/** @file
 * IPRT / No-CRT - Minimal C++ ios header.
 */

/*
 * Copyright (C) 2022 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 */

#ifndef IPRT_INCLUDED_nocrt_ios
#define IPRT_INCLUDED_nocrt_ios
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif

#include <iprt/nocrt/iosfwd>
#include <iprt/nocrt/string>

/** @todo something for cdecl.h   */
#define RTNOCRT_IOS_ENUM_BIT_OPS(a_EnumType, a_IntType) \
    inline a_EnumType operator~(a_EnumType a_fLeft) RT_NOEXCEPT \
    { return a_EnumType(~static_cast<a_IntType>(a_fLeft)); } \
    \
    inline a_EnumType operator&(a_EnumType a_fLeft, a_EnumType a_fRight) RT_NOEXCEPT \
    { return a_EnumType(static_cast<a_IntType>(a_fLeft) & static_cast<a_IntType>(a_fRight)); } \
    inline a_EnumType operator|(a_EnumType a_fLeft, a_EnumType a_fRight) RT_NOEXCEPT \
    { return a_EnumType(static_cast<a_IntType>(a_fLeft) | static_cast<a_IntType>(a_fRight)); } \
    inline a_EnumType operator^(a_EnumType a_fLeft, a_EnumType a_fRight) RT_NOEXCEPT \
    { return a_EnumType(static_cast<a_IntType>(a_fLeft) ^ static_cast<a_IntType>(a_fRight)); } \
    \
    inline const a_EnumType &operator&=(a_EnumType &a_rfLeft, a_EnumType a_fRight) RT_NOEXCEPT \
    { return a_rfLeft = a_rfLeft & a_fRight; } \
    inline const a_EnumType &operator|=(a_EnumType &a_rfLeft, a_EnumType a_fRight) RT_NOEXCEPT \
    { return a_rfLeft = a_rfLeft | a_fRight; } \
    inline const a_EnumType &operator^=(a_EnumType &a_rfLeft, a_EnumType a_fRight) RT_NOEXCEPT \
    { return a_rfLeft = a_rfLeft ^ a_fRight; } \

namespace std
{
    typedef ptrdiff_t streamsize;

    /**
     * I/O stream format flags.
     */
    class rtNoCrtIosEnums
    {
    public:
        enum fmtflags
        {
            /* int: */
            dec         = 0x00000001,
            oct         = 0x00000002,
            hex         = 0x00000004,
            basefield   = 0x00000007,
            /* float: */
            scientific  = 0x00000010,
            fixed       = 0x00000020,
            floatfield  = 0x00000030,
            /* int and float output tweaks: */
            showbase    = 0x00000100,
            showpoint   = 0x00000200,
            showpos     = 0x00000400,
            /* bool: */
            boolalpha   = 0x00000800,
            /* adjustment: */
            left        = 0x00001000,
            right       = 0x00002000,
            internal    = 0x00004000,
            adjustfield = 0x00007000,
            /* misc: */
            skipws      = 0x00010000,
            unitbuf     = 0x00020000,
            uppercase   = 0x00040000,
        };

        enum seekdir
        {
            beg = 1,
            end,
            cur,
        };

        enum openmode
        {
            app = 1,
            binary,
            in,
            out,
            trunc,
            ate
        };

        enum iostate
        {
            goodbit = 0,
            badbit  = 1,
            failbit = 2,
            eofbit  = 4
        };
    };
    RTNOCRT_IOS_ENUM_BIT_OPS(rtNoCrtIosEnums::fmtflags, int)
    RTNOCRT_IOS_ENUM_BIT_OPS(rtNoCrtIosEnums::seekdir, int)
    RTNOCRT_IOS_ENUM_BIT_OPS(rtNoCrtIosEnums::openmode, int)
    RTNOCRT_IOS_ENUM_BIT_OPS(rtNoCrtIosEnums::iostate, int)


    /**
     * I/O stream base class.
     */
    class ios_base : public rtNoCrtIosEnums
    {
    public:
        //typedef rtNoCrtIosFmtFlags fmtflags;
        //typedef rtNoCrtIosSeekDir  seekdir;
        //typedef rtNoCrtIosOpenMode openmode;
        //typedef rtNoCrtIosState    iostate;

    protected:
        streamsize  m_cWidth;
        streamsize  m_cPrecision;
        fmtflags    m_fFlags;
        iostate     m_fState;

    protected:
        ios_base()
            : m_cWidth(0)
            , m_cPrecision(0)
            , m_fFlags(dec | skipws)
            , m_fState(goodbit)
        {
        }
    private:
        ios_base(const ios_base &);                 /* not copyable */
        ios_base &operator=(const ios_base &);  /* not copyable */

    public:
        virtual ~ios_base()
        {
        }

        streamsize width() const RT_NOEXCEPT
        {
            return m_cWidth;
        }

        streamsize width(streamsize a_cWidth) RT_NOEXCEPT
        {
            streamsize cOldWidth = m_cWidth;
            m_cWidth = a_cWidth;
            return cOldWidth;
        }

        streamsize precision() const RT_NOEXCEPT
        {
            return m_cPrecision;
        }

        streamsize precision(streamsize a_cPrecision) RT_NOEXCEPT
        {
            streamsize cOldPrecision = m_cPrecision;
            m_cPrecision = a_cPrecision;
            return cOldPrecision;
        }

        fmtflags flags() const RT_NOEXCEPT
        {
            return m_fFlags;
        }

        fmtflags flags(fmtflags a_fNew) RT_NOEXCEPT
        {
            fmtflags const fOld = m_fFlags;
            m_fFlags = a_fNew;
            return fOld;
        }

        fmtflags setf(fmtflags a_fAdd) RT_NOEXCEPT
        {
            fmtflags const fOld = m_fFlags;
            m_fFlags = static_cast<fmtflags>(fOld | a_fAdd);
            return fOld;
        }

        fmtflags setf(fmtflags a_fAdd, fmtflags a_fMask) RT_NOEXCEPT
        {
            fmtflags const fOld = m_fFlags;
            m_fFlags = static_cast<fmtflags>((fOld & ~a_fMask) | (a_fAdd & a_fMask));
            return fOld;
        }

        void unsetf(fmtflags a_fClear) RT_NOEXCEPT
        {
            m_fFlags = static_cast<fmtflags>(m_fFlags & ~a_fClear);
        }
    };


    /**
     * Stream buffer.
     */
    template<typename a_CharType, typename a_CharTraits /*= std::char_traits<a_CharType>*/ >
    class basic_streambuf
    {
    public:
        typedef a_CharType                          char_type;
        typedef a_CharTraits                        traits_type;
        typedef typename a_CharTraits::int_type     int_type;
        typedef typename a_CharTraits::pos_type     pos_type;
        typedef typename a_CharTraits::off_type     off_type;

    protected:
        /** @name Put buffering
         * @{ */
        char_type   *m_pachPut;     /**< The put buffer pointer. */
        std::size_t  m_cchPut;      /**< Put buffer size. */
        std::size_t  m_offPutNext;  /**< The current put buffer position (where to write next). */
        std::size_t  m_offPutStart; /**< Where the buffered put sequence starts. */

        void setp(char_type *a_pachNewBuf, char_type *a_pachNewBufEnd)
        {
            Assert((uintptr_t)a_pachNewBuf <= (uintptr_t)a_pachNewBufEnd);
            m_pachPut     = a_pachNewBuf;
            m_cchPut      = static_cast<std::size_t>(a_pachNewBufEnd - a_pachNewBuf);
            m_offPutNext  = 0;
            m_offPutStart = 0;
        }

        char_type *pbbase() const RT_NOEXCEPT
        {
            Assert(m_offPutNext >= m_offPutStart); Assert(m_offPutNext <= m_cchPut); Assert(m_offPutStart <= m_cchPut);
            return &m_pachPut[m_offPutStart];
        }

        char_type *pptr()  const RT_NOEXCEPT
        {
            Assert(m_offPutNext <= m_cchPut);
            return &m_pachPut[m_offPutNext];
        }

        char_type *epptr()  const RT_NOEXCEPT
        {
            return &m_pachBuf[m_cchPut];
        }

        void pbump(int a_cchAdvance)  const RT_NOEXCEPT
        {
            Assert(m_offPutNext <= m_cchPut);
            m_offPutNext      += a_cchAdvance;
            Assert(m_offPutNext <= m_cchPut);
        }
        /** @} */

    protected:
        basic_streambuf() RT_NOEXCEPT
            : m_pachPut(NULL)
            , m_cchPut(0)
            , m_offPutNext(0)
            , m_offPutStart(0)
        {
        }

        basic_streambuf(const basic_streambuf &a_rSrc) RT_NOEXCEPT
            : m_pachPut(a_rSrc.m_pachPut)
            , m_cchPut(a_rSrc.m_cchPut)
            , m_offPutNext(a_rSrc.m_offPutNext)
            , m_offPutStart(a_rSrc.m_offPutStart)
        {
        }

    public:
        virtual ~basic_streambuf()
        {
        }

        /** @name Positioning
         * @{ */
    protected:
        virtual basic_streambuf *setbuf(char_type *a_pchBuf, std::streamsize a_cchBuf)
        {
            RT_NOREF(a_pchBuf, a_cchBuf);
            return this;
        }
    public:
        basic_streambuf *pubsetbuf(char_type *a_pchBuf, std::streamsize a_cchBuf)
        {
            return setbuf(a_pchBuf, a_cchBuf);
        }

    protected:
        virtual pos_type seekoff(off_type a_off, std::ios_base::seekdir a_enmDir,
                                 std::ios_base::openmode a_enmTarget = ios_base::in | ios_base::out)
        {
            RT_NOREF(a_off, a_enmDir, a_enmTarget);
            return pos_type(off_type(-1));
        }
    public:
        pos_type pubseekoff(off_type a_off, std::ios_base::seekdir a_enmDir,
                            std::ios_base::openmode a_enmTarget = ios_base::in | ios_base::out)
        {
            return seekoff(a_off, a_enmDir, a_enmTarget);
        }

    protected:
        virtual pos_type seekpos(pos_type a_pos, std::ios_base::openmode a_enmTarget = ios_base::in | ios_base::out)
        {
            RT_NOREF(a_pos, a_enmTarget);
            return pos_type(off_type(-1));
        }
    public:
        pos_type pubseekpos(pos_type a_pos, std::ios_base::openmode a_enmTarget = ios_base::in | ios_base::out)
        {
            return seekpos(a_pos, a_enmTarget);
        }

    protected:
        virtual int sync()
        {
            return 0;
        }
    public:
        pos_type pubsync()
        {
            return sync();
        }
        /** @} */

        /** @name Output
         * @{ */
    protected:
        virtual int_type overflow(int_type a_iChar)
        {
            RT_NOREF(a_iChar);
            return traits_type::eof();
        }

        virtual std::streamsize xsputn(char_type const *a_pchSrc, std::streamsize a_cchSrc)
        {
            std::streamsize cchWritten = 0;
            while (a_cchSrc > 0)
            {
                std::size_t cchCopied = m_cchPut - m_offPutNext;
                if (cchCopied > 0)
                {
                    cchCopied = RT_MIN(cchCopied, static_cast<std::size_t>(a_cchSrc));
                    traits_type::copy(&m_pachPut[m_offPutNext], a_pchSrc, cchCopied);
                    m_cchPut += cchCopied;
                }
                else
                {
                    if (overflow(traits_type::to_int_type(m_pachPut[m_offPutNext])) != traits_type::eof())
                        cchCopied = 1;
                    else
                        break;
                }
                a_pchSrc += cchCopied;
                a_cchSrc -= cchCopied;
            }
            return cchWritten;
        }

    public:
        int_type sputc(char_type a_ch)
        {
            if (m_offPutNext < m_cchPut)
            {
                m_pachPut[m_offPutNext++] = a_ch;
                return traits_type::to_int_type(a_ch);
            }
            return overflow(traits_type::to_int_type(a_ch));
        }

        std::streamsize sputn(char_type const *a_pchSrc, std::streamsize a_cchSrc)
        {
            AssertReturn(a_cchSrc >= 0, 0);
            return xsputn(a_pchSrc, a_cchSrc);
        }

        /** @} */

        /** @todo add the remaining members... */
    };


    /**
     * Basic I/O stream.
     */
    template<typename a_CharType, typename a_CharTraits /*= std::char_traits<a_CharType>*/ >
    class basic_ios : public ios_base
    {
    public:
        typedef a_CharType                          char_type;
        typedef a_CharTraits                        traits_type;
        typedef typename a_CharTraits::int_type     int_type;
        typedef typename a_CharTraits::pos_type     pos_type;
        typedef typename a_CharTraits::off_type     off_type;

    protected:
        basic_streambuf<a_CharType, a_CharTraits>  *m_pBuf;
        basic_ostream<a_CharType, a_CharTraits>    *m_pTiedStream;

    protected:
        void init(std::basic_streambuf<a_CharType, a_CharTraits> *a_pBuf)
        {
            m_pBuf         = a_pBuf;
            m_cWidth       = 0;
            m_cPrecision   = 6;
            m_fFlags       = ios_base::dec | ios_base::skipws;
            m_fState       = ios_base::goodbit;
        }

    public:
        basic_ios()
            : ios_base()
            , m_pBuf(NULL)
            , m_pTiedStream(NULL)
        {
        }

        basic_ios(std::basic_streambuf<a_CharType, a_CharTraits> *a_pBuf)
            : ios_base()
            , m_pBuf(NULL)
            , m_pTiedStream(NULL)
        {
            init(a_pBuf);
        }
    private:
        basic_ios(const basic_ios &a_rSrc);             /* not copyable */
        basic_ios &operator=(const basic_ios &a_rSrc);  /* not copyable */

    public:
        virtual ~basic_ios()
        {
        }

        /** @name State methods
         * @{ */
        bool good() const RT_NOEXCEPT { return m_fState == ios_base::goodbit; }
        bool fail() const RT_NOEXCEPT { return (m_fState & (ios_base::failbit | ios_base::badbit)) != ios_base::goodbit; }
        bool bad()  const RT_NOEXCEPT { return (m_fState & ios_base::badbit) == ios_base::badbit; }
        bool eof()  const RT_NOEXCEPT { return (m_fState & ios_base::eofbit) != ios_base::eofbit; }
#if RT_CPLUSPLUS_PREREQ(201100)
        operator bool()  const RT_NOEXCEPT { return good(); }
#else
        operator void*() const RT_NOEXCEPT { return good() ? NULL : this; }
#endif
        bool operator!() const RT_NOEXCEPT { return fail(); }

        iostate rdstate() const RT_NOEXCEPT
        {
            return m_fState;
        }

        void    clear(iostate a_fNewState = goodbit)
        {
            m_fState = a_fNewState;
            if (!m_pBuf)
                m_fState |= badbit;
            /** @todo failure exception */
        }

        void    setstate(iostate a_fNewState)
        {
            clear(m_fState | a_fNewState);
        }
        /** @} */

        /** @name Misc
         * @{ */
        std::basic_streambuf<a_CharType, a_CharTraits> *rdbuf() const RT_NOEXCEPT
        {
            return m_pBuf;
        }

        std::basic_streambuf<a_CharType, a_CharTraits> *rdbuf(std::basic_streambuf<a_CharType, a_CharTraits> *a_pNewbuf) RT_NOEXCEPT
        {
            std::basic_streambuf<a_CharType, a_CharTraits> *pOldBuf = m_pBuf;
            m_pBuf = a_pNewBuf;
            return pOldBuf;
        }

        std::basic_ostream<a_CharType, a_CharTraits> *tie() const
        {
            return m_pTiedStream;
        }

        std::basic_ostream<a_CharType, a_CharTraits> tie(std::basic_ostream<a_CharType, a_CharTraits> *a_pNew) const RT_NOEXCEPT
        {
            std::basic_ostream<a_CharType, a_CharTraits> * const pOld = m_pTiedStream;
            m_pTiedStream = a_pNew;
            return pOld;
        }
        /** @}  */

        /** @todo implement the rest... */
    };
}

#endif /* !IPRT_INCLUDED_nocrt_ios */