#ifndef BOOST_ARCHIVE_ITERATORS_TRANSFORM_WIDTH_HPP | |
#define BOOST_ARCHIVE_ITERATORS_TRANSFORM_WIDTH_HPP | |
// MS compatible compilers support #pragma once | |
#if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
# pragma once | |
#endif | |
/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8 | |
// transform_width.hpp | |
// (C) Copyright 2002 Robert Ramey - http://www.rrsd.com . | |
// Use, modification and distribution is subject to the Boost Software | |
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
// http://www.boost.org/LICENSE_1_0.txt) | |
// See http://www.boost.org for updates, documentation, and revision history. | |
// iterator which takes elements of x bits and returns elements of y bits. | |
// used to change streams of 8 bit characters into streams of 6 bit characters. | |
// and vice-versa for implementing base64 encodeing/decoding. Be very careful | |
// when using and end iterator. end is only reliable detected when the input | |
// stream length is some common multiple of x and y. E.G. Base64 6 bit | |
// character and 8 bit bytes. Lowest common multiple is 24 => 4 6 bit characters | |
// or 3 8 bit characters | |
#include <algorithm> | |
#include <boost/config.hpp> // for BOOST_DEDUCED_TYPENAME & PTFO | |
#include <boost/serialization/pfto.hpp> | |
#include <boost/iterator/iterator_adaptor.hpp> | |
#include <boost/iterator/iterator_traits.hpp> | |
namespace boost { | |
namespace archive { | |
namespace iterators { | |
/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8 | |
// class used by text archives to translate char strings to wchar_t | |
// strings of the currently selected locale | |
template< | |
class Base, | |
int BitsOut, | |
int BitsIn, | |
class CharType = BOOST_DEDUCED_TYPENAME boost::iterator_value<Base>::type // output character | |
> | |
class transform_width : | |
public boost::iterator_adaptor< | |
transform_width<Base, BitsOut, BitsIn, CharType>, | |
Base, | |
CharType, | |
single_pass_traversal_tag, | |
CharType | |
> | |
{ | |
friend class boost::iterator_core_access; | |
typedef BOOST_DEDUCED_TYPENAME boost::iterator_adaptor< | |
transform_width<Base, BitsOut, BitsIn, CharType>, | |
Base, | |
CharType, | |
single_pass_traversal_tag, | |
CharType | |
> super_t; | |
typedef transform_width<Base, BitsOut, BitsIn, CharType> this_t; | |
typedef BOOST_DEDUCED_TYPENAME iterator_value<Base>::type base_value_type; | |
CharType fill(); | |
CharType dereference_impl(){ | |
if(! m_full){ | |
m_current_value = fill(); | |
m_full = true; | |
} | |
return m_current_value; | |
} | |
CharType dereference() const { | |
return const_cast<this_t *>(this)->dereference_impl(); | |
} | |
// test for iterator equality | |
bool equal(const this_t & rhs) const { | |
return | |
this->base_reference() == rhs.base_reference(); | |
; | |
} | |
void increment(){ | |
m_displacement += BitsOut; | |
while(m_displacement >= BitsIn){ | |
m_displacement -= BitsIn; | |
if(0 == m_displacement) | |
m_bufferfull = false; | |
if(! m_bufferfull){ | |
// note: suspect that this is not invoked for borland | |
++(this->base_reference()); | |
} | |
} | |
m_full = false; | |
} | |
CharType m_current_value; | |
// number of bits left in current input character buffer | |
unsigned int m_displacement; | |
base_value_type m_buffer; | |
// flag to current output character is ready - just used to save time | |
bool m_full; | |
// flag to indicate that m_buffer has data | |
bool m_bufferfull; | |
public: | |
// make composible buy using templated constructor | |
template<class T> | |
transform_width(BOOST_PFTO_WRAPPER(T) start) : | |
super_t(Base(BOOST_MAKE_PFTO_WRAPPER(static_cast< T >(start)))), | |
m_displacement(0), | |
m_full(false), | |
m_bufferfull(false) | |
{} | |
// intel 7.1 doesn't like default copy constructor | |
transform_width(const transform_width & rhs) : | |
super_t(rhs.base_reference()), | |
m_current_value(rhs.m_current_value), | |
m_displacement(rhs.m_displacement), | |
m_buffer(rhs.m_buffer), | |
m_full(rhs.m_full), | |
m_bufferfull(rhs.m_bufferfull) | |
{} | |
}; | |
template<class Base, int BitsOut, int BitsIn, class CharType> | |
CharType transform_width<Base, BitsOut, BitsIn, CharType>::fill(){ | |
CharType retval = 0; | |
unsigned int missing_bits = BitsOut; | |
for(;;){ | |
unsigned int bcount; | |
if(! m_bufferfull){ | |
m_buffer = * this->base_reference(); | |
m_bufferfull = true; | |
bcount = BitsIn; | |
} | |
else | |
bcount = BitsIn - m_displacement; | |
unsigned int i = (std::min)(bcount, missing_bits); | |
// shift interesting bits to least significant position | |
unsigned int j = m_buffer >> (bcount - i); | |
// strip off uninteresting bits | |
// (note presumption of two's complement arithmetic) | |
j &= ~(-(1 << i)); | |
// append then interesting bits to the output value | |
retval <<= i; | |
retval |= j; | |
missing_bits -= i; | |
if(0 == missing_bits) | |
break; | |
// note: suspect that this is not invoked for borland 5.51 | |
++(this->base_reference()); | |
m_bufferfull = false; | |
} | |
return retval; | |
} | |
} // namespace iterators | |
} // namespace archive | |
} // namespace boost | |
#endif // BOOST_ARCHIVE_ITERATORS_TRANSFORM_WIDTH_HPP |