js/src/frontend/TypedIndex.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef frontend_TypedIndex_h
   8 #define frontend_TypedIndex_h
   9
  10 #include <cstdint>
  11 #include <stddef.h>
  12
  13 namespace js {
  14 namespace frontend {
  15
  16 // TypedIndex allows discrimination in variants between different
  17 // index types. Used as a typesafe index for various stencil arrays.
  18 template <typename Tag>
  19 struct TypedIndex {
  20   TypedIndex() = default;
  21   constexpr explicit TypedIndex(uint32_t index) : index(index){};
  22
  23   uint32_t index = 0;
  24
  25   // For Vector::operator[]
  26   operator size_t() const { return index; }
  27
  28   TypedIndex& operator=(size_t idx) {
  29     index = idx;
  30     return *this;
  31   }
  32
  33   bool operator<(TypedIndex other) const { return index < other.index; }
  34   bool operator<=(TypedIndex other) const { return index <= other.index; }
  35   bool operator>(TypedIndex other) const { return index > other.index; }
  36   bool operator>=(TypedIndex other) const { return index >= other.index; }
  37 };
  38
  39 }  // namespace frontend
  40 }  // namespace js
  41
  42 #endif