arabica/Utils/convert_adaptor.h
2003-10-27 16:09:54 +00:00

345 lines
12 KiB
C++

#ifndef ARABICA_CONVERT_ADAPTOR_H
#define ARABICA_CONVERT_ADAPTOR_H
//////////////////////////////////////////////////////
//
// $Id$
// Written by Jez Higgins <jez@jezuk.co.uk>
// Copyright 1999-2003 Jez UK Ltd, http://www.jezuk.co.uk/
//
// convert_adaptor is a stream that wraps around another stream. This
// may not seem like a big deal, but convert_adaptor applies codecvt
// facets along the way. This allows you to apply encryption or
// decryption (or any other transcoding) transparently. It can
// also adapt wchar_t streams to char streams, or vice versa, allowing
// you to write std::wstrings out as UTF-8 chars to a file, for instance.
//////////////////////////////////////////////////////
#include <locale>
#include <istream>
#include <ostream>
#include <vector>
#include <algorithm>
#include <SAX/ArabicaConfig.h>
#ifdef ARABICA_VS6_WORKAROUND
#include <Utils/impl/VS6Workaround.h>
#endif
namespace Arabica
{
namespace convert
{
template<typename charT,
typename traitsT = std::char_traits<charT>,
typename externalCharT = charT,
typename externalTraitsT = std::char_traits<externalCharT> >
class convert_bufadaptor : public std::basic_streambuf<charT, traitsT>
{
public:
typedef typename traitsT::int_type int_type;
typedef std::basic_streambuf<externalCharT, externalTraitsT> externalStreambufT;
explicit convert_bufadaptor(externalStreambufT& externalbuf) : externalbuf_(&externalbuf), inEof_(false) { }
virtual ~convert_bufadaptor() { }
void set_buffer(externalStreambufT& externalbuf) { externalbuf_ = &externalbuf; inEof_ = false; }
protected:
virtual int_type overflow(int_type c = traitsT::eof());
virtual int sync();
virtual int_type underflow();
virtual int_type pbackfail(int_type c);
private:
typedef typename externalTraitsT::int_type external_int_type;
typedef typename traitsT::state_type state_t;
externalStreambufT* externalbuf_;
std::vector<charT> outBuffer_;
state_t outState_;
std::vector<charT> inBuffer_;
state_t inState_;
bool inEof_;
void growOutBuffer();
bool flushOut();
void growInBuffer();
std::streamsize readIn();
static const std::streamsize bufferSize_;
static const std::streamsize pbSize_;
}; // convert_bufadaptor
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
const std::streamsize convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::bufferSize_ = 1024;
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
const std::streamsize convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::pbSize_ = 4;
// why 4? both Josuttis and Langer&Kreft use 4.
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
typename convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::int_type convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::overflow(int_type c)
{
if(traitsT::eq_int_type(traitsT::eof(), c))
return traitsT::not_eof(c);
growOutBuffer();
sputc(traitsT::to_char_type(c));
return traitsT::not_eof(c);
} // overflow
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
int convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::sync()
{
return flushOut() ? 0 : -1;
} // sync
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
typename convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::int_type convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::underflow()
{
if(gptr() != 0 && gptr() < egptr())
return (traitsT::to_int_type(*gptr()));
if(!readIn())
return traitsT::eof();
return traitsT::to_int_type(*gptr());
} // underflow
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
typename convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::int_type convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::pbackfail(int_type c)
{
if(gptr() == eback())
return traitsT::eof();
gbump(-1);
if(!traitsT::eq_int_type(c, traitsT::eof()))
*(gptr()) = traitsT::to_char_type(c);
return traitsT::not_eof(c);
} // pbackfail
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
void convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::growOutBuffer()
{
size_t oldsize = outBuffer_.capacity();
size_t newsize = (oldsize ? oldsize*2 : bufferSize_);
outBuffer_.resize(newsize);
setp(&outBuffer_[0] + oldsize, &outBuffer_[0] + outBuffer_.capacity());
} // growOutBuffer
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
void convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::growInBuffer()
{
size_t oldsize = inBuffer_.capacity();
size_t newsize = (oldsize ? oldsize*2 : bufferSize_) + pbSize_;
inBuffer_.resize(newsize);
} // growInBuffer
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
bool convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::flushOut()
{
size_t length = pptr() - &outBuffer_[0];
if(!length)
return true;
bool ok(true);
const std::codecvt<charT, char, state_t>& cvt =
#ifndef ARABICA_VS6_WORKAROUND
std::use_facet<std::codecvt<charT, char, std::mbstate_t> >(this->getloc());
#else
std::use_facet(this->getloc(), (std::codecvt<charT, char, std::mbstate_t>*)0, true);
#endif
if(cvt.always_noconv())
std::copy(&outBuffer_[0], &outBuffer_[0] + length, std::ostreambuf_iterator<externalCharT>(externalbuf_));
else
{
// we must do code conversion
length += cvt.max_length(); // add a little
std::vector<externalCharT> to(length);
const charT* from_next = &(outBuffer_[0]);
std::codecvt_base::result r;
do
{
externalCharT* to_next;
r = cvt.out(outState_, from_next, pptr(), from_next,
&to[0], &to[0]+length, to_next);
if(r == std::codecvt_base::noconv)
{
std::copy(&outBuffer_[0], &outBuffer_[0] + length, std::ostreambuf_iterator<externalCharT>(externalbuf_));
break;
}
std::copy(&to[0], to_next, std::ostreambuf_iterator<externalCharT>(externalbuf_));
}
while(r == std::codecvt_base::partial);
ok = ok ? (r != std::codecvt_base::error) : false;
} // if(cvt.always_noconv())
if(ok)
setp(&outBuffer_[0], &outBuffer_[0] + outBuffer_.capacity());
return ok;
} // flushOut
template<class charT, class traitsT, class externalCharT, class externalTraitsT>
std::streamsize convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT>::readIn()
{
if(!inBuffer_.capacity())
growInBuffer();
size_t pbCount = std::min<size_t>(gptr() - eback(), pbSize_);
memcpy(&(inBuffer_[0]) + (pbSize_-pbCount)*sizeof(charT),
gptr() - pbCount*sizeof(charT),
pbCount*sizeof(charT));
const std::codecvt<charT, char, state_t>& cvt =
#ifndef ARABICA_VS6_WORKAROUND
std::use_facet<std::codecvt<charT, char, std::mbstate_t> >(this->getloc());
#else
std::use_facet(this->getloc(), (std::codecvt<charT, char, std::mbstate_t>*)0, true);
#endif
externalCharT from[1024];
std::streamsize res = 0;
if(!inEof_)
{
external_int_type ec = externalbuf_->sgetc();
while((!externalTraitsT::eq_int_type(externalTraitsT::eof(), ec)) && (res != bufferSize_))
{
from[res++] = static_cast<externalCharT>(ec);
ec = externalbuf_->snextc();
}
inEof_ = (externalTraitsT::eq_int_type(externalTraitsT::eof(), ec));
} // if ...
std::streamsize converted = 0;
if(res > 0)
{
std::codecvt_base::result r;
const externalCharT* from_next = from;
do
{
// can't cache this as may reallocate buffer
charT* const to = &(inBuffer_[0])+pbSize_;
charT* const to_end = &(inBuffer_[0]) + inBuffer_.capacity() - pbSize_;
charT* to_next;
externalCharT* const from_end = from + res;
r = cvt.in(inState_, from_next, from_end, from_next,
to + converted, to_end, to_next);
if(r == std::codecvt_base::noconv)
{
memcpy(&(inBuffer_[0])+pbSize_, from, res);
converted = res;
}
else
converted += static_cast<std::streamsize>(to_next - (to + converted));
if(r == std::codecvt_base::partial)
{
// haven't done everything
if(to_next == to_end)
growInBuffer(); // need more room!
else
{
int shortfall = (from + res) - from_next;
memcpy(from, from_next, shortfall);
res = externalbuf_->sgetn(from + shortfall, static_cast<std::streamsize>(bufferSize_ - shortfall));
from_next = &from[0];
if(res == 0) // oh dear
break; // let's bail!
res += shortfall;
}
} // if(r == std::codecvt_base::partial)
}
while(r == std::codecvt_base::partial);
if(r == std::codecvt_base::error)
{
// couldn't convert - let's bail
return 0;
} // if(r == std::codecvt_base::error)
}
setg(&(inBuffer_[0]) + (pbSize_-pbCount), &(inBuffer_[0])+pbSize_, &(inBuffer_[0])+pbSize_+converted);
return static_cast<int_type>(res);
} // readIn
////////////////////////////////////////////////////
// iconvert_adaptor
template<typename charT, typename traitsT, typename externalCharT, typename externalTraitsT>
class convert_adaptor_buffer
{
protected:
typedef std::basic_streambuf<externalCharT, externalTraitsT> externalStreambufT;
explicit convert_adaptor_buffer(externalStreambufT& externalbuf) : bufadaptor_(externalbuf) { }
convert_bufadaptor<charT, traitsT, externalCharT, externalTraitsT> bufadaptor_;
}; // convert_adaptor_buffer
template<typename charT,
typename traitsT = std::char_traits<charT>,
typename fromCharT = charT,
typename fromTraitsT = std::char_traits<fromCharT> >
class iconvert_adaptor : private convert_adaptor_buffer<charT, traitsT, fromCharT, fromTraitsT>,
public std::basic_istream<charT, traitsT>
{
typedef std::basic_istream<fromCharT, fromTraitsT> fromStreamT;
public:
explicit iconvert_adaptor(fromStreamT& fromstream) :
convert_adaptor_buffer<charT, traitsT, fromCharT, fromTraitsT>(*(fromstream.rdbuf())),
std::basic_istream<charT, traitsT>(&bufadaptor_)
{
} // iconvert_adaptor
virtual ~iconvert_adaptor() { }
convert_bufadaptor<charT,traitsT>* rdbuf() const
{
return const_cast<convert_bufadaptor<charT, traitsT, fromCharT, fromTraitsT>*>(&bufadaptor_);
} // rdbuf
void set_stream(fromStreamT& fromStream) { bufadaptor_.set_buffer(*fromStream.rdbuf()); }
}; // class iconvert_adaptor
////////////////////////////////////////////////////////
// oconvert_adaptor
template<typename charT,
typename traitsT = std::char_traits<charT>,
typename toCharT = charT,
typename toTraitsT = std::char_traits<toCharT> >
class oconvert_adaptor : private convert_adaptor_buffer<charT, traitsT, toCharT, toTraitsT>,
public std::basic_ostream<charT, traitsT>
{
typedef std::basic_ostream<toCharT, toTraitsT> toStreamT;
public:
explicit oconvert_adaptor(toStreamT &toStream) :
convert_adaptor_buffer<charT, traitsT, toCharT, toTraitsT>(*(toStream.rdbuf())),
std::basic_ostream<charT, traitsT>(&bufadaptor_)
{
} // oconvert_adaptor
virtual ~oconvert_adaptor()
{
flush();
} // ~oconvert_adaptor
convert_bufadaptor<charT, traitsT>* rdbuf() const
{
return const_cast<convert_bufadaptor<charT, traitsT, toCharT, toTraitsT>*>(&bufadaptor_);
} // rdbuf
void set_stream(toStreamT& toStream) { bufadaptor_.set_buffer(*toStream.rdbuf()); }
}; // class oconvert_adaptor
} // namespace convert
} // namespace Arabica
#endif