/*=============================================================================
Wave: A Standard compliant C++ preprocessor
Definition of the unput queue iterator
Copyright (c) 2001-2003 Hartmut Kaiser
http://spirit.sourceforge.net/
Permission to copy, use, modify, sell and distribute this software
is granted provided this copyright notice appears in all copies.
This software is provided "as is" without express or implied
warranty, and with no claim as to its suitability for any purpose.
See Copyright.txt for full copyright notices and acknowledgements.
=============================================================================*/
#if !defined(UNPUT_QUEUE_ITERATOR_HPP_76DA23D0_4893_4AD5_ABCC_6CED7CFB89BC_INCLUDED)
#define UNPUT_QUEUE_ITERATOR_HPP_76DA23D0_4893_4AD5_ABCC_6CED7CFB89BC_INCLUDED
#include <list>
#include <boost/iterator_adaptors.hpp>
///////////////////////////////////////////////////////////////////////////////
namespace wave {
namespace util {
template <typename TokenT, typename ContainerT>
class unput_queue_policies : public boost::default_iterator_policies
{
public:
unput_queue_policies(ContainerT &unput_queue_)
: unput_queue(unput_queue_)
{}
unput_queue_policies &operator= (unput_queue_policies const &rhs)
{
unput_queue = rhs.unput_queue;
return *this;
}
template <typename BaseT>
void initialize(BaseT &)
{}
template <typename IteratorAdaptorT>
typename IteratorAdaptorT::reference
dereference(const IteratorAdaptorT &x) const
{
if (x.policies().unput_queue.size() > 0)
return x.policies().unput_queue.front();
return *x.base();
}
template <typename IteratorAdaptorT>
void
increment(IteratorAdaptorT &x)
{
if (x.policies().unput_queue.size() > 0) {
// there exist pending tokens in the unput queue
x.policies().unput_queue.pop_front();
}
else {
// the unput_queue is empty, so advance the base iterator
++x.base();
}
}
template <typename IteratorAdaptorT1, typename IteratorAdaptorT2>
bool
equal(const IteratorAdaptorT1 &x, const IteratorAdaptorT2 &y) const
{
// two iterators are equal, if both begin() iterators of the queue objects
// are equal and the base iterators too
return
(x.policies().unput_queue.begin() == y.policies().unput_queue.begin() ||
(0 == x.policies().queuesize() && 0 == y.policies().queuesize())) &&
x.base() == y.base();
}
typename ContainerT::size_type queuesize() const
{ return unput_queue.size(); }
ContainerT &get_unput_queue() { return unput_queue; }
private:
ContainerT &unput_queue;
};
///////////////////////////////////////////////////////////////////////////////
//
// unput_queue_iterator
//
// The unput_queue_iterator templates encapsulates an unput_queue together
// with the direct input to be read after the unput queue is emptied
//
///////////////////////////////////////////////////////////////////////////////
template <typename IteratorT, typename TokenT, typename ContainerT>
class unput_queue_iterator
: public boost::iterator_adaptor<
IteratorT, unput_queue_policies<TokenT, ContainerT>, TokenT,
TokenT const &, TokenT const *>
{
typedef
boost::iterator_adaptor<
IteratorT, unput_queue_policies<TokenT, ContainerT>, TokenT,
TokenT const &, TokenT const *
>
base_t;
public:
typedef ContainerT container_t;
typedef IteratorT iterator_t;
unput_queue_iterator(IteratorT const &it,
unput_queue_policies<TokenT, ContainerT> policies)
: base_t(it, policies)
{}
ContainerT &get_unput_queue() { return policies().get_unput_queue(); }
IteratorT &get_base_iterator() { return base(); }
};
namespace impl {
///////////////////////////////////////////////////////////////////////////
template <typename IteratorT, typename TokenT, typename ContainerT>
struct gen_unput_queue_iterator {
typedef unput_queue_iterator<IteratorT, TokenT, ContainerT> return_t;
typedef unput_queue_policies<TokenT, ContainerT> policies_t;
static return_t
generate(ContainerT &queue, IteratorT const &it)
{
return return_t(it, policies_t(queue));
}
};
template <typename IteratorT, typename TokenT, typename ContainerT>
struct gen_unput_queue_iterator<
unput_queue_iterator<IteratorT, TokenT, ContainerT>,
TokenT, ContainerT>
{
typedef unput_queue_iterator<IteratorT, TokenT, ContainerT> return_t;
typedef unput_queue_policies<TokenT, ContainerT> policies_t;
static return_t
generate(ContainerT &queue, return_t const &it)
{
return return_t(it.base(), policies_t(queue));
}
};
///////////////////////////////////////////////////////////////////////////
template <typename IteratorT>
struct assign_iterator {
static void
do_ (IteratorT &dest, IteratorT const &src)
{
dest = src;
}
};
template <typename IteratorT, typename TokenT, typename ContainerT>
struct assign_iterator<
unput_queue_iterator<IteratorT, TokenT, ContainerT> > {
typedef unput_queue_iterator<IteratorT, TokenT, ContainerT> iterator_t;
static void
do_ (iterator_t &dest, iterator_t const &src)
{
dest.base() = src.base();
dest.policies() = src.policies();
}
};
///////////////////////////////////////////////////////////////////////////
//
// Look for the first non-whitespace token and return this token id.
// Note though, that the embedded unput_queues are not touched in any way!
//
template <typename IteratorT>
struct next_token {
static wave::cpplexer::token_id
peek(IteratorT it, IteratorT end, bool skip_whitespace = true)
{
using namespace wave::cpplexer;
if (skip_whitespace) {
for (++it; it != end; ++it) {
if (!IS_CATEGORY(*it, WhiteSpaceTokenType) &&
T_NEWLINE != token_id(*it))
{
break; // stop at the first non-whitespace token
}
}
}
else {
++it; // we have at least to look ahead
}
if (it != end)
return token_id(*it);
return T_EOI;
}
};
template <typename IteratorT, typename TokenT, typename ContainerT>
struct next_token<
unput_queue_iterator<IteratorT, TokenT, ContainerT> > {
typedef unput_queue_iterator<IteratorT, TokenT, ContainerT> iterator_t;
static wave::cpplexer::token_id
peek(iterator_t it, iterator_t end, bool skip_whitespace = true)
{
using namespace wave::cpplexer;
typename iterator_t::container_t &queue = it.get_unput_queue();
// first try to find it in the unput_queue
if (0 != queue.size()) {
typename iterator_t::container_t::iterator cit = queue.begin();
typename iterator_t::container_t::iterator cend = queue.end();
if (skip_whitespace) {
for (++cit; cit != cend; ++cit) {
if (!IS_CATEGORY(*cit, WhiteSpaceTokenType) &&
T_NEWLINE != token_id(*cit))
{
break; // stop at the first non-whitespace token
}
}
}
else {
++cit; // we have at least to look ahead
}
if (cit != cend)
return token_id(*cit);
}
// second try to move on into the base iterator stream
typename iterator_t::iterator_t base_it = it.get_base_iterator();
typename iterator_t::iterator_t base_end = end.get_base_iterator();
if (0 == queue.size())
++base_it; // advance, if the unput queue is empty
if (skip_whitespace) {
for (/**/; base_it != base_end; ++base_it) {
if (!IS_CATEGORY(*base_it, WhiteSpaceTokenType) &&
T_NEWLINE != token_id(*base_it))
{
break; // stop at the first non-whitespace token
}
}
}
if (base_it == base_end)
return T_EOI;
return token_id(*base_it);
}
};
// Skip all whitespace characters and queue the skipped characters into the
// given container
template <typename IteratorT>
inline wave::cpplexer::token_id
skip_whitespace(IteratorT &first, IteratorT const &last)
{
using namespace cpplexer;
token_id id = next_token<IteratorT>::peek(first, last, false);
if (IS_CATEGORY(id, WhiteSpaceTokenType)) {
do {
++first;
id = next_token<IteratorT>::peek(first, last, false);
} while (IS_CATEGORY(id, WhiteSpaceTokenType));
}
++first;
return id;
}
template <typename IteratorT, typename ContainerT>
inline wave::cpplexer::token_id
skip_whitespace(IteratorT &first, IteratorT const &last, ContainerT &queue)
{
using namespace cpplexer;
queue.push_back (*first); // queue up the current token
token_id id = next_token<IteratorT>::peek(first, last, false);
if (IS_CATEGORY(id, WhiteSpaceTokenType)) {
do {
queue.push_back(*++first); // queue up the next whitespace
id = next_token<IteratorT>::peek(first, last, false);
} while (IS_CATEGORY(id, WhiteSpaceTokenType));
}
++first;
return id;
}
///////////////////////////////////////////////////////////////////////////////
} // namespace impl
///////////////////////////////////////////////////////////////////////////////
} // namespace util
} // namespace wave
#endif // !defined(UNPUT_QUEUE_ITERATOR_HPP_76DA23D0_4893_4AD5_ABCC_6CED7CFB89BC_INCLUDED)
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