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Update implementation of find_last_of

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This commit is contained in:
Peter Dimov
2021-10-09 06:47:39 +03:00
parent 969a201c75
commit b251310a8f
1 changed files with 34 additions and 41 deletions
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75
include/boost/core/string_view.hpp
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@ -104,11 +104,44 @@ template<class Ch> BOOST_CXX14_CONSTEXPR std::size_t find_first_of( Ch const* p_
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 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
{ {
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;
}
}
std::size_t const npos = static_cast< std::size_t >( -1 ); std::size_t const npos = static_cast< std::size_t >( -1 );
std::size_t i = pos; std::size_t i = pos;
if( n >= 16 ) if( use_table )
{
do
{
UCh ch = p_[ i ];
if( ch >= 0 && ch < 256 && table[ ch ] ) return i;
--i;
}
while( i != npos );
}
else if( n >= 16 )
{ {
do do
{ {
@ -139,46 +172,6 @@ template<class Ch> BOOST_CXX14_CONSTEXPR std::size_t find_last_of( Ch const* p_,
return npos; return npos;
} }
#if CHAR_BIT == 8
BOOST_CXX14_CONSTEXPR std::size_t find_last_of( char const* p_, 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;
}
std::size_t const npos = static_cast< std::size_t >( -1 );
std::size_t i = pos;
do
{
unsigned char ch = p_[ i ];
if( table[ ch ] ) return i;
--i;
}
while( i != npos );
return npos;
}
#endif
#if defined(__cpp_char8_t) && __cpp_char8_t >= 201811L
std::size_t find_last_of( char8_t const* p_, char8_t const* s, std::size_t pos, std::size_t n ) BOOST_NOEXCEPT
{
return detail::find_last_of( reinterpret_cast< char const* >( p_ ), reinterpret_cast< char const* >( s ), pos, n );
}
#endif
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 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; typedef typename sv_to_uchar<Ch>::type UCh;