source: vbox/trunk/include/iprt/nocrt/string@ 96354

/** @file
 * IPRT / No-CRT - Minimal C++ string 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_string
#define IPRT_INCLUDED_nocrt_string
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif

#include <iprt/nocrt/string.h>
#include <iprt/nocrt/cstddef> /* for std::size_t */
#include <iprt/cpp/ministring.h>

#ifndef RT_NOCRT_EOF /* also in stdio.h */
# define RT_NOCRT_EOF   (-1)
#endif

namespace std
{
    using streamoff = ::RTFOFF;

    /**
     * @note This should be in iosfwd, not string.
     */
    template<typename a_MbStateType>
    class fpos
    {
    protected:
        std::streamoff  m_off;
        a_MbStateType   m_MbState;

    public:
        fpos()
            : m_off(0)
            , m_MbState()
        { }

        fpos(std::streamoff a_off)
            : m_off(a_off)
            , m_MbState()
        { }

        a_MbStateType state() const RT_NOEXCEPT
        {
            return m_MbState;
        }

        void state(a_MbStateType a_NewMbState) const RT_NOEXCEPT
        {
            m_MbState = a_NewMbState;
        }
    };
    using mbstate_t = ::RT_NOCRT(mbstate_t);
    using streampos = fpos<std::mbstate_t>;

    /* Use RTCString as std::string, it should be a reasonable match. */
    typedef ::RTCString string;

    /**
     * Character traits.
     */
    template<typename a_CharType>
    struct char_traits
    {
        /** @name Types
         * @{ */
        typedef a_CharType                  char_type;
        typedef unsigned long               int_type;
        typedef std::streamoff              off_type;
        typedef std::streampos              pos_type;
        typedef std::mbstate_t              state_type;
        /** @} */

        static void assign(char_type &a_rchDst, const char_type &a_rchSrc) RT_NOEXCEPT
        {
            a_rchDst = a_rchSrc;
        }

        static bool eq(const char_type &a_rchLeft, const char_type &a_rchRight) RT_NOEXCEPT
        {
            return a_rchLeft == a_rchRight;
        }

        static bool lt(const char_type &a_rchLeft, const char_type &a_rchRight) RT_NOEXCEPT
        {
            return a_rchLeft < a_rchRight;
        }

        static std::size_t      length(const char_type *a_psz) RT_NOEXCEPT;
        static int              compare(const char_type *a_pchLeft, const char_type *a_pchRight, std::size_t a_cch) RT_NOEXCEPT;
        static const char_type *find(const char_type *a_pchHaystack, std::size_t a_cchHaystack, const char_type &a_rchNeedle) RT_NOEXCEPT;
        static char_type       *assign(char_type *a_pchDst, std::size_t a_cchDst, char_type a_chFill) RT_NOEXCEPT;
        static char_type       *copy(char_type *a_pchDst, const char_type *a_pchSrc, std::size_t a_cch) RT_NOEXCEPT;
        static char_type       *move(char_type *a_pchDst, const char_type *a_pchSrc, std::size_t a_cch) RT_NOEXCEPT;

        static char_type to_char_type(const int_type &a_riChar)
        {
            return static_cast<char_type>(a_riChar);
        }

        static int_type to_int_type(const char_type &a_rch)
        {
            return static_cast<int_type>(a_rch);
        }

        static bool eq_int_type(const int_type &a_riLeft, const int_type &a_riRight) RT_NOEXCEPT
        {
            return a_riLeft == a_riRight;
        }

        static int_type eof() RT_NOEXCEPT
        {
            return static_cast<int_type>(RT_NOCRT_EOF);
        }

        static int_type not_eof(const int_type &a_riChar) RT_NOEXCEPT
        {
            if (!eq_int_type(a_riChar, eof()))
                return a_riChar;
            return to_int_type(char_type());
        }
    };

    template<typename a_CharType>
    /*static*/ std::size_t char_traits<a_CharType>::length(const char_type *a_psz) RT_NOEXCEPT
    {
        const char_type * const pszStart = a_psz;
        while (!eq(*a_pszLeft, char_type()))
               a_psz++;
        return static_cast<std::size_t>(a_psz - pszStart);
    }

    template<typename a_CharType>
    /*static*/ int char_traits<a_CharType>::compare(const char_type *a_pchLeft, const char_type *a_pchRight,
                                                    std::size_t a_cch) RT_NOEXCEPT
    {
        for (std::size_t off = 0; off < a_cch; off++)
            if (eq(a_pchLeft[off], a_pchRight[off]))
            { /* likely? */ }
            else
                return lt(a_pchLeft[off], a_pchRight[off]) ? -1 : 1;
        return 0;
    }

    template<typename a_CharType>
    /*static*/ const typename char_traits<a_CharType>::char_type *
    char_traits<a_CharType>::find(const char_type *a_pchHaystack, std::size_t a_cchHaystack,
                                  const char_type &a_rchNeedle) RT_NOEXCEPT
    {
        while (a_cchHaystack-- > 0)
        {
            if (eq(*a_pchHaystack, a_rchNeedle))
                return a_pchHaystack;
            a_pchHaystack++;
        }
        return NULL;
    }

    template<typename a_CharType>
    /*static*/ typename char_traits<a_CharType>::char_type *
    char_traits<a_CharType>::assign(char_type *a_pchDst, std::size_t a_cchDst, char_type a_chFill) RT_NOEXCEPT
    {
        char_type * const pchRet = a_pchDst;
        while (a_cchDst-- > 0)
            *a_pchDst++ = a_chFill;
        return pchRet;
    }

    template<typename a_CharType>
    /*static*/ typename char_traits<a_CharType>::char_type *
    char_traits<a_CharType>::copy(char_type *a_pchDst, const char_type *a_pchSrc, std::size_t a_cch) RT_NOEXCEPT
    {
        char_type * const pchRet = a_pchDst;
        while (a_cch-- > 0)
            *a_pchDst++ = *a_pchSrc++;
        return pchRet;
    }

    template<typename a_CharType>
    /*static*/ typename char_traits<a_CharType>::char_type *
    char_traits<a_CharType>::move(char_type *a_pchDst, const char_type *a_pchSrc, std::size_t a_cch) RT_NOEXCEPT
    {
        char_type * const         pchRet  = a_pchDst;
        char_type volatile       *pchDstV = static_cast<char_type const volatile *>(a_pchDst);
        char_type const volatile *pchSrcV = static_cast<char_type const volatile *>(a_pchSrc);
        if ((uintptr_t)a_pchDst < (uintptr_t)a_pchSrc)
        {
            /* forward copy */
            while (a_cch-- > 0)
                *a_pchDstV++ = *a_pchSrcV++;
        }
        else
        {
            /* reverse copy */
            a_pchSrcV += a_cch;
            a_pchDstV += a_cch;
            while (a_cchDst-- > 0)
                *a_pchDstV-- = *a_pchSrcV--;
        }
        return pchRet;
    }

    /*
     * Character train specializations.
     */
    template <>
    struct char_traits<char>
    {
        typedef char                        char_type;
        typedef int                         int_type;
        typedef std::streamoff              off_type;
        typedef std::streampos              pos_type;
        typedef std::mbstate_t              state_type;

        static void assign(char_type &a_rchDst, const char_type &a_rchSrc) RT_NOEXCEPT
        {
            a_rchDst = a_rchSrc;
        }

        static bool eq(const char_type &a_rchLeft, const char_type &a_rchRight) RT_NOEXCEPT
        {
            return a_rchLeft == a_rchRight;
        }

        static bool lt(const char_type &a_rchLeft, const char_type &a_rchRight) RT_NOEXCEPT
        {
            return a_rchLeft < a_rchRight;
        }

        static std::size_t      length(const char_type *a_psz) RT_NOEXCEPT
        {
            return ::RT_NOCRT(strlen)(a_psz);
        }

        static int              compare(const char_type *a_pchLeft, const char_type *a_pchRight, std::size_t a_cch) RT_NOEXCEPT
        {
            return ::RT_NOCRT(memcmp)(a_pchLeft, a_pchRight, a_cch);
        }

        static const char_type *find(const char_type *a_pchHaystack, std::size_t a_cchHaystack, const char_type &a_rchNeedle) RT_NOEXCEPT
        {
            return static_cast<const char_type *>(::RT_NOCRT(memchr)(a_pchHaystack, a_rchNeedle, a_cchHaystack));
        }

        static char_type       *assign(char_type *a_pchDst, std::size_t a_cchDst, char_type a_chFill) RT_NOEXCEPT
        {
            return static_cast<char_type *>(::RT_NOCRT(memset)(a_pchDst, a_chFill, a_cchDst));
        }

        static char_type       *copy(char_type *a_pchDst, const char_type *a_pchSrc, std::size_t a_cch) RT_NOEXCEPT
        {
            return static_cast<char_type *>(::RT_NOCRT(memcpy)(a_pchDst, a_pchSrc, a_cch));
        }

        static char_type       *move(char_type *a_pchDst, const char_type *a_pchSrc, std::size_t a_cch) RT_NOEXCEPT
        {
            return static_cast<char_type *>(::RT_NOCRT(memmove)(a_pchDst, a_pchSrc, a_cch));
        }

        static char_type to_char_type(const int_type &a_riChar)
        {
            return static_cast<char_type>(a_riChar);
        }

        static int_type to_int_type(const char_type &a_rch)
        {
            return static_cast<int_type>(a_rch);
        }

        static bool eq_int_type(const int_type &a_riLeft, const int_type &a_riRight) RT_NOEXCEPT
        {
            return a_riLeft == a_riRight;
        }

        static int_type eof() RT_NOEXCEPT
        {
            return static_cast<int_type>(RT_NOCRT_EOF);
        }

        static int_type not_eof(const int_type &a_riChar) RT_NOEXCEPT
        {
            if (!eq_int_type(a_riChar, eof()))
                return a_riChar;
            return 0;
        }
    };
}


#endif /* !IPRT_INCLUDED_nocrt_string */