/*=============================================================================

    Boost.Wave: A Standard compliant C++ preprocessor library

    Whitespace eater

    http://www.boost.org/

    Copyright (c) 2003 Paul Mensonides

    Copyright (c) 2001-2007 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(WHITESPACE_HANDLING_HPP_INCLUDED)

#define WHITESPACE_HANDLING_HPP_INCLUDED

#include <boost/wave/wave_config.hpp>   

#include <boost/wave/token_ids.hpp>   

#include <boost/wave/preprocessing_hooks.hpp>

// this must occur after all of the includes and before any code appears

#ifdef BOOST_HAS_ABI_HEADERS

#include BOOST_ABI_PREFIX

#endif

///////////////////////////////////////////////////////////////////////////////

namespace boost {

namespace wave {

namespace context_policies {

namespace util {

    ///////////////////////////////////////////////////////////////////////////

    //  This function returns true if the given C style comment contains at 

    //  least one newline

    template <typename TokenT>

    bool ccomment_has_newline(TokenT const& token)

    {

        using namespace boost::wave;

        if (T_CCOMMENT == token_id(token) &&

            TokenT::string_type::npos != token.get_value().find_first_of("\n"))

        {

            return true;

        }

        return false;

    }

    ///////////////////////////////////////////////////////////////////////////

    //  This function returns the number of newlines in the given C style 

    //  comment 

    template <typename TokenT>

    int ccomment_count_newlines(TokenT const& token)

    {

        using namespace boost::wave;

        int newlines = 0;

        if (T_CCOMMENT == token_id(token)) {

        typename TokenT::string_type const& value = token.get_value();

        typename TokenT::string_type::size_type p = value.find_first_of("\n");

            while (TokenT::string_type::npos != p) {

                ++newlines;

                p = value.find_first_of("\n", p+1);

            } 

        }

        return newlines;

    }

}

///////////////////////////////////////////////////////////////////////////////

template <typename TokenT>

class eat_whitespace 

:   public default_preprocessing_hooks

{

public:

    eat_whitespace();

    template <typename ContextT>

    bool may_skip_whitespace(ContextT const& ctx, TokenT &token, 

        bool &skipped_newline);

protected:

    bool skip_cppcomment(boost::wave::token_id id)

    {

        return !preserve_comments && T_CPPCOMMENT == id;

    }

private:

    typedef bool state_t(TokenT &token, bool &skipped_newline);

    state_t eat_whitespace::* state;

    state_t general, newline, newline_2nd, whitespace;

    bool preserve_comments;

};

template <typename TokenT>

inline 

eat_whitespace<TokenT>::eat_whitespace()

:   state(&eat_whitespace::newline), preserve_comments(false)

{

}

template <typename TokenT>

template <typename ContextT>

inline bool 

eat_whitespace<TokenT>::may_skip_whitespace(ContextT const& ctx, TokenT &token, 

    bool &skipped_newline) 

{

    // re-initialize the preserve comments state

    preserve_comments = boost::wave::need_preserve_comments(ctx.get_language());

    return (this->*state)(token, skipped_newline);

}

template <typename TokenT>

inline bool 

eat_whitespace<TokenT>::general(TokenT &token, bool &skipped_newline) 

{

    using namespace boost::wave;

    token_id id = token_id(token);

    if (T_NEWLINE == id || T_CPPCOMMENT == id) {

        state = &eat_whitespace::newline;

    }

    else if (T_SPACE == id || T_SPACE2 == id || T_CCOMMENT == id) {

        state = &eat_whitespace::whitespace;

        if (util::ccomment_has_newline(token)) 

            skipped_newline = true;

        if ((!preserve_comments || T_CCOMMENT != id) && 

            token.get_value().size() > 1)

        {

            token.set_value(" ");   // replace with a single space

        }

    }

    else {

        state = &eat_whitespace::general;

    }

    return false;

}

template <typename TokenT>

inline bool 

eat_whitespace<TokenT>::newline(TokenT &token, bool &skipped_newline) 

{

    using namespace boost::wave;

    token_id id = token_id(token);

    if (T_NEWLINE == id || T_CPPCOMMENT == id) {

        skipped_newline = true;

        state = &eat_whitespace::newline_2nd;

        return T_NEWLINE == id || skip_cppcomment(id);

    }

    else if (T_SPACE != id && T_SPACE2 != id && T_CCOMMENT != id) {

        return general(token, skipped_newline);

    }

    if (T_CCOMMENT == id) {

        if (util::ccomment_has_newline(token)) {

            skipped_newline = true;

            state = &eat_whitespace::newline_2nd;

        }

        if (preserve_comments) {

            state = &eat_whitespace::general;

            return false;

        }

        // fall through...

    }

    return true;

}

template <typename TokenT>

inline bool 

eat_whitespace<TokenT>::newline_2nd(TokenT &token, bool &skipped_newline) 

{

    using namespace boost::wave;

    token_id id = token_id(token);

    if (T_SPACE == id || T_SPACE2 == id)

        return true;

    if (T_CCOMMENT == id) {

        if (util::ccomment_has_newline(token))

            skipped_newline = true;

        if (preserve_comments) {

            state = &eat_whitespace::general;

            return false;

        }

        return  true;

    }

    if (T_NEWLINE != id && T_CPPCOMMENT != id) 

        return general(token, skipped_newline);

    skipped_newline = true;

    return T_NEWLINE == id || skip_cppcomment(id);

}

template <typename TokenT>

inline bool 

eat_whitespace<TokenT>::whitespace(TokenT &token, bool &skipped_newline) 

{

    using namespace boost::wave;

    token_id id = token_id(token);

    if (T_SPACE != id && T_SPACE2 != id && 

        T_CCOMMENT != id && T_CPPCOMMENT != id) 

    {

        return general(token, skipped_newline);

    }

    if (T_CCOMMENT == id) {

        if (util::ccomment_has_newline(token))

            skipped_newline = true;

        return !preserve_comments;

    }

    return T_SPACE == id || T_SPACE2 == id || skip_cppcomment(id);

}

///////////////////////////////////////////////////////////////////////////////

}   // namespace context_policies

}   // namespace wave

}   // namespace boost

// the suffix header occurs after all of the code

#ifdef BOOST_HAS_ABI_HEADERS

#include BOOST_ABI_SUFFIX

#endif

#endif // !defined(WHITESPACE_HANDLING_HPP_INCLUDED)