//
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// Copyright (c) 2012 Artyom Beilis (Tonkikh)
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// Copyright (c) 2019-2020 Alexander Grund
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef BOOST_NOWIDE_FILEBUF_HPP_INCLUDED
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#define BOOST_NOWIDE_FILEBUF_HPP_INCLUDED
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#include <boost/nowide/config.hpp>
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#if BOOST_NOWIDE_USE_FILEBUF_REPLACEMENT
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#include <boost/nowide/cstdio.hpp>
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#include <boost/nowide/stackstring.hpp>
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#include <cassert>
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#include <cstdio>
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#include <ios>
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#include <limits>
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#include <locale>
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#include <stdexcept>
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#include <streambuf>
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#else
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#include <fstream>
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#endif
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namespace boost {
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namespace nowide {
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namespace detail {
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/// Same as std::ftell but potentially with Large File Support
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BOOST_NOWIDE_DECL std::streampos ftell(FILE* file);
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/// Same as std::fseek but potentially with Large File Support
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BOOST_NOWIDE_DECL int fseek(FILE* file, std::streamoff offset, int origin);
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} // namespace detail
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#if !BOOST_NOWIDE_USE_FILEBUF_REPLACEMENT && !defined(BOOST_NOWIDE_DOXYGEN)
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using std::basic_filebuf;
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using std::filebuf;
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#else // Windows
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///
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/// \brief This forward declaration defines the basic_filebuf type.
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///
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/// it is implemented and specialized for CharType = char, it
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/// implements std::filebuf over standard C I/O
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///
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template<typename CharType, typename Traits = std::char_traits<CharType>>
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class basic_filebuf;
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///
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/// \brief This is the implementation of std::filebuf
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///
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/// it is implemented and specialized for CharType = char, it
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/// implements std::filebuf over standard C I/O
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///
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template<>
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class basic_filebuf<char> : public std::basic_streambuf<char>
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{
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using Traits = std::char_traits<char>;
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public:
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#ifdef BOOST_MSVC
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#pragma warning(push)
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#pragma warning(disable : 4351) // new behavior : elements of array will be default initialized
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#endif
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///
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/// Creates new filebuf
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///
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basic_filebuf() :
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buffer_size_(BUFSIZ), buffer_(0), file_(0), owns_buffer_(false), last_char_(),
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mode_(std::ios_base::openmode(0))
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{
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setg(0, 0, 0);
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setp(0, 0);
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}
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#ifdef BOOST_MSVC
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#pragma warning(pop)
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#endif
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basic_filebuf(const basic_filebuf&) = delete;
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basic_filebuf& operator=(const basic_filebuf&) = delete;
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basic_filebuf(basic_filebuf&& other) noexcept : basic_filebuf()
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{
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swap(other);
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}
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basic_filebuf& operator=(basic_filebuf&& other) noexcept
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{
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swap(other);
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return *this;
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}
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void swap(basic_filebuf& rhs)
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{
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std::basic_streambuf<char>::swap(rhs);
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using std::swap;
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swap(buffer_size_, rhs.buffer_size_);
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swap(buffer_, rhs.buffer_);
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swap(file_, rhs.file_);
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swap(owns_buffer_, rhs.owns_buffer_);
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swap(last_char_[0], rhs.last_char_[0]);
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swap(mode_, rhs.mode_);
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// Fixup last_char references
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if(epptr() == rhs.last_char_)
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setp(last_char_, last_char_);
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if(egptr() == rhs.last_char_)
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rhs.setg(last_char_, gptr() == rhs.last_char_ ? last_char_ : last_char_ + 1, last_char_ + 1);
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if(rhs.epptr() == last_char_)
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setp(rhs.last_char_, rhs.last_char_);
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if(rhs.egptr() == rhs.last_char_)
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{
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rhs.setg(rhs.last_char_,
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rhs.gptr() == last_char_ ? rhs.last_char_ : rhs.last_char_ + 1,
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rhs.last_char_ + 1);
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}
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}
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virtual ~basic_filebuf()
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{
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close();
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}
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///
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/// Same as std::filebuf::open but s is UTF-8 string
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///
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basic_filebuf* open(const std::string& s, std::ios_base::openmode mode)
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{
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return open(s.c_str(), mode);
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}
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///
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/// Same as std::filebuf::open but s is UTF-8 string
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///
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basic_filebuf* open(const char* s, std::ios_base::openmode mode)
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{
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const wstackstring name(s);
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return open(name.get(), mode);
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}
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/// Opens the file with the given name, see std::filebuf::open
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basic_filebuf* open(const wchar_t* s, std::ios_base::openmode mode)
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{
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if(is_open())
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return NULL;
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validate_cvt(this->getloc());
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const bool ate = (mode & std::ios_base::ate) != 0;
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if(ate)
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mode &= ~std::ios_base::ate;
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const wchar_t* smode = get_mode(mode);
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if(!smode)
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return 0;
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file_ = detail::wfopen(s, smode);
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if(!file_)
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return 0;
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if(ate && detail::fseek(file_, 0, SEEK_END) != 0)
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{
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close();
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return 0;
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}
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mode_ = mode;
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return this;
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}
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///
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/// Same as std::filebuf::close()
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///
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basic_filebuf* close()
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{
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if(!is_open())
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return NULL;
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bool res = sync() == 0;
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if(std::fclose(file_) != 0)
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res = false;
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file_ = NULL;
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mode_ = std::ios_base::openmode(0);
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if(owns_buffer_)
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{
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delete[] buffer_;
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buffer_ = NULL;
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owns_buffer_ = false;
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}
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return res ? this : NULL;
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}
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///
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/// Same as std::filebuf::is_open()
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///
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bool is_open() const
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{
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return file_ != NULL;
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}
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private:
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void make_buffer()
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{
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if(buffer_)
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return;
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if(buffer_size_ > 0)
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{
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buffer_ = new char[buffer_size_];
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owns_buffer_ = true;
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}
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}
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void validate_cvt(const std::locale& loc)
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{
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if(!std::use_facet<std::codecvt<char, char, std::mbstate_t>>(loc).always_noconv())
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throw std::runtime_error("Converting codecvts are not supported");
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}
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protected:
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std::streambuf* setbuf(char* s, std::streamsize n) override
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{
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assert(n >= 0);
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// Maximum compatibility: Discard all local buffers and use user-provided values
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// Users should call sync() before or better use it before any IO is done or any file is opened
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setg(NULL, NULL, NULL);
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setp(NULL, NULL);
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if(owns_buffer_)
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delete[] buffer_;
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buffer_ = s;
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buffer_size_ = (n >= 0) ? static_cast<size_t>(n) : 0;
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return this;
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}
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int overflow(int c = EOF) override
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{
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if(!(mode_ & std::ios_base::out))
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return EOF;
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if(!stop_reading())
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return EOF;
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size_t n = pptr() - pbase();
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if(n > 0)
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{
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if(std::fwrite(pbase(), 1, n, file_) != n)
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return -1;
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setp(buffer_, buffer_ + buffer_size_);
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if(c != EOF)
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{
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*buffer_ = Traits::to_char_type(c);
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pbump(1);
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}
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} else if(c != EOF)
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{
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if(buffer_size_ > 0)
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{
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make_buffer();
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setp(buffer_, buffer_ + buffer_size_);
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*buffer_ = Traits::to_char_type(c);
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pbump(1);
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} else if(std::fputc(c, file_) == EOF)
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{
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return EOF;
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} else if(!pptr())
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{
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// Set to dummy value so we know we have written something
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setp(last_char_, last_char_);
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}
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}
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return Traits::not_eof(c);
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}
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int sync() override
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{
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if(!file_)
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return 0;
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bool result;
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if(pptr())
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{
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result = overflow() != EOF;
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// Only flush if anything was written, otherwise behavior of fflush is undefined
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if(std::fflush(file_) != 0)
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return result = false;
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} else
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result = stop_reading();
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return result ? 0 : -1;
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}
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int underflow() override
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{
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if(!(mode_ & std::ios_base::in))
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return EOF;
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if(!stop_writing())
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return EOF;
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if(buffer_size_ == 0)
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{
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const int c = std::fgetc(file_);
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if(c == EOF)
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return EOF;
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last_char_[0] = Traits::to_char_type(c);
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setg(last_char_, last_char_, last_char_ + 1);
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} else
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{
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make_buffer();
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const size_t n = std::fread(buffer_, 1, buffer_size_, file_);
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setg(buffer_, buffer_, buffer_ + n);
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if(n == 0)
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return EOF;
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}
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return Traits::to_int_type(*gptr());
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}
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int pbackfail(int c = EOF) override
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{
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if(!(mode_ & std::ios_base::in))
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return EOF;
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if(!stop_writing())
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return EOF;
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if(gptr() > eback())
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gbump(-1);
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else if(seekoff(-1, std::ios_base::cur) != std::streampos(std::streamoff(-1)))
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{
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if(underflow() == EOF)
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return EOF;
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} else
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return EOF;
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// Case 1: Caller just wanted space for 1 char
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if(c == EOF)
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return Traits::not_eof(c);
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// Case 2: Caller wants to put back different char
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// gptr now points to the (potentially newly read) previous char
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if(*gptr() != c)
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*gptr() = Traits::to_char_type(c);
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return Traits::not_eof(c);
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}
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std::streampos seekoff(std::streamoff off,
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std::ios_base::seekdir seekdir,
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std::ios_base::openmode = std::ios_base::in | std::ios_base::out) override
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{
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if(!file_)
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return EOF;
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// Switching between input<->output requires a seek
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// So do NOT optimize for seekoff(0, cur) as No-OP
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// On some implementations a seek also flushes, so do a full sync
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if(sync() != 0)
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return EOF;
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int whence;
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switch(seekdir)
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{
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case std::ios_base::beg: whence = SEEK_SET; break;
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case std::ios_base::cur: whence = SEEK_CUR; break;
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case std::ios_base::end: whence = SEEK_END; break;
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default: assert(false); return EOF;
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}
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if(detail::fseek(file_, off, whence) != 0)
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return EOF;
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return detail::ftell(file_);
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}
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std::streampos seekpos(std::streampos pos,
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std::ios_base::openmode m = std::ios_base::in | std::ios_base::out) override
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{
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// Standard mandates "as-if fsetpos", but assume the effect is the same as fseek
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return seekoff(pos, std::ios_base::beg, m);
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}
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void imbue(const std::locale& loc) override
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{
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validate_cvt(loc);
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}
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private:
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/// Stop reading adjusting the file pointer if necessary
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/// Postcondition: gptr() == NULL
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bool stop_reading()
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{
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if(!gptr())
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return true;
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const auto off = gptr() - egptr();
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setg(0, 0, 0);
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if(!off)
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return true;
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#if defined(__clang__)
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wtautological-constant-out-of-range-compare"
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#endif
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// coverity[result_independent_of_operands]
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if(off > std::numeric_limits<std::streamoff>::max())
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return false;
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#if defined(__clang__)
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#pragma clang diagnostic pop
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#endif
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return detail::fseek(file_, static_cast<std::streamoff>(off), SEEK_CUR) == 0;
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}
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/// Stop writing. If any bytes are to be written, writes them to file
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/// Postcondition: pptr() == NULL
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bool stop_writing()
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{
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if(pptr())
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{
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const char* const base = pbase();
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const size_t n = pptr() - base;
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setp(0, 0);
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if(n && std::fwrite(base, 1, n, file_) != n)
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return false;
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}
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return true;
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}
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void reset(FILE* f = 0)
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{
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sync();
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if(file_)
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{
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fclose(file_);
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file_ = 0;
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}
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file_ = f;
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}
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static const wchar_t* get_mode(std::ios_base::openmode mode)
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{
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//
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// done according to n2914 table 106 27.9.1.4
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//
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// note can't use switch case as overload operator can't be used
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// in constant expression
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if(mode == (std::ios_base::out))
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return L"w";
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if(mode == (std::ios_base::out | std::ios_base::app))
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return L"a";
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if(mode == (std::ios_base::app))
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return L"a";
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if(mode == (std::ios_base::out | std::ios_base::trunc))
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return L"w";
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if(mode == (std::ios_base::in))
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return L"r";
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if(mode == (std::ios_base::in | std::ios_base::out))
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return L"r+";
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if(mode == (std::ios_base::in | std::ios_base::out | std::ios_base::trunc))
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return L"w+";
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if(mode == (std::ios_base::in | std::ios_base::out | std::ios_base::app))
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return L"a+";
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if(mode == (std::ios_base::in | std::ios_base::app))
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return L"a+";
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if(mode == (std::ios_base::binary | std::ios_base::out))
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return L"wb";
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if(mode == (std::ios_base::binary | std::ios_base::out | std::ios_base::app))
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return L"ab";
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if(mode == (std::ios_base::binary | std::ios_base::app))
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return L"ab";
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if(mode == (std::ios_base::binary | std::ios_base::out | std::ios_base::trunc))
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return L"wb";
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if(mode == (std::ios_base::binary | std::ios_base::in))
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return L"rb";
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if(mode == (std::ios_base::binary | std::ios_base::in | std::ios_base::out))
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return L"r+b";
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if(mode == (std::ios_base::binary | std::ios_base::in | std::ios_base::out | std::ios_base::trunc))
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return L"w+b";
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if(mode == (std::ios_base::binary | std::ios_base::in | std::ios_base::out | std::ios_base::app))
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return L"a+b";
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if(mode == (std::ios_base::binary | std::ios_base::in | std::ios_base::app))
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return L"a+b";
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return 0;
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}
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size_t buffer_size_;
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char* buffer_;
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FILE* file_;
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bool owns_buffer_;
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char last_char_[1];
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std::ios::openmode mode_;
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};
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///
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/// \brief Convenience typedef
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///
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using filebuf = basic_filebuf<char>;
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#endif // windows
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} // namespace nowide
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} // namespace boost
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#endif
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