Add a portable floating point classification API
Ceres has traditionally battled with portability issues
when trying to classify floating point values as one
type or another. For example, in C99 'isnan' is a
macro. Since it is a macro, it is impossible to
override the name in other namespaces.
Instead of trying to use preprocessor hacks to work
around the issue, define our own set of camel-case
names for use internally and by Ceres clients. For
example do this:
template<typename T>
void MyFunction(T x, T y) {
if (ceres::IsNaN(x)) {
...
}
}
instead of using "isnan" or "std::isnan". Note that
while GCC and Apple GCC both import 'isnan' into
the std namespace, it is not standard until C++11
which Ceres will not require for some years.
Change-Id: Ibcc96a8bb4ba63aa67cbbc58658b2e5671cd5824
diff --git a/include/ceres/fpclassify.h b/include/ceres/fpclassify.h
new file mode 100644
index 0000000..59424bf
--- /dev/null
+++ b/include/ceres/fpclassify.h
@@ -0,0 +1,49 @@
+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2012 Google Inc. All rights reserved.
+// http://code.google.com/p/ceres-solver/
+//
+// 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 Google 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
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// 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_
+
+namespace ceres {
+
+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); }
+
+} // namespace ceres
+
+#endif // CERES_PUBLIC_FPCLASSIFY_H_
