/src/hermes/include/hermes/ADT/HalfPairIterator.h

Source
/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#ifndef HERMES_ADT_HALFPAIRITERATOR_H
#define HERMES_ADT_HALFPAIRITERATOR_H

#include <iterator>

namespace hermes {

/// Declare iterators over a single field in a tuple.
#define HERMES_DECLARE_PARTIAL_ITERATOR(Field, FIELD)                          \
  template <class IT>                                                          \
  class Pair##Field##Iterator {                                                \
    IT it_;                                                                    \
                                                                               \
   public:                                                                     \
    using iterator_category = std::input_iterator_tag;                         \
    using value_type = decltype(std::iterator_traits<IT>::value_type::FIELD);  \
    using difference_type = std::ptrdiff_t;                                    \
    using pointer = value_type *;                                              \
    using reference = value_type &;                                            \
                                                                               \
    Pair##Field##Iterator(const IT &it) : it_(it) {}                           \
    Pair##Field##Iterator(const Pair##Field##Iterator &) = default;            \
    Pair##Field##Iterator &operator=(const Pair##Field##Iterator &) = default; \
                                                                               \
    Pair##Field##Iterator &operator++() {                                      \
      ++it_;                                                                   \
      return *this;                                                            \
    }                                                                          \
    bool operator==(const Pair##Field##Iterator &a) const {                    \
      return it_ == a.it_;                                                     \
    }                                                                          \
    bool operator!=(const Pair##Field##Iterator &a) const {                    \
      return it_ != a.it_;                                                     \
    }                                                                          \
                                                                               \
    decltype((*it_).FIELD) operator*() {                                       \
      return (*it_).FIELD;                                                     \
    }                                                                          \
                                                                               \
    ptrdiff_t operator-(const Pair##Field##Iterator &it) const {               \
      return std::distance(it_, it.it_);                                       \
    }                                                                          \
  };                                                                           \
  template <class IT>                                                          \
  Pair##Field##Iterator<IT> makePair##Field##Iterator(const IT &it) {          \
    return Pair##Field##Iterator<IT>(it);                                      \
  }

/// PairFirstIterator: iterate over pair::first.
HERMES_DECLARE_PARTIAL_ITERATOR(First, first);
/// PairSecondIterator: iterate over pair::second.
HERMES_DECLARE_PARTIAL_ITERATOR(Second, second);

} // namespace hermes

#endif // HERMES_ADT_HALFPAIRITERATOR_H

Line	Count	Source
1		/*
2		* Copyright (c) Meta Platforms, Inc. and affiliates.
3		*
4		* This source code is licensed under the MIT license found in the
5		* LICENSE file in the root directory of this source tree.
6		*/
7
8		#ifndef HERMES_ADT_HALFPAIRITERATOR_H
9		#define HERMES_ADT_HALFPAIRITERATOR_H
10
11		#include <iterator>
12
13		namespace hermes {
14
15		/// Declare iterators over a single field in a tuple.
16		#define HERMES_DECLARE_PARTIAL_ITERATOR(Field, FIELD) \
17		template <class IT> \
18		class Pair##Field##Iterator { \
19		IT it_; \
20		\
21		public: \
22		using iterator_category = std::input_iterator_tag; \
23		using value_type = decltype(std::iterator_traits<IT>::value_type::FIELD); \
24		using difference_type = std::ptrdiff_t; \
25		using pointer = value_type *; \
26		using reference = value_type &; \
27		\
28	0	Pair##Field##Iterator(const IT &it) : it_(it) {} \ Unexecuted instantiation: hermes::PairFirstIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>::PairFirstIterator(std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue> const&) Unexecuted instantiation: hermes::PairSecondIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>::PairSecondIterator(std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue> const&)
29		Pair##Field##Iterator(const Pair##Field##Iterator &) = default; \
30		Pair##Field##Iterator &operator=(const Pair##Field##Iterator &) = default; \
31		\
32	0	Pair##Field##Iterator &operator++() { \
33	0	++it_; \
34	0	return *this; \
35	0	} \ Unexecuted instantiation: hermes::PairFirstIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>::operator++() Unexecuted instantiation: hermes::PairSecondIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>::operator++()
36		bool operator==(const Pair##Field##Iterator &a) const { \
37		return it_ == a.it_; \
38		} \
39	0	bool operator!=(const Pair##Field##Iterator &a) const { \
40	0	return it_ != a.it_; \
41	0	} \ Unexecuted instantiation: hermes::PairFirstIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>::operator!=(hermes::PairFirstIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>> const&) const Unexecuted instantiation: hermes::PairSecondIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>::operator!=(hermes::PairSecondIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>> const&) const
42		\
43	0	decltype((it_).FIELD) operator() { \
44	0	return (*it_).FIELD; \
45	0	} \ Unexecuted instantiation: hermes::PairFirstIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>::operator() Unexecuted instantiation: hermes::PairSecondIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>::operator()
46		\
47		ptrdiff_t operator-(const Pair##Field##Iterator &it) const { \
48		return std::distance(it_, it.it_); \
49		} \
50		}; \
51		template <class IT> \
52	0	Pair##Field##Iterator<IT> makePair##Field##Iterator(const IT &it) { \
53	0	return Pair##Field##Iterator<IT>(it); \
54	0	} Unexecuted instantiation: hermes::PairFirstIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>> hermes::makePairFirstIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>(std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>* const&) Unexecuted instantiation: hermes::PairSecondIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>> hermes::makePairSecondIterator<std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>>(std::__1::pair<hermes::parser::JSONString, hermes::parser::JSONValue>* const&)
55
56		/// PairFirstIterator: iterate over pair::first.
57		HERMES_DECLARE_PARTIAL_ITERATOR(First, first);
58		/// PairSecondIterator: iterate over pair::second.
59		HERMES_DECLARE_PARTIAL_ITERATOR(Second, second);
60
61		} // namespace hermes
62
63		#endif // HERMES_ADT_HALFPAIRITERATOR_H

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Created: 2025-12-12 07:27