Revision control
++ // Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
++ // Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
++ // SPDX-FileCopyrightText: Copyright (c) 2008-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
++ // SPDX-License-Identifier: Apache-2.0
++
++ #ifndef PX_STRIDE_ITERATOR_H
++ #define PX_STRIDE_ITERATOR_H
++
++ #include "foundation/PxAssert.h"
++
++
++ #if !PX_DOXYGEN
++ namespace physx
++ {
++ #endif
++
++ /**
++ \brief Iterator class for iterating over arrays of data that may be interleaved with other data.
++
++ This class is used for iterating over arrays of elements that may have a larger element to element
++ offset, called the stride, than the size of the element itself (non-contiguous).
++
++ The template parameter T denotes the type of the element accessed. The stride itself
++ is stored as a member field so multiple instances of a PxStrideIterator class can have
++ different strides. This is useful for cases were the stride depends on runtime configuration.
++
++ The stride iterator can be used for index based access, e.g.:
++ \code
++ PxStrideIterator<PxVec3> strideArray(...);
++ for (unsigned i = 0; i < 10; ++i)
++ {
++ PxVec3& vec = strideArray[i];
++ ...
++ }
++ \endcode
++ or iteration by increment, e.g.:
++ \code
++ PxStrideIterator<PxVec3> strideBegin(...);
++ PxStrideIterator<PxVec3> strideEnd(strideBegin + 10);
++ for (PxStrideIterator<PxVec3> it = strideBegin; it < strideEnd; ++it)
++ {
++ PxVec3& vec = *it;
++ ...
++ }
++ \endcode
++
++ Two special cases:
++ - A stride of sizeof(T) represents a regular c array of type T.
++ - A stride of 0 can be used to describe re-occurrence of the same element multiple times.
++
++ */
++ template <typename T>
++ class PxStrideIterator
++ {
++
++ #if !PX_DOXYGEN
++ template <typename X>
++ struct StripConst
++ {
++ typedef X Type;
++ };
++
++ template <typename X>
++ struct StripConst<const X>
++ {
++ typedef X Type;
++ };
++ #endif
++
++ public:
++ /**
++ \brief Constructor.
++
++ Optionally takes a pointer to an element and a stride.
++
++ \param[in] ptr pointer to element, defaults to NULL.
++ \param[in] stride stride for accessing consecutive elements, defaults to the size of one element.
++ */
++ explicit PX_INLINE PxStrideIterator(T* ptr = NULL, PxU32 stride = sizeof(T)) : mPtr(ptr), mStride(stride)
++ {
++ PX_ASSERT(mStride == 0 || sizeof(T) <= mStride);
++ }
++
++ /**
++ \brief Copy constructor.
++
++ \param[in] strideIterator PxStrideIterator to be copied.
++ */
++ PX_INLINE PxStrideIterator(const PxStrideIterator<typename StripConst<T>::Type>& strideIterator)
++ : mPtr(strideIterator.ptr()), mStride(strideIterator.stride())
++ {
++ PX_ASSERT(mStride == 0 || sizeof(T) <= mStride);
++ }
++
++ /**
++ \brief Get pointer to element.
++ */
++ PX_INLINE T* ptr() const
++ {
++ return mPtr;
++ }
++
++ /**
++ \brief Get stride.
++ */
++ PX_INLINE PxU32 stride() const
++ {
++ return mStride;
++ }
++
++ /**
++ \brief Indirection operator.
++ */
++ PX_INLINE T& operator*() const
++ {
++ return *mPtr;
++ }
++
++ /**
++ \brief Dereferencing operator.
++ */
++ PX_INLINE T* operator->() const
++ {
++ return mPtr;
++ }
++
++ /**
++ \brief Indexing operator.
++ */
++ PX_INLINE T& operator[](unsigned int i) const
++ {
++ return *byteAdd(mPtr, i * stride());
++ }
++
++ /**
++ \brief Pre-increment operator.
++ */
++ PX_INLINE PxStrideIterator& operator++()
++ {
++ mPtr = byteAdd(mPtr, stride());
++ return *this;
++ }
++
++ /**
++ \brief Post-increment operator.
++ */
++ PX_INLINE PxStrideIterator operator++(int)
++ {
++ PxStrideIterator tmp = *this;
++ mPtr = byteAdd(mPtr, stride());
++ return tmp;
++ }
++
++ /**
++ \brief Pre-decrement operator.
++ */
++ PX_INLINE PxStrideIterator& operator--()
++ {
++ mPtr = byteSub(mPtr, stride());
++ return *this;
++ }
++
++ /**
++ \brief Post-decrement operator.
++ */
++ PX_INLINE PxStrideIterator operator--(int)
++ {
++ PxStrideIterator tmp = *this;
++ mPtr = byteSub(mPtr, stride());
++ return tmp;
++ }
++
++ /**
++ \brief Addition operator.
++ */
++ PX_INLINE PxStrideIterator operator+(unsigned int i) const
++ {
++ return PxStrideIterator(byteAdd(mPtr, i * stride()), stride());
++ }
++
++ /**
++ \brief Subtraction operator.
++ */
++ PX_INLINE PxStrideIterator operator-(unsigned int i) const
++ {
++ return PxStrideIterator(byteSub(mPtr, i * stride()), stride());
++ }
++
++ /**
++ \brief Addition compound assignment operator.
++ */
++ PX_INLINE PxStrideIterator& operator+=(unsigned int i)
++ {
++ mPtr = byteAdd(mPtr, i * stride());
++ return *this;
++ }
++
++ /**
++ \brief Subtraction compound assignment operator.
++ */
++ PX_INLINE PxStrideIterator& operator-=(unsigned int i)
++ {
++ mPtr = byteSub(mPtr, i * stride());
++ return *this;
++ }
++
++ /**
++ \brief Iterator difference.
++ */
++ PX_INLINE int operator-(const PxStrideIterator& other) const
++ {
++ PX_ASSERT(isCompatible(other));
++ int byteDiff = static_cast<int>(reinterpret_cast<const PxU8*>(mPtr) - reinterpret_cast<const PxU8*>(other.mPtr));
++ return byteDiff / static_cast<int>(stride());
++ }
++
++ /**
++ \brief Equality operator.
++ */
++ PX_INLINE bool operator==(const PxStrideIterator& other) const
++ {
++ PX_ASSERT(isCompatible(other));
++ return mPtr == other.mPtr;
++ }
++
++ /**
++ \brief Inequality operator.
++ */
++ PX_INLINE bool operator!=(const PxStrideIterator& other) const
++ {
++ PX_ASSERT(isCompatible(other));
++ return mPtr != other.mPtr;
++ }
++
++ /**
++ \brief Less than operator.
++ */
++ PX_INLINE bool operator<(const PxStrideIterator& other) const
++ {
++ PX_ASSERT(isCompatible(other));
++ return mPtr < other.mPtr;
++ }
++
++ /**
++ \brief Greater than operator.
++ */
++ PX_INLINE bool operator>(const PxStrideIterator& other) const
++ {
++ PX_ASSERT(isCompatible(other));
++ return mPtr > other.mPtr;
++ }
++
++ /**
++ \brief Less or equal than operator.
++ */
++ PX_INLINE bool operator<=(const PxStrideIterator& other) const
++ {
++ PX_ASSERT(isCompatible(other));
++ return mPtr <= other.mPtr;
++ }
++
++ /**
++ \brief Greater or equal than operator.
++ */
++ PX_INLINE bool operator>=(const PxStrideIterator& other) const
++ {
++ PX_ASSERT(isCompatible(other));
++ return mPtr >= other.mPtr;
++ }
++
++ private:
++ PX_INLINE static T* byteAdd(T* ptr, PxU32 bytes)
++ {
++ return const_cast<T*>(reinterpret_cast<const T*>(reinterpret_cast<const PxU8*>(ptr) + bytes));
++ }
++
++ PX_INLINE static T* byteSub(T* ptr, PxU32 bytes)
++ {
++ return const_cast<T*>(reinterpret_cast<const T*>(reinterpret_cast<const PxU8*>(ptr) - bytes));
++ }
++
++ PX_INLINE bool isCompatible(const PxStrideIterator& other) const
++ {
++ int byteDiff = static_cast<int>(reinterpret_cast<const PxU8*>(mPtr) - reinterpret_cast<const PxU8*>(other.mPtr));
++ return (stride() == other.stride()) && (abs(byteDiff) % stride() == 0);
++ }
++
++ T* mPtr;
++ PxU32 mStride;
++ };
++
++ /**
++ \brief Addition operator.
++ */
++ template <typename T>
++ PX_INLINE PxStrideIterator<T> operator+(int i, PxStrideIterator<T> it)
++ {
++ it += i;
++ return it;
++ }
++
++ /**
++ \brief Stride iterator factory function which infers the iterator type.
++ */
++ template <typename T>
++ PX_INLINE PxStrideIterator<T> PxMakeIterator(T* ptr, PxU32 stride = sizeof(T))
++ {
++ return PxStrideIterator<T>(ptr, stride);
++ }
++
++ /**
++ \brief Stride iterator factory function which infers the iterator type.
++ */
++ template <typename T>
++ PX_INLINE PxStrideIterator<const T> PxMakeIterator(const T* ptr, PxU32 stride = sizeof(T))
++ {
++ return PxStrideIterator<const T>(ptr, stride);
++ }
++
++ #if !PX_DOXYGEN
++ } // namespace physx
++ #endif
++
++ #endif
++