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278 lines
8.2 KiB
278 lines
8.2 KiB
#ifndef BOOST_DATE_TIME_STRING_PARSE_TREE___HPP__ |
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#define BOOST_DATE_TIME_STRING_PARSE_TREE___HPP__ |
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/* Copyright (c) 2004-2005 CrystalClear Software, Inc. |
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* Use, modification and distribution is subject to the |
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* Boost Software License, Version 1.0. (See accompanying |
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* file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
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* Author: Jeff Garland, Bart Garst |
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* $Date: 2008-11-12 14:37:53 -0500 (Wed, 12 Nov 2008) $ |
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*/ |
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#include "boost/lexical_cast.hpp" //error without? |
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#include "boost/algorithm/string/case_conv.hpp" |
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#include <map> |
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#include <string> |
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#include <vector> |
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#include <algorithm> |
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namespace boost { namespace date_time { |
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template<typename charT> |
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struct parse_match_result |
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{ |
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parse_match_result() : |
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match_depth(0), |
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current_match(-1)// -1 is match_not-found value |
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{} |
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typedef std::basic_string<charT> string_type; |
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string_type remaining() const |
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{ |
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if (match_depth == cache.size()) { |
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return string_type(); |
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} |
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if (current_match == -1) { |
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return cache; |
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} |
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//some of the cache was used return the rest |
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return string_type(cache, match_depth); |
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} |
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charT last_char() const |
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{ |
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return cache[cache.size()-1]; |
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} |
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//! Returns true if more characters were parsed than was necessary |
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/*! Should be used in conjunction with last_char() |
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* to get the remaining character. |
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*/ |
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bool has_remaining() const |
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{ |
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return (cache.size() > match_depth); |
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} |
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// cache will hold characters that have been read from the stream |
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string_type cache; |
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unsigned short match_depth; |
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short current_match; |
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enum PARSE_STATE { PARSE_ERROR= -1 }; |
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}; |
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//for debug -- really only char streams... |
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template<typename charT> |
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std::basic_ostream<charT>& |
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operator<<(std::basic_ostream<charT>& os, parse_match_result<charT>& mr) |
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{ |
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os << "cm: " << mr.current_match |
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<< " C: '" << mr.cache |
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<< "' md: " << mr.match_depth |
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<< " R: " << mr.remaining(); |
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return os; |
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} |
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//! Recursive data structure to allow efficient parsing of various strings |
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/*! This class provides a quick lookup by building what amounts to a |
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* tree data structure. It also features a match function which can |
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* can handle nasty input interators by caching values as it recurses |
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* the tree so that it can backtrack as needed. |
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*/ |
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template<typename charT> |
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struct string_parse_tree |
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{ |
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#if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581) ) |
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typedef std::multimap<charT, string_parse_tree< charT> > ptree_coll; |
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#else |
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typedef std::multimap<charT, string_parse_tree > ptree_coll; |
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#endif |
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typedef typename ptree_coll::value_type value_type; |
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typedef typename ptree_coll::iterator iterator; |
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typedef typename ptree_coll::const_iterator const_iterator; |
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typedef std::basic_string<charT> string_type; |
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typedef std::vector<std::basic_string<charT> > collection_type; |
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typedef parse_match_result<charT> parse_match_result_type; |
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/*! Parameter "starting_point" designates where the numbering begins. |
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* A starting_point of zero will start the numbering at zero |
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* (Sun=0, Mon=1, ...) were a starting_point of one starts the |
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* numbering at one (Jan=1, Feb=2, ...). The default is zero, |
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* negative vaules are not allowed */ |
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string_parse_tree(collection_type names, unsigned int starting_point=0) |
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{ |
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// iterate thru all the elements and build the tree |
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unsigned short index = 0; |
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while (index != names.size() ) { |
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string_type s = boost::algorithm::to_lower_copy(names[index]); |
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insert(s, static_cast<unsigned short>(index + starting_point)); |
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index++; |
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} |
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//set the last tree node = index+1 indicating a value |
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index++; |
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} |
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string_parse_tree(short value = -1) : |
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m_value(value) |
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{} |
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ptree_coll m_next_chars; |
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short m_value; |
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void insert(const string_type& s, unsigned short value) |
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{ |
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unsigned int i = 0; |
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iterator ti; |
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while(i < s.size()) { |
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if (i==0) { |
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if (i == (s.size()-1)) { |
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ti = m_next_chars.insert(value_type(s[i], |
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string_parse_tree<charT>(value))); |
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} |
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else { |
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ti = m_next_chars.insert(value_type(s[i], |
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string_parse_tree<charT>())); |
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} |
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} |
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else { |
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if (i == (s.size()-1)) { |
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ti = ti->second.m_next_chars.insert(value_type(s[i], |
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string_parse_tree<charT>(value))); |
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} |
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else { |
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ti = ti->second.m_next_chars.insert(value_type(s[i], |
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string_parse_tree<charT>())); |
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} |
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} |
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i++; |
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} |
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} |
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//! Recursive function that finds a matching string in the tree. |
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/*! Must check match_results::has_remaining() after match() is |
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* called. This is required so the user can determine if |
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* stream iterator is already pointing to the expected |
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* character or not (match() might advance sitr to next char in stream). |
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* |
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* A parse_match_result that has been returned from a failed match |
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* attempt can be sent in to the match function of a different |
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* string_parse_tree to attempt a match there. Use the iterators |
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* for the partially consumed stream, the parse_match_result object, |
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* and '0' for the level parameter. */ |
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short |
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match(std::istreambuf_iterator<charT>& sitr, |
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std::istreambuf_iterator<charT>& stream_end, |
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parse_match_result_type& result, |
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unsigned int& level) const |
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{ |
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level++; |
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charT c; |
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// if we conditionally advance sitr, we won't have |
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// to consume the next character past the input |
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bool adv_itr = true; |
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if (level > result.cache.size()) { |
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if (sitr == stream_end) return 0; //bail - input exhausted |
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c = static_cast<charT>(std::tolower(*sitr)); |
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//result.cache += c; |
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//sitr++; |
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} |
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else { |
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// if we're looking for characters from the cache, |
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// we don't want to increment sitr |
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adv_itr = false; |
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c = static_cast<charT>(std::tolower(result.cache[level-1])); |
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} |
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const_iterator litr = m_next_chars.lower_bound(c); |
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const_iterator uitr = m_next_chars.upper_bound(c); |
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while (litr != uitr) { // equal if not found |
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if(adv_itr) { |
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sitr++; |
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result.cache += c; |
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} |
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if (litr->second.m_value != -1) { // -1 is default value |
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if (result.match_depth < level) { |
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result.current_match = litr->second.m_value; |
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result.match_depth = static_cast<unsigned short>(level); |
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} |
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litr->second.match(sitr, stream_end, |
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result, level); |
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level--; |
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} |
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else { |
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litr->second.match(sitr, stream_end, |
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result, level); |
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level--; |
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} |
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if(level <= result.cache.size()) { |
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adv_itr = false; |
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} |
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litr++; |
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} |
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return result.current_match; |
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} |
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/*! Must check match_results::has_remaining() after match() is |
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* called. This is required so the user can determine if |
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* stream iterator is already pointing to the expected |
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* character or not (match() might advance sitr to next char in stream). |
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*/ |
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parse_match_result_type |
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match(std::istreambuf_iterator<charT>& sitr, |
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std::istreambuf_iterator<charT>& stream_end) const |
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{ |
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// lookup to_lower of char in tree. |
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unsigned int level = 0; |
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// string_type cache; |
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parse_match_result_type result; |
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match(sitr, stream_end, result, level); |
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return result; |
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} |
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void printme(std::ostream& os, int& level) |
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{ |
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level++; |
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iterator itr = m_next_chars.begin(); |
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iterator end = m_next_chars.end(); |
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// os << "starting level: " << level << std::endl; |
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while (itr != end) { |
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os << "level: " << level |
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<< " node: " << itr->first |
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<< " value: " << itr->second.m_value |
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<< std::endl; |
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itr->second.printme(os, level); |
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itr++; |
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} |
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level--; |
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} |
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void print(std::ostream& os) |
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{ |
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int level = 0; |
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printme(os, level); |
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} |
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void printmatch(std::ostream& os, charT c) |
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{ |
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iterator litr = m_next_chars.lower_bound(c); |
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iterator uitr = m_next_chars.upper_bound(c); |
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os << "matches for: " << c << std::endl; |
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while (litr != uitr) { |
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os << " node: " << litr->first |
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<< " value: " << litr->second.m_value |
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<< std::endl; |
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litr++; |
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} |
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} |
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}; |
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} } //namespace |
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#endif
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