1 | /* |
2 | * Copyright Andrey Semashev 2022. |
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 snprintf.hpp |
9 | * \author Andrey Semashev |
10 | * \date 06.12.2022 |
11 | * |
12 | * \brief The header provides more portable definition of snprintf and vsnprintf, |
13 | * as well as \c wchar_t counterparts. |
14 | */ |
15 | |
16 | #ifndef BOOST_CORE_SNPRINTF_HPP_INCLUDED_ |
17 | #define BOOST_CORE_SNPRINTF_HPP_INCLUDED_ |
18 | |
19 | #include <stdio.h> |
20 | #include <wchar.h> |
21 | #include <boost/config.hpp> |
22 | |
23 | #ifdef BOOST_HAS_PRAGMA_ONCE |
24 | #pragma once |
25 | #endif |
26 | |
27 | #if defined(__MINGW32__) |
28 | |
29 | #include <cstddef> |
30 | #include <cstdarg> |
31 | #if !defined(__MINGW64_VERSION_MAJOR) |
32 | #include <climits> |
33 | #endif |
34 | |
35 | // MinGW32 and MinGW-w64 provide their own snprintf implementations that are compliant with the C standard. |
36 | #define BOOST_CORE_DETAIL_MINGW_SNPRINTF |
37 | |
38 | #elif (defined(BOOST_MSSTL_VERSION) && BOOST_MSSTL_VERSION < 140) |
39 | |
40 | #include <cstddef> |
41 | #include <cstdarg> |
42 | #include <climits> |
43 | |
44 | // MSVC snprintfs are not conforming but they are good enough for typical use cases. |
45 | #define BOOST_CORE_DETAIL_MSVC_LEGACY_SNPRINTF |
46 | |
47 | #endif |
48 | |
49 | namespace boost { |
50 | |
51 | namespace core { |
52 | |
53 | #if defined(BOOST_CORE_DETAIL_MINGW_SNPRINTF) || defined(BOOST_CORE_DETAIL_MSVC_LEGACY_SNPRINTF) |
54 | |
55 | #if defined(BOOST_CORE_DETAIL_MINGW_SNPRINTF) |
56 | |
57 | inline int vsnprintf(char* buf, std::size_t size, const char* format, std::va_list args) |
58 | { |
59 | return __mingw_vsnprintf(buf, size, format, args); |
60 | } |
61 | |
62 | inline int vswprintf(wchar_t* buf, std::size_t size, const wchar_t* format, std::va_list args) |
63 | { |
64 | #if defined(__MINGW64_VERSION_MAJOR) |
65 | int res = __mingw_vsnwprintf(buf, size, format, args); |
66 | // __mingw_vsnwprintf returns the number of characters to be printed, but (v)swprintf is expected to return -1 on truncation |
67 | if (static_cast< unsigned int >(res) >= size) |
68 | res = -1; |
69 | return res; |
70 | #else |
71 | // Legacy MinGW32 does not provide __mingw_vsnwprintf, so use _vsnwprintf from MSVC CRT |
72 | if (BOOST_UNLIKELY(size == 0u || size > static_cast< std::size_t >(INT_MAX))) |
73 | return -1; |
74 | |
75 | int res = _vsnwprintf(buf, size, format, args); |
76 | // (v)swprintf is expected to return -1 on truncation, so we only need to ensure the output is null-terminated |
77 | if (static_cast< unsigned int >(res) >= size) |
78 | { |
79 | buf[size - 1u] = L'\0'; |
80 | res = -1; |
81 | } |
82 | |
83 | return res; |
84 | #endif |
85 | } |
86 | |
87 | #elif defined(BOOST_CORE_DETAIL_MSVC_LEGACY_SNPRINTF) |
88 | |
89 | #if defined(_MSC_VER) |
90 | #pragma warning(push) |
91 | // '_vsnprintf': This function or variable may be unsafe. Consider using _vsnprintf_s instead. |
92 | #pragma warning(disable: 4996) |
93 | #endif |
94 | |
95 | inline int vsnprintf(char* buf, std::size_t size, const char* format, std::va_list args) |
96 | { |
97 | if (BOOST_UNLIKELY(size == 0u)) |
98 | return 0; |
99 | if (BOOST_UNLIKELY(size > static_cast< std::size_t >(INT_MAX))) |
100 | return -1; |
101 | |
102 | buf[size - 1u] = '\0'; |
103 | int res = _vsnprintf(buf, size, format, args); |
104 | if (static_cast< unsigned int >(res) >= size) |
105 | { |
106 | // _vsnprintf returns -1 if the output was truncated and in case of other errors. |
107 | // Detect truncation by checking whether the output buffer was written over entirely. |
108 | if (buf[size - 1u] != '\0') |
109 | { |
110 | buf[size - 1u] = '\0'; |
111 | res = static_cast< int >(size); |
112 | } |
113 | } |
114 | |
115 | return res; |
116 | } |
117 | |
118 | inline int vswprintf(wchar_t* buf, std::size_t size, const wchar_t* format, std::va_list args) |
119 | { |
120 | if (BOOST_UNLIKELY(size == 0u || size > static_cast< std::size_t >(INT_MAX))) |
121 | return -1; |
122 | |
123 | int res = _vsnwprintf(buf, size, format, args); |
124 | // (v)swprintf is expected to return -1 on truncation, so we only need to ensure the output is null-terminated |
125 | if (static_cast< unsigned int >(res) >= size) |
126 | { |
127 | buf[size - 1u] = L'\0'; |
128 | res = -1; |
129 | } |
130 | |
131 | return res; |
132 | } |
133 | |
134 | #if defined(_MSC_VER) |
135 | #pragma warning(pop) |
136 | #endif |
137 | |
138 | #endif |
139 | |
140 | inline int snprintf(char* buf, std::size_t size, const char* format, ...) |
141 | { |
142 | std::va_list args; |
143 | va_start(args, format); |
144 | int res = vsnprintf(buf, size, format, args); |
145 | va_end(args); |
146 | return res; |
147 | } |
148 | |
149 | inline int swprintf(wchar_t* buf, std::size_t size, const wchar_t* format, ...) |
150 | { |
151 | std::va_list args; |
152 | va_start(args, format); |
153 | int res = vswprintf(buf, size, format, args); |
154 | va_end(args); |
155 | return res; |
156 | } |
157 | |
158 | #else // defined(BOOST_CORE_DETAIL_MINGW_SNPRINTF) || defined(BOOST_CORE_DETAIL_MSVC_LEGACY_SNPRINTF) |
159 | |
160 | // Standard-conforming compilers already have the correct snprintfs |
161 | using ::snprintf; |
162 | using ::vsnprintf; |
163 | |
164 | using ::swprintf; |
165 | using ::vswprintf; |
166 | |
167 | #endif // defined(BOOST_CORE_DETAIL_MINGW_SNPRINTF) || defined(BOOST_CORE_DETAIL_MSVC_LEGACY_SNPRINTF) |
168 | |
169 | } // namespace core |
170 | |
171 | } // namespace boost |
172 | |
173 | #endif // BOOST_CORE_SNPRINTF_HPP_INCLUDED_ |
174 | |