libcxx/include/__std_stream

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___STD_STREAM
#define _LIBCPP___STD_STREAM

#include <__config>
#include <ostream>
#include <istream>
#include <__locale>
#include <cstdio>

#pragma GCC system_header

_LIBCPP_BEGIN_NAMESPACE_STD

static const unsigned __limit = 8;

// __stdinbuf

template <class _CharT>
class _LIBCPP_HIDDEN __stdinbuf
    : public basic_streambuf<_CharT, char_traits<_CharT> >
{
public:
    typedef _CharT                           char_type;
    typedef char_traits<char_type>           traits_type;
    typedef typename traits_type::int_type   int_type;
    typedef typename traits_type::pos_type   pos_type;
    typedef typename traits_type::off_type   off_type;
    typedef typename traits_type::state_type state_type;

    explicit __stdinbuf(FILE* __fp);

protected:
    virtual int_type underflow();
    virtual int_type uflow();
    virtual int_type pbackfail(int_type __c = traits_type::eof());
    virtual void imbue(const locale& __loc);

private:

    FILE* __file_;
    const codecvt<char_type, char, state_type>* __cv_;
    state_type __st_;
    int __encoding_;
    bool __always_noconv_;

    __stdinbuf(const __stdinbuf&);
    __stdinbuf& operator=(const __stdinbuf&);

    int_type __getchar(bool __consume);
};

template <class _CharT>
__stdinbuf<_CharT>::__stdinbuf(FILE* __fp)
    : __file_(__fp),
      __st_()
{
    imbue(this->getloc());
}

template <class _CharT>
void
__stdinbuf<_CharT>::imbue(const locale& __loc)
{
    __cv_ = &use_facet<codecvt<char_type, char, state_type> >(__loc);
    __encoding_ = __cv_->encoding();
    __always_noconv_ = __cv_->always_noconv();
    if (__encoding_ > __limit)
        __throw_runtime_error("unsupported locale for standard input");
}

template <class _CharT>
typename __stdinbuf<_CharT>::int_type
__stdinbuf<_CharT>::underflow()
{
    return __getchar(false);
}

template <class _CharT>
typename __stdinbuf<_CharT>::int_type
__stdinbuf<_CharT>::uflow()
{
    return __getchar(true);
}

template <class _CharT>
typename __stdinbuf<_CharT>::int_type
__stdinbuf<_CharT>::__getchar(bool __consume)
{
    char __extbuf[__limit];
    int __nread = _STD::max(1, __encoding_);
    for (int __i = 0; __i < __nread; ++__i)
    {
        char __c = getc(__file_);
        if (__c == EOF)
            return traits_type::eof();
        __extbuf[__i] = static_cast<char>(__c);
    }
    char_type __1buf;
    if (__always_noconv_)
        __1buf = static_cast<char_type>(__extbuf[0]);
    else
    {
        const char* __enxt;
        char_type* __inxt;
        codecvt_base::result __r;
        do
        {
            state_type __sv_st = __st_;
            __r = __cv_->in(__st_, __extbuf, __extbuf + __nread, __enxt,
                                   &__1buf, &__1buf + 1, __inxt);
            switch (__r)
            {
            case _STD::codecvt_base::ok:
                break;
            case codecvt_base::partial:
                __st_ = __sv_st;
                if (__nread == sizeof(__extbuf))
                    return traits_type::eof();
                {
                    char __c = getc(__file_);
                    if (__c == EOF)
                        return traits_type::eof();
                    __extbuf[__nread] = static_cast<char>(__c);
                }
                ++__nread;
                break;
            case codecvt_base::error:
                return traits_type::eof();
            case _STD::codecvt_base::noconv:
                __1buf = static_cast<char_type>(__extbuf[0]);
                break;
            }
        } while (__r == _STD::codecvt_base::partial);
    }
    if (!__consume)
    {
        for (int __i = __nread; __i > 0;)
        {
            if (ungetc(__extbuf[--__i], __file_) == EOF)
                return traits_type::eof();
        }
    }
    return traits_type::to_int_type(__1buf);
}

template <class _CharT>
typename __stdinbuf<_CharT>::int_type
__stdinbuf<_CharT>::pbackfail(int_type __c)
{
    if (traits_type::eq_int_type(__c, traits_type::eof()))
        return __c;
    char __extbuf[__limit];
    char* __enxt;
    const char_type __ci = traits_type::to_char_type(__c);
    const char_type* __inxt;
    switch (__cv_->out(__st_, &__ci, &__ci + 1, __inxt,
                              __extbuf, __extbuf + sizeof(__extbuf), __enxt))
    {
    case _STD::codecvt_base::ok:
        break;
    case _STD::codecvt_base::noconv:
        __extbuf[0] = static_cast<char>(__c);
        __enxt = __extbuf + 1;
        break;
    case codecvt_base::partial:
    case codecvt_base::error:
        return traits_type::eof();
    }
    while (__enxt > __extbuf)
        if (ungetc(*--__enxt, __file_) == EOF)
            return traits_type::eof();
 return traits_type::not_eof(__c);
}

// __stdoutbuf

template <class _CharT>
class _LIBCPP_HIDDEN __stdoutbuf
    : public basic_streambuf<_CharT, char_traits<_CharT> >
{
public:
    typedef _CharT                           char_type;
    typedef char_traits<char_type>           traits_type;
    typedef typename traits_type::int_type   int_type;
    typedef typename traits_type::pos_type   pos_type;
    typedef typename traits_type::off_type   off_type;
    typedef typename traits_type::state_type state_type;

    explicit __stdoutbuf(FILE* __fp);

protected:
    virtual int_type overflow (int_type __c = traits_type::eof());
    virtual int sync();
    virtual void imbue(const locale& __loc);

private:
    FILE* __file_;
    const codecvt<char_type, char, state_type>* __cv_;
    state_type __st_;
    bool __always_noconv_;

    __stdoutbuf(const __stdoutbuf&);
    __stdoutbuf& operator=(const __stdoutbuf&);
};

template <class _CharT>
__stdoutbuf<_CharT>::__stdoutbuf(FILE* __fp)
    : __file_(__fp),
      __cv_(&use_facet<codecvt<char_type, char, state_type> >(this->getloc())),
      __st_(),
      __always_noconv_(__cv_->always_noconv())
{
}

template <class _CharT>
typename __stdoutbuf<_CharT>::int_type
__stdoutbuf<_CharT>::overflow(int_type __c)
{
    char __extbuf[__limit];
    char_type __1buf;
    if (!traits_type::eq_int_type(__c, traits_type::eof()))
    {
        this->setp(&__1buf, &__1buf+1);
        *this->pptr() = traits_type::to_char_type(__c);
        this->pbump(1);
        if (__always_noconv_)
        {
            if (fwrite(this->pbase(), sizeof(char_type), 1, __file_) != 1)
                return traits_type::eof();
        }
        else
        {
            char* __extbe = __extbuf;
            codecvt_base::result __r;
            do
            {
                const char_type* __e;
                __r = __cv_->out(__st_, this->pbase(), this->pptr(), __e,
                                        __extbuf,
                                        __extbuf + sizeof(__extbuf),
                                        __extbe);
                if (__e == this->pbase())
                    return traits_type::eof();
                if (__r == codecvt_base::noconv)
                {
                    if (fwrite(this->pbase(), 1, 1, __file_) != 1)
                        return traits_type::eof();
                }
                else if (__r == codecvt_base::ok || __r == codecvt_base::partial)
                {
                    size_t __nmemb = static_cast<size_t>(__extbe - __extbuf);
                    if (fwrite(__extbuf, 1, __nmemb, __file_) != __nmemb)
                        return traits_type::eof();
                    if (__r == codecvt_base::partial)
                    {
                        this->setp((char_type*)__e, this->pptr());
                        this->pbump(this->epptr() - this->pbase());
                    }
                }
                else
                    return traits_type::eof();
            } while (__r == codecvt_base::partial);
        }
        this->setp(0, 0);
    }
    return traits_type::not_eof(__c);
}

template <class _CharT>
int
__stdoutbuf<_CharT>::sync()
{
    char __extbuf[__limit];
    codecvt_base::result __r;
    do
    {
        char* __extbe;
        __r = __cv_->unshift(__st_, __extbuf,
                                    __extbuf + sizeof(__extbuf),
                                    __extbe);
        size_t __nmemb = static_cast<size_t>(__extbe - __extbuf);
        if (fwrite(__extbuf, 1, __nmemb, __file_) != __nmemb)
            return -1;
    } while (__r == codecvt_base::partial);
    if (__r == codecvt_base::error)
        return -1;
    if (fflush(__file_))
        return -1;
    return 0;
}

template <class _CharT>
void
__stdoutbuf<_CharT>::imbue(const locale& __loc)
{
    sync();
    __cv_ = &use_facet<codecvt<char_type, char, state_type> >(__loc);
    __always_noconv_ = __cv_->always_noconv();
}

_LIBCPP_END_NAMESPACE_STD

#endif  // _LIBCPP___STD_STREAM