Diff: Utilities/optional.hpp

Revision:

6:a8c83a2e6fa4

Child:

7:471901a04573

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Utilities/optional.hpp	Wed Jan 23 13:11:04 2019 -0600
@@ -0,0 +1,318 @@
+/*******************************************************************************
+* Copyright (C) 2018 Maxim Integrated Products, Inc., All Rights Reserved.
+*
+* Permission is hereby granted, free of charge, to any person obtaining a
+* copy of this software and associated documentation files (the "Software"),
+* to deal in the Software without restriction, including without limitation
+* the rights to use, copy, modify, merge, publish, distribute, sublicense,
+* and/or sell copies of the Software, and to permit persons to whom the
+* Software is furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included
+* in all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+* IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+* OTHER DEALINGS IN THE SOFTWARE.
+*
+* Except as contained in this notice, the name of Maxim Integrated
+* Products, Inc. shall not be used except as stated in the Maxim Integrated
+* Products, Inc. Branding Policy.
+*
+* The mere transfer of this software does not imply any licenses
+* of trade secrets, proprietary technology, copyrights, patents,
+* trademarks, maskwork rights, or any other form of intellectual
+* property whatsoever. Maxim Integrated Products, Inc. retains all
+* ownership rights.
+*******************************************************************************/
+
+#ifndef MaximInterface_optional
+#define MaximInterface_optional
+
+#include "SafeBool.hpp"
+
+// Include for std::swap.
+#include <algorithm>
+#include <utility>
+
+namespace MaximInterface {
+
+struct nullopt_t {
+  explicit nullopt_t(int) {}
+};
+
+static const nullopt_t nullopt(0);
+
+/// Optional value container similar to std::optional.
+/// @details
+/// To prevent the need for aligned storage, this implementation imposes that
+/// types must be DefaultConstructible, CopyConstructible, and CopyAssignable.
+/// No exceptions are thrown when accessing a valueless optional.
+template <typename T> class optional {
+public:
+  typedef T value_type;
+
+  optional() : value_(), has_value_(false) {}
+  
+  optional(nullopt_t) : value_(), has_value_(false) {}
+
+  optional(const T & value) : value_(value), has_value_(true) {}
+
+  template <typename U>
+  explicit optional(const optional<U> & other)
+      : value_(other.value_), has_value_(other.has_value_) {}
+
+  optional & operator=(nullopt_t) {
+    reset();
+    return *this;
+  }
+
+  optional & operator=(const T & value) {
+    value_ = value;
+    has_value_ = true;
+    return *this;
+  }
+
+  template <typename U> optional & operator=(const optional<U> & other) {
+    if (has_value_ || other.has_value_) {
+      value_ = other.value_;
+      has_value_ = other.has_value_;
+    }
+    return *this;
+  }
+
+  bool has_value() const { return has_value_; }
+  
+  operator SafeBool() const { return makeSafeBool(has_value()); }
+
+  const T & value() const { return value_; }
+  
+  T & value() {
+    return const_cast<T &>(static_cast<const optional &>(*this).value());
+  }
+  
+  const T & operator*() const { return value(); }
+  
+  T & operator*() {
+    return const_cast<T &>(static_cast<const optional &>(*this).operator*());
+  }
+  
+  const T * operator->() const { return &value(); }
+  
+  T * operator->() {
+    return const_cast<T *>(static_cast<const optional &>(*this).operator->());
+  }
+
+  const T & value_or(const T & default_value) const {
+    return has_value() ? value() : default_value;
+  }
+
+  void swap(optional & other) {
+    if (has_value_ || other.has_value_) {
+      using std::swap;
+      swap(value_, other.value_);
+      swap(has_value_, other.has_value_);
+    }
+  }
+
+  void reset() {
+    if (has_value_) {
+      has_value_ = false;
+      value_ = T();
+    }
+  }
+
+private:
+  T value_;
+  bool has_value_;
+};
+
+template <typename T> optional<T> make_optional(const T & value) {
+  return value;
+}
+
+template <typename T> void swap(optional<T> & lhs, optional<T> & rhs) {
+  lhs.swap(rhs);
+}
+
+template <typename T, typename U>
+bool operator==(const optional<T> & lhs, const optional<U> & rhs) {
+  if (lhs.has_value() != rhs.has_value()) {
+    return false;
+  }
+  if (!lhs.has_value()) {
+    return true;
+  }
+  return lhs.value() == rhs.value();
+}
+
+template <typename T, typename U>
+bool operator!=(const optional<T> & lhs, const optional<U> & rhs) {
+  if (lhs.has_value() != rhs.has_value()) {
+    return true;
+  }
+  if (!lhs.has_value()) {
+    return false;
+  }
+  return lhs.value() != rhs.value();
+}
+
+template <typename T, typename U>
+bool operator<(const optional<T> & lhs, const optional<U> & rhs) {
+  if (!rhs.has_value()) {
+    return false;
+  }
+  if (!lhs.has_value()) {
+    return true;
+  }
+  return lhs.value() < rhs.value();
+}
+
+template <typename T, typename U>
+bool operator<=(const optional<T> & lhs, const optional<U> & rhs) {
+  if (!lhs.has_value()) {
+    return true;
+  }
+  if (!rhs.has_value()) {
+    return false;
+  }
+  return lhs.value() <= rhs.value();
+}
+
+template <typename T, typename U>
+bool operator>(const optional<T> & lhs, const optional<U> & rhs) {
+  if (!lhs.has_value()) {
+    return false;
+  }
+  if (!rhs.has_value()) {
+    return true;
+  }
+  return lhs.value() > rhs.value();
+}
+
+template <typename T, typename U>
+bool operator>=(const optional<T> & lhs, const optional<U> & rhs) {
+  if (!rhs.has_value()) {
+    return true;
+  }
+  if (!lhs.has_value()) {
+    return false;
+  }
+  return lhs.value() >= rhs.value();
+}
+
+template <typename T> bool operator==(const optional<T> & opt, nullopt_t) {
+  return !opt.has_value();
+}
+
+template <typename T> bool operator==(nullopt_t, const optional<T> & opt) {
+  return operator==(opt, nullopt);
+}
+
+template <typename T> bool operator!=(const optional<T> & opt, nullopt_t) {
+  return !operator==(opt, nullopt);
+}
+
+template <typename T> bool operator!=(nullopt_t, const optional<T> & opt) {
+  return operator!=(opt, nullopt);
+}
+
+template <typename T> bool operator<(const optional<T> &, nullopt_t) {
+  return false;
+}
+
+template <typename T> bool operator<(nullopt_t, const optional<T> & opt) {
+  return opt.has_value();
+}
+
+template <typename T> bool operator<=(const optional<T> & opt, nullopt_t) {
+  return !operator>(opt, nullopt);
+}
+
+template <typename T> bool operator<=(nullopt_t, const optional<T> & opt) {
+  return !operator>(nullopt, opt);
+}
+
+template <typename T> bool operator>(const optional<T> & opt, nullopt_t) {
+  return operator<(nullopt, opt);
+}
+
+template <typename T> bool operator>(nullopt_t, const optional<T> & opt) {
+  return operator<(opt, nullopt);
+}
+
+template <typename T> bool operator>=(const optional<T> & opt, nullopt_t) {
+  return !operator<(opt, nullopt);
+}
+
+template <typename T> bool operator>=(nullopt_t, const optional<T> & opt) {
+  return !operator<(nullopt, opt);
+}
+
+template <typename T, typename U>
+bool operator==(const optional<T> & opt, const U & value) {
+  return opt.has_value() ? opt.value() == value : false;
+}
+
+template <typename T, typename U>
+bool operator==(const T & value, const optional<U> & opt) {
+  return operator==(opt, value);
+}
+
+template <typename T, typename U>
+bool operator!=(const optional<T> & opt, const U & value) {
+  return opt.has_value() ? opt.value() != value : true;
+}
+
+template <typename T, typename U>
+bool operator!=(const T & value, const optional<U> & opt) {
+  return operator!=(opt, value);
+}
+
+template <typename T, typename U>
+bool operator<(const optional<T> & opt, const U & value) {
+  return opt.has_value() ? opt.value() < value : true;
+}
+
+template <typename T, typename U>
+bool operator<(const T & value, const optional<U> & opt) {
+  return opt.has_value() ? value < opt.value() : false;
+}
+
+template <typename T, typename U>
+bool operator<=(const optional<T> & opt, const U & value) {
+  return opt.has_value() ? opt.value() <= value : true;
+}
+
+template <typename T, typename U>
+bool operator<=(const T & value, const optional<U> & opt) {
+  return opt.has_value() ? value <= opt.value() : false;
+}
+
+template <typename T, typename U>
+bool operator>(const optional<T> & opt, const U & value) {
+  return opt.has_value() ? opt.value() > value : false;
+}
+
+template <typename T, typename U>
+bool operator>(const T & value, const optional<U> & opt) {
+  return opt.has_value() ? value > opt.value() : true;
+}
+
+template <typename T, typename U>
+bool operator>=(const optional<T> & opt, const U & value) {
+  return opt.has_value() ? opt.value() >= value : false;
+}
+
+template <typename T, typename U>
+bool operator>=(const T & value, const optional<U> & opt) {
+  return opt.has_value() ? value >= opt.value() : true;
+}
+
+} // namespace MaximInterface
+
+#endif