include/ceres/fpclassify.h

// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2012 Google Inc. All rights reserved.
// http://code.google.com/p/ceres-solver/
//
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// Author: keir@google.com (Keir Mierle)
//
// Portable floating point classification. The names are picked such that they
// do not collide with macros. For example, "isnan" in C99 is a macro and hence
// does not respect namespaces.
//
// TODO(keir): Finish porting!

#ifndef CERES_PUBLIC_FPCLASSIFY_H_
#define CERES_PUBLIC_FPCLASSIFY_H_

#if defined(_MSC_VER)
#include <float.h>
#endif

#include <limits>

namespace ceres {

#if defined(_MSC_VER)

inline bool IsFinite  (double x) { return _finite(x) != 0;                   }
inline bool IsInfinite(double x) { return _finite(x) == 0 && _isnan(x) == 0; }
inline bool IsNaN     (double x) { return _isnan(x) != 0;                    }
inline bool IsNormal  (double x) {
  int classification = _fpclass(x);
  return classification == _FPCLASS_NN ||
         classification == _FPCLASS_PN;
}

#elif defined(ANDROID) && defined(_STLPORT_VERSION)

// On Android, when using the STLPort, the C++ isnan and isnormal functions
// are defined as macros.
inline bool IsNaN     (double x) { return isnan(x);    }
inline bool IsNormal  (double x) { return isnormal(x); }
// On Android NDK r6, when using STLPort, the isinf and isfinite functions are
// not available, so reimplement them.
inline bool IsInfinite(double x) {
  return x ==  std::numeric_limits<double>::infinity() ||
         x == -std::numeric_limits<double>::infinity();
}
inline bool IsFinite(double x) {
  return !isnan(x) && !IsInfinite(x);
}

# else

// These definitions are for the normal Unix suspects.
inline bool IsFinite  (double x) { return std::isfinite(x); }
inline bool IsInfinite(double x) { return std::isinf(x);    }
inline bool IsNaN     (double x) { return std::isnan(x);    }
inline bool IsNormal  (double x) { return std::isnormal(x); }

#endif

}  // namespace ceres

#endif  // CERES_PUBLIC_FPCLASSIFY_H_