  28 long long
  29 read(const char* first, const char* last, int base)
  30 {
  31   long long val = 0;
  32   unsigned long long place = 1;
  33   while (last > first)
  34   {
  35     val += (*--last - '0') * place;
  36     place *= base;
  37   }
  38   return val;
  39 }
  40
  41 void
  42 test01()
  43 {
  44   std::from_chars_result res;
  45   long long val;
  46   for (auto s : { "10001", "10010", "10011", "10101", "10110", "10111",
  47                   "11001", "11010", "11011", "11101", "11110", "11111" })
  48   {
  49     std::string ss[2] = { s, std::string(64, '0') + s };
  50     for (const auto& str : ss)
  51     {
  52       const char* first = str.data();
  53       for (int base = 2; base < 37; ++base)
  54       {
  55         const char* last = str.data() + str.length();
  56         for (size_t n = 0; n < ss[0].length(); ++n)
  57         {
  58 #ifdef DEBUG
  59           printf("Parsing \"%.*s\" in base %d\n", int(last - first), first,
  60                  base);
  61 #endif
  62           res = std::from_chars(first, last, val, base);
  63           VERIFY( res.ptr == last );
  64           VERIFY( res.ec == std::errc{} );
  65           VERIFY( val == read(first, last, base) );
  66           // Test again with shorter string to check from_chars doesn't read
  67           // the digits past the last pointer.
  68           --last;
  69         }
  70       }
  71     }
  72   }
  73 }
  74
  75 int
  76 main()
  77 {
  78   test01();
  79 }