| |
| #ifndef DATE_TIME_SPECIAL_VALUES_PARSER_HPP__ |
| #define DATE_TIME_SPECIAL_VALUES_PARSER_HPP__ |
| |
| /* Copyright (c) 2005 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/date_time/string_parse_tree.hpp" |
| #include "boost/date_time/special_defs.hpp" |
| #include <string> |
| #include <vector> |
| |
| namespace boost { namespace date_time { |
| |
| //! Class for special_value parsing |
| /*! |
| * TODO: add doc-comments for which elements can be changed |
| * Parses input stream for strings representing special_values. |
| * Special values parsed are: |
| * - not_a_date_time |
| * - neg_infin |
| * - pod_infin |
| * - min_date_time |
| * - max_date_time |
| */ |
| template<class date_type, typename charT> |
| class special_values_parser |
| { |
| public: |
| typedef std::basic_string<charT> string_type; |
| typedef std::basic_stringstream<charT> stringstream_type; |
| typedef std::istreambuf_iterator<charT> stream_itr_type; |
| typedef typename date_type::duration_type duration_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; |
| |
| typedef charT char_type; |
| static const char_type nadt_string[16]; |
| static const char_type neg_inf_string[10]; |
| static const char_type pos_inf_string[10]; |
| static const char_type min_date_time_string[18]; |
| static const char_type max_date_time_string[18]; |
| |
| //! Creates a special_values_parser with the default set of "sv_strings" |
| special_values_parser() |
| { |
| sv_strings(string_type(nadt_string), |
| string_type(neg_inf_string), |
| string_type(pos_inf_string), |
| string_type(min_date_time_string), |
| string_type(max_date_time_string)); |
| } |
| |
| //! Creates a special_values_parser using a user defined set of element strings |
| special_values_parser(const string_type& nadt_str, |
| const string_type& neg_inf_str, |
| const string_type& pos_inf_str, |
| const string_type& min_dt_str, |
| const string_type& max_dt_str) |
| { |
| sv_strings(nadt_str, neg_inf_str, pos_inf_str, min_dt_str, max_dt_str); |
| } |
| |
| special_values_parser(typename collection_type::iterator beg, typename collection_type::iterator end) |
| { |
| collection_type phrases; |
| std::copy(beg, end, std::back_inserter(phrases)); |
| m_sv_strings = parse_tree_type(phrases, static_cast<int>(not_a_date_time)); |
| } |
| |
| //! Replace special value strings |
| void sv_strings(const string_type& nadt_str, |
| const string_type& neg_inf_str, |
| const string_type& pos_inf_str, |
| const string_type& min_dt_str, |
| const string_type& max_dt_str) |
| { |
| collection_type phrases; |
| phrases.push_back(nadt_str); |
| phrases.push_back(neg_inf_str); |
| phrases.push_back(pos_inf_str); |
| phrases.push_back(min_dt_str); |
| phrases.push_back(max_dt_str); |
| m_sv_strings = parse_tree_type(phrases, static_cast<int>(not_a_date_time)); |
| } |
| |
| //! The parser is expensive to create, and not thread-safe so it cannot be static |
| //! therefore given a string, determine if it is likely to be a special value. |
| //! A negative response is a definite no, whereas a positive is only likely and |
| //! match() should be called and return value checked. |
| //! \param[in] str the string to check |
| //! \returns false if it is definitely not a special value |
| static bool likely(const string_type& str) |
| { |
| if (!str.empty()) { |
| switch (str[0]) { |
| // See string definitions at the end of this class.. |
| case '+': |
| case '-': |
| case 'n': |
| case 'm': |
| return true; |
| |
| default: |
| break; |
| } |
| } |
| |
| return false; |
| } |
| |
| //! Given an input iterator, attempt to match it to a known special value |
| //! \param[in] sitr the start iterator |
| //! \param[in] str_end the end iterator |
| //! \param[out] mr the match result: |
| //! mr.current_match is set to the corresponding special_value or -1 |
| //! \returns whether something matched |
| bool match(stream_itr_type& sitr, |
| stream_itr_type& str_end, |
| match_results& mr) const |
| { |
| unsigned int level = 0; |
| m_sv_strings.match(sitr, str_end, mr, level); |
| return (mr.current_match != match_results::PARSE_ERROR); |
| } |
| |
| private: |
| parse_tree_type m_sv_strings; |
| |
| }; |
| |
| template<class date_type, class CharT> |
| const typename special_values_parser<date_type, CharT>::char_type |
| special_values_parser<date_type, CharT>::nadt_string[16] = |
| {'n','o','t','-','a','-','d','a','t','e','-','t','i','m','e'}; |
| template<class date_type, class CharT> |
| const typename special_values_parser<date_type, CharT>::char_type |
| special_values_parser<date_type, CharT>::neg_inf_string[10] = |
| {'-','i','n','f','i','n','i','t','y'}; |
| template<class date_type, class CharT> |
| const typename special_values_parser<date_type, CharT>::char_type |
| special_values_parser<date_type, CharT>::pos_inf_string[10] = |
| {'+','i','n','f','i','n','i','t','y'}; |
| template<class date_type, class CharT> |
| const typename special_values_parser<date_type, CharT>::char_type |
| special_values_parser<date_type, CharT>::min_date_time_string[18] = |
| {'m','i','n','i','m','u','m','-','d','a','t','e','-','t','i','m','e'}; |
| template<class date_type, class CharT> |
| const typename special_values_parser<date_type, CharT>::char_type |
| special_values_parser<date_type, CharT>::max_date_time_string[18] = |
| {'m','a','x','i','m','u','m','-','d','a','t','e','-','t','i','m','e'}; |
| |
| } } //namespace |
| |
| #endif // DATE_TIME_SPECIAL_VALUES_PARSER_HPP__ |
| |