boost/date_time/period_parser.hpp
#ifndef DATETIME_PERIOD_PARSER_HPP___ #define DATETIME_PERIOD_PARSER_HPP___ /* Copyright (c) 2002-2004 CrystalClear Software, Inc. * Use, modification and distribution is subject to the * Boost Software License, Version 1.0. (See accompanying * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) * Author: Jeff Garland, Bart Garst * $Date$ */ #include <boost/throw_exception.hpp> #include <boost/date_time/string_parse_tree.hpp> #include <boost/date_time/string_convert.hpp> namespace boost { namespace date_time { //! Not a facet, but a class used to specify and control period parsing /*! Provides settings for the following: * - period_separator -- default '/' * - period_open_start_delimeter -- default '[' * - period_open_range_end_delimeter -- default ')' * - period_closed_range_end_delimeter -- default ']' * - display_as_open_range, display_as_closed_range -- default closed_range * * For a typical date_period, the contents of the input stream would be *@code * [2004-Jan-04/2004-Feb-01] *@endcode * where the date format is controlled by the date facet */ template<class date_type, typename CharT> class period_parser { public: typedef std::basic_string<CharT> string_type; typedef CharT char_type; //typedef typename std::basic_string<char_type>::const_iterator const_itr_type; typedef std::istreambuf_iterator<CharT> stream_itr_type; typedef string_parse_tree<CharT> parse_tree_type; typedef typename parse_tree_type::parse_match_result_type match_results; typedef std::vector<std::basic_string<CharT> > collection_type; static const char_type default_period_separator[2]; static const char_type default_period_start_delimeter[2]; static const char_type default_period_open_range_end_delimeter[2]; static const char_type default_period_closed_range_end_delimeter[2]; enum period_range_option { AS_OPEN_RANGE, AS_CLOSED_RANGE }; //! Constructor that sets up period parser options period_parser(period_range_option range_opt = AS_CLOSED_RANGE, const char_type* const period_separator = default_period_separator, const char_type* const period_start_delimeter = default_period_start_delimeter, const char_type* const period_open_range_end_delimeter = default_period_open_range_end_delimeter, const char_type* const period_closed_range_end_delimeter = default_period_closed_range_end_delimeter) : m_range_option(range_opt) { delimiters.push_back(string_type(period_separator)); delimiters.push_back(string_type(period_start_delimeter)); delimiters.push_back(string_type(period_open_range_end_delimeter)); delimiters.push_back(string_type(period_closed_range_end_delimeter)); } period_parser(const period_parser<date_type,CharT>& p_parser) { this->delimiters = p_parser.delimiters; this->m_range_option = p_parser.m_range_option; } period_range_option range_option() const { return m_range_option; } void range_option(period_range_option option) { m_range_option = option; } collection_type delimiter_strings() const { return delimiters; } void delimiter_strings(const string_type& separator, const string_type& start_delim, const string_type& open_end_delim, const string_type& closed_end_delim) { delimiters.clear(); delimiters.push_back(separator); delimiters.push_back(start_delim); delimiters.push_back(open_end_delim); delimiters.push_back(closed_end_delim); } //! Generic code to parse a period -- no matter the period type. /*! This generic code will parse any period using a facet to * to get the 'elements'. For example, in the case of a date_period * the elements will be instances of a date which will be parsed * according the to setup in the passed facet parameter. * * The steps for parsing a period are always the same: * - consume the start delimiter * - get start element * - consume the separator * - get either last or end element depending on range settings * - consume the end delimeter depending on range settings * * Thus for a typical date period the contents of the input stream * might look like this: *@code * * [March 01, 2004/June 07, 2004] <-- closed range * [March 01, 2004/June 08, 2004) <-- open range * *@endcode */ template<class period_type, class duration_type, class facet_type> period_type get_period(stream_itr_type& sitr, stream_itr_type& stream_end, std::ios_base& a_ios, const period_type& /* p */, const duration_type& dur_unit, const facet_type& facet) const { // skip leading whitespace while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; } typedef typename period_type::point_type point_type; point_type p1(not_a_date_time), p2(not_a_date_time); consume_delim(sitr, stream_end, delimiters[START]); // start delim facet.get(sitr, stream_end, a_ios, p1); // first point consume_delim(sitr, stream_end, delimiters[SEPARATOR]); // separator facet.get(sitr, stream_end, a_ios, p2); // second point // period construction parameters are always open range [begin, end) if (m_range_option == AS_CLOSED_RANGE) { consume_delim(sitr, stream_end, delimiters[CLOSED_END]);// end delim // add 1 duration unit to p2 to make range open p2 += dur_unit; } else { consume_delim(sitr, stream_end, delimiters[OPEN_END]); // end delim } return period_type(p1, p2); } private: collection_type delimiters; period_range_option m_range_option; enum delim_ids { SEPARATOR, START, OPEN_END, CLOSED_END }; //! throws ios_base::failure if delimiter and parsed data do not match void consume_delim(stream_itr_type& sitr, stream_itr_type& stream_end, const string_type& delim) const { /* string_parse_tree will not parse a string of punctuation characters * without knowing exactly how many characters to process * Ex [2000. Will not parse out the '[' string without knowing * to process only one character. By using length of the delimiter * string we can safely iterate past it. */ string_type s; for(unsigned int i = 0; i < delim.length() && sitr != stream_end; ++i) { s += *sitr; ++sitr; } if(s != delim) { boost::throw_exception(std::ios_base::failure("Parse failed. Expected '" + convert_string_type<char_type,char>(delim) + "' but found '" + convert_string_type<char_type,char>(s) + "'")); } } }; template <class date_type, class char_type> const typename period_parser<date_type, char_type>::char_type period_parser<date_type, char_type>::default_period_separator[2] = {'/'}; template <class date_type, class char_type> const typename period_parser<date_type, char_type>::char_type period_parser<date_type, char_type>::default_period_start_delimeter[2] = {'['}; template <class date_type, class char_type> const typename period_parser<date_type, char_type>::char_type period_parser<date_type, char_type>::default_period_open_range_end_delimeter[2] = {')'}; template <class date_type, class char_type> const typename period_parser<date_type, char_type>::char_type period_parser<date_type, char_type>::default_period_closed_range_end_delimeter[2] = {']'}; } } //namespace boost::date_time #endif // DATETIME_PERIOD_PARSER_HPP___