1 files changed, 72 insertions, 0 deletions
diff --git a/sc/source/core/tool/math.cxx b/sc/source/core/tool/math.cxx
new file mode 100644
index 000000000..e61d39386
--- /dev/null
+++ b/sc/source/core/tool/math.cxx
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <math.hxx>
+#include <cmath>
+#include <cerrno>
+#include <cfenv>
+
+#include <o3tl/float_int_conversion.hxx>
+#include <rtl/math.hxx>
+
+namespace sc
+{
+static double err_pow(const double& fVal1, const double& fVal2)
+{
+    // pow() is expected to set domain error or pole error or range error (or
+    // flag them via exceptions) or return NaN or Inf.
+    assert((math_errhandling & (MATH_ERRNO | MATH_ERREXCEPT)) != 0);
+    std::feclearexcept(FE_ALL_EXCEPT);
+    errno = 0;
+    return pow(fVal1, fVal2);
+}
+
+double power(const double& fVal1, const double& fVal2)
+{
+    double fPow;
+    if (fVal1 < 0 && fVal2 != 0.0)
+    {
+        const double f = 1.0 / fVal2 + ((fVal2 < 0.0) ? -0.5 : 0.5);
+        if (!(o3tl::convertsToAtLeast(f, SAL_MIN_INT64)
+              && o3tl::convertsToAtMost(f, SAL_MAX_INT64)))
+        {
+            // Casting to int would be undefined behaviour.
+            fPow = err_pow(fVal1, fVal2);
+        }
+        else
+        {
+            const sal_Int64 i = static_cast<sal_Int64>(f);
+            if (i % 2 != 0 && rtl::math::approxEqual(1 / static_cast<double>(i), fVal2))
+                fPow = -err_pow(-fVal1, fVal2);
+            else
+                fPow = err_pow(fVal1, fVal2);
+        }
+    }
+    else
+    {
+        fPow = err_pow(fVal1, fVal2);
+    }
+    // The pow() call must had been the most recent call to check errno or exception.
+    if ((((math_errhandling & MATH_ERRNO) != 0) && (errno == EDOM || errno == ERANGE))
+// emscripten is currently broken by https://github.com/emscripten-core/emscripten/pull/11087
+// While the removal is correct for C99, it's not for C++11 (see http://www.cplusplus.com/reference/cfenv/FE_INEXACT/)
+// But since emscripten currently doesn't support any math exceptions, we simply ignore them
+#ifndef __EMSCRIPTEN__
+        || (((math_errhandling & MATH_ERREXCEPT) != 0)
+            && std::fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW))
+#endif
+        || !std::isfinite(fPow))
+    {
+        fPow = CreateDoubleError(FormulaError::IllegalFPOperation);
+    }
+    return fPow;
+}
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */