@ -15,49 +15,60 @@
* @ tparam N Number to convert
* @ tparam base Desired base , can be from 2 to 36
*/
template < auto N , unsigned int base ,
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 < ( 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`
// fits to the number perfectly.
char buf [ ( [ ] {
unsigned int len = N > = 0 ? 1 : 2 ;
for ( auto n = N ; n ; len + + , n / = base ) ;
return len ;
} ( ) ) ] ;
char_type buf [ ( [ ] ( ) constexpr noexcept {
unsigned int len = N > 0 ? 1 : 2 ;
for ( auto n = N ; n ; len + + , n / = base ) ;
return len ;
} ( ) ) ] = { } ;
public :
/**
* Constructs the object , filling ` buf ` with the string representation of N .
*/
constexpr to_string_t ( ) {
auto ptr = buf + sizeof ( buf ) / sizeof ( buf [ 0 ] ) ;
constexpr to_string_t ( ) noexcept {
auto ptr = end( ) ;
* - - ptr = ' \0 ' ;
for ( auto n = N ; n ; n / = base )
* - - ptr = " 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ " [ ( N < 0 ? - 1 : 1 ) * ( n % base ) ] ;
if ( N < 0 )
* - - ptr = ' - ' ;
if ( N ! = 0 ) {
for ( auto n = N < 0 ? - N : N ; n ; n / = base )
* - - ptr = " 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ " [ ( N < 0 ? - 1 : 1 ) * ( n % base ) ] ;
if ( N < 0 )
* - - ptr = ' - ' ;
} else {
buf [ 0 ] = ' 0 ' ;
}
}
/**
* Allows implicit conversion of this object to a ` char * ` .
*/
constexpr operator char * ( ) {
return buf ;
}
/**
* Allows implicit conversion of this object to a ` const char * ` .
*/
constexpr operator const char * ( ) const {
return buf ;
}
// Support implicit casting to `char *` or `const char *`.
constexpr operator char_type * ( ) noexcept { return buf ; }
constexpr operator const char_type * ( ) const noexcept { return buf ; }
constexpr auto size ( ) const noexcept { return sizeof ( buf ) / sizeof ( buf [ 0 ] ) ; }
// Element access
constexpr auto data ( ) noexcept { return buf ; }
constexpr const auto data ( ) const noexcept { return buf ; }
constexpr auto & operator [ ] ( unsigned int i ) noexcept { return buf [ i ] ; }
constexpr const auto & operator [ ] ( unsigned int i ) const noexcept { return buf [ i ] ; }
constexpr auto & front ( ) noexcept { return buf [ 0 ] ; }
constexpr const auto & front ( ) const noexcept { return buf [ 0 ] ; }
constexpr auto & back ( ) noexcept { return buf [ size ( ) - 1 ] ; }
constexpr const auto & back ( ) const noexcept { return buf [ size ( ) - 1 ] ; }
// Iterators
constexpr auto begin ( ) noexcept { return buf ; }
constexpr const auto begin ( ) const noexcept { return buf ; }
constexpr auto end ( ) noexcept { return buf + size ( ) ; }
constexpr const auto end ( ) const noexcept { return buf + size ( ) ; }
} ;
/**
* Simplifies use of ` to_string_t ` from ` to_string_t < N > ( ) ` to ` to_string < N > ` .
*/
template < auto N , unsigned int base = 10 >
to_string_t < N , bas e> to_string ;
template < auto N , unsigned int base = 10 , typename char_type = char >
constexpr to_string_t < N , bas e, char_typ e> to_string ;
# endif // TCSULLIVAN_TO_STRING_HPP_