// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_STREAMBUF
#define _LIBCPP_STREAMBUF

/*
    streambuf synopsis

namespace std
{

template <class charT, class traits = char_traits<charT> >
class basic_streambuf
{
public:
    // types:
    typedef charT char_type;
    typedef traits 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;

    virtual ~basic_streambuf();

    // 27.6.2.2.1 locales:
    locale pubimbue(const locale& loc);
    locale getloc() const;

    // 27.6.2.2.2 buffer and positioning:
    basic_streambuf* pubsetbuf(char_type* s, streamsize n);
    pos_type pubseekoff(off_type off, ios_base::seekdir way,
                        ios_base::openmode which = ios_base::in | ios_base::out);
    pos_type pubseekpos(pos_type sp,
                        ios_base::openmode which = ios_base::in | ios_base::out);
    int pubsync();

    // Get and put areas:
    // 27.6.2.2.3 Get area:
    streamsize in_avail();
    int_type snextc();
    int_type sbumpc();
    int_type sgetc();
    streamsize sgetn(char_type* s, streamsize n);

    // 27.6.2.2.4 Putback:
    int_type sputbackc(char_type c);
    int_type sungetc();

    // 27.6.2.2.5 Put area:
    int_type sputc(char_type c);
    streamsize sputn(const char_type* s, streamsize n);

protected:
    basic_streambuf();
    basic_streambuf(const basic_streambuf& rhs);
    basic_streambuf& operator=(const basic_streambuf& rhs);
    void swap(basic_streambuf& rhs);

    // 27.6.2.3.2 Get area:
    char_type* eback() const;
    char_type* gptr() const;
    char_type* egptr() const;
    void gbump(int n);
    void setg(char_type* gbeg, char_type* gnext, char_type* gend);

    // 27.6.2.3.3 Put area:
    char_type* pbase() const;
    char_type* pptr() const;
    char_type* epptr() const;
    void pbump(int n);
    void setp(char_type* pbeg, char_type* pend);

    // 27.6.2.4 virtual functions:
    // 27.6.2.4.1 Locales:
    virtual void imbue(const locale& loc);

    // 27.6.2.4.2 Buffer management and positioning:
    virtual basic_streambuf* setbuf(char_type* s, streamsize n);
    virtual pos_type seekoff(off_type off, ios_base::seekdir way,
                             ios_base::openmode which = ios_base::in | ios_base::out);
    virtual pos_type seekpos(pos_type sp,
                             ios_base::openmode which = ios_base::in | ios_base::out);
    virtual int sync();

    // 27.6.2.4.3 Get area:
    virtual streamsize showmanyc();
    virtual streamsize xsgetn(char_type* s, streamsize n);
    virtual int_type underflow();
    virtual int_type uflow();

    // 27.6.2.4.4 Putback:
    virtual int_type pbackfail(int_type c = traits_type::eof());

    // 27.6.2.4.5 Put area:
    virtual streamsize xsputn(const char_type* s, streamsize n);
    virtual int_type overflow (int_type c = traits_type::eof());
};

}  // std

*/

#include <__assert> // all public C++ headers provide the assertion handler
#include <__config>
#include <cstdint>
#include <ios>
#include <iosfwd>
#include <version>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _CharT, class _Traits>
class _LIBCPP_TEMPLATE_VIS basic_streambuf
{
public:
    // types:
    typedef _CharT                         char_type;
    typedef _Traits                        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;

    static_assert((is_same<_CharT, typename traits_type::char_type>::value),
                  "traits_type::char_type must be the same type as CharT");

    virtual ~basic_streambuf();

    // 27.6.2.2.1 locales:
    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    locale pubimbue(const locale& __loc) {
        imbue(__loc);
        locale __r = __loc_;
        __loc_ = __loc;
        return __r;
    }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    locale getloc() const { return __loc_; }

    // 27.6.2.2.2 buffer and positioning:
    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    basic_streambuf* pubsetbuf(char_type* __s, streamsize __n)
    { return setbuf(__s, __n); }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    pos_type pubseekoff(off_type __off, ios_base::seekdir __way,
                        ios_base::openmode __which = ios_base::in | ios_base::out)
    { return seekoff(__off, __way, __which); }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    pos_type pubseekpos(pos_type __sp,
                        ios_base::openmode __which = ios_base::in | ios_base::out)
    { return seekpos(__sp, __which); }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    int pubsync() { return sync(); }

    // Get and put areas:
    // 27.6.2.2.3 Get area:
    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    streamsize in_avail() {
        if (__ninp_ < __einp_)
            return static_cast<streamsize>(__einp_ - __ninp_);
        return showmanyc();
    }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    int_type snextc() {
        if (sbumpc() == traits_type::eof())
            return traits_type::eof();
        return sgetc();
    }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    int_type sbumpc() {
        if (__ninp_ == __einp_)
            return uflow();
        return traits_type::to_int_type(*__ninp_++);
    }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    int_type sgetc() {
        if (__ninp_ == __einp_)
            return underflow();
        return traits_type::to_int_type(*__ninp_);
    }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    streamsize sgetn(char_type* __s, streamsize __n)
    { return xsgetn(__s, __n); }

    // 27.6.2.2.4 Putback:
    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    int_type sputbackc(char_type __c) {
        if (__binp_ == __ninp_ || !traits_type::eq(__c, __ninp_[-1]))
            return pbackfail(traits_type::to_int_type(__c));
        return traits_type::to_int_type(*--__ninp_);
    }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    int_type sungetc() {
        if (__binp_ == __ninp_)
          return pbackfail();
        return traits_type::to_int_type(*--__ninp_);
    }

    // 27.6.2.2.5 Put area:
    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    int_type sputc(char_type __c) {
        if (__nout_ == __eout_)
            return overflow(traits_type::to_int_type(__c));
        *__nout_++ = __c;
        return traits_type::to_int_type(__c);
    }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    streamsize sputn(const char_type* __s, streamsize __n)
    { return xsputn(__s, __n); }

protected:
    basic_streambuf();
    basic_streambuf(const basic_streambuf& __rhs);
    basic_streambuf& operator=(const basic_streambuf& __rhs);
    void swap(basic_streambuf& __rhs);

    // 27.6.2.3.2 Get area:
    _LIBCPP_INLINE_VISIBILITY char_type* eback() const {return __binp_;}
    _LIBCPP_INLINE_VISIBILITY char_type* gptr()  const {return __ninp_;}
    _LIBCPP_INLINE_VISIBILITY char_type* egptr() const {return __einp_;}

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    void gbump(int __n) { __ninp_ += __n; }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    void setg(char_type* __gbeg, char_type* __gnext, char_type* __gend) {
        __binp_ = __gbeg;
        __ninp_ = __gnext;
        __einp_ = __gend;
    }

    // 27.6.2.3.3 Put area:
    _LIBCPP_INLINE_VISIBILITY char_type* pbase() const {return __bout_;}
    _LIBCPP_INLINE_VISIBILITY char_type* pptr()  const {return __nout_;}
    _LIBCPP_INLINE_VISIBILITY char_type* epptr() const {return __eout_;}

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    void pbump(int __n) { __nout_ += __n; }

    _LIBCPP_INLINE_VISIBILITY
    void __pbump(streamsize __n) { __nout_ += __n; }

    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
    void setp(char_type* __pbeg, char_type* __pend) {
        __bout_ = __nout_ = __pbeg;
        __eout_ = __pend;
    }

    // 27.6.2.4 virtual functions:
    // 27.6.2.4.1 Locales:
    virtual void imbue(const locale& __loc);

    // 27.6.2.4.2 Buffer management and positioning:
    virtual basic_streambuf* setbuf(char_type* __s, streamsize __n);
    virtual pos_type seekoff(off_type __off, ios_base::seekdir __way,
                             ios_base::openmode __which = ios_base::in | ios_base::out);
    virtual pos_type seekpos(pos_type __sp,
                             ios_base::openmode __which = ios_base::in | ios_base::out);
    virtual int sync();

    // 27.6.2.4.3 Get area:
    virtual streamsize showmanyc();
    virtual streamsize xsgetn(char_type* __s, streamsize __n);
    virtual int_type underflow();
    virtual int_type uflow();

    // 27.6.2.4.4 Putback:
    virtual int_type pbackfail(int_type __c = traits_type::eof());

    // 27.6.2.4.5 Put area:
    virtual streamsize xsputn(const char_type* __s, streamsize __n);
    virtual int_type overflow(int_type __c = traits_type::eof());

private:
    locale __loc_;
    char_type* __binp_;
    char_type* __ninp_;
    char_type* __einp_;
    char_type* __bout_;
    char_type* __nout_;
    char_type* __eout_;
};

template <class _CharT, class _Traits>
basic_streambuf<_CharT, _Traits>::~basic_streambuf()
{
}

template <class _CharT, class _Traits>
basic_streambuf<_CharT, _Traits>::basic_streambuf()
    : __binp_(nullptr),
      __ninp_(nullptr),
      __einp_(nullptr),
      __bout_(nullptr),
      __nout_(nullptr),
      __eout_(nullptr)
{
}

template <class _CharT, class _Traits>
basic_streambuf<_CharT, _Traits>::basic_streambuf(const basic_streambuf& __sb)
    : __loc_(__sb.__loc_),
      __binp_(__sb.__binp_),
      __ninp_(__sb.__ninp_),
      __einp_(__sb.__einp_),
      __bout_(__sb.__bout_),
      __nout_(__sb.__nout_),
      __eout_(__sb.__eout_)
{
}

template <class _CharT, class _Traits>
basic_streambuf<_CharT, _Traits>&
basic_streambuf<_CharT, _Traits>::operator=(const basic_streambuf& __sb)
{
    __loc_ = __sb.__loc_;
    __binp_ = __sb.__binp_;
    __ninp_ = __sb.__ninp_;
    __einp_ = __sb.__einp_;
    __bout_ = __sb.__bout_;
    __nout_ = __sb.__nout_;
    __eout_ = __sb.__eout_;
    return *this;
}

template <class _CharT, class _Traits>
void
basic_streambuf<_CharT, _Traits>::swap(basic_streambuf& __sb)
{
    _VSTD::swap(__loc_, __sb.__loc_);
    _VSTD::swap(__binp_, __sb.__binp_);
    _VSTD::swap(__ninp_, __sb.__ninp_);
    _VSTD::swap(__einp_, __sb.__einp_);
    _VSTD::swap(__bout_, __sb.__bout_);
    _VSTD::swap(__nout_, __sb.__nout_);
    _VSTD::swap(__eout_, __sb.__eout_);
}

template <class _CharT, class _Traits>
void
basic_streambuf<_CharT, _Traits>::imbue(const locale&)
{
}

template <class _CharT, class _Traits>
basic_streambuf<_CharT, _Traits>*
basic_streambuf<_CharT, _Traits>::setbuf(char_type*, streamsize)
{
    return this;
}

template <class _CharT, class _Traits>
typename basic_streambuf<_CharT, _Traits>::pos_type
basic_streambuf<_CharT, _Traits>::seekoff(off_type, ios_base::seekdir,
                                          ios_base::openmode)
{
    return pos_type(off_type(-1));
}

template <class _CharT, class _Traits>
typename basic_streambuf<_CharT, _Traits>::pos_type
basic_streambuf<_CharT, _Traits>::seekpos(pos_type, ios_base::openmode)
{
    return pos_type(off_type(-1));
}

template <class _CharT, class _Traits>
int
basic_streambuf<_CharT, _Traits>::sync()
{
    return 0;
}

template <class _CharT, class _Traits>
streamsize
basic_streambuf<_CharT, _Traits>::showmanyc()
{
    return 0;
}

template <class _CharT, class _Traits>
streamsize
basic_streambuf<_CharT, _Traits>::xsgetn(char_type* __s, streamsize __n)
{
    const int_type __eof = traits_type::eof();
    int_type __c;
    streamsize __i = 0;
    while(__i < __n)
    {
        if (__ninp_ < __einp_)
        {
            const streamsize __len = _VSTD::min(static_cast<streamsize>(INT_MAX),
                                _VSTD::min(__einp_ - __ninp_, __n - __i));
            traits_type::copy(__s, __ninp_, __len);
            __s +=  __len;
            __i +=  __len;
            this->gbump(__len);
        }
        else if ((__c = uflow()) != __eof)
        {
            *__s = traits_type::to_char_type(__c);
            ++__s;
            ++__i;
        }
        else
            break;
    }
    return __i;
}

template <class _CharT, class _Traits>
typename basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::underflow()
{
    return traits_type::eof();
}

template <class _CharT, class _Traits>
typename basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::uflow()
{
    if (underflow() == traits_type::eof())
        return traits_type::eof();
    return traits_type::to_int_type(*__ninp_++);
}

template <class _CharT, class _Traits>
typename basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::pbackfail(int_type)
{
    return traits_type::eof();
}

template <class _CharT, class _Traits>
streamsize
basic_streambuf<_CharT, _Traits>::xsputn(const char_type* __s, streamsize __n)
{
    streamsize __i = 0;
    int_type __eof = traits_type::eof();
    while( __i < __n)
    {
        if (__nout_ >= __eout_)
        {
            if (overflow(traits_type::to_int_type(*__s)) == __eof)
                break;
            ++__s;
            ++__i;
        }
        else
        {
            streamsize __chunk_size = _VSTD::min(__eout_ - __nout_, __n - __i);
            traits_type::copy(__nout_, __s, __chunk_size);
            __nout_ += __chunk_size;
            __s     += __chunk_size;
            __i     += __chunk_size;
        }
    }
    return __i;
}

template <class _CharT, class _Traits>
typename basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::overflow(int_type)
{
    return traits_type::eof();
}

extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_streambuf<char>;
extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ios<char>;

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_streambuf<wchar_t>;
extern template class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ios<wchar_t>;
#endif

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP_STREAMBUF
