48 lines
1.2 KiB
C++
48 lines
1.2 KiB
C++
// Copyright (c) 2014-2016 Dr. Colin Hirsch and Daniel Frey
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// Please see LICENSE for license or visit https://github.com/ColinH/PEGTL/
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#ifndef TAO_CPP_PEGTL_INTERNAL_PEEK_UTF32_HH
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#define TAO_CPP_PEGTL_INTERNAL_PEEK_UTF32_HH
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#include <cstddef>
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#include "input_pair.hh"
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namespace tao_json_pegtl
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{
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namespace internal
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{
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struct peek_utf32
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{
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using data_t = char32_t;
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using pair_t = input_pair< char32_t >;
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static_assert( sizeof( char32_t ) == 4, "expected size 4 for 32bit value" );
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// suppress warning with GCC 4.7
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template< typename T >
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static inline bool dummy_less_or_equal( const T a, const T b )
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{
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return a <= b;
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}
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template< typename Input >
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static pair_t peek( Input & in )
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{
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const std::size_t s = in.size( 4 );
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if ( s >= 4 ) {
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const char32_t t = * reinterpret_cast< const char32_t * >( in.begin() );
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if ( dummy_less_or_equal< char32_t >( 0, t ) && dummy_less_or_equal< char32_t >( t, 0x10ffff ) ) {
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return { t, 4 };
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}
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}
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return { 0, 0 };
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}
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};
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} // namespace internal
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} // namespace tao_json_pegtl
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#endif
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