util.h

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/* This file is part of the Tomographer project, which is distributed under the
 * terms of the MIT license.
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 ETH Zurich, Institute for Theoretical Physics, Philippe Faist
 *
 * 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 THE
 * AUTHORS OR COPYRIGHT HOLDERS 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.
 */

#ifndef TOMOGRAPHER_TOOLS_UTILS_H
#define TOMOGRAPHER_TOOLS_UTILS_H

#include <type_traits>

#include <Eigen/Core> // Eigen::Dynamic

#include <tomographer/tools/conststr.h>


// -----------------------------------------------------------------------------
// Define functions with printf-safe arguments, with compiler-generated warnings
// -----------------------------------------------------------------------------


// The PRINTFX_ARGS_SAFE macros are defined here, so that in the future we may support a
// wider range of compilers which may not understand the __attribute__(format)
// instruction.


#define PRINTF1_ARGS_SAFE  __attribute__ ((__format__ (__printf__, 1, 2)))

#define PRINTF2_ARGS_SAFE  __attribute__ ((__format__ (__printf__, 2, 3)))

#define PRINTF3_ARGS_SAFE  __attribute__ ((__format__ (__printf__, 3, 4)))

#define PRINTF4_ARGS_SAFE  __attribute__ ((__format__ (__printf__, 4, 5)))



// -----------------------------------------------------------------------------
// Some C++ helpers
// -----------------------------------------------------------------------------

namespace Tomographer
{
namespace Tools
{

// taken from http://stackoverflow.com/a/25510879/1694896

namespace tomo_internal {
  template <typename F>
  struct FinalAction {
    FinalAction(F f) : clean_{f} {}
    ~FinalAction() { clean_(); }
    F clean_;
  };
} // namespace tomo_internal

template <typename F>
inline tomo_internal::FinalAction<F> finally(F f)
{
  return tomo_internal::FinalAction<F>(f);
}






// -----------------------------------------------------------------------------


template<typename T_, int Value>
class static_or_dynamic
{
public:
  typedef T_ T;
  static constexpr T ValueAtCTime = Value;

  inline static_or_dynamic() { }
  inline explicit static_or_dynamic(T val) {
    assert(val == ValueAtCTime);
    (void)val; // silence "unused parameter" warning
  }

  inline T value() const { return ValueAtCTime; }

  inline T operator()() const { return ValueAtCTime; }
};

template<typename T_>
class static_or_dynamic<T_, Eigen::Dynamic>
{
public:
  typedef T_ T;
  static constexpr T ValueAtCTime = Eigen::Dynamic;
  
  static_or_dynamic() = delete;  // no default constructor.
  inline explicit static_or_dynamic(T val) : _dyn_value(val) { }

  inline T value() const { return _dyn_value; }
  inline T operator()() const { return value(); }
private:
  const T _dyn_value;
};


// -----------------------------------------------------------------------------


template<typename T_, bool enabled>
struct store_if_enabled
{
  typedef T_ T;
  static constexpr bool is_enabled = false;

  template<typename... Args>
  explicit store_if_enabled(Args...) { }
};
template<typename T_>
struct store_if_enabled<T_, true>
{
  typedef T_ T;
  static constexpr bool is_enabled = true;

  T value;

  template<typename... ArgTypes>
  explicit store_if_enabled(const ArgTypes& ...  args) : value(args...) { }
};

template<typename T>
inline std::ostream & operator<<(std::ostream & str, store_if_enabled<T, false> /*val*/)
{
  return str << "[-]";
}
template<typename T>
inline std::ostream & operator<<(std::ostream & str, store_if_enabled<T, true> val)
{
  return str << val.value;
}



// -----------------------------------------------------------------------------

inline constexpr bool is_power_of_two(int N)
{
  // taken from http://stackoverflow.com/q/10585450/1694896
  return N && !(N & (N - 1));
}




// -----------------------------------------------------------------------------



#define TOMO_FUNCTION __PRETTY_FUNCTION__



namespace tomo_internal {
// logic taken from KLatexFormula/klftools: klfdefs.cpp / klfShortFuncSignature()
struct extractFuncName_helper {
  struct extracted {
    const std::size_t decl_pos;
    const conststr extr;
    constexpr extracted(std::size_t dp, const conststr& s) : decl_pos(dp), extr(s) { }
  };
  static constexpr conststr alltofirstparen(const conststr& s)
  {
    return s.substr(0, s.find(conststr("("), 0, s.size()));
  }
  static constexpr std::size_t declpos_from_found_spc(std::size_t found_pos)
  {
    return found_pos == std::string::npos ? 0 : found_pos + 1;
  }
  static constexpr std::size_t pos_decl(const conststr& s)
  {
    return ((s.size() > 2)
            ? declpos_from_found_spc(s.rfind(conststr(" "), std::string::npos))
            : 0);
  }
  static constexpr extracted allfromfirstspace(const conststr& s)
  {
    return extracted(pos_decl(s),
                     s.substr_e(pos_decl(s),
                                s.size()));
  }
  static constexpr extracted do_extract(const conststr& funcname)
  {
    return allfromfirstspace(alltofirstparen(funcname));
  }
  static constexpr conststr extract_choose(const extracted& do_extracted,
                                           const conststr& funcname)
  {
    return (do_extracted.extr.substr(0,8) == conststr("operator")
            ? funcname.substr(do_extracted.decl_pos)
            : do_extracted.extr);
  }
  static constexpr conststr extract(const conststr& funcname)
  {
    return extract_choose(do_extract(funcname), funcname);
  }
}; // helper struct
} // namespace tomo_internal


constexpr inline conststr extractFuncName(const conststr & funcname)
{
  return tomo_internal::extractFuncName_helper::extract(funcname);
}




#define TOMO_STATIC_ASSERT_EXPR(...)                            \
  static_assert(__VA_ARGS__, #__VA_ARGS__)



// -----------------------------------------------------------------------------

#ifndef TOMOGRAPHER_PARSED_BY_DOXYGEN
// WARNING!!! CHECK OUT  http://stackoverflow.com/q/29363532/1694896
// FOR VERY SUBTLE BUGS....... :( :(   -- TEST WITH INTEL ICC!!
#define TOMOGRAPHER_ENABLED_IF(...)                                     \
  template<bool _dummy__enabledif = false,                              \
           typename std::enable_if<_dummy__enabledif || (__VA_ARGS__), bool>::type \
                                                        _dummy__enabledif2 = false>
#define TOMOGRAPHER_ENABLED_IF_TMPL(...)                                \
  bool _dummy__enabledif = false,                               \
  typename std::enable_if<_dummy__enabledif || (__VA_ARGS__), bool>::type \
                                                 _dummy__enabledif2 = true
#endif


} // namespace Tools
} // namespace Tomographer



#endif