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30586bf0 PP |
1 | // |
2 | // span for C++98 and later. | |
3 | // Based on http://wg21.link/p0122r7 | |
4 | // For more information see https://github.com/martinmoene/span-lite | |
5 | // | |
6 | // Copyright 2018-2021 Martin Moene | |
7 | // | |
8 | // Distributed under the Boost Software License, Version 1.0. | |
9 | // (See accompanying file LICENSE.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
10 | ||
11 | #ifndef NONSTD_SPAN_HPP_INCLUDED | |
12 | #define NONSTD_SPAN_HPP_INCLUDED | |
13 | ||
14 | #define span_lite_MAJOR 0 | |
15 | #define span_lite_MINOR 11 | |
16 | #define span_lite_PATCH 0 | |
17 | ||
18 | #define span_lite_VERSION span_STRINGIFY(span_lite_MAJOR) "." span_STRINGIFY(span_lite_MINOR) "." span_STRINGIFY(span_lite_PATCH) | |
19 | ||
20 | #define span_STRINGIFY( x ) span_STRINGIFY_( x ) | |
21 | #define span_STRINGIFY_( x ) #x | |
22 | ||
23 | // span configuration: | |
24 | ||
25 | #define span_SPAN_DEFAULT 0 | |
26 | #define span_SPAN_NONSTD 1 | |
27 | #define span_SPAN_STD 2 | |
28 | ||
29 | // tweak header support: | |
30 | ||
31 | #ifdef __has_include | |
32 | # if __has_include(<nonstd/span.tweak.hpp>) | |
33 | # include <nonstd/span.tweak.hpp> | |
34 | # endif | |
35 | #define span_HAVE_TWEAK_HEADER 1 | |
36 | #else | |
37 | #define span_HAVE_TWEAK_HEADER 0 | |
38 | //# pragma message("span.hpp: Note: Tweak header not supported.") | |
39 | #endif | |
40 | ||
41 | // span selection and configuration: | |
42 | ||
43 | #define span_HAVE( feature ) ( span_HAVE_##feature ) | |
44 | ||
45 | #ifndef span_CONFIG_SELECT_SPAN | |
46 | # define span_CONFIG_SELECT_SPAN ( span_HAVE_STD_SPAN ? span_SPAN_STD : span_SPAN_NONSTD ) | |
47 | #endif | |
48 | ||
49 | #ifndef span_CONFIG_EXTENT_TYPE | |
50 | # define span_CONFIG_EXTENT_TYPE std::size_t | |
51 | #endif | |
52 | ||
53 | #ifndef span_CONFIG_SIZE_TYPE | |
54 | # define span_CONFIG_SIZE_TYPE std::size_t | |
55 | #endif | |
56 | ||
57 | #ifdef span_CONFIG_INDEX_TYPE | |
58 | # error `span_CONFIG_INDEX_TYPE` is deprecated since v0.7.0; it is replaced by `span_CONFIG_SIZE_TYPE`. | |
59 | #endif | |
60 | ||
61 | // span configuration (features): | |
62 | ||
63 | #ifndef span_FEATURE_WITH_INITIALIZER_LIST_P2447 | |
64 | # define span_FEATURE_WITH_INITIALIZER_LIST_P2447 0 | |
65 | #endif | |
66 | ||
67 | #ifndef span_FEATURE_WITH_CONTAINER | |
68 | #ifdef span_FEATURE_WITH_CONTAINER_TO_STD | |
69 | # define span_FEATURE_WITH_CONTAINER span_IN_STD( span_FEATURE_WITH_CONTAINER_TO_STD ) | |
70 | #else | |
71 | # define span_FEATURE_WITH_CONTAINER 0 | |
72 | # define span_FEATURE_WITH_CONTAINER_TO_STD 0 | |
73 | #endif | |
74 | #endif | |
75 | ||
76 | #ifndef span_FEATURE_CONSTRUCTION_FROM_STDARRAY_ELEMENT_TYPE | |
77 | # define span_FEATURE_CONSTRUCTION_FROM_STDARRAY_ELEMENT_TYPE 0 | |
78 | #endif | |
79 | ||
80 | #ifndef span_FEATURE_MEMBER_AT | |
81 | # define span_FEATURE_MEMBER_AT 0 | |
82 | #endif | |
83 | ||
84 | #ifndef span_FEATURE_MEMBER_BACK_FRONT | |
85 | # define span_FEATURE_MEMBER_BACK_FRONT 1 | |
86 | #endif | |
87 | ||
88 | #ifndef span_FEATURE_MEMBER_CALL_OPERATOR | |
89 | # define span_FEATURE_MEMBER_CALL_OPERATOR 0 | |
90 | #endif | |
91 | ||
92 | #ifndef span_FEATURE_MEMBER_SWAP | |
93 | # define span_FEATURE_MEMBER_SWAP 0 | |
94 | #endif | |
95 | ||
96 | #ifndef span_FEATURE_NON_MEMBER_FIRST_LAST_SUB | |
97 | # define span_FEATURE_NON_MEMBER_FIRST_LAST_SUB 0 | |
98 | #elif span_FEATURE_NON_MEMBER_FIRST_LAST_SUB | |
99 | # define span_FEATURE_NON_MEMBER_FIRST_LAST_SUB_SPAN 1 | |
100 | # define span_FEATURE_NON_MEMBER_FIRST_LAST_SUB_CONTAINER 1 | |
101 | #endif | |
102 | ||
103 | #ifndef span_FEATURE_NON_MEMBER_FIRST_LAST_SUB_SPAN | |
104 | # define span_FEATURE_NON_MEMBER_FIRST_LAST_SUB_SPAN 0 | |
105 | #endif | |
106 | ||
107 | #ifndef span_FEATURE_NON_MEMBER_FIRST_LAST_SUB_CONTAINER | |
108 | # define span_FEATURE_NON_MEMBER_FIRST_LAST_SUB_CONTAINER 0 | |
109 | #endif | |
110 | ||
111 | #ifndef span_FEATURE_COMPARISON | |
112 | # define span_FEATURE_COMPARISON 0 // Note: C++20 does not provide comparison | |
113 | #endif | |
114 | ||
115 | #ifndef span_FEATURE_SAME | |
116 | # define span_FEATURE_SAME 0 | |
117 | #endif | |
118 | ||
119 | #if span_FEATURE_SAME && !span_FEATURE_COMPARISON | |
120 | # error `span_FEATURE_SAME` requires `span_FEATURE_COMPARISON` | |
121 | #endif | |
122 | ||
123 | #ifndef span_FEATURE_MAKE_SPAN | |
124 | #ifdef span_FEATURE_MAKE_SPAN_TO_STD | |
125 | # define span_FEATURE_MAKE_SPAN span_IN_STD( span_FEATURE_MAKE_SPAN_TO_STD ) | |
126 | #else | |
127 | # define span_FEATURE_MAKE_SPAN 0 | |
128 | # define span_FEATURE_MAKE_SPAN_TO_STD 0 | |
129 | #endif | |
130 | #endif | |
131 | ||
132 | #ifndef span_FEATURE_BYTE_SPAN | |
133 | # define span_FEATURE_BYTE_SPAN 0 | |
134 | #endif | |
135 | ||
136 | // Control presence of exception handling (try and auto discover): | |
137 | ||
138 | #ifndef span_CONFIG_NO_EXCEPTIONS | |
139 | # if defined(_MSC_VER) | |
140 | # include <cstddef> // for _HAS_EXCEPTIONS | |
141 | # endif | |
142 | # if defined(__cpp_exceptions) || defined(__EXCEPTIONS) || (_HAS_EXCEPTIONS) | |
143 | # define span_CONFIG_NO_EXCEPTIONS 0 | |
144 | # else | |
145 | # define span_CONFIG_NO_EXCEPTIONS 1 | |
146 | # undef span_CONFIG_CONTRACT_VIOLATION_THROWS | |
147 | # undef span_CONFIG_CONTRACT_VIOLATION_TERMINATES | |
148 | # define span_CONFIG_CONTRACT_VIOLATION_THROWS 0 | |
149 | # define span_CONFIG_CONTRACT_VIOLATION_TERMINATES 1 | |
150 | # endif | |
151 | #endif | |
152 | ||
153 | // Control pre- and postcondition violation behaviour: | |
154 | ||
155 | #if defined( span_CONFIG_CONTRACT_LEVEL_ON ) | |
156 | # define span_CONFIG_CONTRACT_LEVEL_MASK 0x11 | |
157 | #elif defined( span_CONFIG_CONTRACT_LEVEL_OFF ) | |
158 | # define span_CONFIG_CONTRACT_LEVEL_MASK 0x00 | |
159 | #elif defined( span_CONFIG_CONTRACT_LEVEL_EXPECTS_ONLY ) | |
160 | # define span_CONFIG_CONTRACT_LEVEL_MASK 0x01 | |
161 | #elif defined( span_CONFIG_CONTRACT_LEVEL_ENSURES_ONLY ) | |
162 | # define span_CONFIG_CONTRACT_LEVEL_MASK 0x10 | |
163 | #else | |
164 | # define span_CONFIG_CONTRACT_LEVEL_MASK 0x11 | |
165 | #endif | |
166 | ||
167 | #if defined( span_CONFIG_CONTRACT_VIOLATION_THROWS ) | |
168 | # define span_CONFIG_CONTRACT_VIOLATION_THROWS_V span_CONFIG_CONTRACT_VIOLATION_THROWS | |
169 | #else | |
170 | # define span_CONFIG_CONTRACT_VIOLATION_THROWS_V 0 | |
171 | #endif | |
172 | ||
173 | #if defined( span_CONFIG_CONTRACT_VIOLATION_THROWS ) && span_CONFIG_CONTRACT_VIOLATION_THROWS && \ | |
174 | defined( span_CONFIG_CONTRACT_VIOLATION_TERMINATES ) && span_CONFIG_CONTRACT_VIOLATION_TERMINATES | |
175 | # error Please define none or one of span_CONFIG_CONTRACT_VIOLATION_THROWS and span_CONFIG_CONTRACT_VIOLATION_TERMINATES to 1, but not both. | |
176 | #endif | |
177 | ||
178 | // C++ language version detection (C++23 is speculative): | |
179 | // Note: VC14.0/1900 (VS2015) lacks too much from C++14. | |
180 | ||
181 | #ifndef span_CPLUSPLUS | |
182 | # if defined(_MSVC_LANG ) && !defined(__clang__) | |
183 | # define span_CPLUSPLUS (_MSC_VER == 1900 ? 201103L : _MSVC_LANG ) | |
184 | # else | |
185 | # define span_CPLUSPLUS __cplusplus | |
186 | # endif | |
187 | #endif | |
188 | ||
189 | #define span_CPP98_OR_GREATER ( span_CPLUSPLUS >= 199711L ) | |
190 | #define span_CPP11_OR_GREATER ( span_CPLUSPLUS >= 201103L ) | |
191 | #define span_CPP14_OR_GREATER ( span_CPLUSPLUS >= 201402L ) | |
192 | #define span_CPP17_OR_GREATER ( span_CPLUSPLUS >= 201703L ) | |
193 | #define span_CPP20_OR_GREATER ( span_CPLUSPLUS >= 202002L ) | |
194 | #define span_CPP23_OR_GREATER ( span_CPLUSPLUS >= 202300L ) | |
195 | ||
196 | // C++ language version (represent 98 as 3): | |
197 | ||
198 | #define span_CPLUSPLUS_V ( span_CPLUSPLUS / 100 - (span_CPLUSPLUS > 200000 ? 2000 : 1994) ) | |
199 | ||
200 | #define span_IN_STD( v ) ( ((v) == 98 ? 3 : (v)) >= span_CPLUSPLUS_V ) | |
201 | ||
202 | #define span_CONFIG( feature ) ( span_CONFIG_##feature ) | |
203 | #define span_FEATURE( feature ) ( span_FEATURE_##feature ) | |
204 | #define span_FEATURE_TO_STD( feature ) ( span_IN_STD( span_FEATURE( feature##_TO_STD ) ) ) | |
205 | ||
206 | // Use C++20 std::span if available and requested: | |
207 | ||
208 | #if span_CPP20_OR_GREATER && defined(__has_include ) | |
209 | # if __has_include( <span> ) | |
210 | # define span_HAVE_STD_SPAN 1 | |
211 | # else | |
212 | # define span_HAVE_STD_SPAN 0 | |
213 | # endif | |
214 | #else | |
215 | # define span_HAVE_STD_SPAN 0 | |
216 | #endif | |
217 | ||
218 | #define span_USES_STD_SPAN ( (span_CONFIG_SELECT_SPAN == span_SPAN_STD) || ((span_CONFIG_SELECT_SPAN == span_SPAN_DEFAULT) && span_HAVE_STD_SPAN) ) | |
219 | ||
220 | // | |
221 | // Use C++20 std::span: | |
222 | // | |
223 | ||
224 | #if span_USES_STD_SPAN | |
225 | ||
226 | #include <span> | |
227 | ||
228 | namespace nonstd { | |
229 | ||
230 | using std::span; | |
231 | using std::dynamic_extent; | |
232 | ||
233 | // Note: C++20 does not provide comparison | |
234 | // using std::operator==; | |
235 | // using std::operator!=; | |
236 | // using std::operator<; | |
237 | // using std::operator<=; | |
238 | // using std::operator>; | |
239 | // using std::operator>=; | |
240 | } // namespace nonstd | |
241 | ||
242 | #else // span_USES_STD_SPAN | |
243 | ||
244 | #include <algorithm> | |
245 | ||
246 | // Compiler versions: | |
247 | // | |
248 | // MSVC++ 6.0 _MSC_VER == 1200 span_COMPILER_MSVC_VERSION == 60 (Visual Studio 6.0) | |
249 | // MSVC++ 7.0 _MSC_VER == 1300 span_COMPILER_MSVC_VERSION == 70 (Visual Studio .NET 2002) | |
250 | // MSVC++ 7.1 _MSC_VER == 1310 span_COMPILER_MSVC_VERSION == 71 (Visual Studio .NET 2003) | |
251 | // MSVC++ 8.0 _MSC_VER == 1400 span_COMPILER_MSVC_VERSION == 80 (Visual Studio 2005) | |
252 | // MSVC++ 9.0 _MSC_VER == 1500 span_COMPILER_MSVC_VERSION == 90 (Visual Studio 2008) | |
253 | // MSVC++ 10.0 _MSC_VER == 1600 span_COMPILER_MSVC_VERSION == 100 (Visual Studio 2010) | |
254 | // MSVC++ 11.0 _MSC_VER == 1700 span_COMPILER_MSVC_VERSION == 110 (Visual Studio 2012) | |
255 | // MSVC++ 12.0 _MSC_VER == 1800 span_COMPILER_MSVC_VERSION == 120 (Visual Studio 2013) | |
256 | // MSVC++ 14.0 _MSC_VER == 1900 span_COMPILER_MSVC_VERSION == 140 (Visual Studio 2015) | |
257 | // MSVC++ 14.1 _MSC_VER >= 1910 span_COMPILER_MSVC_VERSION == 141 (Visual Studio 2017) | |
258 | // MSVC++ 14.2 _MSC_VER >= 1920 span_COMPILER_MSVC_VERSION == 142 (Visual Studio 2019) | |
259 | ||
260 | #if defined(_MSC_VER ) && !defined(__clang__) | |
261 | # define span_COMPILER_MSVC_VER (_MSC_VER ) | |
262 | # define span_COMPILER_MSVC_VERSION (_MSC_VER / 10 - 10 * ( 5 + (_MSC_VER < 1900 ) ) ) | |
263 | #else | |
264 | # define span_COMPILER_MSVC_VER 0 | |
265 | # define span_COMPILER_MSVC_VERSION 0 | |
266 | #endif | |
267 | ||
268 | #define span_COMPILER_VERSION( major, minor, patch ) ( 10 * ( 10 * (major) + (minor) ) + (patch) ) | |
269 | ||
270 | #if defined(__clang__) | |
271 | # define span_COMPILER_CLANG_VERSION span_COMPILER_VERSION(__clang_major__, __clang_minor__, __clang_patchlevel__) | |
272 | #else | |
273 | # define span_COMPILER_CLANG_VERSION 0 | |
274 | #endif | |
275 | ||
276 | #if defined(__GNUC__) && !defined(__clang__) | |
277 | # define span_COMPILER_GNUC_VERSION span_COMPILER_VERSION(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__) | |
278 | #else | |
279 | # define span_COMPILER_GNUC_VERSION 0 | |
280 | #endif | |
281 | ||
282 | // half-open range [lo..hi): | |
283 | #define span_BETWEEN( v, lo, hi ) ( (lo) <= (v) && (v) < (hi) ) | |
284 | ||
285 | // Compiler warning suppression: | |
286 | ||
287 | #if defined(__clang__) | |
288 | # pragma clang diagnostic push | |
289 | # pragma clang diagnostic ignored "-Wundef" | |
290 | # pragma clang diagnostic ignored "-Wmismatched-tags" | |
291 | # define span_RESTORE_WARNINGS() _Pragma( "clang diagnostic pop" ) | |
292 | ||
293 | #elif defined __GNUC__ | |
294 | # pragma GCC diagnostic push | |
295 | # pragma GCC diagnostic ignored "-Wundef" | |
296 | # define span_RESTORE_WARNINGS() _Pragma( "GCC diagnostic pop" ) | |
297 | ||
298 | #elif span_COMPILER_MSVC_VER >= 1900 | |
299 | # define span_DISABLE_MSVC_WARNINGS(codes) __pragma(warning(push)) __pragma(warning(disable: codes)) | |
300 | # define span_RESTORE_WARNINGS() __pragma(warning(pop )) | |
301 | ||
302 | // Suppress the following MSVC GSL warnings: | |
303 | // - C26439, gsl::f.6 : special function 'function' can be declared 'noexcept' | |
304 | // - C26440, gsl::f.6 : function 'function' can be declared 'noexcept' | |
305 | // - C26472, gsl::t.1 : don't use a static_cast for arithmetic conversions; | |
306 | // use brace initialization, gsl::narrow_cast or gsl::narrow | |
307 | // - C26473: gsl::t.1 : don't cast between pointer types where the source type and the target type are the same | |
308 | // - C26481: gsl::b.1 : don't use pointer arithmetic. Use span instead | |
309 | // - C26490: gsl::t.1 : don't use reinterpret_cast | |
310 | ||
311 | span_DISABLE_MSVC_WARNINGS( 26439 26440 26472 26473 26481 26490 ) | |
312 | ||
313 | #else | |
314 | # define span_RESTORE_WARNINGS() /*empty*/ | |
315 | #endif | |
316 | ||
317 | // Presence of language and library features: | |
318 | ||
319 | #ifdef _HAS_CPP0X | |
320 | # define span_HAS_CPP0X _HAS_CPP0X | |
321 | #else | |
322 | # define span_HAS_CPP0X 0 | |
323 | #endif | |
324 | ||
325 | #define span_CPP11_80 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1400) | |
326 | #define span_CPP11_90 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1500) | |
327 | #define span_CPP11_100 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1600) | |
328 | #define span_CPP11_110 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1700) | |
329 | #define span_CPP11_120 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1800) | |
330 | #define span_CPP11_140 (span_CPP11_OR_GREATER || span_COMPILER_MSVC_VER >= 1900) | |
331 | ||
332 | #define span_CPP14_000 (span_CPP14_OR_GREATER) | |
333 | #define span_CPP14_120 (span_CPP14_OR_GREATER || span_COMPILER_MSVC_VER >= 1800) | |
334 | #define span_CPP14_140 (span_CPP14_OR_GREATER || span_COMPILER_MSVC_VER >= 1900) | |
335 | ||
336 | #define span_CPP17_000 (span_CPP17_OR_GREATER) | |
337 | ||
338 | // Presence of C++11 language features: | |
339 | ||
340 | #define span_HAVE_ALIAS_TEMPLATE span_CPP11_140 | |
341 | #define span_HAVE_AUTO span_CPP11_100 | |
342 | #define span_HAVE_CONSTEXPR_11 span_CPP11_140 | |
343 | #define span_HAVE_DEFAULT_FUNCTION_TEMPLATE_ARG span_CPP11_120 | |
344 | #define span_HAVE_EXPLICIT_CONVERSION span_CPP11_140 | |
345 | #define span_HAVE_INITIALIZER_LIST span_CPP11_120 | |
346 | #define span_HAVE_IS_DEFAULT span_CPP11_140 | |
347 | #define span_HAVE_IS_DELETE span_CPP11_140 | |
348 | #define span_HAVE_NOEXCEPT span_CPP11_140 | |
349 | #define span_HAVE_NORETURN ( span_CPP11_140 && ! span_BETWEEN( span_COMPILER_GNUC_VERSION, 1, 480 ) ) | |
350 | #define span_HAVE_NULLPTR span_CPP11_100 | |
351 | #define span_HAVE_STATIC_ASSERT span_CPP11_100 | |
352 | ||
353 | // Presence of C++14 language features: | |
354 | ||
355 | #define span_HAVE_CONSTEXPR_14 span_CPP14_000 | |
356 | ||
357 | // Presence of C++17 language features: | |
358 | ||
359 | #define span_HAVE_DEPRECATED span_CPP17_000 | |
360 | #define span_HAVE_NODISCARD span_CPP17_000 | |
361 | ||
362 | // MSVC: template parameter deduction guides since Visual Studio 2017 v15.7 | |
363 | ||
364 | #if defined(__cpp_deduction_guides) | |
365 | # define span_HAVE_DEDUCTION_GUIDES 1 | |
366 | #else | |
367 | # define span_HAVE_DEDUCTION_GUIDES (span_CPP17_OR_GREATER && ! span_BETWEEN( span_COMPILER_MSVC_VER, 1, 1913 )) | |
368 | #endif | |
369 | ||
370 | // Presence of C++ library features: | |
371 | ||
372 | #define span_HAVE_ADDRESSOF span_CPP17_000 | |
373 | #define span_HAVE_ARRAY span_CPP11_110 | |
374 | #define span_HAVE_BYTE span_CPP17_000 | |
375 | #define span_HAVE_CONDITIONAL span_CPP11_120 | |
376 | #define span_HAVE_CONTAINER_DATA_METHOD (span_CPP11_140 || ( span_COMPILER_MSVC_VER >= 1500 && span_HAS_CPP0X )) | |
377 | #define span_HAVE_DATA span_CPP17_000 | |
378 | #define span_HAVE_LONGLONG span_CPP11_80 | |
379 | #define span_HAVE_REMOVE_CONST span_CPP11_110 | |
380 | #define span_HAVE_SNPRINTF span_CPP11_140 | |
381 | #define span_HAVE_STRUCT_BINDING span_CPP11_120 | |
382 | #define span_HAVE_TYPE_TRAITS span_CPP11_90 | |
383 | ||
384 | // Presence of byte-lite: | |
385 | ||
386 | #ifdef NONSTD_BYTE_LITE_HPP | |
387 | # define span_HAVE_NONSTD_BYTE 1 | |
388 | #else | |
389 | # define span_HAVE_NONSTD_BYTE 0 | |
390 | #endif | |
391 | ||
392 | // C++ feature usage: | |
393 | ||
394 | #if span_HAVE_ADDRESSOF | |
395 | # define span_ADDRESSOF(x) std::addressof(x) | |
396 | #else | |
397 | # define span_ADDRESSOF(x) (&x) | |
398 | #endif | |
399 | ||
400 | #if span_HAVE_CONSTEXPR_11 | |
401 | # define span_constexpr constexpr | |
402 | #else | |
403 | # define span_constexpr /*span_constexpr*/ | |
404 | #endif | |
405 | ||
406 | #if span_HAVE_CONSTEXPR_14 | |
407 | # define span_constexpr14 constexpr | |
408 | #else | |
409 | # define span_constexpr14 /*span_constexpr*/ | |
410 | #endif | |
411 | ||
412 | #if span_HAVE_EXPLICIT_CONVERSION | |
413 | # define span_explicit explicit | |
414 | #else | |
415 | # define span_explicit /*explicit*/ | |
416 | #endif | |
417 | ||
418 | #if span_HAVE_IS_DELETE | |
419 | # define span_is_delete = delete | |
420 | #else | |
421 | # define span_is_delete | |
422 | #endif | |
423 | ||
424 | #if span_HAVE_IS_DELETE | |
425 | # define span_is_delete_access public | |
426 | #else | |
427 | # define span_is_delete_access private | |
428 | #endif | |
429 | ||
430 | #if span_HAVE_NOEXCEPT && ! span_CONFIG_CONTRACT_VIOLATION_THROWS_V | |
431 | # define span_noexcept noexcept | |
432 | #else | |
433 | # define span_noexcept /*noexcept*/ | |
434 | #endif | |
435 | ||
436 | #if span_HAVE_NULLPTR | |
437 | # define span_nullptr nullptr | |
438 | #else | |
439 | # define span_nullptr NULL | |
440 | #endif | |
441 | ||
442 | #if span_HAVE_DEPRECATED | |
443 | # define span_deprecated(msg) [[deprecated(msg)]] | |
444 | #else | |
445 | # define span_deprecated(msg) /*[[deprecated]]*/ | |
446 | #endif | |
447 | ||
448 | #if span_HAVE_NODISCARD | |
449 | # define span_nodiscard [[nodiscard]] | |
450 | #else | |
451 | # define span_nodiscard /*[[nodiscard]]*/ | |
452 | #endif | |
453 | ||
454 | #if span_HAVE_NORETURN | |
455 | # define span_noreturn [[noreturn]] | |
456 | #else | |
457 | # define span_noreturn /*[[noreturn]]*/ | |
458 | #endif | |
459 | ||
460 | // Other features: | |
461 | ||
462 | #define span_HAVE_CONSTRAINED_SPAN_CONTAINER_CTOR span_HAVE_DEFAULT_FUNCTION_TEMPLATE_ARG | |
463 | #define span_HAVE_ITERATOR_CTOR span_HAVE_DEFAULT_FUNCTION_TEMPLATE_ARG | |
464 | ||
465 | // Additional includes: | |
466 | ||
467 | #if span_HAVE( ADDRESSOF ) | |
468 | # include <memory> | |
469 | #endif | |
470 | ||
471 | #if span_HAVE( ARRAY ) | |
472 | # include <array> | |
473 | #endif | |
474 | ||
475 | #if span_HAVE( BYTE ) | |
476 | # include <cstddef> | |
477 | #endif | |
478 | ||
479 | #if span_HAVE( DATA ) | |
480 | # include <iterator> // for std::data(), std::size() | |
481 | #endif | |
482 | ||
483 | #if span_HAVE( TYPE_TRAITS ) | |
484 | # include <type_traits> | |
485 | #endif | |
486 | ||
487 | #if ! span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR ) | |
488 | # include <vector> | |
489 | #endif | |
490 | ||
491 | #if span_FEATURE( MEMBER_AT ) > 1 | |
492 | # include <cstdio> | |
493 | #endif | |
494 | ||
495 | #if ! span_CONFIG( NO_EXCEPTIONS ) | |
496 | # include <stdexcept> | |
497 | #endif | |
498 | ||
499 | // Contract violation | |
500 | ||
501 | #define span_ELIDE_CONTRACT_EXPECTS ( 0 == ( span_CONFIG_CONTRACT_LEVEL_MASK & 0x01 ) ) | |
502 | #define span_ELIDE_CONTRACT_ENSURES ( 0 == ( span_CONFIG_CONTRACT_LEVEL_MASK & 0x10 ) ) | |
503 | ||
504 | #if span_ELIDE_CONTRACT_EXPECTS | |
505 | # define span_constexpr_exp span_constexpr | |
506 | # define span_EXPECTS( cond ) /* Expect elided */ | |
507 | #else | |
508 | # define span_constexpr_exp span_constexpr14 | |
509 | # define span_EXPECTS( cond ) span_CONTRACT_CHECK( "Precondition", cond ) | |
510 | #endif | |
511 | ||
512 | #if span_ELIDE_CONTRACT_ENSURES | |
513 | # define span_constexpr_ens span_constexpr | |
514 | # define span_ENSURES( cond ) /* Ensures elided */ | |
515 | #else | |
516 | # define span_constexpr_ens span_constexpr14 | |
517 | # define span_ENSURES( cond ) span_CONTRACT_CHECK( "Postcondition", cond ) | |
518 | #endif | |
519 | ||
520 | #define span_CONTRACT_CHECK( type, cond ) \ | |
521 | cond ? static_cast< void >( 0 ) \ | |
522 | : nonstd::span_lite::detail::report_contract_violation( span_LOCATION( __FILE__, __LINE__ ) ": " type " violation." ) | |
523 | ||
524 | #ifdef __GNUG__ | |
525 | # define span_LOCATION( file, line ) file ":" span_STRINGIFY( line ) | |
526 | #else | |
527 | # define span_LOCATION( file, line ) file "(" span_STRINGIFY( line ) ")" | |
528 | #endif | |
529 | ||
530 | // Method enabling | |
531 | ||
532 | #if span_HAVE( DEFAULT_FUNCTION_TEMPLATE_ARG ) | |
533 | ||
534 | #define span_REQUIRES_0(VA) \ | |
535 | template< bool B = (VA), typename std::enable_if<B, int>::type = 0 > | |
536 | ||
537 | # if span_BETWEEN( span_COMPILER_MSVC_VERSION, 1, 140 ) | |
538 | // VS 2013 and earlier seem to have trouble with SFINAE for default non-type arguments | |
539 | # define span_REQUIRES_T(VA) \ | |
540 | , typename = typename std::enable_if< ( VA ), nonstd::span_lite::detail::enabler >::type | |
541 | # else | |
542 | # define span_REQUIRES_T(VA) \ | |
543 | , typename std::enable_if< (VA), int >::type = 0 | |
544 | # endif | |
545 | ||
546 | #define span_REQUIRES_R(R, VA) \ | |
547 | typename std::enable_if< (VA), R>::type | |
548 | ||
549 | #define span_REQUIRES_A(VA) \ | |
550 | , typename std::enable_if< (VA), void*>::type = nullptr | |
551 | ||
552 | #else | |
553 | ||
554 | # define span_REQUIRES_0(VA) /*empty*/ | |
555 | # define span_REQUIRES_T(VA) /*empty*/ | |
556 | # define span_REQUIRES_R(R, VA) R | |
557 | # define span_REQUIRES_A(VA) /*empty*/ | |
558 | ||
559 | #endif | |
560 | ||
561 | namespace nonstd { | |
562 | namespace span_lite { | |
563 | ||
564 | // [views.constants], constants | |
565 | ||
566 | typedef span_CONFIG_EXTENT_TYPE extent_t; | |
567 | typedef span_CONFIG_SIZE_TYPE size_t; | |
568 | ||
569 | span_constexpr const extent_t dynamic_extent = static_cast<extent_t>( -1 ); | |
570 | ||
571 | template< class T, extent_t Extent = dynamic_extent > | |
572 | class span; | |
573 | ||
574 | // Tag to select span constructor taking a container (prevent ms-gsl warning C26426): | |
575 | ||
576 | struct with_container_t { span_constexpr with_container_t() span_noexcept {} }; | |
577 | const span_constexpr with_container_t with_container; | |
578 | ||
579 | // C++11 emulation: | |
580 | ||
581 | namespace std11 { | |
582 | ||
583 | #if span_HAVE( REMOVE_CONST ) | |
584 | ||
585 | using std::remove_cv; | |
586 | using std::remove_const; | |
587 | using std::remove_volatile; | |
588 | ||
589 | #else | |
590 | ||
591 | template< class T > struct remove_const { typedef T type; }; | |
592 | template< class T > struct remove_const< T const > { typedef T type; }; | |
593 | ||
594 | template< class T > struct remove_volatile { typedef T type; }; | |
595 | template< class T > struct remove_volatile< T volatile > { typedef T type; }; | |
596 | ||
597 | template< class T > | |
598 | struct remove_cv | |
599 | { | |
600 | typedef typename std11::remove_volatile< typename std11::remove_const< T >::type >::type type; | |
601 | }; | |
602 | ||
603 | #endif // span_HAVE( REMOVE_CONST ) | |
604 | ||
605 | #if span_HAVE( TYPE_TRAITS ) | |
606 | ||
607 | using std::is_same; | |
608 | using std::is_signed; | |
609 | using std::integral_constant; | |
610 | using std::true_type; | |
611 | using std::false_type; | |
612 | using std::remove_reference; | |
613 | ||
614 | #else | |
615 | ||
616 | template< class T, T v > struct integral_constant { enum { value = v }; }; | |
617 | typedef integral_constant< bool, true > true_type; | |
618 | typedef integral_constant< bool, false > false_type; | |
619 | ||
620 | template< class T, class U > struct is_same : false_type{}; | |
621 | template< class T > struct is_same<T, T> : true_type{}; | |
622 | ||
623 | template< typename T > struct is_signed : false_type {}; | |
624 | template<> struct is_signed<signed char> : true_type {}; | |
625 | template<> struct is_signed<signed int > : true_type {}; | |
626 | template<> struct is_signed<signed long> : true_type {}; | |
627 | ||
628 | #endif | |
629 | ||
630 | } // namespace std11 | |
631 | ||
632 | // C++17 emulation: | |
633 | ||
634 | namespace std17 { | |
635 | ||
636 | template< bool v > struct bool_constant : std11::integral_constant<bool, v>{}; | |
637 | ||
638 | #if span_CPP11_120 | |
639 | ||
640 | template< class...> | |
641 | using void_t = void; | |
642 | ||
643 | #endif | |
644 | ||
645 | #if span_HAVE( DATA ) | |
646 | ||
647 | using std::data; | |
648 | using std::size; | |
649 | ||
650 | #elif span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR ) | |
651 | ||
652 | template< typename T, std::size_t N > | |
653 | inline span_constexpr auto size( const T(&)[N] ) span_noexcept -> size_t | |
654 | { | |
655 | return N; | |
656 | } | |
657 | ||
658 | template< typename C > | |
659 | inline span_constexpr auto size( C const & cont ) -> decltype( cont.size() ) | |
660 | { | |
661 | return cont.size(); | |
662 | } | |
663 | ||
664 | template< typename T, std::size_t N > | |
665 | inline span_constexpr auto data( T(&arr)[N] ) span_noexcept -> T* | |
666 | { | |
667 | return &arr[0]; | |
668 | } | |
669 | ||
670 | template< typename C > | |
671 | inline span_constexpr auto data( C & cont ) -> decltype( cont.data() ) | |
672 | { | |
673 | return cont.data(); | |
674 | } | |
675 | ||
676 | template< typename C > | |
677 | inline span_constexpr auto data( C const & cont ) -> decltype( cont.data() ) | |
678 | { | |
679 | return cont.data(); | |
680 | } | |
681 | ||
682 | template< typename E > | |
683 | inline span_constexpr auto data( std::initializer_list<E> il ) span_noexcept -> E const * | |
684 | { | |
685 | return il.begin(); | |
686 | } | |
687 | ||
688 | #endif // span_HAVE( DATA ) | |
689 | ||
690 | #if span_HAVE( BYTE ) | |
691 | using std::byte; | |
692 | #elif span_HAVE( NONSTD_BYTE ) | |
693 | using nonstd::byte; | |
694 | #endif | |
695 | ||
696 | } // namespace std17 | |
697 | ||
698 | // C++20 emulation: | |
699 | ||
700 | namespace std20 { | |
701 | ||
702 | #if span_HAVE( DEDUCTION_GUIDES ) | |
703 | template< class T > | |
704 | using iter_reference_t = decltype( *std::declval<T&>() ); | |
705 | #endif | |
706 | ||
707 | } // namespace std20 | |
708 | ||
709 | // Implementation details: | |
710 | ||
711 | namespace detail { | |
712 | ||
713 | /*enum*/ struct enabler{}; | |
714 | ||
715 | template< typename T > | |
716 | span_constexpr bool is_positive( T x ) | |
717 | { | |
718 | return std11::is_signed<T>::value ? x >= 0 : true; | |
719 | } | |
720 | ||
721 | #if span_HAVE( TYPE_TRAITS ) | |
722 | ||
723 | template< class Q > | |
724 | struct is_span_oracle : std::false_type{}; | |
725 | ||
726 | template< class T, span_CONFIG_EXTENT_TYPE Extent > | |
727 | struct is_span_oracle< span<T, Extent> > : std::true_type{}; | |
728 | ||
729 | template< class Q > | |
730 | struct is_span : is_span_oracle< typename std::remove_cv<Q>::type >{}; | |
731 | ||
732 | template< class Q > | |
733 | struct is_std_array_oracle : std::false_type{}; | |
734 | ||
735 | #if span_HAVE( ARRAY ) | |
736 | ||
737 | template< class T, std::size_t Extent > | |
738 | struct is_std_array_oracle< std::array<T, Extent> > : std::true_type{}; | |
739 | ||
740 | #endif | |
741 | ||
742 | template< class Q > | |
743 | struct is_std_array : is_std_array_oracle< typename std::remove_cv<Q>::type >{}; | |
744 | ||
745 | template< class Q > | |
746 | struct is_array : std::false_type {}; | |
747 | ||
748 | template< class T > | |
749 | struct is_array<T[]> : std::true_type {}; | |
750 | ||
751 | template< class T, std::size_t N > | |
752 | struct is_array<T[N]> : std::true_type {}; | |
753 | ||
754 | #if span_CPP11_140 && ! span_BETWEEN( span_COMPILER_GNUC_VERSION, 1, 500 ) | |
755 | ||
756 | template< class, class = void > | |
757 | struct has_size_and_data : std::false_type{}; | |
758 | ||
759 | template< class C > | |
760 | struct has_size_and_data | |
761 | < | |
762 | C, std17::void_t< | |
763 | decltype( std17::size(std::declval<C>()) ), | |
764 | decltype( std17::data(std::declval<C>()) ) > | |
765 | > : std::true_type{}; | |
766 | ||
767 | template< class, class, class = void > | |
768 | struct is_compatible_element : std::false_type {}; | |
769 | ||
770 | template< class C, class E > | |
771 | struct is_compatible_element | |
772 | < | |
773 | C, E, std17::void_t< | |
774 | decltype( std17::data(std::declval<C>()) ) > | |
775 | > : std::is_convertible< typename std::remove_pointer<decltype( std17::data( std::declval<C&>() ) )>::type(*)[], E(*)[] >{}; | |
776 | ||
777 | template< class C > | |
778 | struct is_container : std17::bool_constant | |
779 | < | |
780 | ! is_span< C >::value | |
781 | && ! is_array< C >::value | |
782 | && ! is_std_array< C >::value | |
783 | && has_size_and_data< C >::value | |
784 | >{}; | |
785 | ||
786 | template< class C, class E > | |
787 | struct is_compatible_container : std17::bool_constant | |
788 | < | |
789 | is_container<C>::value | |
790 | && is_compatible_element<C,E>::value | |
791 | >{}; | |
792 | ||
793 | #else // span_CPP11_140 | |
794 | ||
795 | template< | |
796 | class C, class E | |
797 | span_REQUIRES_T(( | |
798 | ! is_span< C >::value | |
799 | && ! is_array< C >::value | |
800 | && ! is_std_array< C >::value | |
801 | && ( std::is_convertible< typename std::remove_pointer<decltype( std17::data( std::declval<C&>() ) )>::type(*)[], E(*)[] >::value) | |
802 | // && has_size_and_data< C >::value | |
803 | )) | |
804 | , class = decltype( std17::size(std::declval<C>()) ) | |
805 | , class = decltype( std17::data(std::declval<C>()) ) | |
806 | > | |
807 | struct is_compatible_container : std::true_type{}; | |
808 | ||
809 | #endif // span_CPP11_140 | |
810 | ||
811 | #endif // span_HAVE( TYPE_TRAITS ) | |
812 | ||
813 | #if ! span_CONFIG( NO_EXCEPTIONS ) | |
814 | #if span_FEATURE( MEMBER_AT ) > 1 | |
815 | ||
816 | // format index and size: | |
817 | ||
818 | #if defined(__clang__) | |
819 | # pragma clang diagnostic ignored "-Wlong-long" | |
820 | #elif defined __GNUC__ | |
821 | # pragma GCC diagnostic ignored "-Wformat=ll" | |
822 | # pragma GCC diagnostic ignored "-Wlong-long" | |
823 | #endif | |
824 | ||
825 | span_noreturn inline void throw_out_of_range( size_t idx, size_t size ) | |
826 | { | |
827 | const char fmt[] = "span::at(): index '%lli' is out of range [0..%lli)"; | |
828 | char buffer[ 2 * 20 + sizeof fmt ]; | |
829 | sprintf( buffer, fmt, static_cast<long long>(idx), static_cast<long long>(size) ); | |
830 | ||
831 | throw std::out_of_range( buffer ); | |
832 | } | |
833 | ||
834 | #else // MEMBER_AT | |
835 | ||
836 | span_noreturn inline void throw_out_of_range( size_t /*idx*/, size_t /*size*/ ) | |
837 | { | |
838 | throw std::out_of_range( "span::at(): index outside span" ); | |
839 | } | |
840 | #endif // MEMBER_AT | |
841 | #endif // NO_EXCEPTIONS | |
842 | ||
843 | #if span_CONFIG( CONTRACT_VIOLATION_THROWS_V ) | |
844 | ||
845 | struct contract_violation : std::logic_error | |
846 | { | |
847 | explicit contract_violation( char const * const message ) | |
848 | : std::logic_error( message ) | |
849 | {} | |
850 | }; | |
851 | ||
852 | inline void report_contract_violation( char const * msg ) | |
853 | { | |
854 | throw contract_violation( msg ); | |
855 | } | |
856 | ||
857 | #else // span_CONFIG( CONTRACT_VIOLATION_THROWS_V ) | |
858 | ||
859 | span_noreturn inline void report_contract_violation( char const * /*msg*/ ) span_noexcept | |
860 | { | |
861 | std::terminate(); | |
862 | } | |
863 | ||
864 | #endif // span_CONFIG( CONTRACT_VIOLATION_THROWS_V ) | |
865 | ||
866 | } // namespace detail | |
867 | ||
868 | // Prevent signed-unsigned mismatch: | |
869 | ||
870 | #define span_sizeof(T) static_cast<extent_t>( sizeof(T) ) | |
871 | ||
872 | template< class T > | |
873 | inline span_constexpr size_t to_size( T size ) | |
874 | { | |
875 | return static_cast<size_t>( size ); | |
876 | } | |
877 | ||
878 | // | |
879 | // [views.span] - A view over a contiguous, single-dimension sequence of objects | |
880 | // | |
881 | template< class T, extent_t Extent /*= dynamic_extent*/ > | |
882 | class span | |
883 | { | |
884 | public: | |
885 | // constants and types | |
886 | ||
887 | typedef T element_type; | |
888 | typedef typename std11::remove_cv< T >::type value_type; | |
889 | ||
890 | typedef T & reference; | |
891 | typedef T * pointer; | |
892 | typedef T const * const_pointer; | |
893 | typedef T const & const_reference; | |
894 | ||
895 | typedef size_t size_type; | |
896 | typedef extent_t extent_type; | |
897 | ||
898 | typedef pointer iterator; | |
899 | typedef const_pointer const_iterator; | |
900 | ||
901 | typedef std::ptrdiff_t difference_type; | |
902 | ||
903 | typedef std::reverse_iterator< iterator > reverse_iterator; | |
904 | typedef std::reverse_iterator< const_iterator > const_reverse_iterator; | |
905 | ||
906 | // static constexpr extent_type extent = Extent; | |
907 | enum { extent = Extent }; | |
908 | ||
909 | // 26.7.3.2 Constructors, copy, and assignment [span.cons] | |
910 | ||
911 | span_REQUIRES_0( | |
912 | ( Extent == 0 ) || | |
913 | ( Extent == dynamic_extent ) | |
914 | ) | |
915 | span_constexpr span() span_noexcept | |
916 | : data_( span_nullptr ) | |
917 | , size_( 0 ) | |
918 | { | |
919 | // span_EXPECTS( data() == span_nullptr ); | |
920 | // span_EXPECTS( size() == 0 ); | |
921 | } | |
922 | ||
923 | #if span_HAVE( ITERATOR_CTOR ) | |
924 | // Didn't yet succeed in combining the next two constructors: | |
925 | ||
926 | span_constexpr_exp span( std::nullptr_t, size_type count ) | |
927 | : data_( span_nullptr ) | |
928 | , size_( count ) | |
929 | { | |
930 | span_EXPECTS( data_ == span_nullptr && count == 0 ); | |
931 | } | |
932 | ||
933 | template< typename It | |
934 | span_REQUIRES_T(( | |
935 | std::is_convertible<decltype(*std::declval<It&>()), element_type &>::value | |
936 | )) | |
937 | > | |
938 | span_constexpr_exp span( It first, size_type count ) | |
939 | : data_( to_address( first ) ) | |
940 | , size_( count ) | |
941 | { | |
942 | span_EXPECTS( | |
943 | ( data_ == span_nullptr && count == 0 ) || | |
944 | ( data_ != span_nullptr && detail::is_positive( count ) ) | |
945 | ); | |
946 | } | |
947 | #else | |
948 | span_constexpr_exp span( pointer ptr, size_type count ) | |
949 | : data_( ptr ) | |
950 | , size_( count ) | |
951 | { | |
952 | span_EXPECTS( | |
953 | ( ptr == span_nullptr && count == 0 ) || | |
954 | ( ptr != span_nullptr && detail::is_positive( count ) ) | |
955 | ); | |
956 | } | |
957 | #endif | |
958 | ||
959 | #if span_HAVE( ITERATOR_CTOR ) | |
960 | template< typename It, typename End | |
961 | span_REQUIRES_T(( | |
962 | std::is_convertible<decltype(&*std::declval<It&>()), element_type *>::value | |
963 | && ! std::is_convertible<End, std::size_t>::value | |
964 | )) | |
965 | > | |
966 | span_constexpr_exp span( It first, End last ) | |
967 | : data_( to_address( first ) ) | |
968 | , size_( to_size( last - first ) ) | |
969 | { | |
970 | span_EXPECTS( | |
971 | last - first >= 0 | |
972 | ); | |
973 | } | |
974 | #else | |
975 | span_constexpr_exp span( pointer first, pointer last ) | |
976 | : data_( first ) | |
977 | , size_( to_size( last - first ) ) | |
978 | { | |
979 | span_EXPECTS( | |
980 | last - first >= 0 | |
981 | ); | |
982 | } | |
983 | #endif | |
984 | ||
985 | template< std::size_t N | |
986 | span_REQUIRES_T(( | |
987 | (Extent == dynamic_extent || Extent == static_cast<extent_t>(N)) | |
988 | && std::is_convertible< value_type(*)[], element_type(*)[] >::value | |
989 | )) | |
990 | > | |
991 | span_constexpr span( element_type ( &arr )[ N ] ) span_noexcept | |
992 | : data_( span_ADDRESSOF( arr[0] ) ) | |
993 | , size_( N ) | |
994 | {} | |
995 | ||
996 | #if span_HAVE( ARRAY ) | |
997 | ||
998 | template< std::size_t N | |
999 | span_REQUIRES_T(( | |
1000 | (Extent == dynamic_extent || Extent == static_cast<extent_t>(N)) | |
1001 | && std::is_convertible< value_type(*)[], element_type(*)[] >::value | |
1002 | )) | |
1003 | > | |
1004 | # if span_FEATURE( CONSTRUCTION_FROM_STDARRAY_ELEMENT_TYPE ) | |
1005 | span_constexpr span( std::array< element_type, N > & arr ) span_noexcept | |
1006 | # else | |
1007 | span_constexpr span( std::array< value_type, N > & arr ) span_noexcept | |
1008 | # endif | |
1009 | : data_( arr.data() ) | |
1010 | , size_( to_size( arr.size() ) ) | |
1011 | {} | |
1012 | ||
1013 | template< std::size_t N | |
1014 | # if span_HAVE( DEFAULT_FUNCTION_TEMPLATE_ARG ) | |
1015 | span_REQUIRES_T(( | |
1016 | (Extent == dynamic_extent || Extent == static_cast<extent_t>(N)) | |
1017 | && std::is_convertible< value_type(*)[], element_type(*)[] >::value | |
1018 | )) | |
1019 | # endif | |
1020 | > | |
1021 | span_constexpr span( std::array< value_type, N> const & arr ) span_noexcept | |
1022 | : data_( arr.data() ) | |
1023 | , size_( to_size( arr.size() ) ) | |
1024 | {} | |
1025 | ||
1026 | #endif // span_HAVE( ARRAY ) | |
1027 | ||
1028 | #if span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR ) | |
1029 | template< class Container | |
1030 | span_REQUIRES_T(( | |
1031 | detail::is_compatible_container< Container, element_type >::value | |
1032 | )) | |
1033 | > | |
1034 | span_constexpr span( Container & cont ) | |
1035 | : data_( std17::data( cont ) ) | |
1036 | , size_( to_size( std17::size( cont ) ) ) | |
1037 | {} | |
1038 | ||
1039 | template< class Container | |
1040 | span_REQUIRES_T(( | |
1041 | std::is_const< element_type >::value | |
1042 | && detail::is_compatible_container< Container, element_type >::value | |
1043 | )) | |
1044 | > | |
1045 | span_constexpr span( Container const & cont ) | |
1046 | : data_( std17::data( cont ) ) | |
1047 | , size_( to_size( std17::size( cont ) ) ) | |
1048 | {} | |
1049 | ||
1050 | #endif // span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR ) | |
1051 | ||
1052 | #if span_FEATURE( WITH_CONTAINER ) | |
1053 | ||
1054 | template< class Container > | |
1055 | span_constexpr span( with_container_t, Container & cont ) | |
1056 | : data_( cont.size() == 0 ? span_nullptr : span_ADDRESSOF( cont[0] ) ) | |
1057 | , size_( to_size( cont.size() ) ) | |
1058 | {} | |
1059 | ||
1060 | template< class Container > | |
1061 | span_constexpr span( with_container_t, Container const & cont ) | |
1062 | : data_( cont.size() == 0 ? span_nullptr : const_cast<pointer>( span_ADDRESSOF( cont[0] ) ) ) | |
1063 | , size_( to_size( cont.size() ) ) | |
1064 | {} | |
1065 | #endif | |
1066 | ||
1067 | #if span_FEATURE( WITH_INITIALIZER_LIST_P2447 ) && span_HAVE( INITIALIZER_LIST ) | |
1068 | ||
1069 | // constexpr explicit(extent != dynamic_extent) span(std::initializer_list<value_type> il) noexcept; | |
1070 | ||
1071 | #if !span_BETWEEN( span_COMPILER_MSVC_VERSION, 120, 130 ) | |
1072 | ||
1073 | template< extent_t U = Extent | |
1074 | span_REQUIRES_T(( | |
1075 | U != dynamic_extent | |
1076 | )) | |
1077 | > | |
1078 | #if span_COMPILER_GNUC_VERSION >= 900 // prevent GCC's "-Winit-list-lifetime" | |
1079 | span_constexpr14 explicit span( std::initializer_list<value_type> il ) span_noexcept | |
1080 | { | |
1081 | data_ = il.begin(); | |
1082 | size_ = il.size(); | |
1083 | } | |
1084 | #else | |
1085 | span_constexpr explicit span( std::initializer_list<value_type> il ) span_noexcept | |
1086 | : data_( il.begin() ) | |
1087 | , size_( il.size() ) | |
1088 | {} | |
1089 | #endif | |
1090 | ||
1091 | #endif // MSVC 120 (VS2013) | |
1092 | ||
1093 | template< extent_t U = Extent | |
1094 | span_REQUIRES_T(( | |
1095 | U == dynamic_extent | |
1096 | )) | |
1097 | > | |
1098 | #if span_COMPILER_GNUC_VERSION >= 900 // prevent GCC's "-Winit-list-lifetime" | |
1099 | span_constexpr14 /*explicit*/ span( std::initializer_list<value_type> il ) span_noexcept | |
1100 | { | |
1101 | data_ = il.begin(); | |
1102 | size_ = il.size(); | |
1103 | } | |
1104 | #else | |
1105 | span_constexpr /*explicit*/ span( std::initializer_list<value_type> il ) span_noexcept | |
1106 | : data_( il.begin() ) | |
1107 | , size_( il.size() ) | |
1108 | {} | |
1109 | #endif | |
1110 | ||
1111 | #endif // P2447 | |
1112 | ||
1113 | #if span_HAVE( IS_DEFAULT ) | |
1114 | span_constexpr span( span const & other ) span_noexcept = default; | |
1115 | ||
1116 | ~span() span_noexcept = default; | |
1117 | ||
1118 | span_constexpr14 span & operator=( span const & other ) span_noexcept = default; | |
1119 | #else | |
1120 | span_constexpr span( span const & other ) span_noexcept | |
1121 | : data_( other.data_ ) | |
1122 | , size_( other.size_ ) | |
1123 | {} | |
1124 | ||
1125 | ~span() span_noexcept | |
1126 | {} | |
1127 | ||
1128 | span_constexpr14 span & operator=( span const & other ) span_noexcept | |
1129 | { | |
1130 | data_ = other.data_; | |
1131 | size_ = other.size_; | |
1132 | ||
1133 | return *this; | |
1134 | } | |
1135 | #endif | |
1136 | ||
1137 | template< class OtherElementType, extent_type OtherExtent | |
1138 | span_REQUIRES_T(( | |
1139 | (Extent == dynamic_extent || OtherExtent == dynamic_extent || Extent == OtherExtent) | |
1140 | && std::is_convertible<OtherElementType(*)[], element_type(*)[]>::value | |
1141 | )) | |
1142 | > | |
1143 | span_constexpr_exp span( span<OtherElementType, OtherExtent> const & other ) span_noexcept | |
1144 | : data_( other.data() ) | |
1145 | , size_( other.size() ) | |
1146 | { | |
1147 | span_EXPECTS( OtherExtent == dynamic_extent || other.size() == to_size(OtherExtent) ); | |
1148 | } | |
1149 | ||
1150 | // 26.7.3.3 Subviews [span.sub] | |
1151 | ||
1152 | template< extent_type Count > | |
1153 | span_constexpr_exp span< element_type, Count > | |
1154 | first() const | |
1155 | { | |
1156 | span_EXPECTS( detail::is_positive( Count ) && Count <= size() ); | |
1157 | ||
1158 | return span< element_type, Count >( data(), Count ); | |
1159 | } | |
1160 | ||
1161 | template< extent_type Count > | |
1162 | span_constexpr_exp span< element_type, Count > | |
1163 | last() const | |
1164 | { | |
1165 | span_EXPECTS( detail::is_positive( Count ) && Count <= size() ); | |
1166 | ||
1167 | return span< element_type, Count >( data() + (size() - Count), Count ); | |
1168 | } | |
1169 | ||
1170 | #if span_HAVE( DEFAULT_FUNCTION_TEMPLATE_ARG ) | |
1171 | template< size_type Offset, extent_type Count = dynamic_extent > | |
1172 | #else | |
1173 | template< size_type Offset, extent_type Count /*= dynamic_extent*/ > | |
1174 | #endif | |
1175 | span_constexpr_exp span< element_type, Count > | |
1176 | subspan() const | |
1177 | { | |
1178 | span_EXPECTS( | |
1179 | ( detail::is_positive( Offset ) && Offset <= size() ) && | |
1180 | ( Count == dynamic_extent || (detail::is_positive( Count ) && Count + Offset <= size()) ) | |
1181 | ); | |
1182 | ||
1183 | return span< element_type, Count >( | |
1184 | data() + Offset, Count != dynamic_extent ? Count : (Extent != dynamic_extent ? Extent - Offset : size() - Offset) ); | |
1185 | } | |
1186 | ||
1187 | span_constexpr_exp span< element_type, dynamic_extent > | |
1188 | first( size_type count ) const | |
1189 | { | |
1190 | span_EXPECTS( detail::is_positive( count ) && count <= size() ); | |
1191 | ||
1192 | return span< element_type, dynamic_extent >( data(), count ); | |
1193 | } | |
1194 | ||
1195 | span_constexpr_exp span< element_type, dynamic_extent > | |
1196 | last( size_type count ) const | |
1197 | { | |
1198 | span_EXPECTS( detail::is_positive( count ) && count <= size() ); | |
1199 | ||
1200 | return span< element_type, dynamic_extent >( data() + ( size() - count ), count ); | |
1201 | } | |
1202 | ||
1203 | span_constexpr_exp span< element_type, dynamic_extent > | |
1204 | subspan( size_type offset, size_type count = static_cast<size_type>(dynamic_extent) ) const | |
1205 | { | |
1206 | span_EXPECTS( | |
1207 | ( ( detail::is_positive( offset ) && offset <= size() ) ) && | |
1208 | ( count == static_cast<size_type>(dynamic_extent) || ( detail::is_positive( count ) && offset + count <= size() ) ) | |
1209 | ); | |
1210 | ||
1211 | return span< element_type, dynamic_extent >( | |
1212 | data() + offset, count == static_cast<size_type>(dynamic_extent) ? size() - offset : count ); | |
1213 | } | |
1214 | ||
1215 | // 26.7.3.4 Observers [span.obs] | |
1216 | ||
1217 | span_constexpr size_type size() const span_noexcept | |
1218 | { | |
1219 | return size_; | |
1220 | } | |
1221 | ||
1222 | span_constexpr std::ptrdiff_t ssize() const span_noexcept | |
1223 | { | |
1224 | return static_cast<std::ptrdiff_t>( size_ ); | |
1225 | } | |
1226 | ||
1227 | span_constexpr size_type size_bytes() const span_noexcept | |
1228 | { | |
1229 | return size() * to_size( sizeof( element_type ) ); | |
1230 | } | |
1231 | ||
1232 | span_nodiscard span_constexpr bool empty() const span_noexcept | |
1233 | { | |
1234 | return size() == 0; | |
1235 | } | |
1236 | ||
1237 | // 26.7.3.5 Element access [span.elem] | |
1238 | ||
1239 | span_constexpr_exp reference operator[]( size_type idx ) const | |
1240 | { | |
1241 | span_EXPECTS( detail::is_positive( idx ) && idx < size() ); | |
1242 | ||
1243 | return *( data() + idx ); | |
1244 | } | |
1245 | ||
1246 | #if span_FEATURE( MEMBER_CALL_OPERATOR ) | |
1247 | span_deprecated("replace operator() with operator[]") | |
1248 | ||
1249 | span_constexpr_exp reference operator()( size_type idx ) const | |
1250 | { | |
1251 | span_EXPECTS( detail::is_positive( idx ) && idx < size() ); | |
1252 | ||
1253 | return *( data() + idx ); | |
1254 | } | |
1255 | #endif | |
1256 | ||
1257 | #if span_FEATURE( MEMBER_AT ) | |
1258 | span_constexpr14 reference at( size_type idx ) const | |
1259 | { | |
1260 | #if span_CONFIG( NO_EXCEPTIONS ) | |
1261 | return this->operator[]( idx ); | |
1262 | #else | |
1263 | if ( !detail::is_positive( idx ) || size() <= idx ) | |
1264 | { | |
1265 | detail::throw_out_of_range( idx, size() ); | |
1266 | } | |
1267 | return *( data() + idx ); | |
1268 | #endif | |
1269 | } | |
1270 | #endif | |
1271 | ||
1272 | span_constexpr pointer data() const span_noexcept | |
1273 | { | |
1274 | return data_; | |
1275 | } | |
1276 | ||
1277 | #if span_FEATURE( MEMBER_BACK_FRONT ) | |
1278 | ||
1279 | span_constexpr_exp reference front() const span_noexcept | |
1280 | { | |
1281 | span_EXPECTS( ! empty() ); | |
1282 | ||
1283 | return *data(); | |
1284 | } | |
1285 | ||
1286 | span_constexpr_exp reference back() const span_noexcept | |
1287 | { | |
1288 | span_EXPECTS( ! empty() ); | |
1289 | ||
1290 | return *( data() + size() - 1 ); | |
1291 | } | |
1292 | ||
1293 | #endif | |
1294 | ||
1295 | // xx.x.x.x Modifiers [span.modifiers] | |
1296 | ||
1297 | #if span_FEATURE( MEMBER_SWAP ) | |
1298 | ||
1299 | span_constexpr14 void swap( span & other ) span_noexcept | |
1300 | { | |
1301 | using std::swap; | |
1302 | swap( data_, other.data_ ); | |
1303 | swap( size_, other.size_ ); | |
1304 | } | |
1305 | #endif | |
1306 | ||
1307 | // 26.7.3.6 Iterator support [span.iterators] | |
1308 | ||
1309 | span_constexpr iterator begin() const span_noexcept | |
1310 | { | |
1311 | #if span_CPP11_OR_GREATER | |
1312 | return { data() }; | |
1313 | #else | |
1314 | return iterator( data() ); | |
1315 | #endif | |
1316 | } | |
1317 | ||
1318 | span_constexpr iterator end() const span_noexcept | |
1319 | { | |
1320 | #if span_CPP11_OR_GREATER | |
1321 | return { data() + size() }; | |
1322 | #else | |
1323 | return iterator( data() + size() ); | |
1324 | #endif | |
1325 | } | |
1326 | ||
1327 | span_constexpr const_iterator cbegin() const span_noexcept | |
1328 | { | |
1329 | #if span_CPP11_OR_GREATER | |
1330 | return { data() }; | |
1331 | #else | |
1332 | return const_iterator( data() ); | |
1333 | #endif | |
1334 | } | |
1335 | ||
1336 | span_constexpr const_iterator cend() const span_noexcept | |
1337 | { | |
1338 | #if span_CPP11_OR_GREATER | |
1339 | return { data() + size() }; | |
1340 | #else | |
1341 | return const_iterator( data() + size() ); | |
1342 | #endif | |
1343 | } | |
1344 | ||
1345 | span_constexpr reverse_iterator rbegin() const span_noexcept | |
1346 | { | |
1347 | return reverse_iterator( end() ); | |
1348 | } | |
1349 | ||
1350 | span_constexpr reverse_iterator rend() const span_noexcept | |
1351 | { | |
1352 | return reverse_iterator( begin() ); | |
1353 | } | |
1354 | ||
1355 | span_constexpr const_reverse_iterator crbegin() const span_noexcept | |
1356 | { | |
1357 | return const_reverse_iterator ( cend() ); | |
1358 | } | |
1359 | ||
1360 | span_constexpr const_reverse_iterator crend() const span_noexcept | |
1361 | { | |
1362 | return const_reverse_iterator( cbegin() ); | |
1363 | } | |
1364 | ||
1365 | private: | |
1366 | ||
1367 | // Note: C++20 has std::pointer_traits<Ptr>::to_address( it ); | |
1368 | ||
1369 | #if span_HAVE( ITERATOR_CTOR ) | |
1370 | static inline span_constexpr pointer to_address( std::nullptr_t ) span_noexcept | |
1371 | { | |
1372 | return nullptr; | |
1373 | } | |
1374 | ||
1375 | template< typename U > | |
1376 | static inline span_constexpr U * to_address( U * p ) span_noexcept | |
1377 | { | |
1378 | return p; | |
1379 | } | |
1380 | ||
1381 | template< typename Ptr | |
1382 | span_REQUIRES_T(( ! std::is_pointer<Ptr>::value )) | |
1383 | > | |
1384 | static inline span_constexpr pointer to_address( Ptr const & it ) span_noexcept | |
1385 | { | |
1386 | return to_address( it.operator->() ); | |
1387 | } | |
1388 | #endif // span_HAVE( ITERATOR_CTOR ) | |
1389 | ||
1390 | private: | |
1391 | pointer data_; | |
1392 | size_type size_; | |
1393 | }; | |
1394 | ||
1395 | // class template argument deduction guides: | |
1396 | ||
1397 | #if span_HAVE( DEDUCTION_GUIDES ) | |
1398 | ||
1399 | template< class T, size_t N > | |
1400 | span( T (&)[N] ) -> span<T, static_cast<extent_t>(N)>; | |
1401 | ||
1402 | template< class T, size_t N > | |
1403 | span( std::array<T, N> & ) -> span<T, static_cast<extent_t>(N)>; | |
1404 | ||
1405 | template< class T, size_t N > | |
1406 | span( std::array<T, N> const & ) -> span<const T, static_cast<extent_t>(N)>; | |
1407 | ||
1408 | #if span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR ) | |
1409 | ||
1410 | template< class Container > | |
1411 | span( Container& ) -> span<typename Container::value_type>; | |
1412 | ||
1413 | template< class Container > | |
1414 | span( Container const & ) -> span<const typename Container::value_type>; | |
1415 | ||
1416 | #endif | |
1417 | ||
1418 | // iterator: constraints: It satisfies contiguous_Âiterator. | |
1419 | ||
1420 | template< class It, class EndOrSize > | |
1421 | span( It, EndOrSize ) -> span< typename std11::remove_reference< typename std20::iter_reference_t<It> >::type >; | |
1422 | ||
1423 | #endif // span_HAVE( DEDUCTION_GUIDES ) | |
1424 | ||
1425 | // 26.7.3.7 Comparison operators [span.comparison] | |
1426 | ||
1427 | #if span_FEATURE( COMPARISON ) | |
1428 | #if span_FEATURE( SAME ) | |
1429 | ||
1430 | template< class T1, extent_t E1, class T2, extent_t E2 > | |
1431 | inline span_constexpr bool same( span<T1,E1> const & l, span<T2,E2> const & r ) span_noexcept | |
1432 | { | |
1433 | return std11::is_same<T1, T2>::value | |
1434 | && l.size() == r.size() | |
1435 | && static_cast<void const*>( l.data() ) == r.data(); | |
1436 | } | |
1437 | ||
1438 | #endif | |
1439 | ||
1440 | template< class T1, extent_t E1, class T2, extent_t E2 > | |
1441 | inline span_constexpr bool operator==( span<T1,E1> const & l, span<T2,E2> const & r ) | |
1442 | { | |
1443 | return | |
1444 | #if span_FEATURE( SAME ) | |
1445 | same( l, r ) || | |
1446 | #endif | |
1447 | ( l.size() == r.size() && std::equal( l.begin(), l.end(), r.begin() ) ); | |
1448 | } | |
1449 | ||
1450 | template< class T1, extent_t E1, class T2, extent_t E2 > | |
1451 | inline span_constexpr bool operator<( span<T1,E1> const & l, span<T2,E2> const & r ) | |
1452 | { | |
1453 | return std::lexicographical_compare( l.begin(), l.end(), r.begin(), r.end() ); | |
1454 | } | |
1455 | ||
1456 | template< class T1, extent_t E1, class T2, extent_t E2 > | |
1457 | inline span_constexpr bool operator!=( span<T1,E1> const & l, span<T2,E2> const & r ) | |
1458 | { | |
1459 | return !( l == r ); | |
1460 | } | |
1461 | ||
1462 | template< class T1, extent_t E1, class T2, extent_t E2 > | |
1463 | inline span_constexpr bool operator<=( span<T1,E1> const & l, span<T2,E2> const & r ) | |
1464 | { | |
1465 | return !( r < l ); | |
1466 | } | |
1467 | ||
1468 | template< class T1, extent_t E1, class T2, extent_t E2 > | |
1469 | inline span_constexpr bool operator>( span<T1,E1> const & l, span<T2,E2> const & r ) | |
1470 | { | |
1471 | return ( r < l ); | |
1472 | } | |
1473 | ||
1474 | template< class T1, extent_t E1, class T2, extent_t E2 > | |
1475 | inline span_constexpr bool operator>=( span<T1,E1> const & l, span<T2,E2> const & r ) | |
1476 | { | |
1477 | return !( l < r ); | |
1478 | } | |
1479 | ||
1480 | #endif // span_FEATURE( COMPARISON ) | |
1481 | ||
1482 | // 26.7.2.6 views of object representation [span.objectrep] | |
1483 | ||
1484 | #if span_HAVE( BYTE ) || span_HAVE( NONSTD_BYTE ) | |
1485 | ||
1486 | // Avoid MSVC 14.1 (1910), VS 2017: warning C4307: '*': integral constant overflow: | |
1487 | ||
1488 | template< typename T, extent_t Extent > | |
1489 | struct BytesExtent | |
1490 | { | |
1491 | #if span_CPP11_OR_GREATER | |
1492 | enum ET : extent_t { value = span_sizeof(T) * Extent }; | |
1493 | #else | |
1494 | enum ET { value = span_sizeof(T) * Extent }; | |
1495 | #endif | |
1496 | }; | |
1497 | ||
1498 | template< typename T > | |
1499 | struct BytesExtent< T, dynamic_extent > | |
1500 | { | |
1501 | #if span_CPP11_OR_GREATER | |
1502 | enum ET : extent_t { value = dynamic_extent }; | |
1503 | #else | |
1504 | enum ET { value = dynamic_extent }; | |
1505 | #endif | |
1506 | }; | |
1507 | ||
1508 | template< class T, extent_t Extent > | |
1509 | inline span_constexpr span< const std17::byte, BytesExtent<T, Extent>::value > | |
1510 | as_bytes( span<T,Extent> spn ) span_noexcept | |
1511 | { | |
1512 | #if 0 | |
1513 | return { reinterpret_cast< std17::byte const * >( spn.data() ), spn.size_bytes() }; | |
1514 | #else | |
1515 | return span< const std17::byte, BytesExtent<T, Extent>::value >( | |
1516 | reinterpret_cast< std17::byte const * >( spn.data() ), spn.size_bytes() ); // NOLINT | |
1517 | #endif | |
1518 | } | |
1519 | ||
1520 | template< class T, extent_t Extent > | |
1521 | inline span_constexpr span< std17::byte, BytesExtent<T, Extent>::value > | |
1522 | as_writable_bytes( span<T,Extent> spn ) span_noexcept | |
1523 | { | |
1524 | #if 0 | |
1525 | return { reinterpret_cast< std17::byte * >( spn.data() ), spn.size_bytes() }; | |
1526 | #else | |
1527 | return span< std17::byte, BytesExtent<T, Extent>::value >( | |
1528 | reinterpret_cast< std17::byte * >( spn.data() ), spn.size_bytes() ); // NOLINT | |
1529 | #endif | |
1530 | } | |
1531 | ||
1532 | #endif // span_HAVE( BYTE ) || span_HAVE( NONSTD_BYTE ) | |
1533 | ||
1534 | // 27.8 Container and view access [iterator.container] | |
1535 | ||
1536 | template< class T, extent_t Extent /*= dynamic_extent*/ > | |
1537 | span_constexpr std::size_t size( span<T,Extent> const & spn ) | |
1538 | { | |
1539 | return static_cast<std::size_t>( spn.size() ); | |
1540 | } | |
1541 | ||
1542 | template< class T, extent_t Extent /*= dynamic_extent*/ > | |
1543 | span_constexpr std::ptrdiff_t ssize( span<T,Extent> const & spn ) | |
1544 | { | |
1545 | return static_cast<std::ptrdiff_t>( spn.size() ); | |
1546 | } | |
1547 | ||
1548 | } // namespace span_lite | |
1549 | } // namespace nonstd | |
1550 | ||
1551 | // make available in nonstd: | |
1552 | ||
1553 | namespace nonstd { | |
1554 | ||
1555 | using span_lite::dynamic_extent; | |
1556 | ||
1557 | using span_lite::span; | |
1558 | ||
1559 | using span_lite::with_container; | |
1560 | ||
1561 | #if span_FEATURE( COMPARISON ) | |
1562 | #if span_FEATURE( SAME ) | |
1563 | using span_lite::same; | |
1564 | #endif | |
1565 | ||
1566 | using span_lite::operator==; | |
1567 | using span_lite::operator!=; | |
1568 | using span_lite::operator<; | |
1569 | using span_lite::operator<=; | |
1570 | using span_lite::operator>; | |
1571 | using span_lite::operator>=; | |
1572 | #endif | |
1573 | ||
1574 | #if span_HAVE( BYTE ) | |
1575 | using span_lite::as_bytes; | |
1576 | using span_lite::as_writable_bytes; | |
1577 | #endif | |
1578 | ||
1579 | using span_lite::size; | |
1580 | using span_lite::ssize; | |
1581 | ||
1582 | } // namespace nonstd | |
1583 | ||
1584 | #endif // span_USES_STD_SPAN | |
1585 | ||
1586 | // make_span() [span-lite extension]: | |
1587 | ||
1588 | #if span_FEATURE( MAKE_SPAN ) || span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_SPAN ) || span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_CONTAINER ) | |
1589 | ||
1590 | #if span_USES_STD_SPAN | |
1591 | # define span_constexpr constexpr | |
1592 | # define span_noexcept noexcept | |
1593 | # define span_nullptr nullptr | |
1594 | # ifndef span_CONFIG_EXTENT_TYPE | |
1595 | # define span_CONFIG_EXTENT_TYPE std::size_t | |
1596 | # endif | |
1597 | using extent_t = span_CONFIG_EXTENT_TYPE; | |
1598 | #endif // span_USES_STD_SPAN | |
1599 | ||
1600 | namespace nonstd { | |
1601 | namespace span_lite { | |
1602 | ||
1603 | template< class T > | |
1604 | inline span_constexpr span<T> | |
1605 | make_span( T * ptr, size_t count ) span_noexcept | |
1606 | { | |
1607 | return span<T>( ptr, count ); | |
1608 | } | |
1609 | ||
1610 | template< class T > | |
1611 | inline span_constexpr span<T> | |
1612 | make_span( T * first, T * last ) span_noexcept | |
1613 | { | |
1614 | return span<T>( first, last ); | |
1615 | } | |
1616 | ||
1617 | template< class T, std::size_t N > | |
1618 | inline span_constexpr span<T, static_cast<extent_t>(N)> | |
1619 | make_span( T ( &arr )[ N ] ) span_noexcept | |
1620 | { | |
1621 | return span<T, static_cast<extent_t>(N)>( &arr[ 0 ], N ); | |
1622 | } | |
1623 | ||
1624 | #if span_USES_STD_SPAN || span_HAVE( ARRAY ) | |
1625 | ||
1626 | template< class T, std::size_t N > | |
1627 | inline span_constexpr span<T, static_cast<extent_t>(N)> | |
1628 | make_span( std::array< T, N > & arr ) span_noexcept | |
1629 | { | |
1630 | return span<T, static_cast<extent_t>(N)>( arr ); | |
1631 | } | |
1632 | ||
1633 | template< class T, std::size_t N > | |
1634 | inline span_constexpr span< const T, static_cast<extent_t>(N) > | |
1635 | make_span( std::array< T, N > const & arr ) span_noexcept | |
1636 | { | |
1637 | return span<const T, static_cast<extent_t>(N)>( arr ); | |
1638 | } | |
1639 | ||
1640 | #endif // span_HAVE( ARRAY ) | |
1641 | ||
1642 | #if span_USES_STD_SPAN || span_HAVE( INITIALIZER_LIST ) | |
1643 | ||
1644 | template< class T > | |
1645 | inline span_constexpr span< const T > | |
1646 | make_span( std::initializer_list<T> il ) span_noexcept | |
1647 | { | |
1648 | return span<const T>( il.begin(), il.size() ); | |
1649 | } | |
1650 | ||
1651 | #endif // span_HAVE( INITIALIZER_LIST ) | |
1652 | ||
1653 | #if span_USES_STD_SPAN | |
1654 | ||
1655 | template< class Container, class EP = decltype( std::data(std::declval<Container&>())) > | |
1656 | inline span_constexpr auto | |
1657 | make_span( Container & cont ) span_noexcept -> span< typename std::remove_pointer<EP>::type > | |
1658 | { | |
1659 | return span< typename std::remove_pointer<EP>::type >( cont ); | |
1660 | } | |
1661 | ||
1662 | template< class Container, class EP = decltype( std::data(std::declval<Container&>())) > | |
1663 | inline span_constexpr auto | |
1664 | make_span( Container const & cont ) span_noexcept -> span< const typename std::remove_pointer<EP>::type > | |
1665 | { | |
1666 | return span< const typename std::remove_pointer<EP>::type >( cont ); | |
1667 | } | |
1668 | ||
1669 | #elif span_HAVE( CONSTRAINED_SPAN_CONTAINER_CTOR ) && span_HAVE( AUTO ) | |
1670 | ||
1671 | template< class Container, class EP = decltype( std17::data(std::declval<Container&>())) > | |
1672 | inline span_constexpr auto | |
1673 | make_span( Container & cont ) span_noexcept -> span< typename std::remove_pointer<EP>::type > | |
1674 | { | |
1675 | return span< typename std::remove_pointer<EP>::type >( cont ); | |
1676 | } | |
1677 | ||
1678 | template< class Container, class EP = decltype( std17::data(std::declval<Container&>())) > | |
1679 | inline span_constexpr auto | |
1680 | make_span( Container const & cont ) span_noexcept -> span< const typename std::remove_pointer<EP>::type > | |
1681 | { | |
1682 | return span< const typename std::remove_pointer<EP>::type >( cont ); | |
1683 | } | |
1684 | ||
1685 | #else | |
1686 | ||
1687 | template< class T > | |
1688 | inline span_constexpr span<T> | |
1689 | make_span( span<T> spn ) span_noexcept | |
1690 | { | |
1691 | return spn; | |
1692 | } | |
1693 | ||
1694 | template< class T, class Allocator > | |
1695 | inline span_constexpr span<T> | |
1696 | make_span( std::vector<T, Allocator> & cont ) span_noexcept | |
1697 | { | |
1698 | return span<T>( with_container, cont ); | |
1699 | } | |
1700 | ||
1701 | template< class T, class Allocator > | |
1702 | inline span_constexpr span<const T> | |
1703 | make_span( std::vector<T, Allocator> const & cont ) span_noexcept | |
1704 | { | |
1705 | return span<const T>( with_container, cont ); | |
1706 | } | |
1707 | ||
1708 | #endif // span_USES_STD_SPAN || ( ... ) | |
1709 | ||
1710 | #if ! span_USES_STD_SPAN && span_FEATURE( WITH_CONTAINER ) | |
1711 | ||
1712 | template< class Container > | |
1713 | inline span_constexpr span<typename Container::value_type> | |
1714 | make_span( with_container_t, Container & cont ) span_noexcept | |
1715 | { | |
1716 | return span< typename Container::value_type >( with_container, cont ); | |
1717 | } | |
1718 | ||
1719 | template< class Container > | |
1720 | inline span_constexpr span<const typename Container::value_type> | |
1721 | make_span( with_container_t, Container const & cont ) span_noexcept | |
1722 | { | |
1723 | return span< const typename Container::value_type >( with_container, cont ); | |
1724 | } | |
1725 | ||
1726 | #endif // ! span_USES_STD_SPAN && span_FEATURE( WITH_CONTAINER ) | |
1727 | ||
1728 | // extensions: non-member views: | |
1729 | // this feature implies the presence of make_span() | |
1730 | ||
1731 | #if span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_SPAN ) | |
1732 | ||
1733 | template< extent_t Count, class T, extent_t Extent > | |
1734 | span_constexpr span<T, Count> | |
1735 | first( span<T, Extent> spn ) | |
1736 | { | |
1737 | return spn.template first<Count>(); | |
1738 | } | |
1739 | ||
1740 | template< class T, extent_t Extent > | |
1741 | span_constexpr span<T> | |
1742 | first( span<T, Extent> spn, size_t count ) | |
1743 | { | |
1744 | return spn.first( count ); | |
1745 | } | |
1746 | ||
1747 | template< extent_t Count, class T, extent_t Extent > | |
1748 | span_constexpr span<T, Count> | |
1749 | last( span<T, Extent> spn ) | |
1750 | { | |
1751 | return spn.template last<Count>(); | |
1752 | } | |
1753 | ||
1754 | template< class T, extent_t Extent > | |
1755 | span_constexpr span<T> | |
1756 | last( span<T, Extent> spn, size_t count ) | |
1757 | { | |
1758 | return spn.last( count ); | |
1759 | } | |
1760 | ||
1761 | template< size_t Offset, extent_t Count, class T, extent_t Extent > | |
1762 | span_constexpr span<T, Count> | |
1763 | subspan( span<T, Extent> spn ) | |
1764 | { | |
1765 | return spn.template subspan<Offset, Count>(); | |
1766 | } | |
1767 | ||
1768 | template< class T, extent_t Extent > | |
1769 | span_constexpr span<T> | |
1770 | subspan( span<T, Extent> spn, size_t offset, extent_t count = dynamic_extent ) | |
1771 | { | |
1772 | return spn.subspan( offset, count ); | |
1773 | } | |
1774 | ||
1775 | #endif // span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_SPAN ) | |
1776 | ||
1777 | #if span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_CONTAINER ) && span_CPP11_120 | |
1778 | ||
1779 | template< extent_t Count, class T > | |
1780 | span_constexpr auto | |
1781 | first( T & t ) -> decltype( make_span(t).template first<Count>() ) | |
1782 | { | |
1783 | return make_span( t ).template first<Count>(); | |
1784 | } | |
1785 | ||
1786 | template< class T > | |
1787 | span_constexpr auto | |
1788 | first( T & t, size_t count ) -> decltype( make_span(t).first(count) ) | |
1789 | { | |
1790 | return make_span( t ).first( count ); | |
1791 | } | |
1792 | ||
1793 | template< extent_t Count, class T > | |
1794 | span_constexpr auto | |
1795 | last( T & t ) -> decltype( make_span(t).template last<Count>() ) | |
1796 | { | |
1797 | return make_span(t).template last<Count>(); | |
1798 | } | |
1799 | ||
1800 | template< class T > | |
1801 | span_constexpr auto | |
1802 | last( T & t, extent_t count ) -> decltype( make_span(t).last(count) ) | |
1803 | { | |
1804 | return make_span( t ).last( count ); | |
1805 | } | |
1806 | ||
1807 | template< size_t Offset, extent_t Count = dynamic_extent, class T > | |
1808 | span_constexpr auto | |
1809 | subspan( T & t ) -> decltype( make_span(t).template subspan<Offset, Count>() ) | |
1810 | { | |
1811 | return make_span( t ).template subspan<Offset, Count>(); | |
1812 | } | |
1813 | ||
1814 | template< class T > | |
1815 | span_constexpr auto | |
1816 | subspan( T & t, size_t offset, extent_t count = dynamic_extent ) -> decltype( make_span(t).subspan(offset, count) ) | |
1817 | { | |
1818 | return make_span( t ).subspan( offset, count ); | |
1819 | } | |
1820 | ||
1821 | #endif // span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_CONTAINER ) | |
1822 | ||
1823 | } // namespace span_lite | |
1824 | } // namespace nonstd | |
1825 | ||
1826 | // make available in nonstd: | |
1827 | ||
1828 | namespace nonstd { | |
1829 | using span_lite::make_span; | |
1830 | ||
1831 | #if span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_SPAN ) || ( span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_CONTAINER ) && span_CPP11_120 ) | |
1832 | ||
1833 | using span_lite::first; | |
1834 | using span_lite::last; | |
1835 | using span_lite::subspan; | |
1836 | ||
1837 | #endif // span_FEATURE( NON_MEMBER_FIRST_LAST_SUB_[SPAN|CONTAINER] ) | |
1838 | ||
1839 | } // namespace nonstd | |
1840 | ||
1841 | #endif // #if span_FEATURE_TO_STD( MAKE_SPAN ) | |
1842 | ||
1843 | #if span_CPP11_OR_GREATER && span_FEATURE( BYTE_SPAN ) && ( span_HAVE( BYTE ) || span_HAVE( NONSTD_BYTE ) ) | |
1844 | ||
1845 | namespace nonstd { | |
1846 | namespace span_lite { | |
1847 | ||
1848 | template< class T > | |
1849 | inline span_constexpr auto | |
1850 | byte_span( T & t ) span_noexcept -> span< std17::byte, span_sizeof(T) > | |
1851 | { | |
1852 | return span< std17::byte, span_sizeof(t) >( reinterpret_cast< std17::byte * >( &t ), span_sizeof(T) ); | |
1853 | } | |
1854 | ||
1855 | template< class T > | |
1856 | inline span_constexpr auto | |
1857 | byte_span( T const & t ) span_noexcept -> span< const std17::byte, span_sizeof(T) > | |
1858 | { | |
1859 | return span< const std17::byte, span_sizeof(t) >( reinterpret_cast< std17::byte const * >( &t ), span_sizeof(T) ); | |
1860 | } | |
1861 | ||
1862 | } // namespace span_lite | |
1863 | } // namespace nonstd | |
1864 | ||
1865 | // make available in nonstd: | |
1866 | ||
1867 | namespace nonstd { | |
1868 | using span_lite::byte_span; | |
1869 | } // namespace nonstd | |
1870 | ||
1871 | #endif // span_FEATURE( BYTE_SPAN ) | |
1872 | ||
1873 | #if span_HAVE( STRUCT_BINDING ) | |
1874 | ||
1875 | #if span_CPP14_OR_GREATER | |
1876 | # include <tuple> | |
1877 | #elif span_CPP11_OR_GREATER | |
1878 | # include <tuple> | |
1879 | namespace std { | |
1880 | template< std::size_t I, typename T > | |
1881 | using tuple_element_t = typename tuple_element<I, T>::type; | |
1882 | } | |
1883 | #else | |
1884 | namespace std { | |
1885 | template< typename T > | |
1886 | class tuple_size; /*undefined*/ | |
1887 | ||
1888 | template< std::size_t I, typename T > | |
1889 | class tuple_element; /* undefined */ | |
1890 | } | |
1891 | #endif // span_CPP14_OR_GREATER | |
1892 | ||
1893 | namespace std { | |
1894 | ||
1895 | // 26.7.X Tuple interface | |
1896 | ||
1897 | // std::tuple_size<>: | |
1898 | ||
1899 | template< typename ElementType, nonstd::span_lite::extent_t Extent > | |
1900 | class tuple_size< nonstd::span<ElementType, Extent> > : public integral_constant<size_t, static_cast<size_t>(Extent)> {}; | |
1901 | ||
1902 | // std::tuple_size<>: Leave undefined for dynamic extent: | |
1903 | ||
1904 | template< typename ElementType > | |
1905 | class tuple_size< nonstd::span<ElementType, nonstd::dynamic_extent> >; | |
1906 | ||
1907 | // std::tuple_element<>: | |
1908 | ||
1909 | template< size_t I, typename ElementType, nonstd::span_lite::extent_t Extent > | |
1910 | class tuple_element< I, nonstd::span<ElementType, Extent> > | |
1911 | { | |
1912 | public: | |
1913 | #if span_HAVE( STATIC_ASSERT ) | |
1914 | static_assert( Extent != nonstd::dynamic_extent && I < Extent, "tuple_element<I,span>: dynamic extent or index out of range" ); | |
1915 | #endif | |
1916 | using type = ElementType; | |
1917 | }; | |
1918 | ||
1919 | // std::get<>(), 2 variants: | |
1920 | ||
1921 | template< size_t I, typename ElementType, nonstd::span_lite::extent_t Extent > | |
1922 | span_constexpr ElementType & get( nonstd::span<ElementType, Extent> & spn ) span_noexcept | |
1923 | { | |
1924 | #if span_HAVE( STATIC_ASSERT ) | |
1925 | static_assert( Extent != nonstd::dynamic_extent && I < Extent, "get<>(span): dynamic extent or index out of range" ); | |
1926 | #endif | |
1927 | return spn[I]; | |
1928 | } | |
1929 | ||
1930 | template< size_t I, typename ElementType, nonstd::span_lite::extent_t Extent > | |
1931 | span_constexpr ElementType const & get( nonstd::span<ElementType, Extent> const & spn ) span_noexcept | |
1932 | { | |
1933 | #if span_HAVE( STATIC_ASSERT ) | |
1934 | static_assert( Extent != nonstd::dynamic_extent && I < Extent, "get<>(span): dynamic extent or index out of range" ); | |
1935 | #endif | |
1936 | return spn[I]; | |
1937 | } | |
1938 | ||
1939 | } // end namespace std | |
1940 | ||
1941 | #endif // span_HAVE( STRUCT_BINDING ) | |
1942 | ||
1943 | #if ! span_USES_STD_SPAN | |
1944 | span_RESTORE_WARNINGS() | |
1945 | #endif // span_USES_STD_SPAN | |
1946 | ||
1947 | #endif // NONSTD_SPAN_HPP_INCLUDED |