cpp_iterator.hpp

C++的一个好库。。。现在很流行

//      Tests if it is necessary to pop the include file context (eof inside
//      a file was reached). If yes, it pops this context. Preprocessing will
//      continue with the next outer file scope.
//
///////////////////////////////////////////////////////////////////////////////
template <typename ContextT> 
inline bool 
pp_iterator_functor<ContextT>::returned_from_include()
{
    if (iter_ctx->first == iter_ctx->last && ctx.get_iteration_depth() > 0) {
    // call the include policy trace function
        ctx.get_trace_policy().returning_from_include_file();
        
    // restore the previous iteration context after finishing the preprocessing 
    // of the included file
        BOOST_WAVE_STRINGTYPE oldfile = iter_ctx->real_filename;
        
        iter_ctx = ctx.pop_iteration_context();

    // ensure the integrity of the #if/#endif stack
        if (iter_ctx->if_block_depth != ctx.get_if_block_depth()) {
            using boost::wave::util::impl::escape_lit;
            BOOST_WAVE_THROW(preprocess_exception, unbalanced_if_endif, 
                escape_lit(oldfile).c_str(), act_pos);
        }
        
        must_emit_line_directive = true;
        seen_newline = true;

    // restore current file position
        act_pos.set_file(iter_ctx->filename);
#if BOOST_WAVE_SUPPORT_PRAGMA_ONCE != 0
        ctx.set_current_filename(iter_ctx->real_filename.c_str());
#endif 

//        last_line = iter_ctx->line;
        act_pos.set_line(iter_ctx->line);
        act_pos.set_column(0);
        
    // restore the actual current directory 
        ctx.set_current_directory(iter_ctx->real_filename.c_str());
        return true;
    }
    return false;
}

///////////////////////////////////////////////////////////////////////////////
//
//  operator()(): get the next preprocessed token
//
//      throws a preprocess_exception, if appropriate
//
///////////////////////////////////////////////////////////////////////////////
template <typename ContextT> 
inline typename pp_iterator_functor<ContextT>::result_type const &
pp_iterator_functor<ContextT>::operator()()
{
    using namespace boost::wave;

// loop over skipable whitespace until something significant is found
bool skipped_newline = false;
bool was_seen_newline = seen_newline;
token_id id = T_ANY;
    
    do {
    // get_next_token assigns result to act_token member
        if (!seen_newline && skipped_newline)
            seen_newline = true;
        get_next_token();

    // if comments shouldn't be preserved replace them with newlines
        id = token_id(act_token);
        if (!need_preserve_comments(ctx.get_language()) &&
            (T_CPPCOMMENT == id || util::ccomment_has_newline(act_token)))
        {
            act_token.set_token_id(id = T_NEWLINE);
            act_token.set_value("\n");
        }
        
    } while (eater.may_skip(act_token, skipped_newline));
    
// if there were skipped any newlines, we must emit a #line directive
    if ((must_emit_line_directive || (was_seen_newline && skipped_newline)) && 
        !IS_CATEGORY(id, WhiteSpaceTokenType) && 
        !IS_CATEGORY(id, EOLTokenType) && !IS_CATEGORY(id, EOFTokenType)) 
    {
    // must emit a #line directive
        emit_line_directive();
        eater.may_skip(act_token, skipped_newline);     // feed ws eater FSM
        id = token_id(act_token);
    }
    
// cleanup of certain tokens required
    seen_newline = skipped_newline;
    switch (static_cast<unsigned int>(id)) {
    case T_NONREPLACABLE_IDENTIFIER:
        act_token.set_token_id(T_IDENTIFIER);
        break;
        
    case T_NEWLINE:
    case T_CPPCOMMENT:
        seen_newline = true;
        ++iter_ctx->emitted_lines;
        break;

    case T_EOF:
        seen_newline = true;
        break;

    default:
        break;
    }

    if (whitespace.must_insert(id, act_token.get_value())) {
    // must insert some whitespace into the output stream to avoid adjacent
    // tokens, which would form different (and wrong) tokens
        whitespace.shift_tokens(T_SPACE);
        pending_queue.push_front(act_token);        // push this token back
        return act_token = result_type(T_SPACE, 
            typename result_type::string_type(" "), 
            act_token.get_position());
    }
    whitespace.shift_tokens(id);
    return act_token;
}


template <typename ContextT> 
inline typename pp_iterator_functor<ContextT>::result_type const &
pp_iterator_functor<ContextT>::get_next_token()
{
    using namespace boost::wave;
    
// if there is something in the unput_queue, then return the next token from
// there (all tokens in the queue are preprocessed already)
    if (pending_queue.size() > 0 || unput_queue.size() > 0) 
        return pp_token();      // return next token
    
// test for EOF, if there is a pending input context, pop it back and continue
// parsing with it
bool returned_from_include_file = returned_from_include();
    
// try to generate the next token 
    if (iter_ctx->first != iter_ctx->last) {
        do {
        // If there are pending tokens in the queue, we'll have to return 
        // these. This may happen from a #pragma directive, which got replaced
        // by some token sequence.
            if (!pending_queue.empty()) {
            util::on_exit::pop_front<token_sequence_type> 
                pop_front_token(pending_queue);

                whitespace.shift_tokens(act_token = pending_queue.front());
                return act_token;
            }
            
        // fetch the current token        
            act_token = *iter_ctx->first;

        // adjust the current position (line and column)
        bool was_seen_newline = seen_newline || returned_from_include_file;
//        int current_line = act_token.get_position().get_line();
//        
//            act_pos.set_line(act_pos.get_line() + current_line - last_line);
//            act_pos.set_column(act_token.get_position().get_column());
//            last_line = current_line;

            act_pos = act_token.get_position();
//            last_line = act_pos.get_line();
            
        // act accordingly on the current token
        token_id id = token_id(act_token);
        
            if (T_EOF == id) {
                if (!seen_newline && 
                    !(support_option_single_line & get_support_options(ctx.get_language()))) 
                {
                // warn, if this file does not end with a newline
                    BOOST_WAVE_THROW(preprocess_exception, 
                        last_line_not_terminated, "", act_pos);
                }
                
            // returned from an include file, continue with the next token
                whitespace.shift_tokens(T_EOF);
                ++iter_ctx->first;
                continue;   // if this is the main file, the while loop breaks
            }
            else if (T_NEWLINE == id || T_CPPCOMMENT == id) {   
            // a newline is to be returned ASAP, a C++ comment too
            // (the C++ comment token includes the trailing newline)
                seen_newline = true;
                ++iter_ctx->first;
                whitespace.shift_tokens(id);  // whitespace controller
                
                if (!ctx.get_if_block_status()) {
                // skip this token because of the disabled #if block
                    continue;
                }
                return act_token; 
            }
            seen_newline = false;

            if (was_seen_newline && pp_directive()) {
            // a pp directive was found
                seen_newline = true;
                must_emit_line_directive = true;

            // loop to the next token to analyze
            // simply fall through, since the iterator was already adjusted 
            // correctly
            }
            else if (ctx.get_if_block_status()) {
            // preprocess this token, eat up more, if appropriate, return 
            // the next preprocessed token
                return pp_token(was_seen_newline);
            }
            else {
            // compilation condition is false: if the current token is a 
            // newline, account for it, otherwise discard the actual token and 
            // try the next one
                if (T_NEWLINE == act_token) {
                    seen_newline = true;
                    must_emit_line_directive = true;
                }

            // next token
                ++iter_ctx->first;
            }
            
        } while (iter_ctx->first != iter_ctx->last || returned_from_include());
    }
    
    if (returned_from_include_file) {
    // if there was an '#include' statement on the last line of the main file 
    // we have to return an additional newline token
        seen_newline = true;
        
        whitespace.shift_tokens(T_NEWLINE);  // whitespace controller
        return act_token = result_type(T_NEWLINE, 
            typename result_type::string_type("\n"), 
            cpp_grammar_type::pos_of_newline);
    }
    
// overall eof reached
    if (ctx.get_if_block_depth() > 0) {
    // missing endif directive(s)
        BOOST_WAVE_THROW(preprocess_exception, missing_matching_endif, "", 
            act_pos);
    }

    whitespace.shift_tokens(T_EOF);     // whitespace controller
    return act_token = eof;             // return eof token
}

///////////////////////////////////////////////////////////////////////////////
//
//  emit_line_directive(): emits a line directive from the act_token data
//
///////////////////////////////////////////////////////////////////////////////
template <typename ContextT> 
inline typename pp_iterator_functor<ContextT>::result_type const &
pp_iterator_functor<ContextT>::emit_line_directive()
{
    using namespace boost::wave;
    
typename ContextT::position_type pos = act_token.get_position();

    if (must_emit_line_directive || 
        iter_ctx->emitted_lines != act_pos.get_line()) 
    {
    // unput the current token
        pending_queue.push_front(act_token);
        pos.set_line(act_pos.get_line());

        if (!must_emit_line_directive &&
            iter_ctx->emitted_lines+1 == act_pos.get_line()) 
        {
        // prefer to output a single newline instead of the #line directive
            whitespace.shift_tokens(T_NEWLINE);
            act_token = result_type(T_NEWLINE, "\n", pos);
        }
        else {
        // account for the newline emitted here
            act_pos.set_line(act_pos.get_line()-1);
            iter_ctx->emitted_lines = act_pos.get_line();
//            --last_line;
        
        // the #line directive has to be pushed back into the pending queue in 
        // reverse order

        // unput the complete #line directive in reverse order
        std::string file("\"");
        boost::filesystem::path filename(act_pos.get_file().c_str(), 
            boost::filesystem::native);
        
            using boost::wave::util::impl::escape_lit;
            file += escape_lit(filename.native_file_string()) + "\"";

        // 21 is the max required size for a 64 bit integer represented as a 
        // string
        char buffer[22];

            using namespace std;    // for some systems sprintf is in namespace std
            sprintf (buffer, "%d", pos.get_line());

        // adjust the generated column numbers accordingly
        // #line<space>number<space>filename<newline>
        unsigned int filenamelen = (unsigned int)file.size();
        unsigned int column = 7 + (unsigned int)strlen(buffer) + filenamelen;

            pos.set_line(pos.get_line() - 1);         // adjust line number
            
            pos.set_column(column);
            pending_queue.push_front(result_type(T_NEWLINE, "\n", pos));
            pos.set_column(column -= filenamelen);    // account for filename
            pending_queue.push_front(result_type(T_STRINGLIT, file.c_str(), pos));
            pos.set_column(--column);                 // account for ' '
            pending_queue.push_front(result_type(T_SPACE, " ", pos));
            pos.set_column(column -= (unsigned int)strlen(buffer)); // account for <number>
            pending_queue.push_front(result_type(T_INTLIT, buffer, pos));
            pos.set_column(--column);                 // account for ' '
            pending_queue.push_front(result_type(T_SPACE, " ", pos));
            
        // return the #line token itself
            whitespace.shift_tokens(T_PP_LINE);
            pos.set_column(1);
            act_token = result_type(T_PP_LINE, "#line", pos);
        }
    }

// we are now in sync
    must_emit_line_directive = false;
    return act_token;
}

///////////////////////////////////////////////////////////////////////////////
//
//  pptoken(): return the next preprocessed token
//
///////////////////////////////////////////////////////////////////////////////
template <typename ContextT> 
inline typename pp_iterator_functor<ContextT>::result_type const &
pp_iterator_functor<ContextT>::pp_token(bool consider_emitting_line_directive)
{
    using namespace boost::wave;

token_id id = token_id(*iter_ctx->first);