1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
#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));
}
special_values_parser(const special_values_parser<date_type,charT>& svp)
{
this->m_sv_strings = svp.m_sv_strings;
}
//! 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__
|
