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1 | // Copyright 2002 The Trustees of Indiana University. |
2 | ||
3 | // Use, modification and distribution is subject to the Boost Software | |
4 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
5 | // http://www.boost.org/LICENSE_1_0.txt) | |
6 | ||
7 | // Boost.MultiArray Library | |
8 | // Authors: Ronald Garcia | |
9 | // Jeremy Siek | |
10 | // Andrew Lumsdaine | |
11 | // See http://www.boost.org/libs/multi_array for documentation. | |
12 | ||
13 | #ifndef BASE_RG071801_HPP | |
14 | #define BASE_RG071801_HPP | |
15 | ||
16 | // | |
17 | // base.hpp - some implementation base classes for from which | |
18 | // functionality is acquired | |
19 | // | |
20 | ||
21 | #include "boost/multi_array/extent_range.hpp" | |
22 | #include "boost/multi_array/extent_gen.hpp" | |
23 | #include "boost/multi_array/index_range.hpp" | |
24 | #include "boost/multi_array/index_gen.hpp" | |
25 | #include "boost/multi_array/storage_order.hpp" | |
26 | #include "boost/multi_array/types.hpp" | |
27 | #include "boost/config.hpp" | |
28 | #include "boost/multi_array/concept_checks.hpp" //for ignore_unused_... | |
29 | #include "boost/mpl/eval_if.hpp" | |
30 | #include "boost/mpl/if.hpp" | |
31 | #include "boost/mpl/size_t.hpp" | |
32 | #include "boost/iterator/reverse_iterator.hpp" | |
33 | #include "boost/static_assert.hpp" | |
34 | #include "boost/type.hpp" | |
35 | #include "boost/assert.hpp" | |
36 | #include <cstddef> | |
37 | #include <memory> | |
38 | ||
39 | namespace boost { | |
40 | ||
41 | ///////////////////////////////////////////////////////////////////////// | |
42 | // class declarations | |
43 | ///////////////////////////////////////////////////////////////////////// | |
44 | ||
45 | template<typename T, std::size_t NumDims, | |
46 | typename Allocator = std::allocator<T> > | |
47 | class multi_array; | |
48 | ||
49 | // This is a public interface for use by end users! | |
50 | namespace multi_array_types { | |
51 | typedef boost::detail::multi_array::size_type size_type; | |
52 | typedef std::ptrdiff_t difference_type; | |
53 | typedef boost::detail::multi_array::index index; | |
54 | typedef detail::multi_array::index_range<index,size_type> index_range; | |
55 | typedef detail::multi_array::extent_range<index,size_type> extent_range; | |
56 | typedef detail::multi_array::index_gen<0,0> index_gen; | |
57 | typedef detail::multi_array::extent_gen<0> extent_gen; | |
58 | } | |
59 | ||
60 | ||
61 | // boost::extents and boost::indices are now a part of the public | |
62 | // interface. That way users don't necessarily have to create their | |
63 | // own objects. On the other hand, one may not want the overhead of | |
64 | // object creation in small-memory environments. Thus, the objects | |
65 | // can be left undefined by defining BOOST_MULTI_ARRAY_NO_GENERATORS | |
66 | // before loading multi_array.hpp. | |
67 | #ifndef BOOST_MULTI_ARRAY_NO_GENERATORS | |
68 | namespace { | |
69 | multi_array_types::extent_gen extents; | |
70 | multi_array_types::index_gen indices; | |
71 | } | |
72 | #endif // BOOST_MULTI_ARRAY_NO_GENERATORS | |
73 | ||
74 | namespace detail { | |
75 | namespace multi_array { | |
76 | ||
77 | template <typename T, std::size_t NumDims> | |
78 | class sub_array; | |
79 | ||
80 | template <typename T, std::size_t NumDims, typename TPtr = const T*> | |
81 | class const_sub_array; | |
82 | ||
83 | template <typename T, typename TPtr, typename NumDims, typename Reference, | |
84 | typename IteratorCategory> | |
85 | class array_iterator; | |
86 | ||
87 | template <typename T, std::size_t NumDims, typename TPtr = const T*> | |
88 | class const_multi_array_view; | |
89 | ||
90 | template <typename T, std::size_t NumDims> | |
91 | class multi_array_view; | |
92 | ||
93 | ///////////////////////////////////////////////////////////////////////// | |
94 | // class interfaces | |
95 | ///////////////////////////////////////////////////////////////////////// | |
96 | ||
97 | class multi_array_base { | |
98 | public: | |
99 | typedef multi_array_types::size_type size_type; | |
100 | typedef multi_array_types::difference_type difference_type; | |
101 | typedef multi_array_types::index index; | |
102 | typedef multi_array_types::index_range index_range; | |
103 | typedef multi_array_types::extent_range extent_range; | |
104 | typedef multi_array_types::index_gen index_gen; | |
105 | typedef multi_array_types::extent_gen extent_gen; | |
106 | }; | |
107 | ||
108 | // | |
109 | // value_accessor_n | |
110 | // contains the routines for accessing elements from | |
111 | // N-dimensional views. | |
112 | // | |
113 | template<typename T, std::size_t NumDims> | |
114 | class value_accessor_n : public multi_array_base { | |
115 | typedef multi_array_base super_type; | |
116 | public: | |
117 | typedef typename super_type::index index; | |
118 | ||
119 | // | |
120 | // public typedefs used by classes that inherit from this base | |
121 | // | |
122 | typedef T element; | |
123 | typedef boost::multi_array<T,NumDims-1> value_type; | |
124 | typedef sub_array<T,NumDims-1> reference; | |
125 | typedef const_sub_array<T,NumDims-1> const_reference; | |
126 | ||
127 | protected: | |
128 | // used by array operator[] and iterators to get reference types. | |
129 | template <typename Reference, typename TPtr> | |
130 | Reference access(boost::type<Reference>,index idx,TPtr base, | |
131 | const size_type* extents, | |
132 | const index* strides, | |
133 | const index* index_bases) const { | |
134 | ||
135 | BOOST_ASSERT(idx - index_bases[0] >= 0); | |
136 | BOOST_ASSERT(size_type(idx - index_bases[0]) < extents[0]); | |
137 | // return a sub_array<T,NDims-1> proxy object | |
138 | TPtr newbase = base + idx * strides[0]; | |
139 | return Reference(newbase,extents+1,strides+1,index_bases+1); | |
140 | ||
141 | } | |
142 | ||
143 | value_accessor_n() { } | |
144 | ~value_accessor_n() { } | |
145 | }; | |
146 | ||
147 | ||
148 | ||
149 | // | |
150 | // value_accessor_one | |
151 | // contains the routines for accessing reference elements from | |
152 | // 1-dimensional views. | |
153 | // | |
154 | template<typename T> | |
155 | class value_accessor_one : public multi_array_base { | |
156 | typedef multi_array_base super_type; | |
157 | public: | |
158 | typedef typename super_type::index index; | |
159 | // | |
160 | // public typedefs for use by classes that inherit it. | |
161 | // | |
162 | typedef T element; | |
163 | typedef T value_type; | |
164 | typedef T& reference; | |
165 | typedef T const& const_reference; | |
166 | ||
167 | protected: | |
168 | // used by array operator[] and iterators to get reference types. | |
169 | template <typename Reference, typename TPtr> | |
170 | Reference access(boost::type<Reference>,index idx,TPtr base, | |
171 | const size_type* extents, | |
172 | const index* strides, | |
173 | const index* index_bases) const { | |
174 | ||
175 | ignore_unused_variable_warning(index_bases); | |
176 | ignore_unused_variable_warning(extents); | |
177 | BOOST_ASSERT(idx - index_bases[0] >= 0); | |
178 | BOOST_ASSERT(size_type(idx - index_bases[0]) < extents[0]); | |
179 | return *(base + idx * strides[0]); | |
180 | } | |
181 | ||
182 | value_accessor_one() { } | |
183 | ~value_accessor_one() { } | |
184 | }; | |
185 | ||
186 | ||
187 | ///////////////////////////////////////////////////////////////////////// | |
188 | // choose value accessor begins | |
189 | // | |
190 | ||
191 | template <typename T, std::size_t NumDims> | |
192 | struct choose_value_accessor_n { | |
193 | typedef value_accessor_n<T,NumDims> type; | |
194 | }; | |
195 | ||
196 | template <typename T> | |
197 | struct choose_value_accessor_one { | |
198 | typedef value_accessor_one<T> type; | |
199 | }; | |
200 | ||
201 | template <typename T, typename NumDims> | |
202 | struct value_accessor_generator { | |
203 | BOOST_STATIC_CONSTANT(std::size_t, dimensionality = NumDims::value); | |
204 | ||
205 | typedef typename | |
206 | mpl::eval_if_c<(dimensionality == 1), | |
207 | choose_value_accessor_one<T>, | |
208 | choose_value_accessor_n<T,dimensionality> | |
209 | >::type type; | |
210 | }; | |
211 | ||
212 | template <class T, class NumDims> | |
213 | struct associated_types | |
214 | : value_accessor_generator<T,NumDims>::type | |
215 | {}; | |
216 | ||
217 | // | |
218 | // choose value accessor ends | |
219 | ///////////////////////////////////////////////////////////////////////// | |
220 | ||
221 | // Due to some imprecision in the C++ Standard, | |
222 | // MSVC 2010 is broken in debug mode: it requires | |
223 | // that an Output Iterator have output_iterator_tag in its iterator_category if | |
224 | // that iterator is not bidirectional_iterator or random_access_iterator. | |
225 | #if BOOST_WORKAROUND(BOOST_MSVC, >= 1600) | |
226 | struct mutable_iterator_tag | |
227 | : boost::random_access_traversal_tag, std::input_iterator_tag | |
228 | { | |
229 | operator std::output_iterator_tag() const { | |
230 | return std::output_iterator_tag(); | |
231 | } | |
232 | }; | |
233 | #endif | |
234 | ||
235 | //////////////////////////////////////////////////////////////////////// | |
236 | // multi_array_base | |
237 | //////////////////////////////////////////////////////////////////////// | |
238 | template <typename T, std::size_t NumDims> | |
239 | class multi_array_impl_base | |
240 | : | |
241 | public value_accessor_generator<T,mpl::size_t<NumDims> >::type | |
242 | { | |
243 | typedef associated_types<T,mpl::size_t<NumDims> > types; | |
244 | public: | |
245 | typedef typename types::index index; | |
246 | typedef typename types::size_type size_type; | |
247 | typedef typename types::element element; | |
248 | typedef typename types::index_range index_range; | |
249 | typedef typename types::value_type value_type; | |
250 | typedef typename types::reference reference; | |
251 | typedef typename types::const_reference const_reference; | |
252 | ||
253 | template <std::size_t NDims> | |
254 | struct subarray { | |
255 | typedef boost::detail::multi_array::sub_array<T,NDims> type; | |
256 | }; | |
257 | ||
258 | template <std::size_t NDims> | |
259 | struct const_subarray { | |
260 | typedef boost::detail::multi_array::const_sub_array<T,NDims> type; | |
261 | }; | |
262 | ||
263 | template <std::size_t NDims> | |
264 | struct array_view { | |
265 | typedef boost::detail::multi_array::multi_array_view<T,NDims> type; | |
266 | }; | |
267 | ||
268 | template <std::size_t NDims> | |
269 | struct const_array_view { | |
270 | public: | |
271 | typedef boost::detail::multi_array::const_multi_array_view<T,NDims> type; | |
272 | }; | |
273 | ||
274 | // | |
275 | // iterator support | |
276 | // | |
277 | #if BOOST_WORKAROUND(BOOST_MSVC, >= 1600) | |
278 | // Deal with VC 2010 output_iterator_tag requirement | |
279 | typedef array_iterator<T,T*,mpl::size_t<NumDims>,reference, | |
280 | mutable_iterator_tag> iterator; | |
281 | #else | |
282 | typedef array_iterator<T,T*,mpl::size_t<NumDims>,reference, | |
283 | boost::random_access_traversal_tag> iterator; | |
284 | #endif | |
285 | typedef array_iterator<T,T const*,mpl::size_t<NumDims>,const_reference, | |
286 | boost::random_access_traversal_tag> const_iterator; | |
287 | ||
288 | typedef ::boost::reverse_iterator<iterator> reverse_iterator; | |
289 | typedef ::boost::reverse_iterator<const_iterator> const_reverse_iterator; | |
290 | ||
291 | BOOST_STATIC_CONSTANT(std::size_t, dimensionality = NumDims); | |
292 | protected: | |
293 | ||
294 | multi_array_impl_base() { } | |
295 | ~multi_array_impl_base() { } | |
296 | ||
297 | // Used by operator() in our array classes | |
298 | template <typename Reference, typename IndexList, typename TPtr> | |
299 | Reference access_element(boost::type<Reference>, | |
300 | const IndexList& indices, | |
301 | TPtr base, | |
302 | const size_type* extents, | |
303 | const index* strides, | |
304 | const index* index_bases) const { | |
305 | boost::function_requires< | |
306 | CollectionConcept<IndexList> >(); | |
307 | ignore_unused_variable_warning(index_bases); | |
308 | ignore_unused_variable_warning(extents); | |
309 | #if !defined(NDEBUG) && !defined(BOOST_DISABLE_ASSERTS) | |
310 | for (size_type i = 0; i != NumDims; ++i) { | |
311 | BOOST_ASSERT(indices[i] - index_bases[i] >= 0); | |
312 | BOOST_ASSERT(size_type(indices[i] - index_bases[i]) < extents[i]); | |
313 | } | |
314 | #endif | |
315 | ||
316 | index offset = 0; | |
317 | { | |
318 | typename IndexList::const_iterator i = indices.begin(); | |
319 | size_type n = 0; | |
320 | while (n != NumDims) { | |
321 | offset += (*i) * strides[n]; | |
322 | ++n; | |
323 | ++i; | |
324 | } | |
325 | } | |
326 | return base[offset]; | |
327 | } | |
328 | ||
329 | template <typename StrideList, typename ExtentList> | |
330 | void compute_strides(StrideList& stride_list, ExtentList& extent_list, | |
331 | const general_storage_order<NumDims>& storage) | |
332 | { | |
333 | // invariant: stride = the stride for dimension n | |
334 | index stride = 1; | |
335 | for (size_type n = 0; n != NumDims; ++n) { | |
336 | index stride_sign = +1; | |
337 | ||
338 | if (!storage.ascending(storage.ordering(n))) | |
339 | stride_sign = -1; | |
340 | ||
341 | // The stride for this dimension is the product of the | |
342 | // lengths of the ranks minor to it. | |
343 | stride_list[storage.ordering(n)] = stride * stride_sign; | |
344 | ||
345 | stride *= extent_list[storage.ordering(n)]; | |
346 | } | |
347 | } | |
348 | ||
349 | // This calculates the offset to the array base pointer due to: | |
350 | // 1. dimensions stored in descending order | |
351 | // 2. non-zero dimension index bases | |
352 | template <typename StrideList, typename ExtentList, typename BaseList> | |
353 | index | |
354 | calculate_origin_offset(const StrideList& stride_list, | |
355 | const ExtentList& extent_list, | |
356 | const general_storage_order<NumDims>& storage, | |
357 | const BaseList& index_base_list) | |
358 | { | |
359 | return | |
360 | calculate_descending_dimension_offset(stride_list,extent_list, | |
361 | storage) + | |
362 | calculate_indexing_offset(stride_list,index_base_list); | |
363 | } | |
364 | ||
365 | // This calculates the offset added to the base pointer that are | |
366 | // caused by descending dimensions | |
367 | template <typename StrideList, typename ExtentList> | |
368 | index | |
369 | calculate_descending_dimension_offset(const StrideList& stride_list, | |
370 | const ExtentList& extent_list, | |
371 | const general_storage_order<NumDims>& storage) | |
372 | { | |
373 | index offset = 0; | |
374 | if (!storage.all_dims_ascending()) | |
375 | for (size_type n = 0; n != NumDims; ++n) | |
376 | if (!storage.ascending(n)) | |
377 | offset -= (extent_list[n] - 1) * stride_list[n]; | |
378 | ||
379 | return offset; | |
380 | } | |
381 | ||
382 | // This is used to reindex array_views, which are no longer | |
383 | // concerned about storage order (specifically, whether dimensions | |
384 | // are ascending or descending) since the viewed array handled it. | |
385 | ||
386 | template <typename StrideList, typename BaseList> | |
387 | index | |
388 | calculate_indexing_offset(const StrideList& stride_list, | |
389 | const BaseList& index_base_list) | |
390 | { | |
391 | index offset = 0; | |
392 | for (size_type n = 0; n != NumDims; ++n) | |
393 | offset -= stride_list[n] * index_base_list[n]; | |
394 | return offset; | |
395 | } | |
396 | ||
397 | // Slicing using an index_gen. | |
398 | // Note that populating an index_gen creates a type that encodes | |
399 | // both the number of dimensions in the current Array (NumDims), and | |
400 | // the Number of dimensions for the resulting view. This allows the | |
401 | // compiler to fail if the dimensions aren't completely accounted | |
402 | // for. For reasons unbeknownst to me, a BOOST_STATIC_ASSERT | |
403 | // within the member function template does not work. I should add a | |
404 | // note to the documentation specifying that you get a damn ugly | |
405 | // error message if you screw up in your slicing code. | |
406 | template <typename ArrayRef, int NDims, typename TPtr> | |
407 | ArrayRef | |
408 | generate_array_view(boost::type<ArrayRef>, | |
409 | const boost::detail::multi_array:: | |
410 | index_gen<NumDims,NDims>& indices, | |
411 | const size_type* extents, | |
412 | const index* strides, | |
413 | const index* index_bases, | |
414 | TPtr base) const { | |
415 | ||
416 | boost::array<index,NDims> new_strides; | |
417 | boost::array<index,NDims> new_extents; | |
418 | ||
419 | index offset = 0; | |
420 | size_type dim = 0; | |
421 | for (size_type n = 0; n != NumDims; ++n) { | |
422 | ||
423 | // Use array specs and input specs to produce real specs. | |
424 | const index default_start = index_bases[n]; | |
425 | const index default_finish = default_start+extents[n]; | |
426 | const index_range& current_range = indices.ranges_[n]; | |
427 | index start = current_range.get_start(default_start); | |
428 | index finish = current_range.get_finish(default_finish); | |
429 | index stride = current_range.stride(); | |
430 | BOOST_ASSERT(stride != 0); | |
431 | ||
432 | // An index range indicates a half-open strided interval | |
433 | // [start,finish) (with stride) which faces upward when stride | |
434 | // is positive and downward when stride is negative, | |
435 | ||
436 | // RG: The following code for calculating length suffers from | |
437 | // some representation issues: if finish-start cannot be represented as | |
438 | // by type index, then overflow may result. | |
439 | ||
440 | index len; | |
441 | if ((finish - start) / stride < 0) { | |
442 | // [start,finish) is empty according to the direction imposed by | |
443 | // the stride. | |
444 | len = 0; | |
445 | } else { | |
446 | // integral trick for ceiling((finish-start) / stride) | |
447 | // taking into account signs. | |
448 | index shrinkage = stride > 0 ? 1 : -1; | |
449 | len = (finish - start + (stride - shrinkage)) / stride; | |
450 | } | |
451 | ||
452 | // start marks the closed side of the range, so it must lie | |
453 | // exactly in the set of legal indices | |
454 | // with a special case for empty arrays | |
455 | BOOST_ASSERT(index_bases[n] <= start && | |
456 | ((start <= index_bases[n]+index(extents[n])) || | |
457 | (start == index_bases[n] && extents[n] == 0))); | |
458 | ||
459 | #ifndef BOOST_DISABLE_ASSERTS | |
460 | // finish marks the open side of the range, so it can go one past | |
461 | // the "far side" of the range (the top if stride is positive, the bottom | |
462 | // if stride is negative). | |
463 | index bound_adjustment = stride < 0 ? 1 : 0; | |
464 | BOOST_ASSERT(((index_bases[n] - bound_adjustment) <= finish) && | |
465 | (finish <= (index_bases[n] + index(extents[n]) - bound_adjustment))); | |
466 | #endif // BOOST_DISABLE_ASSERTS | |
467 | ||
468 | ||
469 | // the array data pointer is modified to account for non-zero | |
470 | // bases during slicing (see [Garcia] for the math involved) | |
471 | offset += start * strides[n]; | |
472 | ||
473 | if (!current_range.is_degenerate()) { | |
474 | ||
475 | // The stride for each dimension is included into the | |
476 | // strides for the array_view (see [Garcia] for the math involved). | |
477 | new_strides[dim] = stride * strides[n]; | |
478 | ||
479 | // calculate new extents | |
480 | new_extents[dim] = len; | |
481 | ++dim; | |
482 | } | |
483 | } | |
484 | BOOST_ASSERT(dim == NDims); | |
485 | ||
486 | return | |
487 | ArrayRef(base+offset, | |
488 | new_extents, | |
489 | new_strides); | |
490 | } | |
491 | ||
492 | ||
493 | }; | |
494 | ||
495 | } // namespace multi_array | |
496 | } // namespace detail | |
497 | ||
498 | } // namespace boost | |
499 | ||
500 | #endif // BASE_RG071801_HPP |