property_value.h

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/*
 * Copyright (c) 2010, Willow Garage, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef RVE_PROPERTIES_PROPERTY_VALUE_H
#define RVE_PROPERTIES_PROPERTY_VALUE_H

#include "forwards.h"

#include <sstream>

#include <ros/types.h>
#include <ros/assert.h>

#include <typeinfo>
#include <stdexcept>

#include <cstdlib>

namespace rve_properties
{

template<typename T>
struct ValueTraits
{
  // Default to stream operators
  inline static const char* typeName() { return "unknown"; }
  inline static std::string toString(void* mem)
  {
    T* val = reinterpret_cast<T*>(mem);
    std::stringstream ss;
    ss << *val;
    return ss.str();
  }

  inline static void fromString(void* mem, const std::string& str)
  {
    T* val = reinterpret_cast<T*>(mem);
    std::istringstream in(str);
    in >> *val;
  }
};

#define RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(type, name) \
  template<> \
  struct ValueTraits<type> \
  { \
    inline static const char* typeName() { return #name; } \
    inline static std::string toString(void* mem) \
    { \
      type* val = reinterpret_cast<type*>(mem); \
      std::stringstream ss; \
      ss << *val; \
      return ss.str(); \
    } \
 \
    inline static void fromString(void* mem, const std::string& str) \
    { \
      type* val = reinterpret_cast<type*>(mem); \
      std::istringstream in(str); \
      in >> *val; \
    } \
  };

RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(bool, bool);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(uint8_t, uint8);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(int8_t, int8);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(uint16_t, uint16);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(int16_t, int16);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(uint32_t, uint32);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(int32_t, int32);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(uint64_t, uint64);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(int64_t, int64);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(float, float);
RVE_PROPERTIES_DEFINE_SIMPLE_VALUE_TRAITS(double, double);

template<>
struct ValueTraits<const char*>
{
  inline static const char* typeName() { return "string"; }

  // Should never actually get into these
  inline static std::string toString(void* mem)
  {
    ROS_BREAK();
    return std::string();
  }
  inline static void fromString(void* mem, const std::string& str)
  {
    ROS_BREAK();
  }
};

template<>
struct ValueTraits<std::string>
{
  inline static const char* typeName() { return "string"; }

  inline static std::string toString(void* mem)
  {
    return *reinterpret_cast<std::string*>(mem);
  }
  inline static void fromString(void* mem, const std::string& str)
  {
    *reinterpret_cast<std::string*>(mem) = str;
  }
};

struct PropertyValueOperators
{
  virtual std::string toString(void* mem) = 0;
  virtual void fromString(void* mem, const std::string& str) = 0;
  virtual void valueDestructor(void* mem) = 0;
  virtual void valueCopy(void* dst, const void* src) = 0;
  virtual const std::type_info& typeInfo() = 0;
  virtual const char* typeName() = 0;
};

template<typename T>
struct PropertyValueOperatorsT : public PropertyValueOperators
{
  virtual std::string toString(void* mem)
  {
    return ValueTraits<T>::toString(mem);
  }

  virtual void fromString(void* mem, const std::string& str)
  {
    return ValueTraits<T>::fromString(mem, str);
  }

  virtual void valueDestructor(void* mem)
  {
    T* val = reinterpret_cast<T*>(mem);
    val->~T();
  }

  virtual void valueCopy(void* dst, const void* src)
  {
    const T* src_val = reinterpret_cast<const T*>(src);
    new(dst) T(*src_val);
  }

  virtual const std::type_info& typeInfo()
  {
    return typeid(T);
  }

  virtual const char* typeName()
  {
    return ValueTraits<T>::typeName();
  }

  static PropertyValueOperatorsT<T> static_copy;
};

template<typename T> PropertyValueOperatorsT<T> PropertyValueOperatorsT<T>::static_copy;

class PropertyValue
{
public:
  PropertyValue()
  : large_buffer_(0)
  , buffer_size_(0)
  , ops_(0)
  {
  }

  ~PropertyValue()
  {
    free(large_buffer_);
  }

  PropertyValue(const PropertyValue& rhs)
  {
    *this = rhs;
  }

  PropertyValue& operator=(const PropertyValue& rhs)
  {
    void* buf = large_buffer_ ? large_buffer_ : small_buffer_;
    if (filled())
    {
      ops_->valueDestructor(buf);
    }

    buffer_size_ = rhs.buffer_size_;
    ops_ = rhs.ops_;

    const void* source_buf = rhs.large_buffer_ ? rhs.large_buffer_ : rhs.small_buffer_;
    void* dest_buf = 0;
    if (rhs.large_buffer_)
    {
      large_buffer_ = (uint8_t*)realloc(large_buffer_, buffer_size_);
      dest_buf = large_buffer_;
    }
    else
    {
      free(large_buffer_);
      dest_buf = small_buffer_;
    }

    ops_->valueCopy(dest_buf, source_buf);

    return *this;
  }

  template<typename T>
  void set(T t)
  {
    void* buf = large_buffer_ ? large_buffer_ : small_buffer_;
    if (filled())
    {
      ops_->valueDestructor(buf);
    }

    buffer_size_ = sizeof(T);
    if (sizeof(T) <= sizeof(small_buffer_))
    {
      free(large_buffer_);
      large_buffer_ = 0;

      T* copy = new (small_buffer_) T;
      *copy = t;
    }
    else
    {
      large_buffer_ = (uint8_t*)realloc(large_buffer_, sizeof(T));
      T* copy = new (large_buffer_) T;
      *copy = t;
    }

    ops_ = &PropertyValueOperatorsT<T>::static_copy;
  }

  template<typename T>
  void get(T& t, T default_value)
  {
    if (!ops_)
    {
      t = default_value;
      set(default_value);
    }

    getImpl(t);
  }

  template<typename T>
  void get(T& t)
  {
    if (!ops_)
    {
      throw std::bad_cast();
    }

    getImpl(t);
  }

  template<typename T>
  T get()
  {
    T t;
    get(t);
    return t;
  }

  bool empty()
  {
    return !ops_;
  }

  bool filled()
  {
    return ops_;
  }

  const char* getTypeName()
  {
    if (!ops_)
    {
      return "empty";
    }

    return ops_->typeName();
  }

  const std::type_info& getTypeInfo()
  {
    if (!ops_)
    {
      return typeid(void);
    }

    return ops_->typeInfo();
  }

private:
  template<typename T>
  void getImpl(T& t)
  {
    void* buf = large_buffer_ ? large_buffer_ : small_buffer_;

    // Types match, just grab the type
    if (typeid(T) == ops_->typeInfo())
    {
      t = *reinterpret_cast<T*>(buf);
      return;
    }

    // Types don't match, have to go through a string
    std::string str = ops_->toString(buf);
    ValueTraits<T>::fromString(&t, str);
  }

  uint8_t small_buffer_[8]; // Used for small values so we don't have to allocate
  uint8_t* large_buffer_;
  size_t buffer_size_;
  PropertyValueOperators* ops_;
};

template<>
inline void PropertyValue::set<const char*>(const char* str)
{
  set<std::string>(std::string(str));
}

template<>
inline void PropertyValue::getImpl<std::string>(std::string& str)
{
  void* buf = large_buffer_ ? large_buffer_ : small_buffer_;

  // Types match, just grab the type
  if (typeid(std::string) == ops_->typeInfo())
  {
    str = *reinterpret_cast<std::string*>(buf);
    return;
  }

  // Types don't match, have to convert
  str = ops_->toString(buf);
}

template<>
inline void PropertyValue::getImpl<char*>(char*& str)
{
  ROS_BREAK();
}

#define PROPERTY_VALUE_EXTERNS(type) \
    extern template class PropertyValueOperatorsT<type>; \
    extern template void PropertyValue::set(type); \
    extern template void PropertyValue::get(type&, type); \
    extern template void PropertyValue::get(type&); \
    extern template type PropertyValue::get(); \
    extern template void PropertyValue::getImpl(type&);

PROPERTY_VALUE_EXTERNS(bool);
PROPERTY_VALUE_EXTERNS(uint8_t);
PROPERTY_VALUE_EXTERNS(int8_t);
PROPERTY_VALUE_EXTERNS(uint16_t);
PROPERTY_VALUE_EXTERNS(int16_t);
PROPERTY_VALUE_EXTERNS(uint32_t);
PROPERTY_VALUE_EXTERNS(int32_t);
PROPERTY_VALUE_EXTERNS(uint64_t);
PROPERTY_VALUE_EXTERNS(int64_t);
PROPERTY_VALUE_EXTERNS(float);
PROPERTY_VALUE_EXTERNS(double);
PROPERTY_VALUE_EXTERNS(std::string);

}

#endif // RVE_PROPERTIES_PROPERTY_VALUE_H