format.cpp

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#include "catch.hpp"
 
#include "kblib/format.h"
#include "kblib/iterators.h"
#include "kblib/stringops.h"
 
#include <iostream>
#include <string_view>
 
#if KBLIB_USE_CXX17
template <typename T>
auto pred_count_digits(T v) {
   return Catch::Predicate<T>(
       [](T v_) -> bool {
          return kblib::count_digits(v_)
                 == kblib::to_signed(std::to_string(v_).length());
       },
       kblib::concat(v, ": digits=", std::to_string(v).length(),
                     "; calc=", kblib::count_digits(v)));
}
#  define REQUIRE_DIGITS(v) REQUIRE_THAT((v), pred_count_digits((v)))
 
template <typename T, typename U>
auto test_count_digits_range(kblib::range_t<T, U> r) {
   // std::clog << kblib::concat("[", *r.begin(), ", ", *r.end(), ") / ",
   //                            r.begin().step, "\n");
   for (auto v : r) {
      // std::clog << v << ' ';
      REQUIRE_DIGITS(v);
      for (auto d : kblib::range(1, 100)) {
         REQUIRE_DIGITS(v + v / d);
      }
   }
   // std::clog << '\n';
}
 
TEST_CASE("count_digits") {
   using namespace std::literals;
   SECTION("signed") {
      CHECK(kblib::count_digits(0) == 1);
      CHECK(kblib::count_digits(1) == 1);
      CHECK(kblib::count_digits(3) == 1);
      CHECK(kblib::count_digits(10) == 2);
      CHECK(kblib::count_digits(42) == 2);
      CHECK(kblib::count_digits(99) == 2);
      CHECK(kblib::count_digits(-1) == 2);
      CHECK(kblib::count_digits(std::numeric_limits<std::int32_t>::max())
            == "2147483647"sv.length());
      CHECK(kblib::count_digits(std::numeric_limits<std::int32_t>::min())
            == "-2147483648"sv.length());
 
      for (auto i : kblib::range(std::numeric_limits<int>::digits - 1)) {
         auto v = 1 << i;
         // std::clog << v << "(1<<" << i << ") ";
         REQUIRE_DIGITS(v);
         for (auto d : kblib::range(1, 100)) {
            REQUIRE_DIGITS(v + v / d);
            REQUIRE(kblib::count_digits(v + v / d)
                    == kblib::to_signed(std::to_string(v + v / d).length()));
         }
      }
      // std::clog << '\n';
 
      {
         std::int32_t tens = 10;
         for (auto prime : {7, 71, 701, 7001, 70'001, 700'001, 7'000'003}) {
            test_count_digits_range(kblib::range(tens, tens * 100, prime));
            tens *= 10;
         }
      }
      for (auto v : kblib::range(std::numeric_limits<int>::max() - 1000000,
                                 std::numeric_limits<int>::max() - 541, 541)) {
         // std::clog << v << ' ';
         REQUIRE_DIGITS(v);
         REQUIRE(kblib::count_digits(v)
                 == kblib::to_signed(std::to_string(v).length()));
      }
      // std::clog << '\n';
   }
 
   SECTION("unsigned") {
      CHECK(kblib::count_digits(0u) == 1);
      CHECK(kblib::count_digits(1u) == 1);
      CHECK(kblib::count_digits(3u) == 1);
      CHECK(kblib::count_digits(10u) == 2);
      CHECK(kblib::count_digits(42u) == 2);
      CHECK(kblib::count_digits(99u) == 2);
      CHECK(kblib::count_digits(std::uint16_t(-1)) == "65535"sv.length());
      CHECK(kblib::count_digits(std::uint32_t(-1)) == "4294967295"sv.length());
      CHECK(kblib::count_digits(std::uint64_t(-1))
            == "18446744073709551615"sv.length());
   }
 
   SECTION("floating-point") {
      CHECK(kblib::count_digits(1.0) == 1);
      CHECK(kblib::count_digits(10.0) == 2);
      CHECK(kblib::count_digits(10.1) == 4);
   }
}
#endif