streambuf

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// -*- C++ -*-
/***************************************************************************
 *
 * streambuf - Declarations for the Standard Library stream buffers
 *
 * $Id: streambuf,v 1.1.1.1 2002/01/10 17:38:29 vkorstan Exp $
 *
 ***************************************************************************
 *
 * Copyright (c) 1994-2001 Rogue Wave Software, Inc.  All Rights Reserved.
 *
 * This computer software is owned by Rogue Wave Software, Inc. and is
 * protected by U.S. copyright laws and other laws and by international
 * treaties.  This computer software is furnished by Rogue Wave Software,
 * Inc. pursuant to a written license agreement and may be used, copied,
 * transmitted, and stored only in accordance with the terms of such
 * license and with the inclusion of the above copyright notice.  This
 * computer software or any other copies thereof may not be provided or
 * otherwise made available to any other person.
 *
 * U.S. Government Restricted Rights.  This computer software is provided
 * with Restricted Rights.  Use, duplication, or disclosure by the
 * Government is subject to restrictions as set forth in subparagraph (c)
 * (1) (ii) of The Rights in Technical Data and Computer Software clause
 * at DFARS 252.227-7013 or subparagraphs (c) (1) and (2) of the
 * Commercial Computer Software--Restricted Rights at 48 CFR 52.227-19,
 * as applicable.  Manufacturer is Rogue Wave Software, Inc., 5500
 * Flatiron Parkway, Boulder, Colorado 80301 USA.
 *
 **************************************************************************/

#ifndef _RWSTD_STREAMBUF_INCLUDED
#define _RWSTD_STREAMBUF_INCLUDED


#include <rw/_iosbase.h>
#include <rw/_mutex.h>
#include <rw/_defs.h>

#include _RWSTD_CSTDLIB


_RWSTD_NAMESPACE_BEGIN (std)


template<class _CharT, class _Traits>
class basic_streambuf: public _RW::__rw_synchronized
{
public:
    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 () { }

    // 27.5.2.2.1, p1
    locale pubimbue (const locale &__loc);

    // 27.5.2.2.1, p4
    locale getloc () const {
        return _C_locale;
    }

    // extension: avoids reference counting in MT builds (may result in
    // a speedup of up to 50%); this is an alternative to caching a reference
    // (pointer) to a facet in each stream and stream buffer object
    locale& getloc () {
        return _C_locale;
    }

    // 27.5.2.2.2, p1
    basic_streambuf* pubsetbuf (char_type *__buf, streamsize __n) {
        return setbuf (__buf, __n);
    }

    // 27.5.2.2.2, p2
    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);
    }
    
    // 27.5.2.2.2, p3
    pos_type
    pubseekpos (pos_type __sp,
                ios_base::openmode __which = ios_base::in | ios_base::out) {
        return seekpos (__sp, __which);
    }
    
    // 27.5.2.2.2, p4
    int pubsync () {
        return sync ();
    }

    // 27.5.2.2.3, p1
    streamsize in_avail () {
        return gptr () < egptr () ? streamsize (egptr () - gptr ())
            : showmanyc ();
    }

    // 27.5.2.2.3, p2
    int_type snextc () {
        return _C_is_eof (sbumpc ()) ? traits_type::eof () : sgetc ();
    }
    
    // 27.5.2.2.3, p4
    int_type sbumpc ();
    
    // 27.5.2.2.3, p5
    int_type sgetc () {
        return gptr () >= egptr () ? underflow ()
            : traits_type::to_int_type (*gptr ());
    }

    // 27.5.2.2.3, p6
    streamsize sgetn (char_type *__s, streamsize __n) {
        _RWSTD_ASSERT_RANGE (__s, __s + __n);
        return xsgetn (__s, __n);
    }
    
    // 27.5.2.2.4, p1
    int_type sputbackc (char_type);

    // 27.5.2.2.4, p2
    int_type sungetc ();

    // 27.5.2.2.5, p1
    int_type sputc (char_type __c);
    
    // 27.5.2.2.5, p2
    streamsize sputn (const char_type *__s, streamsize __n) {
        _RWSTD_ASSERT_RANGE (__s, __s + __n);
        return xsputn (__s, __n);
    }

    ios_base::openmode _C_mode () const {
        return _C_iomode;
    }

protected:

    // 27.5.2.1, p1: default mode argument is extension for convenience
    basic_streambuf (ios_base::openmode __mode = ios_base::in | ios_base::out) 
        : _C_iomode (__mode),
          _C_buffer (0),
          _C_bufsize (0),
          _C_bufstate (0),
          _C_eback (0),
          _C_gptr (0),
          _C_egptr (0),
          _C_pbase (0),
          _C_pptr (0),
          _C_epptr (0)
        { }

    // 27.5.2.3.1, p1
    char_type* eback () const {
        return _C_eback;
    }

    // 27.5.2.3.1, p2
    char_type* gptr () const {
        return _C_gptr;
    }

    // 27.5.2.3.1, p3
    char_type* egptr () const {
        return _C_egptr;
    }

    // 27.5.2.3.1, p4
    void gbump (int __n) {
        _RWSTD_ASSERT (_C_gptr != 0);
        _C_gptr += __n;
    }

    // 27.5.2.3.1, p5
    void setg (char_type *__eback, char_type *__gptr, char_type *__egptr) {
        _C_eback = __eback;
        _C_gptr  = __gptr;
        _C_egptr = __egptr;
    }

    // 27.5.2.3.2, p1
    char_type* pbase () const {
        return _C_pbase;
    }

    // 27.5.2.3.2, p2
    char_type* pptr () const {
        return _C_pptr;
    }

    // 27.5.2.3.2, p3
    char_type* epptr () const {
        return _C_epptr;
    }

    // 27.5.2.3.2, p4
    void pbump (int __n) {
        _C_pptr += __n;
    }

    // 27.5.2.3.2, p5
    void setp (char_type *__pbase, char_type *__epptr) {
        _C_pbase = _C_pptr = __pbase;
        _C_epptr = __epptr;
    }

    // 27.5.2.4.1, p1
    virtual void imbue (const locale &__loc) {
        _C_locale = __loc;
    }

    // 27.5.2.4.2, p1
    virtual basic_streambuf* setbuf (char_type*, streamsize) {
        return this;
    }

    // 27.5.2.4.2, p3
    virtual pos_type
    seekoff (off_type, ios_base::seekdir,
             ios_base::openmode = ios_base::in | ios_base::out) {
        return pos_type (off_type (-1));
    }

    // 27.5.2.4.2, p5
    virtual pos_type
    seekpos (pos_type, ios_base::openmode = ios_base::in | ios_base::out) {
        return pos_type (off_type (-1));
    }

    // 27.5.2.4.3, p1
    virtual streamsize showmanyc () {
        return 0;
    }

    // 27.5.2.4.3, p4
    virtual streamsize xsgetn (char_type *, streamsize);

    // 27.5.2.4.3, p7
    virtual int_type underflow () {
        return traits_type::eof ();
    }

    // 27.5.2.4.3, p15
    virtual int_type uflow ();

    // 27.5.2.4.5, p3
    virtual int_type overflow (int_type = traits_type::eof ()) {
        return traits_type::eof ();
    }

    // 27.5.2.4.4, p1
    virtual int_type pbackfail (int_type = traits_type::eof ()) {
        return traits_type::eof ();  
    }

    // 27.5.2.4.5, p1
    virtual streamsize xsputn (const char_type*, streamsize);

    // 27.5.2.4.2, p7
    virtual int sync () {
        return 0;
    }


    //
    // non-standard convenience functions    
    //

    // is a read position available?
    streamsize _C_read_avail () const {
        return _C_is_in () ? egptr () - gptr () : 0;
    }

    // is a write position available?
    streamsize _C_write_avail () const {
        return _C_is_out () ? epptr () - pptr () : 0;
    }

    // how much space in putback area is available?
    streamsize _C_putback_avail () const {
        return (_C_is_in () && gptr () != 0) ? gptr () - eback () : 0;
    }

    // is buffer in input mode?
    bool _C_is_in () const {
        return 0 != (_C_iomode & ios_base::in);
    }

    // is buffer in output mode?
    bool _C_is_out () const {
        return  0 != (_C_iomode & ios_base::out);
    }

    // is buffer in both input and output mode?
    bool _C_is_inout () const {
        return (_C_iomode & (ios_base::in | ios_base::out))
               == (ios_base::in | ios_base::out);
    }

    // is character eof?
    bool _C_is_eof (int_type __c) const {
        return traits_type::eq_int_type (__c, traits_type::eof ());
    }

    // pointer to end of internal buffer
    char_type* _C_buf_end () const {
        return _C_buffer + _C_bufsize;
    }
    
    // enumerations used in derived classes
    enum {
        _C_allocated   = 0x1,    // buffer allocated internally
        _C_out_mode    = 0x2,    // last virtual operation was an output
        _C_unbuf_mode  = 0x4     // stream is in unbuffered mode
    }; 

    bool _C_own_buf () const {
        return 0 != (_C_bufstate & _C_allocated);
    }

    void _C_own_buf (bool __own) {
        if (__own)
            _C_bufstate |= _C_allocated;
        else
            _C_bufstate &= ~_C_allocated;
    }

    bool _C_out_last () const {
        return 0 != (_C_bufstate & _C_out_mode);
    }

    void _C_out_last (bool __last) {
        if (__last)
            _C_bufstate |= _C_out_mode;
        else
            _C_bufstate &= ~_C_out_mode;
    }

    bool _C_is_unbuffered () const {
        return 0 != (_C_bufstate & _C_unbuf_mode);
    }

    void _C_set_unbuffered (bool __unbuf) {
        if (__unbuf)
            _C_bufstate |= _C_unbuf_mode;
        else
            _C_bufstate &= ~_C_unbuf_mode;
    }

    // debug only - asserts that get and put areas are consistent
    bool _C_is_valid () const;
    
    ios_base::openmode _C_iomode;     // stream buffer's I/O mode
    char_type*         _C_buffer;     // character buffer
    streamsize         _C_bufsize;    // size of buffer in characters
    int                _C_bufstate;   // state of buffer (used in subclasses)

private:

    char_type *_C_eback;   // beginning of input dequence
    char_type *_C_gptr;    // next position of input sequence
    char_type *_C_egptr;   // end of input sequence

    char_type *_C_pbase;   // beginning of output dequence
    char_type *_C_pptr;    // next position of output sequence
    char_type *_C_epptr;   // end of output sequence

    locale     _C_locale;  // locale imbued in this object
};


template<class _CharT, class _Traits>
inline _TYPENAME basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::uflow ()
{
    if (_C_is_eof (underflow ()))
        return traits_type::eof ();

    return traits_type::to_int_type (*_C_gptr++);
}

template<class _CharT, class _Traits>
inline _TYPENAME basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::sbumpc ()
{ 
    if (!_C_read_avail ())
        return uflow ();
    
    char_type __c = *gptr ();  
    gbump (1);
    
    return traits_type::to_int_type (__c);
}

template<class _CharT, class _Traits>
inline _TYPENAME basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::sputbackc (char_type __c)
{
    if (_C_putback_avail () && traits_type::eq (gptr ()[-1], __c) ) { 
        gbump (-1);
        return traits_type::to_int_type (*gptr ());
    }
    
    return pbackfail (traits_type::to_int_type (__c)); 
}

template<class _CharT, class _Traits>
inline _TYPENAME basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::sputc (char_type __c)
{
    if (_C_write_avail ()) {
        traits_type::assign (*_C_pptr++, __c);
        return traits_type::to_int_type (__c);
    }

    return overflow (traits_type::to_int_type (__c));
}

template<class _CharT, class _Traits>
inline _TYPENAME basic_streambuf<_CharT, _Traits>::int_type
basic_streambuf<_CharT, _Traits>::sungetc ()
{
    if (gptr () > eback ()) {
        gbump (-1);
        return traits_type::to_int_type (*gptr ());
    }

    return pbackfail ();
}


template<class _CharT, class _Traits>
inline streamsize
basic_streambuf<_CharT, _Traits>::xsgetn (char_type* __buf, streamsize __n)
{
    // number of characters read
    streamsize __nget = 0;

    while (__n && (gptr () != egptr () || underflow () != int_type (-1))) {

        // number of characters available in get area
        streamsize __inbuf = egptr () - gptr ();
        
        if (__inbuf > __n)
            __inbuf = __n;

        // copy contents of get area to the destination buffer
        traits_type::copy (__buf + __nget, gptr (), __inbuf);

        // increment pointers and counts by the number of characters copied
        gbump (__inbuf);
        __n    -= __inbuf;
        __nget += __inbuf;
    }

    return __nget;
}


template<class _CharT, class _Traits>
inline streamsize
basic_streambuf<_CharT, _Traits>::xsputn (const char_type* __buf,
                                          streamsize __n)
{
    streamsize __nput = 0;

    for (; __nput < __n; ++__nput) 
        if (_C_is_eof (sputc (*__buf++)))
            break;
    
    return __nput;
}


template<class _CharT, class _Traits>
inline locale
basic_streambuf<_CharT, _Traits>::pubimbue (const locale &__loc)
{
    locale __retloc = getloc ();
    imbue (__loc);
    return __retloc; 
}


template<class _CharT, class _Traits>
inline bool basic_streambuf<_CharT, _Traits>::_C_is_valid () const
{
    // verify that get and put areas are consistent
    return    (   eback () && eback () <= gptr () && gptr () <= egptr ()
               || !eback () && !gptr () && !egptr ())
           && (   pbase () && pbase () <= pptr () && pptr () <= epptr ()
               || !pbase () && !pptr () && !epptr ());
}


_RWSTD_NAMESPACE_END   // std


#endif   // _RWSTD_STREAMBUF_INCLUDED