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/*=============================================================================
Copyright (c) 2001-2011 Hartmut Kaiser
Distributed under 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)
==============================================================================*/
#if !defined(BOOST_SPIRIT_ITERATOR_ISTREAM_MAY_05_2007_0110PM)
#define BOOST_SPIRIT_ITERATOR_ISTREAM_MAY_05_2007_0110PM
#if defined(_MSC_VER)
#pragma once
#endif
#include <boost/iostreams/stream.hpp>
#include <boost/detail/iterator.hpp>
///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit { namespace qi { namespace detail
{
///////////////////////////////////////////////////////////////////////////
template <typename Iterator>
struct iterator_source
{
typedef typename
boost::detail::iterator_traits<Iterator>::value_type
char_type;
typedef boost::iostreams::seekable_device_tag category;
iterator_source (Iterator const& first_, Iterator const& last_)
: first(first_), last(last_), pos(0)
{}
// Read up to n characters from the input sequence into the buffer s,
// returning the number of characters read, or -1 to indicate
// end-of-sequence.
std::streamsize read (char_type* s, std::streamsize n)
{
if (first == last)
return -1;
std::streamsize bytes_read = 0;
while (n--) {
*s = *first;
++s; ++bytes_read;
if (++first == last)
break;
}
pos += bytes_read;
return bytes_read;
}
// Write is implemented only to satisfy the requirements of a
// boost::iostreams::seekable_device. We need to have see support to
// be able to figure out how many characters have been actually
// consumed by the stream.
std::streamsize write(const char*, std::streamsize)
{
BOOST_ASSERT(false); // not supported
return -1;
}
std::streampos seek(boost::iostreams::stream_offset, std::ios_base::seekdir way)
{
BOOST_ASSERT(way == std::ios_base::cur); // only support queries
return pos; // return current position
}
Iterator first;
Iterator const& last;
std::streamsize pos;
private:
// silence MSVC warning C4512: assignment operator could not be generated
iterator_source& operator= (iterator_source const&);
};
}}}}
#endif
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