1/*
2 * Copyright Andrey Semashev 2007 - 2015.
3 * Distributed under the Boost Software License, Version 1.0.
4 * (See accompanying file LICENSE_1_0.txt or copy at
5 * http://www.boost.org/LICENSE_1_0.txt)
6 */
7/*!
8 * \file format_parser.cpp
9 * \author Andrey Semashev
10 * \date 16.11.2012
11 *
12 * \brief This header is the Boost.Log library implementation, see the library documentation
13 * at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html.
14 */
15
16#include <boost/log/detail/config.hpp>
17#include <string>
18#include <algorithm>
19#include <boost/throw_exception.hpp>
20#include <boost/exception/exception.hpp>
21#include <boost/move/core.hpp>
22#include <boost/move/utility_core.hpp>
23#include <boost/spirit/include/qi_uint.hpp>
24#include <boost/spirit/include/qi_parse.hpp>
25#include <boost/log/detail/format.hpp>
26#include <boost/log/exceptions.hpp>
27#include <boost/log/support/exception.hpp>
28#include "spirit_encoding.hpp"
29#include <boost/log/detail/header.hpp>
30
31namespace qi = boost::spirit::qi;
32
33namespace boost {
34
35BOOST_LOG_OPEN_NAMESPACE
36
37namespace aux {
38
39template< typename CharT >
40BOOST_LOG_API format_description< CharT > parse_format(const CharT* begin, const CharT* end)
41{
42 typedef CharT char_type;
43 typedef format_description< char_type > description;
44 typedef typename encoding< char_type >::type traits;
45
46 const char_type* original_begin = begin;
47 description descr;
48 unsigned int literal_start_pos = 0;
49
50 while (begin != end)
51 {
52 const char_type* p = std::find(begin, end, static_cast< char_type >('%'));
53 descr.literal_chars.append(begin, p);
54
55 if ((end - p) >= 2)
56 {
57 // Check for a percent placeholder
58 char_type c = p[1];
59 if (c == static_cast< char_type >('%'))
60 {
61 descr.literal_chars.push_back(static_cast< char_type >('%'));
62 begin = p + 2;
63 continue;
64 }
65
66 // From here on, no more literals are possible. Append the literal element.
67 {
68 const unsigned int literal_chars_size = static_cast< unsigned int >(descr.literal_chars.size());
69 if (literal_start_pos < literal_chars_size)
70 {
71 descr.format_elements.push_back(format_element::literal(start_pos: literal_start_pos, len: literal_chars_size - literal_start_pos));
72 literal_start_pos = literal_chars_size;
73 }
74 }
75
76 // Check if this is a positional argument
77 if (traits::isdigit(c))
78 {
79 if (c != static_cast< char_type >('0'))
80 {
81 // Positional argument in the form "%N%"
82 unsigned int n = 0;
83 const char_type* pp = p + 1;
84 qi::parse(pp, end, qi::uint_, n);
85 if (n == 0 || pp == end || *pp != static_cast< char_type >('%'))
86 {
87 boost::throw_exception(e: boost::enable_error_info(x: parse_error("Invalid positional format placeholder")) << boost::throw_file(__FILE__) << boost::throw_line(__LINE__)
88 << boost::log::position_info(static_cast< unsigned int >(p - original_begin))
89 );
90 }
91
92 // Safety check against ridiculously large argument numbers which would lead to excessive memory consumption.
93 // This could be useful if the format string is gathered from an external source (e.g. a config file).
94 if (n > 1000)
95 {
96 boost::throw_exception(e: boost::enable_error_info(x: limitation_error("Positional format placeholder too big")) << boost::throw_file(__FILE__) << boost::throw_line(__LINE__)
97 << boost::log::position_info(static_cast< unsigned int >(p - original_begin))
98 );
99 }
100
101 // We count positional arguments from 0, not from 1 as in format strings
102 descr.format_elements.push_back(format_element::positional_argument(arg_n: n - 1));
103 begin = pp + 1; // skip the closing '%'
104
105 continue;
106 }
107 else
108 {
109 // This must be the filler character, not supported yet
110 }
111 }
112
113 // This must be something else, not supported yet
114 boost::throw_exception(e: boost::enable_error_info(x: parse_error("Unsupported format placeholder")) << boost::throw_file(__FILE__) << boost::throw_line(__LINE__)
115 << boost::log::position_info(static_cast< unsigned int >(p - original_begin))
116 );
117 }
118 else
119 {
120 if (p != end)
121 descr.literal_chars.push_back(static_cast< char_type >('%')); // a single '%' character at the end of the string
122 begin = end;
123 }
124 }
125
126 const unsigned int literal_chars_size = static_cast< unsigned int >(descr.literal_chars.size());
127 if (literal_start_pos < literal_chars_size)
128 descr.format_elements.push_back(format_element::literal(start_pos: literal_start_pos, len: literal_chars_size - literal_start_pos));
129
130 return BOOST_LOG_NRVO_RESULT(descr);
131}
132
133
134#ifdef BOOST_LOG_USE_CHAR
135
136template BOOST_LOG_API
137format_description< char > parse_format(const char* begin, const char* end);
138
139#endif // BOOST_LOG_USE_CHAR
140
141#ifdef BOOST_LOG_USE_WCHAR_T
142
143template BOOST_LOG_API
144format_description< wchar_t > parse_format(const wchar_t* begin, const wchar_t* end);
145
146#endif // BOOST_LOG_USE_WCHAR_T
147
148} // namespace aux
149
150BOOST_LOG_CLOSE_NAMESPACE // namespace log
151
152} // namespace boost
153
154#include <boost/log/detail/footer.hpp>
155

source code of boost/libs/log/src/format_parser.cpp