| #ifndef BOOST_DATE_TIME_STRING_PARSE_TREE___HPP__ |
| #define BOOST_DATE_TIME_STRING_PARSE_TREE___HPP__ |
| |
| /* Copyright (c) 2004-2005 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: 2008-11-12 14:37:53 -0500 (Wed, 12 Nov 2008) $ |
| */ |
| |
| |
| #include "boost/lexical_cast.hpp" //error without? |
| #include "boost/algorithm/string/case_conv.hpp" |
| #include <map> |
| #include <string> |
| #include <vector> |
| #include <algorithm> |
| |
| namespace boost { namespace date_time { |
| |
| |
| template<typename charT> |
| struct parse_match_result |
| { |
| parse_match_result() : |
| match_depth(0), |
| current_match(-1)// -1 is match_not-found value |
| {} |
| typedef std::basic_string<charT> string_type; |
| string_type remaining() const |
| { |
| if (match_depth == cache.size()) { |
| return string_type(); |
| } |
| if (current_match == -1) { |
| return cache; |
| } |
| //some of the cache was used return the rest |
| return string_type(cache, match_depth); |
| } |
| charT last_char() const |
| { |
| return cache[cache.size()-1]; |
| } |
| //! Returns true if more characters were parsed than was necessary |
| /*! Should be used in conjunction with last_char() |
| * to get the remaining character. |
| */ |
| bool has_remaining() const |
| { |
| return (cache.size() > match_depth); |
| } |
| |
| // cache will hold characters that have been read from the stream |
| string_type cache; |
| unsigned short match_depth; |
| short current_match; |
| enum PARSE_STATE { PARSE_ERROR= -1 }; |
| }; |
| |
| //for debug -- really only char streams... |
| template<typename charT> |
| std::basic_ostream<charT>& |
| operator<<(std::basic_ostream<charT>& os, parse_match_result<charT>& mr) |
| { |
| os << "cm: " << mr.current_match |
| << " C: '" << mr.cache |
| << "' md: " << mr.match_depth |
| << " R: " << mr.remaining(); |
| return os; |
| } |
| |
| |
| |
| //! Recursive data structure to allow efficient parsing of various strings |
| /*! This class provides a quick lookup by building what amounts to a |
| * tree data structure. It also features a match function which can |
| * can handle nasty input interators by caching values as it recurses |
| * the tree so that it can backtrack as needed. |
| */ |
| template<typename charT> |
| struct string_parse_tree |
| { |
| #if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581) ) |
| typedef std::multimap<charT, string_parse_tree< charT> > ptree_coll; |
| #else |
| typedef std::multimap<charT, string_parse_tree > ptree_coll; |
| #endif |
| typedef typename ptree_coll::value_type value_type; |
| typedef typename ptree_coll::iterator iterator; |
| typedef typename ptree_coll::const_iterator const_iterator; |
| typedef std::basic_string<charT> string_type; |
| typedef std::vector<std::basic_string<charT> > collection_type; |
| typedef parse_match_result<charT> parse_match_result_type; |
| |
| /*! Parameter "starting_point" designates where the numbering begins. |
| * A starting_point of zero will start the numbering at zero |
| * (Sun=0, Mon=1, ...) were a starting_point of one starts the |
| * numbering at one (Jan=1, Feb=2, ...). The default is zero, |
| * negative vaules are not allowed */ |
| string_parse_tree(collection_type names, unsigned int starting_point=0) |
| { |
| // iterate thru all the elements and build the tree |
| unsigned short index = 0; |
| while (index != names.size() ) { |
| string_type s = boost::algorithm::to_lower_copy(names[index]); |
| insert(s, static_cast<unsigned short>(index + starting_point)); |
| index++; |
| } |
| //set the last tree node = index+1 indicating a value |
| index++; |
| } |
| |
| |
| string_parse_tree(short value = -1) : |
| m_value(value) |
| {} |
| ptree_coll m_next_chars; |
| short m_value; |
| |
| void insert(const string_type& s, unsigned short value) |
| { |
| unsigned int i = 0; |
| iterator ti; |
| while(i < s.size()) { |
| if (i==0) { |
| if (i == (s.size()-1)) { |
| ti = m_next_chars.insert(value_type(s[i], |
| string_parse_tree<charT>(value))); |
| } |
| else { |
| ti = m_next_chars.insert(value_type(s[i], |
| string_parse_tree<charT>())); |
| } |
| } |
| else { |
| if (i == (s.size()-1)) { |
| ti = ti->second.m_next_chars.insert(value_type(s[i], |
| string_parse_tree<charT>(value))); |
| } |
| |
| else { |
| ti = ti->second.m_next_chars.insert(value_type(s[i], |
| string_parse_tree<charT>())); |
| } |
| |
| } |
| i++; |
| } |
| } |
| |
| |
| //! Recursive function that finds a matching string in the tree. |
| /*! Must check match_results::has_remaining() after match() is |
| * called. This is required so the user can determine if |
| * stream iterator is already pointing to the expected |
| * character or not (match() might advance sitr to next char in stream). |
| * |
| * A parse_match_result that has been returned from a failed match |
| * attempt can be sent in to the match function of a different |
| * string_parse_tree to attempt a match there. Use the iterators |
| * for the partially consumed stream, the parse_match_result object, |
| * and '0' for the level parameter. */ |
| short |
| match(std::istreambuf_iterator<charT>& sitr, |
| std::istreambuf_iterator<charT>& stream_end, |
| parse_match_result_type& result, |
| unsigned int& level) const |
| { |
| |
| level++; |
| charT c; |
| // if we conditionally advance sitr, we won't have |
| // to consume the next character past the input |
| bool adv_itr = true; |
| if (level > result.cache.size()) { |
| if (sitr == stream_end) return 0; //bail - input exhausted |
| c = static_cast<charT>(std::tolower(*sitr)); |
| //result.cache += c; |
| //sitr++; |
| } |
| else { |
| // if we're looking for characters from the cache, |
| // we don't want to increment sitr |
| adv_itr = false; |
| c = static_cast<charT>(std::tolower(result.cache[level-1])); |
| } |
| const_iterator litr = m_next_chars.lower_bound(c); |
| const_iterator uitr = m_next_chars.upper_bound(c); |
| while (litr != uitr) { // equal if not found |
| if(adv_itr) { |
| sitr++; |
| result.cache += c; |
| } |
| if (litr->second.m_value != -1) { // -1 is default value |
| if (result.match_depth < level) { |
| result.current_match = litr->second.m_value; |
| result.match_depth = static_cast<unsigned short>(level); |
| } |
| litr->second.match(sitr, stream_end, |
| result, level); |
| level--; |
| } |
| else { |
| litr->second.match(sitr, stream_end, |
| result, level); |
| level--; |
| } |
| |
| if(level <= result.cache.size()) { |
| adv_itr = false; |
| } |
| |
| litr++; |
| } |
| return result.current_match; |
| |
| } |
| |
| /*! Must check match_results::has_remaining() after match() is |
| * called. This is required so the user can determine if |
| * stream iterator is already pointing to the expected |
| * character or not (match() might advance sitr to next char in stream). |
| */ |
| parse_match_result_type |
| match(std::istreambuf_iterator<charT>& sitr, |
| std::istreambuf_iterator<charT>& stream_end) const |
| { |
| // lookup to_lower of char in tree. |
| unsigned int level = 0; |
| // string_type cache; |
| parse_match_result_type result; |
| match(sitr, stream_end, result, level); |
| return result; |
| } |
| |
| void printme(std::ostream& os, int& level) |
| { |
| level++; |
| iterator itr = m_next_chars.begin(); |
| iterator end = m_next_chars.end(); |
| // os << "starting level: " << level << std::endl; |
| while (itr != end) { |
| os << "level: " << level |
| << " node: " << itr->first |
| << " value: " << itr->second.m_value |
| << std::endl; |
| itr->second.printme(os, level); |
| itr++; |
| } |
| level--; |
| } |
| |
| void print(std::ostream& os) |
| { |
| int level = 0; |
| printme(os, level); |
| } |
| |
| void printmatch(std::ostream& os, charT c) |
| { |
| iterator litr = m_next_chars.lower_bound(c); |
| iterator uitr = m_next_chars.upper_bound(c); |
| os << "matches for: " << c << std::endl; |
| while (litr != uitr) { |
| os << " node: " << litr->first |
| << " value: " << litr->second.m_value |
| << std::endl; |
| litr++; |
| } |
| } |
| |
| }; |
| |
| |
| } } //namespace |
| #endif |