// ----------------------------------------------------------------------------

// parsing.hpp :  implementation of the parsing member functions

//                      ( parse, parse_printf_directive)

// ----------------------------------------------------------------------------

//  Copyright Samuel Krempp 2003. Use, modification, and distribution are

//  subject to 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)

// see http://www.boost.org/libs/format for library home page

// ----------------------------------------------------------------------------

#ifndef BOOST_FORMAT_PARSING_HPP

#define BOOST_FORMAT_PARSING_HPP

#include <boost/format/format_class.hpp>

#include <boost/throw_exception.hpp>

#include <boost/assert.hpp>

namespace boost {

namespace io {

namespace detail {

#if defined(BOOST_NO_STD_LOCALE)

    // streams will be used for narrow / widen. but these methods are not const

    template<class T>

    T& const_or_not(const T& x) { 

        return const_cast<T&> (x);

    }

#else

    template<class T>

    const T& const_or_not(const T& x) { 

        return x;

    }

#endif

    template<class Ch, class Facet> inline

    char wrap_narrow(const Facet& fac, Ch c, char deflt) {

        return const_or_not(fac).narrow(c, deflt);

    }

    template<class Ch, class Facet> inline

    bool wrap_isdigit(const Facet& fac, Ch c) {

#if ! defined( BOOST_NO_LOCALE_ISDIGIT )

        return fac.is(std::ctype<Ch>::digit, c);

# else

        using namespace std;

        return isdigit(c); 

#endif 

    }

    template<class Iter, class Facet> 

    Iter wrap_scan_notdigit(const Facet & fac, Iter beg, Iter end) {

        using namespace std;

        for( ; beg!=end && wrap_isdigit(fac, *beg); ++beg) ;

        return beg;

    }

    // Input : [start, last) iterators range and a

    //          a Facet to use its widen/narrow member function

    // Effects : read sequence and convert digits into integral n, of type Res

    // Returns : n

    template<class Res, class Iter, class Facet>

    Iter str2int (const Iter & start, const Iter & last, Res & res, 

                 const Facet& fac) 

    {

        using namespace std;

        Iter it;

        res=0;

        for(it=start; it != last && wrap_isdigit(fac, *it); ++it ) {

            char cur_ch = wrap_narrow(fac, *it, 0); // cant fail.

            res *= 10;

            res += cur_ch - '0'; // 22.2.1.1.2.13 of the C++ standard

        }

        return it;

    }

    // skip printf's "asterisk-fields" directives in the format-string buf

    // Input : char string, with starting index *pos_p

    //         a Facet merely to use its widen/narrow member function

    // Effects : advance *pos_p by skipping printf's asterisk fields.

    // Returns : nothing

    template<class Iter, class Facet>

    Iter skip_asterisk(Iter start, Iter last, const Facet& fac) 

    {

        using namespace std;

        ++ start;

        start = wrap_scan_notdigit(fac, start, last);

        if(start!=last && *start== const_or_not(fac).widen( '$') )

            ++start;

        return start;

    }

    // auxiliary func called by parse_printf_directive

    // for centralising error handling

    // it either throws if user sets the corresponding flag, or does nothing.

    inline void maybe_throw_exception(unsigned char exceptions, 

                                      std::size_t pos, std::size_t size)

    {

        if(exceptions & io::bad_format_string_bit)

            boost::throw_exception(io::bad_format_string(pos, size) );

    }

    // Input: the position of a printf-directive in the format-string

    //    a basic_ios& merely to use its widen/narrow member function

    //    a bitset'exceptions' telling whether to throw exceptions on errors.

    // Returns:

    //  true if parse succeeded (ignore some errors if exceptions disabled)

    //  false if it failed so bad that the directive should be printed verbatim

    // Effects:

    //  start is incremented so that *start is the first char after

    //     this directive

    //  *fpar is set with the parameters read in the directive

    template<class Ch, class Tr, class Alloc, class Iter, class Facet>

    bool parse_printf_directive(Iter & start, const Iter& last, 

                                detail::format_item<Ch, Tr, Alloc> * fpar,

                                const Facet& fac,

                                std::size_t offset, unsigned char exceptions)

    {

        typedef typename basic_format<Ch, Tr, Alloc>::format_item_t format_item_t;

        fpar->argN_ = format_item_t::argN_no_posit;  // if no positional-directive

        bool precision_set = false;

        bool in_brackets=false;

        Iter start0 = start;

        std::size_t fstring_size = last-start0+offset;

        if(*start== const_or_not(fac).widen( '|')) {

            in_brackets=true;

            if( ++start >= last ) {

                maybe_throw_exception(exceptions, start-start0 + offset, fstring_size);

                return false;

            }

        }

        // the flag '0' would be picked as a digit for argument order, but here it's a flag :

        if(*start== const_or_not(fac).widen( '0')) 

            goto parse_flags;

        // handle argument order (%2$d)  or possibly width specification: %2d

        if(wrap_isdigit(fac, *start)) {

            int n;

            start = str2int(start, last, n, fac);

            if( start >= last ) {

                maybe_throw_exception(exceptions, start-start0+offset, fstring_size);

                return false;

            }

            // %N% case : this is already the end of the directive

            if( *start ==  const_or_not(fac).widen( '%') ) {

                fpar->argN_ = n-1;

                ++start;

                if( in_brackets) 

                    maybe_throw_exception(exceptions, start-start0+offset, fstring_size); 

                // but don't return.  maybe "%" was used in lieu of '$', so we go on.

                else

                    return true;

            }

            if ( *start== const_or_not(fac).widen( '$') ) {

                fpar->argN_ = n-1;

                ++start;

            } 

            else {

                // non-positionnal directive

                fpar->fmtstate_.width_ = n;

                fpar->argN_  = format_item_t::argN_no_posit;

                goto parse_precision;

            }

        }

      parse_flags: 

        // handle flags

        while ( start != last) { // as long as char is one of + - = _ # 0 l h   or ' '

            // misc switches

            switch ( wrap_narrow(fac, *start, 0)) {

            case '\'' : break; // no effect yet. (painful to implement)

            case 'l':

            case 'h':  // short/long modifier : for printf-comaptibility (no action needed)

                break;

            case '-':

                fpar->fmtstate_.flags_ |= std::ios_base::left;

                break;

            case '=':

                fpar->pad_scheme_ |= format_item_t::centered;

                break;

            case '_':

                fpar->fmtstate_.flags_ |= std::ios_base::internal;

                break;

            case ' ':

                fpar->pad_scheme_ |= format_item_t::spacepad;

                break;

            case '+':

                fpar->fmtstate_.flags_ |= std::ios_base::showpos;

                break;

            case '0':

                fpar->pad_scheme_ |= format_item_t::zeropad;

                // need to know alignment before really setting flags,

                // so just add 'zeropad' flag for now, it will be processed later.

                break;

            case '#':

                fpar->fmtstate_.flags_ |= std::ios_base::showpoint | std::ios_base::showbase;

                break;

            default:

                goto parse_width;

            }

            ++start;

        } // loop on flag.

        if( start>=last) {

            maybe_throw_exception(exceptions, start-start0+offset, fstring_size);

            return true; 

        }

      parse_width:

        // handle width spec

        // first skip 'asterisk fields' :  *, or *N$

        if(*start == const_or_not(fac).widen( '*') )

            start = skip_asterisk(start, last, fac); 

        if(start!=last && wrap_isdigit(fac, *start))

            start = str2int(start, last, fpar->fmtstate_.width_, fac);

      parse_precision:

        if( start>= last) { 

            maybe_throw_exception(exceptions, start-start0+offset, fstring_size);

            return true;

        }

        // handle precision spec

        if (*start== const_or_not(fac).widen( '.')) {

            ++start;

            if(start != last && *start == const_or_not(fac).widen( '*') )

                start = skip_asterisk(start, last, fac); 

            if(start != last && wrap_isdigit(fac, *start)) {

                start = str2int(start, last, fpar->fmtstate_.precision_, fac);

                precision_set = true;

            }

            else

                fpar->fmtstate_.precision_ =0;

        }

        // handle  formatting-type flags :

        while( start != last && ( *start== const_or_not(fac).widen( 'l') 

                                  || *start== const_or_not(fac).widen( 'L') 

                                  || *start== const_or_not(fac).widen( 'h')) )

            ++start;

        if( start>=last) {

            maybe_throw_exception(exceptions, start-start0+offset, fstring_size);

            return true;

        }

        if( in_brackets && *start== const_or_not(fac).widen( '|') ) {

            ++start;

            return true;

        }

        switch ( wrap_narrow(fac, *start, 0) ) {

        case 'X':

            fpar->fmtstate_.flags_ |= std::ios_base::uppercase;

        case 'p': // pointer => set hex.

        case 'x':

            fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;

            fpar->fmtstate_.flags_ |= std::ios_base::hex;

            break;

        case 'o':

            fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;

            fpar->fmtstate_.flags_ |=  std::ios_base::oct;

            break;

        case 'E':

            fpar->fmtstate_.flags_ |=  std::ios_base::uppercase;

        case 'e':

            fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;

            fpar->fmtstate_.flags_ |=  std::ios_base::scientific;

            fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;

            fpar->fmtstate_.flags_ |=  std::ios_base::dec;

            break;

        case 'f':

            fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;

            fpar->fmtstate_.flags_ |=  std::ios_base::fixed;

        case 'u':

        case 'd':

        case 'i':

            fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;

            fpar->fmtstate_.flags_ |=  std::ios_base::dec;

            break;

        case 'T':

            ++start;

            if( start >= last)

                maybe_throw_exception(exceptions, start-start0+offset, fstring_size);

            else

                fpar->fmtstate_.fill_ = *start;

            fpar->pad_scheme_ |= format_item_t::tabulation;

            fpar->argN_ = format_item_t::argN_tabulation; 

            break;

        case 't': 

            fpar->fmtstate_.fill_ = const_or_not(fac).widen( ' ');

            fpar->pad_scheme_ |= format_item_t::tabulation;

            fpar->argN_ = format_item_t::argN_tabulation; 

            break;

        case 'G':

            fpar->fmtstate_.flags_ |= std::ios_base::uppercase;

            break;

        case 'g': // 'g' conversion is default for floats.

            fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;

            fpar->fmtstate_.flags_ |=  std::ios_base::dec;

            // CLEAR all floatield flags, so stream will CHOOSE

            fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield; 

            break;

        case 'C':

        case 'c': 

            fpar->truncate_ = 1;

            break;

        case 'S':

        case 's': 

            if(precision_set) // handle truncation manually, with own parameter.

                fpar->truncate_ = fpar->fmtstate_.precision_;

            fpar->fmtstate_.precision_ = 6; // default stream precision.

            break;

        case 'n' :  

            fpar->argN_ = format_item_t::argN_ignored;

            break;

        default: 

            maybe_throw_exception(exceptions, start-start0+offset, fstring_size);

        }

        ++start;

        if( in_brackets ) {

            if( start != last && *start== const_or_not(fac).widen( '|') ) {

                ++start;

                return true;

            }

            else  maybe_throw_exception(exceptions, start-start0+offset, fstring_size);

        }

        return true;

    }

    // -end parse_printf_directive()

    template<class String, class Facet>

    int upper_bound_from_fstring(const String& buf, 

                                 const typename String::value_type arg_mark,

                                 const Facet& fac, 

                                 unsigned char exceptions) 

    {

        // quick-parsing of the format-string to count arguments mark (arg_mark, '%')

        // returns : upper bound on the number of format items in the format strings

        using namespace boost::io;

        typename String::size_type i1=0;

        int num_items=0;

        while( (i1=buf.find(arg_mark,i1)) != String::npos ) {

            if( i1+1 >= buf.size() ) {

                if(exceptions & bad_format_string_bit)

                    boost::throw_exception(bad_format_string(i1, buf.size() )); // must not end in ".. %"

                else break; // stop there, ignore last '%'

            }

            if(buf[i1+1] == buf[i1] ) {// escaped "%%"

                i1+=2; continue; 

            }

            ++i1;

            // in case of %N% directives, dont count it double (wastes allocations..) :

            i1 = detail::wrap_scan_notdigit(fac, buf.begin()+i1, buf.end()) - buf.begin();

            if( i1 < buf.size() && buf[i1] == arg_mark )

                ++i1;

            ++num_items;

        }

        return num_items;

    }

    template<class String> inline

    void append_string(String& dst, const String& src, 

                       const typename String::size_type beg, 

                       const typename String::size_type end) {

#if !defined(BOOST_NO_STRING_APPEND)

        dst.append(src.begin()+beg, src.begin()+end);

#else

        dst += src.substr(beg, end-beg);

#endif

    }

} // detail namespace

} // io namespace

// -----------------------------------------------

//  format :: parse(..)

    template<class Ch, class Tr, class Alloc>

    basic_format<Ch, Tr, Alloc>& basic_format<Ch, Tr, Alloc>:: 

    parse (const string_type& buf) {

        // parse the format-string 

        using namespace std;

#if !defined(BOOST_NO_STD_LOCALE)

        const std::ctype<Ch> & fac = BOOST_USE_FACET( std::ctype<Ch>, getloc());

#else

        io::basic_oaltstringstream<Ch, Tr, Alloc> fac; 

        //has widen and narrow even on compilers without locale

#endif

        const Ch arg_mark = io::detail::const_or_not(fac).widen( '%');

        bool ordered_args=true; 

        int max_argN=-1;

        // A: find upper_bound on num_items and allocates arrays

        int num_items = io::detail::upper_bound_from_fstring(buf, arg_mark, fac, exceptions());

        make_or_reuse_data(num_items);

        // B: Now the real parsing of the format string :

        num_items=0;

        typename string_type::size_type i0=0, i1=0;

        typename string_type::const_iterator it;

        bool special_things=false;

        int cur_item=0;

        while( (i1=buf.find(arg_mark,i1)) != string_type::npos ) {

            string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_;

            if( buf[i1+1] == buf[i1] ) { // escaped mark, '%%' 

                io::detail::append_string(piece, buf, i0, i1+1);

                i1+=2; i0=i1;

                continue; 

            }

            BOOST_ASSERT(  static_cast<unsigned int>(cur_item) < items_.size() || cur_item==0);

            if(i1!=i0)

                io::detail::append_string(piece, buf, i0, i1);

            ++i1;

            it = buf.begin()+i1;

            bool parse_ok = io::detail::parse_printf_directive(

                it, buf.end(), &items_[cur_item], fac, i1, exceptions());

            i1 = it - buf.begin();

            if( ! parse_ok ) // the directive will be printed verbatim

                continue; 

            i0=i1;

            items_[cur_item].compute_states(); // process complex options, like zeropad, into params

            int argN=items_[cur_item].argN_;

            if(argN == format_item_t::argN_ignored)

                continue;

            if(argN ==format_item_t::argN_no_posit)

                ordered_args=false;

            else if(argN == format_item_t::argN_tabulation) special_things=true;

            else if(argN > max_argN) max_argN = argN;

            ++num_items;

            ++cur_item;

        } // loop on %'s

        BOOST_ASSERT(cur_item == num_items);

        // store the final piece of string

        {

            string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_;

            io::detail::append_string(piece, buf, i0, buf.size());

        }

        if( !ordered_args) {

            if(max_argN >= 0 ) {  // dont mix positional with non-positionnal directives

                if(exceptions() & io::bad_format_string_bit)

                    boost::throw_exception(io::bad_format_string(max_argN, 0));

                // else do nothing. => positionnal arguments are processed as non-positionnal

            }

            // set things like it would have been with positional directives :

            int non_ordered_items = 0;

            for(int i=0; i< num_items; ++i)

                if(items_[i].argN_ == format_item_t::argN_no_posit) {

                    items_[i].argN_ = non_ordered_items;

                    ++non_ordered_items;

                }

            max_argN = non_ordered_items-1;

        }

        // C: set some member data :

        items_.resize(num_items, format_item_t(io::detail::const_or_not(fac).widen( ' ')) );

        if(special_things) style_ |= special_needs;

        num_args_ = max_argN + 1;

        if(ordered_args) style_ |=  ordered;

        else style_ &= ~ordered;

        return *this;

    }

} // namespace boost

#endif //  BOOST_FORMAT_PARSING_HPP