193 lines
8.0 KiB
C++
193 lines
8.0 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra.
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//
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// Copyright (C) 2007-2010 Benoit Jacob <jacob.benoit.1@gmail.com>
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// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
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//
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// This Source Code Form is subject to the terms of the Mozilla
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// Public License v. 2.0. If a copy of the MPL was not distributed
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// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#ifndef EIGEN_MAP_H
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#define EIGEN_MAP_H
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namespace Eigen {
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/** \class Map
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* \ingroup Core_Module
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*
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* \brief A matrix or vector expression mapping an existing array of data.
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*
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* \tparam PlainObjectType the equivalent matrix type of the mapped data
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* \tparam MapOptions specifies whether the pointer is \c #Aligned, or \c #Unaligned.
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* The default is \c #Unaligned.
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* \tparam StrideType optionally specifies strides. By default, Map assumes the memory layout
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* of an ordinary, contiguous array. This can be overridden by specifying strides.
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* The type passed here must be a specialization of the Stride template, see examples below.
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*
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* This class represents a matrix or vector expression mapping an existing array of data.
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* It can be used to let Eigen interface without any overhead with non-Eigen data structures,
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* such as plain C arrays or structures from other libraries. By default, it assumes that the
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* data is laid out contiguously in memory. You can however override this by explicitly specifying
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* inner and outer strides.
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*
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* Here's an example of simply mapping a contiguous array as a \ref TopicStorageOrders "column-major" matrix:
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* \include Map_simple.cpp
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* Output: \verbinclude Map_simple.out
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*
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* If you need to map non-contiguous arrays, you can do so by specifying strides:
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*
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* Here's an example of mapping an array as a vector, specifying an inner stride, that is, the pointer
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* increment between two consecutive coefficients. Here, we're specifying the inner stride as a compile-time
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* fixed value.
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* \include Map_inner_stride.cpp
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* Output: \verbinclude Map_inner_stride.out
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*
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* Here's an example of mapping an array while specifying an outer stride. Here, since we're mapping
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* as a column-major matrix, 'outer stride' means the pointer increment between two consecutive columns.
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* Here, we're specifying the outer stride as a runtime parameter. Note that here \c OuterStride<> is
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* a short version of \c OuterStride<Dynamic> because the default template parameter of OuterStride
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* is \c Dynamic
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* \include Map_outer_stride.cpp
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* Output: \verbinclude Map_outer_stride.out
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*
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* For more details and for an example of specifying both an inner and an outer stride, see class Stride.
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*
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* \b Tip: to change the array of data mapped by a Map object, you can use the C++
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* placement new syntax:
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*
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* Example: \include Map_placement_new.cpp
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* Output: \verbinclude Map_placement_new.out
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*
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* This class is the return type of PlainObjectBase::Map() but can also be used directly.
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*
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* \sa PlainObjectBase::Map(), \ref TopicStorageOrders
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*/
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namespace internal {
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template<typename PlainObjectType, int MapOptions, typename StrideType>
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struct traits<Map<PlainObjectType, MapOptions, StrideType> >
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: public traits<PlainObjectType>
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{
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typedef traits<PlainObjectType> TraitsBase;
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typedef typename PlainObjectType::Index Index;
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typedef typename PlainObjectType::Scalar Scalar;
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enum {
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InnerStrideAtCompileTime = StrideType::InnerStrideAtCompileTime == 0
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? int(PlainObjectType::InnerStrideAtCompileTime)
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: int(StrideType::InnerStrideAtCompileTime),
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OuterStrideAtCompileTime = StrideType::OuterStrideAtCompileTime == 0
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? int(PlainObjectType::OuterStrideAtCompileTime)
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: int(StrideType::OuterStrideAtCompileTime),
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HasNoInnerStride = InnerStrideAtCompileTime == 1,
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HasNoOuterStride = StrideType::OuterStrideAtCompileTime == 0,
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HasNoStride = HasNoInnerStride && HasNoOuterStride,
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IsAligned = bool(EIGEN_ALIGN) && ((int(MapOptions)&Aligned)==Aligned),
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IsDynamicSize = PlainObjectType::SizeAtCompileTime==Dynamic,
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KeepsPacketAccess = bool(HasNoInnerStride)
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&& ( bool(IsDynamicSize)
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|| HasNoOuterStride
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|| ( OuterStrideAtCompileTime!=Dynamic
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&& ((static_cast<int>(sizeof(Scalar))*OuterStrideAtCompileTime)%16)==0 ) ),
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Flags0 = TraitsBase::Flags & (~NestByRefBit),
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Flags1 = IsAligned ? (int(Flags0) | AlignedBit) : (int(Flags0) & ~AlignedBit),
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Flags2 = (bool(HasNoStride) || bool(PlainObjectType::IsVectorAtCompileTime))
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? int(Flags1) : int(Flags1 & ~LinearAccessBit),
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Flags3 = is_lvalue<PlainObjectType>::value ? int(Flags2) : (int(Flags2) & ~LvalueBit),
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Flags = KeepsPacketAccess ? int(Flags3) : (int(Flags3) & ~PacketAccessBit)
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};
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private:
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enum { Options }; // Expressions don't have Options
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};
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}
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template<typename PlainObjectType, int MapOptions, typename StrideType> class Map
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: public MapBase<Map<PlainObjectType, MapOptions, StrideType> >
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{
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public:
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typedef MapBase<Map> Base;
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EIGEN_DENSE_PUBLIC_INTERFACE(Map)
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typedef typename Base::PointerType PointerType;
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#if EIGEN2_SUPPORT_STAGE <= STAGE30_FULL_EIGEN3_API
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typedef const Scalar* PointerArgType;
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inline PointerType cast_to_pointer_type(PointerArgType ptr) { return const_cast<PointerType>(ptr); }
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#else
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typedef PointerType PointerArgType;
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inline PointerType cast_to_pointer_type(PointerArgType ptr) { return ptr; }
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#endif
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inline Index innerStride() const
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{
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return StrideType::InnerStrideAtCompileTime != 0 ? m_stride.inner() : 1;
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}
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inline Index outerStride() const
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{
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return StrideType::OuterStrideAtCompileTime != 0 ? m_stride.outer()
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: IsVectorAtCompileTime ? this->size()
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: int(Flags)&RowMajorBit ? this->cols()
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: this->rows();
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}
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/** Constructor in the fixed-size case.
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*
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* \param dataPtr pointer to the array to map
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* \param a_stride optional Stride object, passing the strides.
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*/
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inline Map(PointerArgType dataPtr, const StrideType& a_stride = StrideType())
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: Base(cast_to_pointer_type(dataPtr)), m_stride(a_stride)
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{
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PlainObjectType::Base::_check_template_params();
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}
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/** Constructor in the dynamic-size vector case.
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*
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* \param dataPtr pointer to the array to map
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* \param a_size the size of the vector expression
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* \param a_stride optional Stride object, passing the strides.
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*/
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inline Map(PointerArgType dataPtr, Index a_size, const StrideType& a_stride = StrideType())
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: Base(cast_to_pointer_type(dataPtr), a_size), m_stride(a_stride)
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{
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PlainObjectType::Base::_check_template_params();
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}
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/** Constructor in the dynamic-size matrix case.
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*
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* \param dataPtr pointer to the array to map
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* \param nbRows the number of rows of the matrix expression
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* \param nbCols the number of columns of the matrix expression
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* \param a_stride optional Stride object, passing the strides.
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*/
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inline Map(PointerArgType dataPtr, Index nbRows, Index nbCols, const StrideType& a_stride = StrideType())
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: Base(cast_to_pointer_type(dataPtr), nbRows, nbCols), m_stride(a_stride)
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{
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PlainObjectType::Base::_check_template_params();
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}
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EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Map)
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protected:
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StrideType m_stride;
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};
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template<typename _Scalar, int _Rows, int _Cols, int _Options, int _MaxRows, int _MaxCols>
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inline Array<_Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols>
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::Array(const Scalar *data)
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{
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this->_set_noalias(Eigen::Map<const Array>(data));
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}
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template<typename _Scalar, int _Rows, int _Cols, int _Options, int _MaxRows, int _MaxCols>
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inline Matrix<_Scalar, _Rows, _Cols, _Options, _MaxRows, _MaxCols>
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::Matrix(const Scalar *data)
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{
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this->_set_noalias(Eigen::Map<const Matrix>(data));
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}
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} // end namespace Eigen
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#endif // EIGEN_MAP_H
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