sl@0: /*=============================================================================
sl@0:     Boost.Wave: A Standard compliant C++ preprocessor library
sl@0:     Whitespace eater
sl@0:     
sl@0:     http://www.boost.org/
sl@0: 
sl@0:     Copyright (c) 2003 Paul Mensonides
sl@0:     Copyright (c) 2001-2007 Hartmut Kaiser. 
sl@0:     Distributed under the Boost Software License, Version 1.0. (See accompanying 
sl@0:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
sl@0: =============================================================================*/
sl@0: 
sl@0: #if !defined(WHITESPACE_HANDLING_HPP_INCLUDED)
sl@0: #define WHITESPACE_HANDLING_HPP_INCLUDED
sl@0: 
sl@0: #include <boost/wave/wave_config.hpp>   
sl@0: #include <boost/wave/token_ids.hpp>   
sl@0: #include <boost/wave/preprocessing_hooks.hpp>
sl@0: 
sl@0: // this must occur after all of the includes and before any code appears
sl@0: #ifdef BOOST_HAS_ABI_HEADERS
sl@0: #include BOOST_ABI_PREFIX
sl@0: #endif
sl@0: 
sl@0: ///////////////////////////////////////////////////////////////////////////////
sl@0: namespace boost {
sl@0: namespace wave {
sl@0: namespace context_policies {
sl@0: 
sl@0: namespace util {
sl@0:     ///////////////////////////////////////////////////////////////////////////
sl@0:     //  This function returns true if the given C style comment contains at 
sl@0:     //  least one newline
sl@0:     template <typename TokenT>
sl@0:     bool ccomment_has_newline(TokenT const& token)
sl@0:     {
sl@0:         using namespace boost::wave;
sl@0: 
sl@0:         if (T_CCOMMENT == token_id(token) &&
sl@0:             TokenT::string_type::npos != token.get_value().find_first_of("\n"))
sl@0:         {
sl@0:             return true;
sl@0:         }
sl@0:         return false;
sl@0:     }
sl@0: 
sl@0:     ///////////////////////////////////////////////////////////////////////////
sl@0:     //  This function returns the number of newlines in the given C style 
sl@0:     //  comment 
sl@0:     template <typename TokenT>
sl@0:     int ccomment_count_newlines(TokenT const& token)
sl@0:     {
sl@0:         using namespace boost::wave;
sl@0:         int newlines = 0;
sl@0:         if (T_CCOMMENT == token_id(token)) {
sl@0:         typename TokenT::string_type const& value = token.get_value();
sl@0:         typename TokenT::string_type::size_type p = value.find_first_of("\n");
sl@0: 
sl@0:             while (TokenT::string_type::npos != p) {
sl@0:                 ++newlines;
sl@0:                 p = value.find_first_of("\n", p+1);
sl@0:             } 
sl@0:         }
sl@0:         return newlines;
sl@0:     }
sl@0: }
sl@0: 
sl@0: ///////////////////////////////////////////////////////////////////////////////
sl@0: template <typename TokenT>
sl@0: class eat_whitespace 
sl@0: :   public default_preprocessing_hooks
sl@0: {
sl@0: public:
sl@0:     eat_whitespace();
sl@0:     
sl@0:     template <typename ContextT>
sl@0:     bool may_skip_whitespace(ContextT const& ctx, TokenT &token, 
sl@0:         bool &skipped_newline);
sl@0: 
sl@0: protected:
sl@0:     bool skip_cppcomment(boost::wave::token_id id)
sl@0:     {
sl@0:         return !preserve_comments && T_CPPCOMMENT == id;
sl@0:     }
sl@0:     
sl@0: private:
sl@0:     typedef bool state_t(TokenT &token, bool &skipped_newline);
sl@0:     state_t eat_whitespace::* state;
sl@0:     state_t general, newline, newline_2nd, whitespace;
sl@0:     bool preserve_comments;
sl@0: };
sl@0: 
sl@0: template <typename TokenT>
sl@0: inline 
sl@0: eat_whitespace<TokenT>::eat_whitespace()
sl@0: :   state(&eat_whitespace::newline), preserve_comments(false)
sl@0: {
sl@0: }
sl@0: 
sl@0: template <typename TokenT>
sl@0: template <typename ContextT>
sl@0: inline bool 
sl@0: eat_whitespace<TokenT>::may_skip_whitespace(ContextT const& ctx, TokenT &token, 
sl@0:     bool &skipped_newline) 
sl@0: {
sl@0:     // re-initialize the preserve comments state
sl@0:     preserve_comments = boost::wave::need_preserve_comments(ctx.get_language());
sl@0:     return (this->*state)(token, skipped_newline);
sl@0: }
sl@0: 
sl@0: template <typename TokenT>
sl@0: inline bool 
sl@0: eat_whitespace<TokenT>::general(TokenT &token, bool &skipped_newline) 
sl@0: {
sl@0:     using namespace boost::wave;
sl@0: 
sl@0:     token_id id = token_id(token);
sl@0:     if (T_NEWLINE == id || T_CPPCOMMENT == id) {
sl@0:         state = &eat_whitespace::newline;
sl@0:     }
sl@0:     else if (T_SPACE == id || T_SPACE2 == id || T_CCOMMENT == id) {
sl@0:         state = &eat_whitespace::whitespace;
sl@0: 
sl@0:         if (util::ccomment_has_newline(token)) 
sl@0:             skipped_newline = true;
sl@0: 
sl@0:         if ((!preserve_comments || T_CCOMMENT != id) && 
sl@0:             token.get_value().size() > 1)
sl@0:         {
sl@0:             token.set_value(" ");   // replace with a single space
sl@0:         }
sl@0:     }
sl@0:     else {
sl@0:         state = &eat_whitespace::general;
sl@0:     }
sl@0:     return false;
sl@0: }
sl@0: 
sl@0: template <typename TokenT>
sl@0: inline bool 
sl@0: eat_whitespace<TokenT>::newline(TokenT &token, bool &skipped_newline) 
sl@0: {
sl@0:     using namespace boost::wave;
sl@0:     
sl@0:     token_id id = token_id(token);
sl@0:     if (T_NEWLINE == id || T_CPPCOMMENT == id) {
sl@0:         skipped_newline = true;
sl@0:         state = &eat_whitespace::newline_2nd;
sl@0:         return T_NEWLINE == id || skip_cppcomment(id);
sl@0:     }
sl@0:     else if (T_SPACE != id && T_SPACE2 != id && T_CCOMMENT != id) {
sl@0:         return general(token, skipped_newline);
sl@0:     }
sl@0: 
sl@0:     if (T_CCOMMENT == id) {
sl@0:         if (util::ccomment_has_newline(token)) {
sl@0:             skipped_newline = true;
sl@0:             state = &eat_whitespace::newline_2nd;
sl@0:         }
sl@0:         if (preserve_comments) {
sl@0:             state = &eat_whitespace::general;
sl@0:             return false;
sl@0:         }
sl@0:         // fall through...
sl@0:     }
sl@0:     return true;
sl@0: }
sl@0: 
sl@0: template <typename TokenT>
sl@0: inline bool 
sl@0: eat_whitespace<TokenT>::newline_2nd(TokenT &token, bool &skipped_newline) 
sl@0: {
sl@0:     using namespace boost::wave;
sl@0:     
sl@0:     token_id id = token_id(token);
sl@0:     if (T_SPACE == id || T_SPACE2 == id)
sl@0:         return true;
sl@0:     if (T_CCOMMENT == id) {
sl@0:         if (util::ccomment_has_newline(token))
sl@0:             skipped_newline = true;
sl@0: 
sl@0:         if (preserve_comments) {
sl@0:             state = &eat_whitespace::general;
sl@0:             return false;
sl@0:         }
sl@0:         return  true;
sl@0:     }
sl@0:     if (T_NEWLINE != id && T_CPPCOMMENT != id) 
sl@0:         return general(token, skipped_newline);
sl@0: 
sl@0:     skipped_newline = true;
sl@0:     return T_NEWLINE == id || skip_cppcomment(id);
sl@0: }
sl@0: 
sl@0: template <typename TokenT>
sl@0: inline bool 
sl@0: eat_whitespace<TokenT>::whitespace(TokenT &token, bool &skipped_newline) 
sl@0: {
sl@0:     using namespace boost::wave;
sl@0:     
sl@0:     token_id id = token_id(token);
sl@0:     if (T_SPACE != id && T_SPACE2 != id && 
sl@0:         T_CCOMMENT != id && T_CPPCOMMENT != id) 
sl@0:     {
sl@0:         return general(token, skipped_newline);
sl@0:     }
sl@0:     
sl@0:     if (T_CCOMMENT == id) {
sl@0:         if (util::ccomment_has_newline(token))
sl@0:             skipped_newline = true;
sl@0:         return !preserve_comments;
sl@0:     }
sl@0: 
sl@0:     return T_SPACE == id || T_SPACE2 == id || skip_cppcomment(id);
sl@0: }
sl@0: 
sl@0: ///////////////////////////////////////////////////////////////////////////////
sl@0: }   // namespace context_policies
sl@0: }   // namespace wave
sl@0: }   // namespace boost
sl@0: 
sl@0: // the suffix header occurs after all of the code
sl@0: #ifdef BOOST_HAS_ABI_HEADERS
sl@0: #include BOOST_ABI_SUFFIX
sl@0: #endif
sl@0: 
sl@0: #endif // !defined(WHITESPACE_HANDLING_HPP_INCLUDED)
sl@0: