Diff: Utilities/Function.hpp

Revision:

0:f77ad7f72d04

Child:

5:a8c83a2e6fa4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Utilities/Function.hpp	Mon Nov 06 14:39:18 2017 -0600
@@ -0,0 +1,466 @@
+/*******************************************************************************
+* Copyright (C) 2017 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_Function
+#define MaximInterface_Function
+
+#include <stddef.h>
+#include "type_traits.hpp"
+
+// Include for std::swap.
+#include <algorithm>
+#include <utility>
+
+namespace MaximInterface {
+namespace detail {
+
+// Provides char buffer storage for a given type.
+// Suitability of alignment for type should be verified with alignment_of.
+template <typename Type, size_t TypeSize> union TypeStorage {
+public:
+  operator const Type *() const { return reinterpret_cast<const Type *>(data); }
+
+  operator Type *() {
+    return const_cast<Type *>(
+        static_cast<const Type *>(static_cast<const TypeStorage &>(*this)));
+  }
+
+  const Type & operator*() const { return **this; }
+
+  Type & operator*() {
+    return const_cast<Type &>(
+        static_cast<const TypeStorage &>(*this).operator*());
+  }
+
+  const Type * operator->() const { return *this; }
+
+  Type * operator->() {
+    return const_cast<Type *>(
+        static_cast<const TypeStorage &>(*this).operator->());
+  }
+
+private:
+  char data[TypeSize];
+  long double aligner;
+};
+
+// Computes the internal target size for TypeStorage based on a desired total
+// size. No internal storage will be allocated if the requested size is smaller
+// than the required data elements of TypeWrapper or if the requested size is
+// smaller than minimum size of TypeStorage.
+template <typename Target, size_t totalSize> class TypeWrapperTotalSize {
+private:
+  typedef TypeStorage<Target, 1> MinSizeStorage;
+  static const size_t otherDataSize = sizeof(Target *);
+  // Round down to be a multiple of alignment_of<MinSizeTargetStorage>::value.
+  static const size_t internalTargetRawSize =
+      (totalSize - otherDataSize) / alignment_of<MinSizeStorage>::value *
+      alignment_of<MinSizeStorage>::value;
+
+public:
+  // Use internal storage if internalTargetRawSize is valid and at least as
+  // large as the minimum size of TypeStorage.
+  static const size_t internalTargetSize =
+      ((totalSize > otherDataSize) &&
+       (internalTargetRawSize >= sizeof(MinSizeStorage)))
+          ? internalTargetRawSize
+          : 0;
+};
+
+// Basic type erasure implementation with small object optimization.
+template <typename Target, template <typename> class TargetAdapter,
+          size_t internalTargetSize =
+              TypeWrapperTotalSize<Target, 32>::internalTargetSize>
+class TypeWrapper {
+private:
+  typedef TypeStorage<Target, internalTargetSize> TargetStorage;
+
+public:
+  TypeWrapper() : currentTarget(NULL) {}
+
+  TypeWrapper(const TypeWrapper & other) {
+    if (other.currentTarget == other.internalTarget) {
+      other.currentTarget->clone(internalTarget);
+      currentTarget = internalTarget;
+    } else if (other.currentTarget) {
+      currentTarget = other.currentTarget->clone();
+    } else {
+      currentTarget = NULL;
+    }
+  }
+
+  template <typename Source> TypeWrapper(Source source) {
+    if (sizeof(TargetAdapter<Source>) <= internalTargetSize &&
+        alignment_of<TargetAdapter<Source> >::value <=
+            alignment_of<TargetStorage>::value) {
+      new (internalTarget) TargetAdapter<Source>(source);
+      currentTarget = internalTarget;
+    } else {
+      currentTarget = new TargetAdapter<Source>(source);
+    }
+  }
+
+  ~TypeWrapper() {
+    if (currentTarget == internalTarget) {
+      currentTarget->~Target();
+    } else {
+      delete currentTarget;
+    }
+  }
+
+  const TypeWrapper & operator=(const TypeWrapper & rhs) {
+    TypeWrapper(rhs).swap(*this);
+    return *this;
+  }
+
+  template <typename Source> const TypeWrapper & operator=(Source source) {
+    TypeWrapper(source).swap(*this);
+    return *this;
+  }
+
+  void clear() { TypeWrapper().swap(*this); }
+
+  void swap(TypeWrapper & other) {
+    if (this == &other) {
+      return;
+    }
+
+    if (currentTarget == internalTarget &&
+        other.currentTarget == other.internalTarget) {
+      TargetStorage temp;
+      currentTarget->clone(temp);
+      currentTarget->~Target();
+      currentTarget = NULL;
+      other.currentTarget->clone(internalTarget);
+      other.currentTarget->~Target();
+      other.currentTarget = NULL;
+      currentTarget = internalTarget;
+      temp->clone(other.internalTarget);
+      temp->~Target();
+      other.currentTarget = other.internalTarget;
+    } else if (currentTarget == internalTarget) {
+      currentTarget->clone(other.internalTarget);
+      currentTarget->~Target();
+      currentTarget = other.currentTarget;
+      other.currentTarget = other.internalTarget;
+    } else if (other.currentTarget == other.internalTarget) {
+      other.currentTarget->clone(internalTarget);
+      other.currentTarget->~Target();
+      other.currentTarget = currentTarget;
+      currentTarget = internalTarget;
+    } else {
+      using std::swap;
+      swap(currentTarget, other.currentTarget);
+    }
+  }
+
+  const Target * target() const { return currentTarget; }
+
+private:
+  TargetStorage internalTarget;
+  Target * currentTarget;
+};
+
+// TypeWrapper specialization with no internal storage space.
+template <typename Target, template <typename> class TargetAdapter>
+class TypeWrapper<Target, TargetAdapter, 0> {
+public:
+  TypeWrapper() : currentTarget(NULL) {}
+
+  TypeWrapper(const TypeWrapper & other) {
+    if (other.currentTarget) {
+      currentTarget = other.currentTarget->clone();
+    } else {
+      currentTarget = NULL;
+    }
+  }
+
+  template <typename Source>
+  TypeWrapper(Source source)
+      : currentTarget(new TargetAdapter<Source>(source)) {}
+
+  ~TypeWrapper() { delete currentTarget; }
+
+  const TypeWrapper & operator=(const TypeWrapper & rhs) {
+    TypeWrapper(rhs).swap(*this);
+    return *this;
+  }
+
+  template <typename Source> const TypeWrapper & operator=(Source source) {
+    TypeWrapper(source).swap(*this);
+    return *this;
+  }
+
+  void clear() { TypeWrapper().swap(*this); }
+
+  void swap(TypeWrapper & other) {
+    using std::swap;
+    swap(currentTarget, other.currentTarget);
+  }
+
+  const Target * target() const { return currentTarget; }
+
+private:
+  Target * currentTarget;
+};
+
+} // namespace detail
+
+// Function wrapper similar to std::function for 0-2 argument functions.
+template <typename> class Function;
+
+// Function implementation for zero argument functions.
+template <typename ResultType> class Function<ResultType()> {
+public:
+  typedef ResultType result_type;
+
+  Function(ResultType (*func)() = NULL) : callableWrapper() {
+    if (func) {
+      callableWrapper = func;
+    }
+  }
+
+  template <typename F> Function(F func) : callableWrapper(func) {}
+
+  const Function & operator=(ResultType (*func)()) {
+    if (func) {
+      callableWrapper = func;
+    } else {
+      callableWrapper.clear();
+    }
+    return *this;
+  }
+
+  template <typename F> const Function & operator=(F func) {
+    callableWrapper = func;
+    return *this;
+  }
+
+  void swap(Function & other) { callableWrapper.swap(other.callableWrapper); }
+
+  operator bool() const { return callableWrapper.target() != NULL; }
+
+  ResultType operator()() const {
+    return callableWrapper.target() ? (*callableWrapper.target())()
+                                    : ResultType();
+  }
+
+private:
+  class Callable {
+  public:
+    virtual ~Callable() {}
+    virtual ResultType operator()() const = 0;
+    virtual Callable * clone() const = 0;
+    virtual void clone(void * buffer) const = 0;
+  };
+
+  template <typename F> class CallableAdapter : public Callable {
+  public:
+    CallableAdapter(F func) : func(func) {}
+
+    virtual ResultType operator()() const { return func(); }
+
+    virtual Callable * clone() const { return new CallableAdapter(*this); }
+
+    virtual void clone(void * buffer) const {
+      new (buffer) CallableAdapter(*this);
+    }
+
+  private:
+    F func;
+  };
+
+  detail::TypeWrapper<Callable, CallableAdapter> callableWrapper;
+};
+
+template <typename ResultType>
+inline void swap(Function<ResultType()> & lhs, Function<ResultType()> & rhs) {
+  lhs.swap(rhs);
+}
+
+// Function implementation for one argument functions.
+template <typename ArgumentType, typename ResultType>
+class Function<ResultType(ArgumentType)> {
+public:
+  typedef ArgumentType argument_type;
+  typedef ResultType result_type;
+
+  Function(ResultType (*func)(ArgumentType) = NULL) : callableWrapper() {
+    if (func) {
+      callableWrapper = func;
+    }
+  }
+
+  template <typename F> Function(F func) : callableWrapper(func) {}
+
+  const Function & operator=(ResultType (*func)(ArgumentType)) {
+    if (func) {
+      callableWrapper = func;
+    } else {
+      callableWrapper.clear();
+    }
+    return *this;
+  }
+
+  template <typename F> const Function & operator=(F func) {
+    callableWrapper = func;
+    return *this;
+  }
+
+  void swap(Function & other) { callableWrapper.swap(other.callableWrapper); }
+
+  operator bool() const { return callableWrapper.target() != NULL; }
+
+  ResultType operator()(ArgumentType arg) const {
+    return callableWrapper.target() ? (*callableWrapper.target())(arg)
+                                    : ResultType();
+  }
+
+private:
+  class Callable {
+  public:
+    virtual ~Callable() {}
+    virtual ResultType operator()(ArgumentType) const = 0;
+    virtual Callable * clone() const = 0;
+    virtual void clone(void * buffer) const = 0;
+  };
+
+  template <typename F> class CallableAdapter : public Callable {
+  public:
+    CallableAdapter(F func) : func(func) {}
+
+    virtual ResultType operator()(ArgumentType arg) const { return func(arg); }
+
+    virtual Callable * clone() const { return new CallableAdapter(*this); }
+
+    virtual void clone(void * buffer) const {
+      new (buffer) CallableAdapter(*this);
+    }
+
+  private:
+    F func;
+  };
+
+  detail::TypeWrapper<Callable, CallableAdapter> callableWrapper;
+};
+
+template <typename ArgumentType, typename ResultType>
+inline void swap(Function<ResultType(ArgumentType)> & lhs,
+                 Function<ResultType(ArgumentType)> & rhs) {
+  lhs.swap(rhs);
+}
+
+// Function implementation for two argument functions.
+template <typename FirstArgumentType, typename SecondArgumentType,
+          typename ResultType>
+class Function<ResultType(FirstArgumentType, SecondArgumentType)> {
+public:
+  typedef FirstArgumentType first_argument_type;
+  typedef SecondArgumentType second_argument_type;
+  typedef ResultType result_type;
+
+  Function(ResultType (*func)(FirstArgumentType, SecondArgumentType) = NULL)
+      : callableWrapper() {
+    if (func) {
+      callableWrapper = func;
+    }
+  }
+
+  template <typename F> Function(F func) : callableWrapper(func) {}
+
+  const Function & operator=(ResultType (*func)(FirstArgumentType,
+                                                SecondArgumentType)) {
+    if (func) {
+      callableWrapper = func;
+    } else {
+      callableWrapper.clear();
+    }
+    return *this;
+  }
+
+  template <typename F> const Function & operator=(F func) {
+    callableWrapper = func;
+    return *this;
+  }
+
+  void swap(Function & other) { callableWrapper.swap(other.callableWrapper); }
+
+  operator bool() const { return callableWrapper.target() != NULL; }
+
+  ResultType operator()(FirstArgumentType arg1, SecondArgumentType arg2) const {
+    return callableWrapper.target() ? (*callableWrapper.target())(arg1, arg2)
+                                    : ResultType();
+  }
+
+private:
+  class Callable {
+  public:
+    virtual ~Callable() {}
+    virtual ResultType operator()(FirstArgumentType,
+                                  SecondArgumentType) const = 0;
+    virtual Callable * clone() const = 0;
+    virtual void clone(void * buffer) const = 0;
+  };
+
+  template <typename F> class CallableAdapter : public Callable {
+  public:
+    CallableAdapter(F func) : func(func) {}
+
+    virtual ResultType operator()(FirstArgumentType arg1,
+                                  SecondArgumentType arg2) const {
+      return func(arg1, arg2);
+    }
+
+    virtual Callable * clone() const { return new CallableAdapter(*this); }
+
+    virtual void clone(void * buffer) const {
+      new (buffer) CallableAdapter(*this);
+    }
+
+  private:
+    F func;
+  };
+
+  detail::TypeWrapper<Callable, CallableAdapter> callableWrapper;
+};
+
+template <typename FirstArgumentType, typename SecondArgumentType,
+          typename ResultType>
+inline void
+swap(Function<ResultType(FirstArgumentType, SecondArgumentType)> & lhs,
+     Function<ResultType(FirstArgumentType, SecondArgumentType)> & rhs) {
+  lhs.swap(rhs);
+}
+
+} // namespace MaximInterface
+
+#endif