bug #231: initial implementation of STL iterators for dense expressions

1 files changed, 235 insertions, 0 deletions

diff --git a/Eigen/src/Core/StlIterators.h b/Eigen/src/Core/StlIterators.h
new file mode 100644
index 000000000..c2b162a7b
--- /dev/null
+++ b/Eigen/src/Core/StlIterators.h
@@ -0,0 +1,235 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2018 Gael Guennebaud <gael.guennebaud@inria.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+namespace Eigen {
+
+template<typename XprType,typename Derived>
+class DenseStlIteratorBase
+{
+public:
+  typedef std::ptrdiff_t difference_type;
+  typedef std::random_access_iterator_tag iterator_category;
+
+  DenseStlIteratorBase() : mp_xpr(0), m_index(0) {}
+  DenseStlIteratorBase(XprType& xpr, Index index) : mp_xpr(&xpr), m_index(index) {}
+
+  void swap(DenseStlIteratorBase& other) {
+    std::swap(mp_xpr,other.mp_xpr);
+    std::swap(m_index,other.m_index);
+  }
+
+  Derived& operator++() { ++m_index; return derived(); }
+  Derived& operator--() { --m_index; return derived(); }
+
+  Derived operator++(int) { Derived prev(derived()); operator++(); return prev;}
+  Derived operator--(int) { Derived prev(derived()); operator--(); return prev;}
+
+  friend Derived operator+(const DenseStlIteratorBase& a, int b) { Derived ret(a.derived()); ret += b; return ret; }
+  friend Derived operator-(const DenseStlIteratorBase& a, int b) { Derived ret(a.derived()); ret -= b; return ret; }
+  friend Derived operator+(int a, const DenseStlIteratorBase& b) { Derived ret(b.derived()); ret += a; return ret; }
+  friend Derived operator-(int a, const DenseStlIteratorBase& b) { Derived ret(b.derived()); ret -= a; return ret; }
+  
+  Derived& operator+=(int b) { m_index += b; return derived(); }
+  Derived& operator-=(int b) { m_index -= b; return derived(); }
+
+  difference_type operator-(const DenseStlIteratorBase& other) const { eigen_assert(mp_xpr == other.mp_xpr);return m_index - other.m_index; }
+
+  bool operator==(const DenseStlIteratorBase& other) { eigen_assert(mp_xpr == other.mp_xpr); return m_index == other.m_index; }
+  bool operator!=(const DenseStlIteratorBase& other) { eigen_assert(mp_xpr == other.mp_xpr); return m_index != other.m_index; }
+  bool operator< (const DenseStlIteratorBase& other) { eigen_assert(mp_xpr == other.mp_xpr); return m_index <  other.m_index; }
+  bool operator<=(const DenseStlIteratorBase& other) { eigen_assert(mp_xpr == other.mp_xpr); return m_index <= other.m_index; }
+  bool operator> (const DenseStlIteratorBase& other) { eigen_assert(mp_xpr == other.mp_xpr); return m_index >  other.m_index; }
+  bool operator>=(const DenseStlIteratorBase& other) { eigen_assert(mp_xpr == other.mp_xpr); return m_index >= other.m_index; }
+
+protected:
+
+  Derived& derived() { return static_cast<Derived&>(*this); }
+  const Derived& derived() const { return static_cast<const Derived&>(*this); }
+
+  XprType *mp_xpr;
+  Index m_index;
+};
+
+template<typename XprType>
+class DenseStlIterator : public DenseStlIteratorBase<XprType, DenseStlIterator<XprType> >
+{
+public:
+  typedef typename XprType::Scalar value_type;
+
+protected:
+
+  enum {
+    has_direct_access = (internal::traits<XprType>::Flags & DirectAccessBit) ? 1 : 0,
+    has_write_access  = internal::is_lvalue<XprType>::value
+  };
+
+  typedef DenseStlIteratorBase<XprType,DenseStlIterator> Base;
+  using Base::m_index;
+  using Base::mp_xpr;
+
+  typedef typename internal::conditional<bool(has_direct_access), const value_type&, const value_type>::type read_only_ref_t;
+
+public:
+  
+  typedef typename internal::conditional<bool(has_write_access), value_type *, const value_type *>::type pointer;
+  typedef typename internal::conditional<bool(has_write_access), value_type&, read_only_ref_t>::type reference;
+  
+
+  DenseStlIterator() : Base() {}
+  DenseStlIterator(XprType& xpr, Index index) : Base(xpr,index) {}
+
+  reference operator*()       const { return (*mp_xpr)(m_index); }
+  reference operator[](int i) const { return (*mp_xpr)(i);       }
+  
+  pointer   operator->() const { return &((*mp_xpr)(m_index)); }
+};
+
+template<typename XprType,typename Derived>
+void swap(DenseStlIteratorBase<XprType,Derived>& a, DenseStlIteratorBase<XprType,Derived>& b) {
+  a.swap(b);
+}
+
+template<typename Derived>
+inline DenseStlIterator<Derived> DenseBase<Derived>::begin()
+{
+  EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived);
+  return DenseStlIterator<Derived>(derived(), 0);
+}
+
+template<typename Derived>
+inline DenseStlIterator<const Derived> DenseBase<Derived>::begin() const
+{
+  return cbegin();
+}
+
+template<typename Derived>
+inline DenseStlIterator<const Derived> DenseBase<Derived>::cbegin() const
+{
+  EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived);
+  return DenseStlIterator<const Derived>(derived(), 0);
+}
+
+template<typename Derived>
+inline DenseStlIterator<Derived> DenseBase<Derived>::end()
+{
+  EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived);
+  return DenseStlIterator<Derived>(derived(), size());
+}
+
+template<typename Derived>
+inline DenseStlIterator<const Derived> DenseBase<Derived>::end() const
+{
+  return cend();
+}
+
+template<typename Derived>
+inline DenseStlIterator<const Derived> DenseBase<Derived>::cend() const
+{
+  EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived);
+  return DenseStlIterator<const Derived>(derived(), size());
+}
+
+template<typename XprType>
+class DenseColStlIterator : public DenseStlIteratorBase<XprType, DenseColStlIterator<XprType> >
+{
+protected:
+
+  enum { is_lvalue  = internal::is_lvalue<XprType>::value };
+
+  typedef DenseStlIteratorBase<XprType,DenseColStlIterator> Base;
+  using Base::m_index;
+  using Base::mp_xpr;
+
+public:
+  typedef typename internal::conditional<bool(is_lvalue), typename XprType::ColXpr, typename XprType::ConstColXpr>::type value_type;
+  typedef value_type* pointer;
+  typedef value_type  reference;
+  
+  DenseColStlIterator() : Base() {}
+  DenseColStlIterator(XprType& xpr, Index index) : Base(xpr,index) {}
+
+  reference operator*()       const { return (*mp_xpr).col(m_index); }
+  reference operator[](int i) const { return (*mp_xpr).col(i);       }
+  
+  pointer   operator->() const { return &((*mp_xpr).col(m_index)); }
+};
+
+template<typename XprType>
+class DenseRowStlIterator : public DenseStlIteratorBase<XprType, DenseRowStlIterator<XprType> >
+{
+protected:
+
+  enum { is_lvalue  = internal::is_lvalue<XprType>::value };
+
+  typedef DenseStlIteratorBase<XprType,DenseRowStlIterator> Base;
+  using Base::m_index;
+  using Base::mp_xpr;
+
+public:
+  typedef typename internal::conditional<bool(is_lvalue), typename XprType::RowXpr, typename XprType::ConstRowXpr>::type value_type;
+  typedef value_type* pointer;
+  typedef value_type  reference;
+  
+  DenseRowStlIterator() : Base() {}
+  DenseRowStlIterator(XprType& xpr, Index index) : Base(xpr,index) {}
+
+  reference operator*()       const { return (*mp_xpr).row(m_index); }
+  reference operator[](int i) const { return (*mp_xpr).row(i);       }
+  
+  pointer   operator->() const { return &((*mp_xpr).row(m_index)); }
+};
+
+
+template<typename Xpr>
+class ColsProxy
+{
+public:
+  ColsProxy(Xpr& xpr) : m_xpr(xpr) {}
+  DenseColStlIterator<Xpr>       begin()  const { return DenseColStlIterator<Xpr>(m_xpr, 0); }
+  DenseColStlIterator<const Xpr> cbegin() const { return DenseColStlIterator<const Xpr>(m_xpr, 0); }
+
+  DenseColStlIterator<Xpr>       end()    const { return DenseColStlIterator<Xpr>(m_xpr, m_xpr.cols()); }
+  DenseColStlIterator<const Xpr> cend()   const { return DenseColStlIterator<const Xpr>(m_xpr, m_xpr.cols()); }
+
+protected:
+  Xpr& m_xpr;
+};
+
+template<typename Xpr>
+class RowsProxy
+{
+public:
+  RowsProxy(Xpr& xpr) : m_xpr(xpr) {}
+  DenseRowStlIterator<Xpr>       begin()  const { return DenseRowStlIterator<Xpr>(m_xpr, 0); }
+  DenseRowStlIterator<const Xpr> cbegin() const { return DenseRowStlIterator<const Xpr>(m_xpr, 0); }
+
+  DenseRowStlIterator<Xpr>       end()    const { return DenseRowStlIterator<Xpr>(m_xpr, m_xpr.rows()); }
+  DenseRowStlIterator<const Xpr> cend()   const { return DenseRowStlIterator<const Xpr>(m_xpr, m_xpr.rows()); }
+
+protected:
+  Xpr& m_xpr;
+};
+
+template<typename Derived>
+ColsProxy<Derived> DenseBase<Derived>::allCols()
+{ return ColsProxy<Derived>(derived()); }
+
+template<typename Derived>
+ColsProxy<const Derived> DenseBase<Derived>::allCols() const
+{ return ColsProxy<const Derived>(derived()); }
+
+template<typename Derived>
+RowsProxy<Derived> DenseBase<Derived>::allRows()
+{ return RowsProxy<Derived>(derived()); }
+
+template<typename Derived>
+RowsProxy<const Derived> DenseBase<Derived>::allRows() const
+{ return RowsProxy<const Derived>(derived()); }
+
+} // namespace Eigen