container-like #4

Merged
Neargye merged 1 commits from master into master 4 years ago

@ -18,15 +18,16 @@
template<auto N, unsigned int base, typename char_type, template<auto N, unsigned int base, typename char_type,
std::enable_if_t<std::is_integral_v<decltype(N)>, int> = 0, std::enable_if_t<std::is_integral_v<decltype(N)>, int> = 0,
std::enable_if_t<(base > 1 && base < 37), int> = 0> std::enable_if_t<(base > 1 && base < 37), int> = 0>
struct to_string_t { class to_string_t {
// The lambda calculates what the string length of N will be, so that `buf` // The lambda calculates what the string length of N will be, so that `buf`
// fits to the number perfectly. // fits to the number perfectly.
char_type buf[([] { char_type buf[([]() constexpr noexcept {
unsigned int len = N > 0 ? 1 : 2; unsigned int len = N > 0 ? 1 : 2;
for (auto n = N < 0 ? -N : N; n; len++, n /= base); for (auto n = N < 0 ? -N : N; n; len++, n /= base);
return len; return len;
}())] = {}; }())] = {};
public:
/** /**
* Constructs the object, filling `buf` with the string representation of N. * Constructs the object, filling `buf` with the string representation of N.
*/ */
@ -44,14 +45,24 @@ struct to_string_t {
} }
// Support implicit casting to `char *` or `const char *`. // Support implicit casting to `char *` or `const char *`.
constexpr operator char_type *() { return buf; } constexpr operator char_type *() noexcept { return buf; }
constexpr operator const char_type *() const { return buf; } constexpr operator const char_type *() const noexcept { return buf; }
// Support range-based for loops constexpr auto size() const noexcept { return sizeof(buf) / sizeof(buf[0]); }
constexpr auto begin() { return buf; } // Element access
constexpr auto begin() const { return buf; } constexpr auto data() noexcept { return buf; }
constexpr auto end() { return buf + sizeof(buf) / sizeof(buf[0]); } constexpr auto data() const noexcept { return buf; }
constexpr auto end() const { return buf + sizeof(buf) / sizeof(buf[0]); } constexpr auto operator[](unsigned int i) noexcept { return buf[i]; }
constexpr auto operator[](unsigned int i) const noexcept { return buf[i]; }
constexpr auto front() noexcept { return buf[0]; }
constexpr auto front() const noexcept { return buf[0]; }
constexpr auto back() noexcept { return buf[size() - 1]; }
constexpr auto back() const noexcept { return buf[size() - 1]; }
// Iterators
constexpr auto begin() noexcept { return buf; }
constexpr auto begin() const noexcept { return buf; }
constexpr auto end() noexcept { return buf + size(); }
constexpr auto end() const noexcept { return buf + size(); }
}; };
/** /**
@ -59,5 +70,5 @@ struct to_string_t {
*/ */
template<auto N, unsigned int base = 10, typename char_type = char> template<auto N, unsigned int base = 10, typename char_type = char>
constexpr to_string_t<N, base, char_type> to_string; constexpr to_string_t<N, base, char_type> to_string;
#endif // TCSULLIVAN_TO_STRING_HPP_ #endif // TCSULLIVAN_TO_STRING_HPP_

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