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Contents
// Copyright (c) 2014-2020 Dr. Colin Hirsch and Daniel Frey
// Please see LICENSE for license or visit https://github.com/taocpp/PEGTL/
#ifndef TAO_JSON_PEGTL_INTERNAL_PEEK_UTF16_HPP
#define TAO_JSON_PEGTL_INTERNAL_PEEK_UTF16_HPP
#include <type_traits>
#include "../config.hpp"
#include "input_pair.hpp"
#include "read_uint.hpp"
namespace TAO_JSON_PEGTL_NAMESPACE::internal
{
template< typename R >
struct peek_utf16_impl
{
using data_t = char32_t;
using pair_t = input_pair< char32_t >;
using short_t = std::make_unsigned< char16_t >::type;
static_assert( sizeof( short_t ) == 2 );
static_assert( sizeof( char16_t ) == 2 );
static constexpr std::size_t min_input_size = 2;
static constexpr std::size_t max_input_size = 4;
template< typename Input >
[[nodiscard]] static pair_t peek( const Input& in, const std::size_t s ) noexcept
{
const char32_t t = R::read( in.current() );
if( ( t < 0xd800 ) || ( t > 0xdfff ) ) {
return { t, 2 };
}
if( ( t >= 0xdc00 ) || ( s < 4 ) ) {
return { 0, 0 };
}
const char32_t u = R::read( in.current() + 2 );
if( ( u >= 0xdc00 ) && ( u <= 0xdfff ) ) {
const auto cp = ( ( ( t & 0x03ff ) << 10 ) | ( u & 0x03ff ) ) + 0x10000;
return { cp, 4 };
}
return { 0, 0 };
}
};
using peek_utf16_be = peek_utf16_impl< read_uint16_be >;
using peek_utf16_le = peek_utf16_impl< read_uint16_le >;
} // namespace TAO_JSON_PEGTL_NAMESPACE::internal
#endif
Version data entries
24 entries across 24 versions & 1 rubygems