1 | // |
2 | // Format.h |
3 | // |
4 | // Library: Foundation |
5 | // Package: Core |
6 | // Module: Format |
7 | // |
8 | // Definition of the format freestanding function. |
9 | // |
10 | // Copyright (c) 2006, Applied Informatics Software Engineering GmbH. |
11 | // and Contributors. |
12 | // |
13 | // SPDX-License-Identifier: BSL-1.0 |
14 | // |
15 | |
16 | |
17 | #ifndef Foundation_Format_INCLUDED |
18 | #define Foundation_Format_INCLUDED |
19 | |
20 | |
21 | #include "Poco/Foundation.h" |
22 | #include "Poco/Any.h" |
23 | #include <vector> |
24 | #include <type_traits> |
25 | |
26 | |
27 | namespace Poco { |
28 | |
29 | |
30 | std::string Foundation_API format(const std::string& fmt, const Any& value); |
31 | /// This function implements sprintf-style formatting in a typesafe way. |
32 | /// Various variants of the function are available, supporting a |
33 | /// different number of arguments (up to six). |
34 | /// |
35 | /// The formatting is controlled by the format string in fmt. |
36 | /// Format strings are quite similar to those of the std::printf() function, but |
37 | /// there are some minor differences. |
38 | /// |
39 | /// The format string can consist of any sequence of characters; certain |
40 | /// characters have a special meaning. Characters without a special meaning |
41 | /// are copied verbatim to the result. A percent sign (%) marks the beginning |
42 | /// of a format specification. Format specifications have the following syntax: |
43 | /// |
44 | /// %[<index>][<flags>][<width>][.<precision>][<modifier>]<type> |
45 | /// |
46 | /// Index, flags, width, precision and prefix are optional. The only required part of |
47 | /// the format specification, apart from the percent sign, is the type. |
48 | /// |
49 | /// The optional index argument has the format "[<n>]" and allows to |
50 | /// address an argument by its zero-based position (see the example below). |
51 | /// |
52 | /// Following are valid type specifications and their meaning: |
53 | /// |
54 | /// * b boolean (true = 1, false = 0) |
55 | /// * c character |
56 | /// * d signed decimal integer |
57 | /// * i signed decimal integer |
58 | /// * o unsigned octal integer |
59 | /// * u unsigned decimal integer |
60 | /// * x unsigned hexadecimal integer (lower case) |
61 | /// * X unsigned hexadecimal integer (upper case) |
62 | /// * e signed floating-point value in the form [-]d.dddde[<sign>]dd[d] |
63 | /// * E signed floating-point value in the form [-]d.ddddE[<sign>]dd[d] |
64 | /// * f signed floating-point value in the form [-]dddd.dddd |
65 | /// * s std::string |
66 | /// * z std::size_t |
67 | /// |
68 | /// The following flags are supported: |
69 | /// |
70 | /// * - left align the result within the given field width |
71 | /// * + prefix the output value with a sign (+ or -) if the output value is of a signed type |
72 | /// * 0 if width is prefixed with 0, zeros are added until the minimum width is reached |
73 | /// * # For o, x, X, the # flag prefixes any nonzero output value with 0, 0x, or 0X, respectively; |
74 | /// for e, E, f, the # flag forces the output value to contain a decimal point in all cases. |
75 | /// |
76 | /// The following modifiers are supported: |
77 | /// |
78 | /// * (none) argument is char (c), int (d, i), unsigned (o, u, x, X) double (e, E, f, g, G) or string (s) |
79 | /// * l argument is long (d, i), unsigned long (o, u, x, X) or long double (e, E, f, g, G) |
80 | /// * L argument is long long (d, i), unsigned long long (o, u, x, X) |
81 | /// * h argument is short (d, i), unsigned short (o, u, x, X) or float (e, E, f, g, G) |
82 | /// * ? argument is any signed or unsigned int, short, long, or 64-bit integer (d, i, o, x, X) |
83 | /// |
84 | /// The width argument is a nonnegative decimal integer or '*' with an additional nonnegative integer value preceding the value to be formated, controlling the minimum number of characters printed. |
85 | /// If the number of characters in the output value is less than the specified width, blanks or |
86 | /// leading zeros are added, according to the specified flags (-, +, 0). |
87 | /// |
88 | /// Precision is a nonnegative decimal integer or '*' with an additional nonnegative integer value preceding the value to be formated, preceded by a period (.), which specifies the number of characters |
89 | /// to be printed, the number of decimal places, or the number of significant digits. |
90 | /// |
91 | /// Throws an InvalidArgumentException if an argument index is out of range. |
92 | /// |
93 | /// Starting with release 1.4.3, an argument that does not match the format |
94 | /// specifier no longer results in a BadCastException. The string [ERRFMT] is |
95 | /// written to the result string instead. |
96 | /// |
97 | /// If there are more format specifiers than values, the format specifiers without a corresponding value |
98 | /// are copied verbatim to output. |
99 | /// |
100 | /// If there are more values than format specifiers, the superfluous values are ignored. |
101 | /// |
102 | /// Usage Examples: |
103 | /// std::string s1 = format("The answer to life, the universe, and everything is %d", 42); |
104 | /// std::string s2 = format("second: %[1]d, first: %[0]d", 1, 2); |
105 | |
106 | void Foundation_API format(std::string& result, const char *fmt, const std::vector<Any>& values); |
107 | /// Supports a variable number of arguments and is used by |
108 | /// all other variants of format(). |
109 | |
110 | void Foundation_API format(std::string& result, const std::string& fmt, const std::vector<Any>& values); |
111 | /// Supports a variable number of arguments and is used by |
112 | /// all other variants of format(). |
113 | |
114 | |
115 | template <typename T, typename... Args> |
116 | void format(std::string &result, const std::string &fmt, T arg1, Args... args) |
117 | /// Appends the formatted string to result. |
118 | { |
119 | std::vector<Any> values; |
120 | values.push_back(arg1); |
121 | values.insert(values.end(), { args... }); |
122 | format(result, fmt, values); |
123 | } |
124 | |
125 | |
126 | template <typename FMT, typename T, typename... Args, |
127 | typename std::enable_if< std::is_const< typename std::remove_reference<FMT>::type >::value, int >::type = 0> |
128 | std::string format(FMT &fmt, T arg1, Args... args) |
129 | /// Returns the formatted string. |
130 | { |
131 | std::vector<Any> values; |
132 | values.push_back(arg1); |
133 | values.insert(values.end(), { args... }); |
134 | std::string result; |
135 | format(result, fmt, values); |
136 | return result; |
137 | } |
138 | |
139 | |
140 | } // namespace Poco |
141 | |
142 | |
143 | #endif // Foundation_Format_INCLUDED |
144 | |