fmt.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_FMT_H
#define TOMOGRAPHER_TOOLS_FMT_H

#include <cstdio>
#include <cstdarg>

#include <chrono>
#include <string>
#include <sstream> // stringstream
#include <iostream>
#include <utility> // std::declval

#include <tomographer2/tools/cxxutil.h> // PRINTFN_ARGS_SAFE


namespace Tomographer {
namespace Tools {


//
// =============================================================================
//
// Formatting Utilities
//


class BadFmtsFormat : public std::exception
{
  std::string msg;
public:
  BadFmtsFormat(const std::string& msg_) : msg(msg_) { }
  ~BadFmtsFormat() throw() { }

  const char * what() const throw() {
    return msg.c_str();
  }
};



inline std::string vfmts(const char* fmt, va_list vl)
{
  // check out printf() formatting for std::string:
  //    http://stackoverflow.com/a/10150393/1694896
  //    http://stackoverflow.com/a/26197300/1694896
  
  // on MinGW, can't find std::vsnprintf() because for some reason it's declared in the
  // global scope... so just import std namespace here and use generic vsnprintf() call.
  using namespace std;

  int size = 10;
  char * buffer = new char[size];
  va_list ap1;
  va_copy(ap1, vl);
  int nsize = vsnprintf(buffer, size, fmt, ap1);
  if (nsize < 0) {
    // failure: bad format probably
    throw BadFmtsFormat("vsnprintf("+std::string(fmt)+") failure: code="+std::to_string(nsize));
  }
  if(size <= nsize) {
    // buffer too small: delete buffer and try again
    delete[] buffer;
    size = nsize+1; // +1 for "\0"
    buffer = new char[size];
    nsize = vsnprintf(buffer, size, fmt, vl);
  }
  std::string ret(buffer);
  delete[] buffer;
  va_end(ap1);
  return ret;
}


inline std::string fmts(const char * fmt, ...)  PRINTF1_ARGS_SAFE;

// definition. It seems definitions cannot have function attributes (here
// PRINTF1_ARGS_SAFE), so that's why it's separate
inline std::string fmts(const char * fmt, ...)
{
  va_list ap;
  va_start(ap, fmt);
  std::string result = vfmts(fmt, ap);
  va_end(ap);
  return result;
}


#define streamstr(tokens)                       \
  dynamic_cast<std::ostringstream&>(            \
      std::ostringstream().seekp(0) << tokens   \
      ).str()                                   \


#define streamcstr(tokens)  streamstr(tokens).c_str()



//
// utility to stream an object, if possible
//

namespace tomo_internal {
// see http://stackoverflow.com/a/9154394/1694896
// see sfinae_yes and sfinae_no in cxxutil.h
template<typename T> static auto test_has_stream_op(int)
  -> typename sfinae_yes<decltype(*((std::ostream*)(NULL)) << *((T*)(NULL)))>::yes&;
template<typename T> static auto test_has_stream_op(long)
  -> typename sfinae_no<>::no&;
// template<typename T, int dummy_value,
//       typename EnabledIfType = decltype(std::declval<std::ostream&>() << std::declval<T>())>
// struct test_has_stream_op { static constexpr bool value = true; };
// template<typename T, long dummy_value>
// struct test_has_stream_op<T,dummy_value,void> { static constexpr bool value = false; };
// template<typename T>
// struct has_stream_op {
//   static constexpr bool value = test_has_stream_op<T, 0>::value;
// };
} // namespace tomo_internal


template<typename T>
struct hasOStreamOp {
  static constexpr bool value = (sizeof(tomo_internal::test_has_stream_op<T>(0))
                                 == sizeof(typename tomo_internal::sfinae_yes<>::yes));
};


namespace tomo_internal {
template<typename T_>
struct StreamIfPossibleWrapper
{
  typedef T_ T;
  StreamIfPossibleWrapper(
      const T& obj_,
      std::string before_,
      std::string after_,
      std::string alternative_
      )
    : obj(obj_), before(before_), after(after_), alternative(alternative_)
  {
  }

  const T & obj;

  const std::string before;
  const std::string after;
  const std::string alternative;

  // internal :
  
  template<typename OStream, TOMOGRAPHER_ENABLED_IF_TMPL(!hasOStreamOp<T>::value)>
  void stream_into(OStream&& stream) const
  {
    stream << alternative;
  }
  template<typename OStream, TOMOGRAPHER_ENABLED_IF_TMPL(hasOStreamOp<T>::value)>
  void stream_into(OStream&& stream) const
  {
    stream << before << obj << after;
  }
};
template<typename T>
std::ostream & operator<<(std::ostream & stream, const StreamIfPossibleWrapper<T>& wobj)
{
  wobj.stream_into(stream);
  return stream;
}
template<typename T>
std::ostream&& operator<<(std::ostream&& stream, const StreamIfPossibleWrapper<T>& wobj)
{
  wobj.stream_into(stream);
  return std::move(stream);
}
}



#ifndef TOMOGRAPHER_PARSED_BY_DOXYGEN
template<typename T, TOMOGRAPHER_ENABLED_IF_TMPL(!hasOStreamOp<T>::value)>
inline std::string streamIfPossible(const T& /*obj*/)
{
  // obj is not streamable
  return std::string("<")+typeid(T).name()+std::string(">");
}
template<typename T, TOMOGRAPHER_ENABLED_IF_TMPL(hasOStreamOp<T>::value)>
inline const T& streamIfPossible(const T& obj)
{
  return obj;
}
template<typename T>
inline tomo_internal::StreamIfPossibleWrapper<T>
streamIfPossible(const T& obj, std::string before,
                 std::string after = std::string(),
                 std::string alternative = "<"+std::string(typeid(T).name())+">")
{
  return tomo_internal::StreamIfPossibleWrapper<T>(obj, std::move(before),
                                                   std::move(after), std::move(alternative));
}
#else

template<typename T>
inline _Unspecified streamIfPossible(const T& obj)
{
}
template<typename T>
inline _Unspecified streamIfPossible(const T& obj,
                                     std::string before,
                                     std::string after = std::string(),
                                     std::string alternative = "<"+std::string(typeid(T).name())+">")
{
}
#endif







// =============================================================================


inline std::string fmtDuration(double seconds)
{
  // split `seconds' into integral part and fractional part
  double dt_i_d;
  double dt_f = std::modf(seconds, &dt_i_d);
  int dt_i = (int)(dt_i_d+0.5);
  
  return fmts("%d:%02d:%02d.%03d", dt_i/3600, (dt_i/60)%60, dt_i%60, (int)(dt_f*1000+0.5));
};

template<typename Rep, typename Period>
inline std::string fmtDuration(std::chrono::duration<Rep, Period> dt)
{
  typedef std::chrono::duration<Rep, Period> Duration;

  // delta-time, in seconds and fraction of seconds
  double seconds = (double)dt.count() * Duration::period::num / Duration::period::den ;

  return fmtDuration(seconds);
};



} // namespace Tools
} // namespace Tomographer


#endif