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/spirit/home/x3/support/numeric_utils/extract_int.hpp>
   9
  10 #include <boost/core/lightweight_test.hpp>
  11 #include <cmath> // for std::pow
  12 #include <cstdio>
  13 #include <iosfwd>
  14 #include <limits>
  15
  16 #ifdef _MSC_VER
  17 # pragma warning(disable: 4127)   // conditional expression is constant
  18 #endif
  19
  20 template <int Min, int Max>
  21 struct custom_int
  22 {
  23     custom_int() = default;
  24     constexpr custom_int(int value) : value_{value} {}
  25
  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     custom_int operator/(custom_int x) const { return value_ / x.value_; }
  30
  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/=(custom_int x) { value_ /= x.value_; return *this; }
  35     custom_int& operator++() { ++value_; return *this; }
  36     custom_int& operator--() { --value_; return *this; }
  37     custom_int operator++(int) { return value_++; }
  38     custom_int operator--(int) { return value_--; }
  39
  40     custom_int operator+() { return +value_; }
  41     custom_int operator-() { return -value_; }
  42
  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     bool operator!=(custom_int x) const { return value_ != x.value_; }
  49
  50     template <typename Char, typename Traits>
  51     friend std::basic_ostream<Char, Traits>&
  52     operator<<(std::basic_ostream<Char, Traits>& os, custom_int x) {
  53         return os << x.value_;
  54     }
  55
  56     static constexpr int max = Max;
  57     static constexpr int min = Min;
  58
  59 private:
  60     int value_;
  61 };
  62
  63 namespace utils {
  64
  65 template <int Min, int Max> struct digits;
  66 template <> struct digits<-9,  9>  { static constexpr int r2 = 3, r10 = 1; };
  67 template <> struct digits<-10, 10> { static constexpr int r2 = 3, r10 = 1; };
  68 template <> struct digits<-15, 15> { static constexpr int r2 = 3, r10 = 1; };
  69
  70 }
  71
  72 namespace std {
  73
  74 template <int Min, int Max>
  75 class numeric_limits<custom_int<Min, Max>> : public numeric_limits<int>
  76 {
  77 public:
  78     static constexpr custom_int<Min, Max> max() noexcept { return Max; }
  79     static constexpr custom_int<Min, Max> min() noexcept { return Min; }
  80     static constexpr custom_int<Min, Max> lowest() noexcept { return min(); }
  81     static_assert(numeric_limits<int>::radix == 2, "hardcoded for digits of radix 2");
  82     static constexpr int digits = utils::digits<Min, Max>::r2;
  83     static constexpr int digits10 = utils::digits<Min, Max>::r10;
  84 };
  85
  86 }
  87
  88 namespace x3 = boost::spirit::x3;
  89
  90 template <typename T, int Base, int MaxDigits>
  91 void test_overflow_handling(char const* begin, char const* end, int i)
  92 {
  93     // Check that parser fails on overflow
  94     static_assert(std::numeric_limits<T>::is_bounded, "tests prerequest");
  95     BOOST_ASSERT_MSG(MaxDigits == -1 || static_cast<int>(std::pow(float(Base), MaxDigits)) > T::max,
  96                      "test prerequest");
  97     int initial = Base - i % Base; // just a 'random' non-equal to i number
  98     T x { initial };
  99     char const* it = begin;
 100     bool r = x3::extract_int<T, Base, 1, MaxDigits>::call(it, end, x);
 101     if (T::min <= i && i <= T::max) {
 102         BOOST_TEST(r);
 103         BOOST_TEST(it == end);
 104         BOOST_TEST_EQ(x, i);
 105     }
 106     else
 107         if (MaxDigits == -1) // TODO: Looks like a regression. See #430
 108     {
 109         BOOST_TEST(!r);
 110         BOOST_TEST(it == begin);
 111     }
 112 }
 113
 114 template <typename T, int Base>
 115 void test_unparsed_digits_are_not_consumed(char const* it, char const* end, int i)
 116 {
 117     // Check that unparsed digits are not consumed
 118     static_assert(T::min <= -Base+1, "test prerequest");
 119     static_assert(T::max >=  Base-1, "test prerequest");
 120     bool has_sign = *it == '+' || *it == '-';
 121     auto len = end - it;
 122     int initial = Base - i % Base; // just a 'random' non-equal to i number
 123     T x { initial };
 124     bool r = x3::extract_int<T, Base, 1, 1>::call(it, end, x);
 125     BOOST_TEST(r);
 126     if (-Base < i && i < Base) {
 127         BOOST_TEST(it == end);
 128         BOOST_TEST_EQ(x, i);
 129     }
 130     else {
 131         BOOST_TEST_EQ(end - it, len - 1 - has_sign);
 132         BOOST_TEST_EQ(x, i / Base);
 133     }
 134 }
 135
 136 template <typename T, int Base>
 137 void run_tests(char const* begin, char const* end, int i)
 138 {
 139     // Check that parser fails on overflow
 140     test_overflow_handling<T, Base, -1>(begin, end, i);
 141     // Check that MaxDigits > digits10 behave like MaxDigits=-1
 142     test_overflow_handling<T, Base, 2>(begin, end, i);
 143     // Check that unparsed digits are not consumed
 144     test_unparsed_digits_are_not_consumed<T, Base>(begin, end, i);
 145 }
 146
 147 int main()
 148 {
 149     for (int i = -30; i <= 30; ++i) {
 150         char s[4];
 151         std::snprintf(s, 4, "%d", i);
 152         auto begin = &s[0], end = begin + std::strlen(begin);
 153
 154         // log(Base, abs(MinOrMax) + 1) == digits
 155         run_tests<custom_int<-9, 9>, 10>(begin, end, i);
 156         // (MinOrMax % Base) == 0
 157         run_tests<custom_int<-10, 10>, 10>(begin, end, i);
 158         // (MinOrMax % Base) != 0
 159         run_tests<custom_int<-15, 15>, 10>(begin, end, i);
 160     }
 161
 162     return boost::report_errors();
 163 }