include/llvm/ADT/Sequence.h

   1 //===- Sequence.h - Utility for producing sequences of values ---*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 /// \file
   9 /// This routine provides some synthesis utilities to produce sequences of
  10 /// values. The names are intentionally kept very short as they tend to occur
  11 /// in common and widely used contexts.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_ADT_SEQUENCE_H
  16 #define LLVM_ADT_SEQUENCE_H
  17
  18 #include "llvm/ADT/iterator.h"
  19 #include "llvm/ADT/iterator_range.h"
  20 #include <algorithm>
  21 #include <iterator>
  22 #include <utility>
  23
  24 namespace llvm {
  25
  26 namespace detail {
  27
  28 template <typename ValueT>
  29 class value_sequence_iterator
  30     : public iterator_facade_base<value_sequence_iterator<ValueT>,
  31                                   std::random_access_iterator_tag,
  32                                   const ValueT> {
  33   using BaseT = typename value_sequence_iterator::iterator_facade_base;
  34
  35   ValueT Value;
  36
  37 public:
  38   using difference_type = typename BaseT::difference_type;
  39   using reference = typename BaseT::reference;
  40
  41   value_sequence_iterator() = default;
  42   value_sequence_iterator(const value_sequence_iterator &) = default;
  43   value_sequence_iterator(value_sequence_iterator &&Arg)
  44       : Value(std::move(Arg.Value)) {}
  45
  46   template <typename U, typename Enabler = decltype(ValueT(std::declval<U>()))>
  47   value_sequence_iterator(U &&Value) : Value(std::forward<U>(Value)) {}
  48
  49   value_sequence_iterator &operator+=(difference_type N) {
  50     Value += N;
  51     return *this;
  52   }
  53   value_sequence_iterator &operator-=(difference_type N) {
  54     Value -= N;
  55     return *this;
  56   }
  57   using BaseT::operator-;
  58   difference_type operator-(const value_sequence_iterator &RHS) const {
  59     return Value - RHS.Value;
  60   }
  61
  62   bool operator==(const value_sequence_iterator &RHS) const {
  63     return Value == RHS.Value;
  64   }
  65   bool operator<(const value_sequence_iterator &RHS) const {
  66     return Value < RHS.Value;
  67   }
  68
  69   reference operator*() const { return Value; }
  70 };
  71
  72 } // end namespace detail
  73
  74 template <typename ValueT>
  75 iterator_range<detail::value_sequence_iterator<ValueT>> seq(ValueT Begin,
  76                                                             ValueT End) {
  77   return make_range(detail::value_sequence_iterator<ValueT>(Begin),
  78                     detail::value_sequence_iterator<ValueT>(End));
  79 }
  80
  81 } // end namespace llvm
  82
  83 #endif // LLVM_ADT_SEQUENCE_H