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Update implementation of find_first_of

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This commit is contained in:
Peter Dimov
2021-10-09 06:43:48 +03:00
parent b9f1b9f39a
commit 969a201c75
1 changed files with 40 additions and 43 deletions
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83
include/boost/core/string_view.hpp
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@ -37,9 +37,48 @@ namespace core
namespace detail
{
template<class Ch> struct sv_to_uchar
{
typedef Ch type;
};
template<> struct sv_to_uchar<char>
{
typedef unsigned char type;
};
template<class Ch> BOOST_CXX14_CONSTEXPR std::size_t find_first_of( Ch const* p_, std::size_t n_, Ch const* s, std::size_t pos, std::size_t n ) BOOST_NOEXCEPT
{
if( n >= 16 )
typedef typename sv_to_uchar<Ch>::type UCh;
unsigned char table[ 256 ] = {};
bool use_table = true;
for( std::size_t j = 0; j < n; ++j )
{
UCh ch = s[ j ];
if( ch >= 0 && ch < 256 )
{
table[ ch ] = 1;
}
else
{
use_table = false;
break;
}
}
if( use_table )
{
for( std::size_t i = pos; i < n_; ++i )
{
UCh ch = p_[ i ];
if( ch >= 0 && ch < 256 && table[ ch ] ) return i;
}
}
else if( n >= 16 )
{
for( std::size_t i = pos; i < n_; ++i )
{
@ -63,38 +102,6 @@ template<class Ch> BOOST_CXX14_CONSTEXPR std::size_t find_first_of( Ch const* p_
return static_cast<std::size_t>( -1 );
}
#if CHAR_BIT == 8
BOOST_CXX14_CONSTEXPR std::size_t find_first_of( char const* p_, std::size_t n_, char const* s, std::size_t pos, std::size_t n ) BOOST_NOEXCEPT
{
unsigned char table[ 256 ] = {};
for( std::size_t j = 0; j < n; ++j )
{
unsigned char ch = s[ j ];
table[ ch ] = 1;
}
for( std::size_t i = pos; i < n_; ++i )
{
unsigned char ch = p_[ i ];
if( table[ ch ] ) return i;
}
return static_cast<std::size_t>( -1 );
}
#endif
#if defined(__cpp_char8_t) && __cpp_char8_t >= 201811L
std::size_t find_first_of( char8_t const* p_, std::size_t n_, char8_t const* s, std::size_t pos, std::size_t n ) BOOST_NOEXCEPT
{
return detail::find_first_of( reinterpret_cast< char const* >( p_ ), n_, reinterpret_cast< char const* >( s ), pos, n );
}
#endif
template<class Ch> BOOST_CXX14_CONSTEXPR std::size_t find_last_of( Ch const* p_, Ch const* s, std::size_t pos, std::size_t n ) BOOST_NOEXCEPT
{
std::size_t const npos = static_cast< std::size_t >( -1 );
@ -172,16 +179,6 @@ std::size_t find_last_of( char8_t const* p_, char8_t const* s, std::size_t pos,
#endif
template<class Ch> struct sv_to_uchar
{
typedef Ch type;
};
template<> struct sv_to_uchar<char>
{
typedef unsigned char type;
};
template<class Ch> BOOST_CXX14_CONSTEXPR std::size_t find_first_not_of( Ch const* p_, std::size_t n_, Ch const* s, std::size_t pos, std::size_t n ) BOOST_NOEXCEPT
{
typedef typename sv_to_uchar<Ch>::type UCh;