ceph/src/boost/libs/spirit/test/x3/extract_int.cpp

   1 /*=============================================================================
   2   Copyright (c) 2018 Nikita Kniazev
   3
   4   Distributed under the Boost Software License, Version 1.0. (See accompanying
   5   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 =============================================================================*/
   7
   8 #include <boost/detail/lightweight_test.hpp>
   9 #include <boost/spirit/home/x3/support/numeric_utils/extract_int.hpp>
  10 #include <cmath> // for std::pow
  11 #include <cstdio>
  12 #include <iosfwd>
  13 #include <limits>
  14
  15 #ifdef _MSC_VER
  16 # pragma warning(disable: 4127)   // conditional expression is constant
  17 #endif
  18
  19 template <int Min, int Max>
  20 struct custom_int
  21 {
  22     custom_int() = default;
  23     constexpr custom_int(int value) : value_{value} {}
  24
  25     custom_int operator+(custom_int x) const { return value_ + x.value_; }
  26     custom_int operator-(custom_int x) const { return value_ - x.value_; }
  27     custom_int operator*(custom_int x) const { return value_ * x.value_; }
  28     custom_int operator/(custom_int x) const { return value_ / x.value_; }
  29
  30     custom_int& operator+=(custom_int x) { value_ += x.value_; return *this; }
  31     custom_int& operator-=(custom_int x) { value_ -= x.value_; return *this; }
  32     custom_int& operator*=(custom_int x) { value_ *= x.value_; return *this; }
  33     custom_int& operator/=(custom_int x) { value_ /= x.value_; return *this; }
  34     custom_int& operator++() { ++value_; return *this; }
  35     custom_int& operator--() { --value_; return *this; }
  36     custom_int operator++(int) { return value_++; }
  37     custom_int operator--(int) { return value_--; }
  38
  39     custom_int operator+() { return +value_; }
  40     custom_int operator-() { return -value_; }
  41
  42     bool operator< (custom_int x) const { return value_ <  x.value_; }
  43     bool operator> (custom_int x) const { return value_ >  x.value_; }
  44     bool operator<=(custom_int x) const { return value_ <= x.value_; }
  45     bool operator>=(custom_int x) const { return value_ >= x.value_; }
  46     bool operator==(custom_int x) const { return value_ == x.value_; }
  47     bool operator!=(custom_int x) const { return value_ != x.value_; }
  48
  49     template <typename Char, typename Traits>
  50     friend std::basic_ostream<Char, Traits>&
  51     operator<<(std::basic_ostream<Char, Traits>& os, custom_int x) {
  52         return os << x.value_;
  53     }
  54
  55     static constexpr int max = Max;
  56     static constexpr int min = Min;
  57
  58 private:
  59     int value_;
  60 };
  61
  62 namespace utils {
  63
  64 template <int Min, int Max> struct digits;
  65 template <> struct digits<-9,  9>  { static constexpr int r2 = 3, r10 = 1; };
  66 template <> struct digits<-10, 10> { static constexpr int r2 = 3, r10 = 1; };
  67 template <> struct digits<-15, 15> { static constexpr int r2 = 3, r10 = 1; };
  68
  69 }
  70
  71 namespace std {
  72
  73 template <int Min, int Max>
  74 class numeric_limits<custom_int<Min, Max>> : public numeric_limits<int>
  75 {
  76 public:
  77     static constexpr custom_int<Min, Max> max() noexcept { return Max; }
  78     static constexpr custom_int<Min, Max> min() noexcept { return Min; }
  79     static constexpr custom_int<Min, Max> lowest() noexcept { return min(); }
  80     static_assert(numeric_limits<int>::radix == 2, "hardcoded for digits of radix 2");
  81     static constexpr int digits = utils::digits<Min, Max>::r2;
  82     static constexpr int digits10 = utils::digits<Min, Max>::r10;
  83 };
  84
  85 }
  86
  87 namespace x3 = boost::spirit::x3;
  88
  89 template <typename T, int Base, int MaxDigits>
  90 void test_overflow_handling(char const* begin, char const* end, int i)
  91 {
  92     // Check that parser fails on overflow
  93     static_assert(std::numeric_limits<T>::is_bounded, "tests prerequest");
  94     BOOST_ASSERT_MSG(MaxDigits == -1 || static_cast<int>(std::pow(float(Base), MaxDigits)) > T::max,
  95                      "test prerequest");
  96     int initial = Base - i % Base; // just a 'random' non-equal to i number
  97     T x { initial };
  98     char const* it = begin;
  99     bool r = x3::extract_int<T, Base, 1, MaxDigits>::call(it, end, x);
 100     if (T::min <= i && i <= T::max) {
 101         BOOST_TEST(r);
 102         BOOST_TEST(it == end);
 103         BOOST_TEST_EQ(x, i);
 104     }
 105     else
 106         if (MaxDigits == -1) // TODO: Looks like a regression. See #430
 107     {
 108         BOOST_TEST(!r);
 109         BOOST_TEST(it == begin);
 110     }
 111 }
 112
 113 template <typename T, int Base>
 114 void test_unparsed_digits_are_not_consumed(char const* it, char const* end, int i)
 115 {
 116     // Check that unparsed digits are not consumed
 117     static_assert(T::min <= -Base+1, "test prerequest");
 118     static_assert(T::max >=  Base-1, "test prerequest");
 119     bool has_sign = *it == '+' || *it == '-';
 120     auto len = end - it;
 121     int initial = Base - i % Base; // just a 'random' non-equal to i number
 122     T x { initial };
 123     bool r = x3::extract_int<T, Base, 1, 1>::call(it, end, x);
 124     BOOST_TEST(r);
 125     if (-Base < i && i < Base) {
 126         BOOST_TEST(it == end);
 127         BOOST_TEST_EQ(x, i);
 128     }
 129     else {
 130         BOOST_TEST_EQ(end - it, len - 1 - has_sign);
 131         BOOST_TEST_EQ(x, i / Base);
 132     }
 133 }
 134
 135 template <typename T, int Base>
 136 void run_tests(char const* begin, char const* end, int i)
 137 {
 138     // Check that parser fails on overflow
 139     test_overflow_handling<T, Base, -1>(begin, end, i);
 140     // Check that MaxDigits > digits10 behave like MaxDigits=-1
 141     test_overflow_handling<T, Base, 2>(begin, end, i);
 142     // Check that unparsed digits are not consumed
 143     test_unparsed_digits_are_not_consumed<T, Base>(begin, end, i);
 144 }
 145
 146 int main()
 147 {
 148     for (int i = -30; i <= 30; ++i) {
 149         char s[4];
 150         std::snprintf(s, 4, "%d", i);
 151         auto begin = &s[0], end = begin + std::strlen(begin);
 152
 153         // log(Base, abs(MinOrMax) + 1) == digits
 154         run_tests<custom_int<-9, 9>, 10>(begin, end, i);
 155         // (MinOrMax % Base) == 0
 156         run_tests<custom_int<-10, 10>, 10>(begin, end, i);
 157         // (MinOrMax % Base) != 0
 158         run_tests<custom_int<-15, 15>, 10>(begin, end, i);
 159     }
 160
 161     return boost::report_errors();
 162 }