geode/codegen/Broma/PEGTL-3.2.7/include/tao/pegtl/internal/cstream_reader.hpp

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2022-07-30 12:24:03 -04:00
// Copyright (c) 2016-2022 Dr. Colin Hirsch and Daniel Frey
// Please see LICENSE for license or visit https://github.com/taocpp/PEGTL/
#ifndef TAO_PEGTL_INTERNAL_CSTREAM_READER_HPP
#define TAO_PEGTL_INTERNAL_CSTREAM_READER_HPP
#include <cassert>
#include <cstddef>
#include <cstdio>
#if defined( __cpp_exceptions )
#include <system_error>
#else
#include <exception>
#endif
#include "../config.hpp"
namespace TAO_PEGTL_NAMESPACE::internal
{
struct cstream_reader
{
explicit cstream_reader( std::FILE* s ) noexcept
: m_cstream( s )
{
assert( m_cstream != nullptr );
}
[[nodiscard]] std::size_t operator()( char* buffer, const std::size_t length ) const
{
if( const auto r = std::fread( buffer, 1, length, m_cstream ) ) {
return r;
}
if( std::feof( m_cstream ) != 0 ) {
return 0;
}
// Please contact us if you know how to provoke the following exception.
// The example on cppreference.com doesn't work, at least not on macOS.
// LCOV_EXCL_START
#if defined( __cpp_exceptions )
const auto ec = std::ferror( m_cstream );
assert( ec != 0 );
throw std::system_error( ec, std::system_category(), "std::fread() failed" );
#else
std::fputs( "std::fread() failed\n", stderr );
std::terminate();
#endif
// LCOV_EXCL_STOP
}
std::FILE* m_cstream;
};
} // namespace TAO_PEGTL_NAMESPACE::internal
#endif