/src/gdal/port/cpl_enumerate.h

Source
/******************************************************************************
 *
 * Project:  CPL - Common Portability Library
 * Purpose:  Collection enumerator
 * Author:   Even Rouault, even.rouault at spatialys.com
 *
 ******************************************************************************
 * Copyright (c) 2025, Even Rouault <even.rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#ifndef CPL_ENUMERATE_H
#define CPL_ENUMERATE_H

#include <cstddef>   // size_t
#include <iterator>  // std::begin(), std::end()
#include <utility>   // std::declval(), std::pair

namespace cpl
{

//! @cond Doxygen_Suppress

template <class T> class Enumerator
{
  public:
    using TIter = decltype(std::begin(std::declval<T &>()));

    class iterator
    {
      public:
        explicit inline iterator(const TIter &it) : m_iter(it)
        {
        }

        inline bool operator==(const iterator &other) const
        {
            return m_iter == other.m_iter;
        }

        inline bool operator!=(const iterator &other) const
        {
            return m_iter != other.m_iter;
        }

        inline iterator &operator++()
        {
            ++m_index;
            ++m_iter;
            return *this;
        }

        inline iterator operator++(int)
        {
            iterator before = *this;
            ++(*this);
            return before;
        }

        inline auto operator*() const
        {
            return std::pair<size_t, decltype(*m_iter) &>(m_index, *m_iter);
        }

      private:
        TIter m_iter;
        size_t m_index = 0;
    };

    explicit inline Enumerator(T &iterable) : m_iterable(iterable)
    {
    }

    inline iterator begin() const
    {
        return iterator(std::begin(m_iterable));
    }

    inline iterator end() const
    {
        // We could initialize the m_index to SIZE_T_MAX, but this does not
        // really matter as iterator comparison is done on the underlying
        // iterator and not the index.
        return iterator(std::end(m_iterable));
    }

  private:
    T &m_iterable;
};

//! @endcond

/** Function returning an eumerator whose values are
 * a std::pair of (index: size_t, value: iterable::value_type).
 *
 * This is similar to Python enumerate() function and C++23
 * std::ranges::enumerate() (https://en.cppreference.com/w/cpp/ranges/enumerate_view.html)
 *
 * \since GDAL 3.13
 */
template <class T> inline auto enumerate(T &iterable)
{
    return Enumerator<T>(iterable);
}

}  // namespace cpl

#endif

Line	Count	Source
1		/******************************************************************************
2		*
3		* Project: CPL - Common Portability Library
4		* Purpose: Collection enumerator
5		* Author: Even Rouault, even.rouault at spatialys.com
6		*
7		******************************************************************************
8		* Copyright (c) 2025, Even Rouault <even.rouault at spatialys.com>
9		*
10		* SPDX-License-Identifier: MIT
11		****************************************************************************/
12
13		#ifndef CPL_ENUMERATE_H
14		#define CPL_ENUMERATE_H
15
16		#include <cstddef> // size_t
17		#include <iterator> // std::begin(), std::end()
18		#include <utility> // std::declval(), std::pair
19
20		namespace cpl
21		{
22
23		//! @cond Doxygen_Suppress
24
25		template <class T> class Enumerator
26		{
27		public:
28		using TIter = decltype(std::begin(std::declval<T &>()));
29
30		class iterator
31		{
32		public:
33	0	explicit inline iterator(const TIter &it) : m_iter(it)
34	0	{
35	0	} Unexecuted instantiation: cpl::Enumerator<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>::iterator::iterator(OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const>::Iterator const&) Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >::iterator::iterator(std::__1::__wrap_iter<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>> const&) Unexecuted instantiation: cpl::Enumerator<std::__1::vector<int, std::__1::allocator<int> > >::iterator::iterator(std::__1::__wrap_iter<int> const&) Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >::iterator::iterator(std::__1::__wrap_iter<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >> const&) Unexecuted instantiation: gdalalg_vector_concat.cpp:cpl::Enumerator<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>::iterator::iterator(std::__1::__wrap_iter<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc const> const&)
36
37		inline bool operator==(const iterator &other) const
38		{
39		return m_iter == other.m_iter;
40		}
41
42		inline bool operator!=(const iterator &other) const
43	0	{
44	0	return m_iter != other.m_iter;
45	0	} Unexecuted instantiation: cpl::Enumerator<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>::iterator::operator!=(cpl::Enumerator<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>::iterator const&) const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >::iterator::operator!=(cpl::Enumerator<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >::iterator const&) const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<int, std::__1::allocator<int> > >::iterator::operator!=(cpl::Enumerator<std::__1::vector<int, std::__1::allocator<int> > >::iterator const&) const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >::iterator::operator!=(cpl::Enumerator<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >::iterator const&) const Unexecuted instantiation: gdalalg_vector_concat.cpp:cpl::Enumerator<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>::iterator::operator!=(cpl::Enumerator<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>::iterator const&) const
46
47		inline iterator &operator++()
48	0	{
49	0	++m_index;
50	0	++m_iter;
51	0	return *this;
52	0	} Unexecuted instantiation: cpl::Enumerator<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>::iterator::operator++() Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >::iterator::operator++() Unexecuted instantiation: cpl::Enumerator<std::__1::vector<int, std::__1::allocator<int> > >::iterator::operator++() Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >::iterator::operator++() Unexecuted instantiation: gdalalg_vector_concat.cpp:cpl::Enumerator<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>::iterator::operator++()
53
54		inline iterator operator++(int)
55		{
56		iterator before = *this;
57		++(*this);
58		return before;
59		}
60
61		inline auto operator*() const
62	0	{
63	0	return std::pair<size_t, decltype(m_iter) &>(m_index, m_iter);
64	0	} Unexecuted instantiation: cpl::Enumerator<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>::iterator::operator() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >::iterator::operator() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<int, std::__1::allocator<int> > >::iterator::operator() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >::iterator::operator() const Unexecuted instantiation: gdalalg_vector_concat.cpp:cpl::Enumerator<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>::iterator::operator*() const
65
66		private:
67		TIter m_iter;
68		size_t m_index = 0;
69		};
70
71	0	explicit inline Enumerator(T &iterable) : m_iterable(iterable)
72	0	{
73	0	} Unexecuted instantiation: cpl::Enumerator<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>::Enumerator(OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const&) Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >::Enumerator(std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > >&) Unexecuted instantiation: cpl::Enumerator<std::__1::vector<int, std::__1::allocator<int> > >::Enumerator(std::__1::vector<int, std::__1::allocator<int> >&) Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >::Enumerator(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >&) Unexecuted instantiation: gdalalg_vector_concat.cpp:cpl::Enumerator<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>::Enumerator(std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const&)
74
75		inline iterator begin() const
76	0	{
77	0	return iterator(std::begin(m_iterable));
78	0	} Unexecuted instantiation: cpl::Enumerator<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>::begin() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >::begin() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<int, std::__1::allocator<int> > >::begin() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >::begin() const Unexecuted instantiation: gdalalg_vector_concat.cpp:cpl::Enumerator<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>::begin() const
79
80		inline iterator end() const
81	0	{
82		// We could initialize the m_index to SIZE_T_MAX, but this does not
83		// really matter as iterator comparison is done on the underlying
84		// iterator and not the index.
85	0	return iterator(std::end(m_iterable));
86	0	} Unexecuted instantiation: cpl::Enumerator<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>::end() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >::end() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<int, std::__1::allocator<int> > >::end() const Unexecuted instantiation: cpl::Enumerator<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >::end() const Unexecuted instantiation: gdalalg_vector_concat.cpp:cpl::Enumerator<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>::end() const
87
88		private:
89		T &m_iterable;
90		};
91
92		//! @endcond
93
94		/** Function returning an eumerator whose values are
95		* a std::pair of (index: size_t, value: iterable::value_type).
96		*
97		* This is similar to Python enumerate() function and C++23
98		* std::ranges::enumerate() (https://en.cppreference.com/w/cpp/ranges/enumerate_view.html)
99		*
100		* \since GDAL 3.13
101		*/
102		template <class T> inline auto enumerate(T &iterable)
103	0	{
104	0	return Enumerator<T>(iterable);
105	0	} Unexecuted instantiation: auto cpl::enumerate<OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const>(OGRFeatureDefn::Fields<OGRFeatureDefn const, OGRFieldDefn const> const&) Unexecuted instantiation: auto cpl::enumerate<std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > > >(std::__1::vector<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int>, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int> > >&) Unexecuted instantiation: auto cpl::enumerate<std::__1::vector<int, std::__1::allocator<int> > >(std::__1::vector<int, std::__1::allocator<int> >&) Unexecuted instantiation: auto cpl::enumerate<std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > >(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >&) Unexecuted instantiation: gdalalg_vector_concat.cpp:auto cpl::enumerate<std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const>(std::__1::vector<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc, std::__1::allocator<GDALVectorConcatAlgorithm::RunStep(GDALPipelineStepRunContext&)::LayerDesc> > const&)
106
107		} // namespace cpl
108
109		#endif

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Created: 2026-04-10 07:04