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#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
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