[3428] | 1 | #ifndef BOOST_DATE_TIME_STRING_PARSE_TREE___HPP__ |
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| 2 | #define BOOST_DATE_TIME_STRING_PARSE_TREE___HPP__ |
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| 3 | |
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| 4 | /* Copyright (c) 2004-2005 CrystalClear Software, Inc. |
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| 5 | * Use, modification and distribution is subject to the |
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| 6 | * Boost Software License, Version 1.0. (See accompanying |
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| 7 | * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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| 8 | * Author: Jeff Garland, Bart Garst |
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| 9 | * $Date: 2008-11-12 14:37:53 -0500 (Wed, 12 Nov 2008) $ |
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| 10 | */ |
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| 11 | |
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| 12 | |
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| 13 | #include "boost/lexical_cast.hpp" //error without? |
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| 14 | #include "boost/algorithm/string/case_conv.hpp" |
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| 15 | #include <map> |
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| 16 | #include <string> |
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| 17 | #include <vector> |
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| 18 | #include <algorithm> |
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| 19 | |
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| 20 | namespace boost { namespace date_time { |
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| 21 | |
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| 22 | |
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| 23 | template<typename charT> |
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| 24 | struct parse_match_result |
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| 25 | { |
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| 26 | parse_match_result() : |
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| 27 | match_depth(0), |
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| 28 | current_match(-1)// -1 is match_not-found value |
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| 29 | {} |
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| 30 | typedef std::basic_string<charT> string_type; |
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| 31 | string_type remaining() const |
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| 32 | { |
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| 33 | if (match_depth == cache.size()) { |
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| 34 | return string_type(); |
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| 35 | } |
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| 36 | if (current_match == -1) { |
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| 37 | return cache; |
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| 38 | } |
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| 39 | //some of the cache was used return the rest |
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| 40 | return string_type(cache, match_depth); |
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| 41 | } |
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| 42 | charT last_char() const |
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| 43 | { |
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| 44 | return cache[cache.size()-1]; |
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| 45 | } |
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| 46 | //! Returns true if more characters were parsed than was necessary |
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| 47 | /*! Should be used in conjunction with last_char() |
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| 48 | * to get the remaining character. |
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| 49 | */ |
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| 50 | bool has_remaining() const |
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| 51 | { |
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| 52 | return (cache.size() > match_depth); |
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| 53 | } |
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| 54 | |
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| 55 | // cache will hold characters that have been read from the stream |
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| 56 | string_type cache; |
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| 57 | unsigned short match_depth; |
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| 58 | short current_match; |
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| 59 | enum PARSE_STATE { PARSE_ERROR= -1 }; |
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| 60 | }; |
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| 61 | |
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| 62 | //for debug -- really only char streams... |
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| 63 | template<typename charT> |
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| 64 | std::basic_ostream<charT>& |
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| 65 | operator<<(std::basic_ostream<charT>& os, parse_match_result<charT>& mr) |
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| 66 | { |
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| 67 | os << "cm: " << mr.current_match |
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| 68 | << " C: '" << mr.cache |
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| 69 | << "' md: " << mr.match_depth |
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| 70 | << " R: " << mr.remaining(); |
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| 71 | return os; |
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| 72 | } |
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| 73 | |
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| 74 | |
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| 75 | |
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| 76 | //! Recursive data structure to allow efficient parsing of various strings |
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| 77 | /*! This class provides a quick lookup by building what amounts to a |
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| 78 | * tree data structure. It also features a match function which can |
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| 79 | * can handle nasty input interators by caching values as it recurses |
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| 80 | * the tree so that it can backtrack as needed. |
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| 81 | */ |
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| 82 | template<typename charT> |
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| 83 | struct string_parse_tree |
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| 84 | { |
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| 85 | #if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581) ) |
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| 86 | typedef std::multimap<charT, string_parse_tree< charT> > ptree_coll; |
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| 87 | #else |
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| 88 | typedef std::multimap<charT, string_parse_tree > ptree_coll; |
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| 89 | #endif |
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| 90 | typedef typename ptree_coll::value_type value_type; |
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| 91 | typedef typename ptree_coll::iterator iterator; |
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| 92 | typedef typename ptree_coll::const_iterator const_iterator; |
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| 93 | typedef std::basic_string<charT> string_type; |
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| 94 | typedef std::vector<std::basic_string<charT> > collection_type; |
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| 95 | typedef parse_match_result<charT> parse_match_result_type; |
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| 96 | |
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| 97 | /*! Parameter "starting_point" designates where the numbering begins. |
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| 98 | * A starting_point of zero will start the numbering at zero |
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| 99 | * (Sun=0, Mon=1, ...) were a starting_point of one starts the |
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| 100 | * numbering at one (Jan=1, Feb=2, ...). The default is zero, |
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| 101 | * negative vaules are not allowed */ |
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| 102 | string_parse_tree(collection_type names, unsigned int starting_point=0) |
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| 103 | { |
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| 104 | // iterate thru all the elements and build the tree |
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| 105 | unsigned short index = 0; |
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| 106 | while (index != names.size() ) { |
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| 107 | string_type s = boost::algorithm::to_lower_copy(names[index]); |
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| 108 | insert(s, static_cast<unsigned short>(index + starting_point)); |
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| 109 | index++; |
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| 110 | } |
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| 111 | //set the last tree node = index+1 indicating a value |
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| 112 | index++; |
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| 113 | } |
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| 114 | |
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| 115 | |
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| 116 | string_parse_tree(short value = -1) : |
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| 117 | m_value(value) |
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| 118 | {} |
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| 119 | ptree_coll m_next_chars; |
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| 120 | short m_value; |
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| 121 | |
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| 122 | void insert(const string_type& s, unsigned short value) |
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| 123 | { |
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| 124 | unsigned int i = 0; |
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| 125 | iterator ti; |
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| 126 | while(i < s.size()) { |
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| 127 | if (i==0) { |
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| 128 | if (i == (s.size()-1)) { |
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| 129 | ti = m_next_chars.insert(value_type(s[i], |
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| 130 | string_parse_tree<charT>(value))); |
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| 131 | } |
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| 132 | else { |
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| 133 | ti = m_next_chars.insert(value_type(s[i], |
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| 134 | string_parse_tree<charT>())); |
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| 135 | } |
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| 136 | } |
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| 137 | else { |
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| 138 | if (i == (s.size()-1)) { |
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| 139 | ti = ti->second.m_next_chars.insert(value_type(s[i], |
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| 140 | string_parse_tree<charT>(value))); |
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| 141 | } |
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| 142 | |
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| 143 | else { |
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| 144 | ti = ti->second.m_next_chars.insert(value_type(s[i], |
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| 145 | string_parse_tree<charT>())); |
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| 146 | } |
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| 147 | |
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| 148 | } |
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| 149 | i++; |
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| 150 | } |
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| 151 | } |
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| 152 | |
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| 153 | |
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| 154 | //! Recursive function that finds a matching string in the tree. |
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| 155 | /*! Must check match_results::has_remaining() after match() is |
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| 156 | * called. This is required so the user can determine if |
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| 157 | * stream iterator is already pointing to the expected |
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| 158 | * character or not (match() might advance sitr to next char in stream). |
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| 159 | * |
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| 160 | * A parse_match_result that has been returned from a failed match |
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| 161 | * attempt can be sent in to the match function of a different |
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| 162 | * string_parse_tree to attempt a match there. Use the iterators |
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| 163 | * for the partially consumed stream, the parse_match_result object, |
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| 164 | * and '0' for the level parameter. */ |
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| 165 | short |
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| 166 | match(std::istreambuf_iterator<charT>& sitr, |
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| 167 | std::istreambuf_iterator<charT>& stream_end, |
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| 168 | parse_match_result_type& result, |
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| 169 | unsigned int& level) const |
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| 170 | { |
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| 171 | |
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| 172 | level++; |
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| 173 | charT c; |
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| 174 | // if we conditionally advance sitr, we won't have |
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| 175 | // to consume the next character past the input |
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| 176 | bool adv_itr = true; |
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| 177 | if (level > result.cache.size()) { |
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| 178 | if (sitr == stream_end) return 0; //bail - input exhausted |
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| 179 | c = static_cast<charT>(std::tolower(*sitr)); |
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| 180 | //result.cache += c; |
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| 181 | //sitr++; |
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| 182 | } |
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| 183 | else { |
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| 184 | // if we're looking for characters from the cache, |
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| 185 | // we don't want to increment sitr |
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| 186 | adv_itr = false; |
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| 187 | c = static_cast<charT>(std::tolower(result.cache[level-1])); |
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| 188 | } |
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| 189 | const_iterator litr = m_next_chars.lower_bound(c); |
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| 190 | const_iterator uitr = m_next_chars.upper_bound(c); |
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| 191 | while (litr != uitr) { // equal if not found |
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| 192 | if(adv_itr) { |
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| 193 | sitr++; |
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| 194 | result.cache += c; |
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| 195 | } |
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| 196 | if (litr->second.m_value != -1) { // -1 is default value |
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| 197 | if (result.match_depth < level) { |
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| 198 | result.current_match = litr->second.m_value; |
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| 199 | result.match_depth = static_cast<unsigned short>(level); |
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| 200 | } |
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| 201 | litr->second.match(sitr, stream_end, |
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| 202 | result, level); |
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| 203 | level--; |
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| 204 | } |
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| 205 | else { |
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| 206 | litr->second.match(sitr, stream_end, |
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| 207 | result, level); |
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| 208 | level--; |
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| 209 | } |
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| 210 | |
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| 211 | if(level <= result.cache.size()) { |
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| 212 | adv_itr = false; |
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| 213 | } |
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| 214 | |
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| 215 | litr++; |
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| 216 | } |
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| 217 | return result.current_match; |
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| 218 | |
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| 219 | } |
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| 220 | |
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| 221 | /*! Must check match_results::has_remaining() after match() is |
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| 222 | * called. This is required so the user can determine if |
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| 223 | * stream iterator is already pointing to the expected |
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| 224 | * character or not (match() might advance sitr to next char in stream). |
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| 225 | */ |
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| 226 | parse_match_result_type |
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| 227 | match(std::istreambuf_iterator<charT>& sitr, |
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| 228 | std::istreambuf_iterator<charT>& stream_end) const |
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| 229 | { |
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| 230 | // lookup to_lower of char in tree. |
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| 231 | unsigned int level = 0; |
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| 232 | // string_type cache; |
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| 233 | parse_match_result_type result; |
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| 234 | match(sitr, stream_end, result, level); |
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| 235 | return result; |
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| 236 | } |
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| 237 | |
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| 238 | void printme(std::ostream& os, int& level) |
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| 239 | { |
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| 240 | level++; |
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| 241 | iterator itr = m_next_chars.begin(); |
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| 242 | iterator end = m_next_chars.end(); |
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| 243 | // os << "starting level: " << level << std::endl; |
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| 244 | while (itr != end) { |
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| 245 | os << "level: " << level |
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| 246 | << " node: " << itr->first |
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| 247 | << " value: " << itr->second.m_value |
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| 248 | << std::endl; |
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| 249 | itr->second.printme(os, level); |
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| 250 | itr++; |
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| 251 | } |
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| 252 | level--; |
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| 253 | } |
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| 254 | |
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| 255 | void print(std::ostream& os) |
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| 256 | { |
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| 257 | int level = 0; |
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| 258 | printme(os, level); |
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| 259 | } |
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| 260 | |
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| 261 | void printmatch(std::ostream& os, charT c) |
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| 262 | { |
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| 263 | iterator litr = m_next_chars.lower_bound(c); |
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| 264 | iterator uitr = m_next_chars.upper_bound(c); |
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| 265 | os << "matches for: " << c << std::endl; |
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| 266 | while (litr != uitr) { |
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| 267 | os << " node: " << litr->first |
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| 268 | << " value: " << litr->second.m_value |
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| 269 | << std::endl; |
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| 270 | litr++; |
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| 271 | } |
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| 272 | } |
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| 273 | |
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| 274 | }; |
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| 275 | |
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| 276 | |
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| 277 | } } //namespace |
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| 278 | #endif |
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