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27// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
28// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
29
30#ifndef PXFOUNDATION_PXSTRIDEITERATOR_H
31#define PXFOUNDATION_PXSTRIDEITERATOR_H
32
33#include "foundation/Px.h"
34#include "foundation/PxSharedAssert.h"
35
36/** \addtogroup foundation
37 @{
38*/
39
40#if !PX_DOXYGEN
41namespace physx
42{
43#endif
44
45/**
46\brief Iterator class for iterating over arrays of data that may be interleaved with other data.
47
48This class is used for iterating over arrays of elements that may have a larger element to element
49offset, called the stride, than the size of the element itself (non-contiguous).
50
51The template parameter T denotes the type of the element accessed. The stride itself
52is stored as a member field so multiple instances of a PxStrideIterator class can have
53different strides. This is useful for cases were the stride depends on runtime configuration.
54
55The stride iterator can be used for index based access, e.g.:
56\code
57 PxStrideIterator<PxVec3> strideArray(...);
58 for (unsigned i = 0; i < 10; ++i)
59 {
60 PxVec3& vec = strideArray[i];
61 ...
62 }
63\endcode
64or iteration by increment, e.g.:
65\code
66 PxStrideIterator<PxVec3> strideBegin(...);
67 PxStrideIterator<PxVec3> strideEnd(strideBegin + 10);
68 for (PxStrideIterator<PxVec3> it = strideBegin; it < strideEnd; ++it)
69 {
70 PxVec3& vec = *it;
71 ...
72 }
73\endcode
74
75Two special cases:
76- A stride of sizeof(T) represents a regular c array of type T.
77- A stride of 0 can be used to describe re-occurrence of the same element multiple times.
78
79*/
80template <typename T>
81class PxStrideIterator
82{
83
84#if !PX_DOXYGEN
85 template <typename X>
86 struct StripConst
87 {
88 typedef X Type;
89 };
90
91 template <typename X>
92 struct StripConst<const X>
93 {
94 typedef X Type;
95 };
96#endif
97
98 public:
99 /**
100 \brief Constructor.
101
102 Optionally takes a pointer to an element and a stride.
103
104 \param[in] ptr pointer to element, defaults to NULL.
105 \param[in] stride stride for accessing consecutive elements, defaults to the size of one element.
106 */
107 explicit PX_INLINE PxStrideIterator(T* ptr = NULL, PxU32 stride = sizeof(T)) : mPtr(ptr), mStride(stride)
108 {
109 PX_SHARED_ASSERT(mStride == 0 || sizeof(T) <= mStride);
110 }
111
112 /**
113 \brief Copy constructor.
114
115 \param[in] strideIterator PxStrideIterator to be copied.
116 */
117 PX_INLINE PxStrideIterator(const PxStrideIterator<typename StripConst<T>::Type>& strideIterator)
118 : mPtr(strideIterator.ptr()), mStride(strideIterator.stride())
119 {
120 PX_SHARED_ASSERT(mStride == 0 || sizeof(T) <= mStride);
121 }
122
123 /**
124 \brief Get pointer to element.
125 */
126 PX_INLINE T* ptr() const
127 {
128 return mPtr;
129 }
130
131 /**
132 \brief Get stride.
133 */
134 PX_INLINE PxU32 stride() const
135 {
136 return mStride;
137 }
138
139 /**
140 \brief Indirection operator.
141 */
142 PX_INLINE T& operator*() const
143 {
144 return *mPtr;
145 }
146
147 /**
148 \brief Dereferencing operator.
149 */
150 PX_INLINE T* operator->() const
151 {
152 return mPtr;
153 }
154
155 /**
156 \brief Indexing operator.
157 */
158 PX_INLINE T& operator[](unsigned int i) const
159 {
160 return *byteAdd(ptr: mPtr, bytes: i * stride());
161 }
162
163 /**
164 \brief Pre-increment operator.
165 */
166 PX_INLINE PxStrideIterator& operator++()
167 {
168 mPtr = byteAdd(ptr: mPtr, bytes: stride());
169 return *this;
170 }
171
172 /**
173 \brief Post-increment operator.
174 */
175 PX_INLINE PxStrideIterator operator++(int)
176 {
177 PxStrideIterator tmp = *this;
178 mPtr = byteAdd(ptr: mPtr, bytes: stride());
179 return tmp;
180 }
181
182 /**
183 \brief Pre-decrement operator.
184 */
185 PX_INLINE PxStrideIterator& operator--()
186 {
187 mPtr = byteSub(ptr: mPtr, bytes: stride());
188 return *this;
189 }
190
191 /**
192 \brief Post-decrement operator.
193 */
194 PX_INLINE PxStrideIterator operator--(int)
195 {
196 PxStrideIterator tmp = *this;
197 mPtr = byteSub(ptr: mPtr, bytes: stride());
198 return tmp;
199 }
200
201 /**
202 \brief Addition operator.
203 */
204 PX_INLINE PxStrideIterator operator+(unsigned int i) const
205 {
206 return PxStrideIterator(byteAdd(ptr: mPtr, bytes: i * stride()), stride());
207 }
208
209 /**
210 \brief Subtraction operator.
211 */
212 PX_INLINE PxStrideIterator operator-(unsigned int i) const
213 {
214 return PxStrideIterator(byteSub(ptr: mPtr, bytes: i * stride()), stride());
215 }
216
217 /**
218 \brief Addition compound assignment operator.
219 */
220 PX_INLINE PxStrideIterator& operator+=(unsigned int i)
221 {
222 mPtr = byteAdd(ptr: mPtr, bytes: i * stride());
223 return *this;
224 }
225
226 /**
227 \brief Subtraction compound assignment operator.
228 */
229 PX_INLINE PxStrideIterator& operator-=(unsigned int i)
230 {
231 mPtr = byteSub(ptr: mPtr, bytes: i * stride());
232 return *this;
233 }
234
235 /**
236 \brief Iterator difference.
237 */
238 PX_INLINE int operator-(const PxStrideIterator& other) const
239 {
240 PX_SHARED_ASSERT(isCompatible(other));
241 int byteDiff = static_cast<int>(reinterpret_cast<const PxU8*>(mPtr) - reinterpret_cast<const PxU8*>(other.mPtr));
242 return byteDiff / static_cast<int>(stride());
243 }
244
245 /**
246 \brief Equality operator.
247 */
248 PX_INLINE bool operator==(const PxStrideIterator& other) const
249 {
250 PX_SHARED_ASSERT(isCompatible(other));
251 return mPtr == other.mPtr;
252 }
253
254 /**
255 \brief Inequality operator.
256 */
257 PX_INLINE bool operator!=(const PxStrideIterator& other) const
258 {
259 PX_SHARED_ASSERT(isCompatible(other));
260 return mPtr != other.mPtr;
261 }
262
263 /**
264 \brief Less than operator.
265 */
266 PX_INLINE bool operator<(const PxStrideIterator& other) const
267 {
268 PX_SHARED_ASSERT(isCompatible(other));
269 return mPtr < other.mPtr;
270 }
271
272 /**
273 \brief Greater than operator.
274 */
275 PX_INLINE bool operator>(const PxStrideIterator& other) const
276 {
277 PX_SHARED_ASSERT(isCompatible(other));
278 return mPtr > other.mPtr;
279 }
280
281 /**
282 \brief Less or equal than operator.
283 */
284 PX_INLINE bool operator<=(const PxStrideIterator& other) const
285 {
286 PX_SHARED_ASSERT(isCompatible(other));
287 return mPtr <= other.mPtr;
288 }
289
290 /**
291 \brief Greater or equal than operator.
292 */
293 PX_INLINE bool operator>=(const PxStrideIterator& other) const
294 {
295 PX_SHARED_ASSERT(isCompatible(other));
296 return mPtr >= other.mPtr;
297 }
298
299 private:
300 PX_INLINE static T* byteAdd(T* ptr, PxU32 bytes)
301 {
302 return const_cast<T*>(reinterpret_cast<const T*>(reinterpret_cast<const PxU8*>(ptr) + bytes));
303 }
304
305 PX_INLINE static T* byteSub(T* ptr, PxU32 bytes)
306 {
307 return const_cast<T*>(reinterpret_cast<const T*>(reinterpret_cast<const PxU8*>(ptr) - bytes));
308 }
309
310 PX_INLINE bool isCompatible(const PxStrideIterator& other) const
311 {
312 int byteDiff = static_cast<int>(reinterpret_cast<const PxU8*>(mPtr) - reinterpret_cast<const PxU8*>(other.mPtr));
313 return (stride() == other.stride()) && (abs(x: byteDiff) % stride() == 0);
314 }
315
316 T* mPtr;
317 PxU32 mStride;
318};
319
320/**
321\brief Addition operator.
322*/
323template <typename T>
324PX_INLINE PxStrideIterator<T> operator+(int i, PxStrideIterator<T> it)
325{
326 it += i;
327 return it;
328}
329
330/**
331\brief Stride iterator factory function which infers the iterator type.
332*/
333template <typename T>
334PX_INLINE PxStrideIterator<T> PxMakeIterator(T* ptr, PxU32 stride = sizeof(T))
335{
336 return PxStrideIterator<T>(ptr, stride);
337}
338
339/**
340\brief Stride iterator factory function which infers the iterator type.
341*/
342template <typename T>
343PX_INLINE PxStrideIterator<const T> PxMakeIterator(const T* ptr, PxU32 stride = sizeof(T))
344{
345 return PxStrideIterator<const T>(ptr, stride);
346}
347
348#if !PX_DOXYGEN
349} // namespace physx
350#endif
351
352/** @} */
353#endif // PXFOUNDATION_PXSTRIDEITERATOR_H
354

source code of qtquick3dphysics/src/3rdparty/PhysX/pxshared/include/foundation/PxStrideIterator.h