Define fp equality function

-- Based on checks and defaults used by various testing frameworks (primarily GTest and Catch)
-- Moved the header into detail where it should have been to start with (oops)

include/xlnt/utils/serialisation_utils.hpp

@@ -1,44 +0,0 @@
-// Copyright (c) 2014-2018 Thomas Fussell
-//
-// 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, WRISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE
-//
-// @license: http://www.opensource.org/licenses/mit-license.php
-// @author: see AUTHORS file
-
-#pragma once
-
-#include <xlnt/xlnt_config.hpp>
-#include <sstream>
-
-namespace xlnt {
-/// <summary>
-/// Takes in any nuber and outputs a string form of that number which will
-/// serialise and deserialise without loss of precision
-/// </summary>
-template <typename Number>
-std::string serialize_number_to_string(Number num)
-{
-    // more digits and excel won't match
-    constexpr int Excel_Digit_Precision = 15; //sf
-    std::stringstream ss;
-    ss.precision(Excel_Digit_Precision);
-    ss << num;
-    return ss.str();
-}
-}

source/detail/header_footer/header_footer_code.cpp

@@ -22,7 +22,7 @@
 // @author: see AUTHORS file
 
 #include <detail/header_footer/header_footer_code.hpp>
-#include <xlnt/utils/serialisation_utils.hpp>
+#include <detail/numeric_utils.hpp>
 
 namespace xlnt {
 namespace detail {

source/detail/numeric_utils.hpp

@@ -0,0 +1,104 @@
+// Copyright (c) 2014-2018 Thomas Fussell
+//
+// 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, WRISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE
+//
+// @license: http://www.opensource.org/licenses/mit-license.php
+// @author: see AUTHORS file
+
+#pragma once
+
+#include <xlnt/xlnt_config.hpp>
+#include <sstream>
+#include <type_traits>
+
+namespace xlnt {
+namespace detail {
+/// <summary>
+/// Takes in any number and outputs a string form of that number which will
+/// serialise and deserialise without loss of precision
+/// </summary>
+template <typename Number>
+std::string serialize_number_to_string(Number num)
+{
+    // more digits and excel won't match
+    constexpr int Excel_Digit_Precision = 15; //sf
+    std::stringstream ss;
+    ss.precision(Excel_Digit_Precision);
+    ss << num;
+    return ss.str();
+}
+
+/// <summary>
+/// constexpr abs
+/// </summary>
+template <typename Number>
+constexpr Number abs(Number val)
+{
+    if (val < Number{0})
+    {
+        return -val;
+    }
+    return val;
+};
+
+/// <summary>
+/// constexpr max
+/// </summary>
+template <typename Number>
+constexpr Number max(Number lval, Number rval)
+{
+    if (lval < rval)
+    {
+        return rval;
+    }
+    return lval;
+};
+
+/// <summary>
+/// Floating point equality requires a bit of fuzzingdue to the imprecise nature of fp calculation
+/// </summary>
+template <typename LNumber, typename RNumber>
+constexpr bool float_equals(const LNumber &lhs, const RNumber &rhs)
+{
+    static_assert(!std::is_integral<LNumber>::value && !std::is_integral<RNumber>::value,
+        "Using this function with two integers is just wasting time. Use ==");
+
+    // NANs always compare false with themselves
+    if ((lhs != lhs) || (rhs != rhs))
+    {
+        return false;
+    }
+    // a type that lhs and rhs can agree on
+    using common_t = std::common_type_t<LNumber, RNumber>;
+    // The lower precision epsilon.
+    // In comparison between different types, the lower precision type must be used for epsilon
+    constexpr common_t epsilon = detail::max<common_t>(std::numeric_limits<LNumber>::epsilon(), std::numeric_limits<RNumber>::epsilon());
+    // 100 * epsilon selected as an arbitrary range
+    constexpr common_t fuzz = 100 * epsilon;
+    // the "epsilon" then needs to be scaled into the comparison range
+    // epsilon for numeric_limits is valid when abs(x) <1.0, scaling only needs to be upwards
+    // in particular, this prevents a lhs of 0 from requiring an exact comparison
+    common_t scaled_fuzz = fuzz * max(xlnt::detail::abs<common_t>(lhs), common_t{1});
+    return ((lhs + scaled_fuzz) >= rhs) && ((rhs + scaled_fuzz) >= lhs);
+}
+
+//static_assert(0.1 != 0.1f, "Built in equality fails");
+//static_assert(float_equals(0.1, 0.1f), "fuzzy equality allows comparison between double and float");
+} // namespace detail
+} // namespace xlnt

source/detail/serialization/xlsx_producer.cpp

@@ -33,12 +33,12 @@
 #include <detail/serialization/vector_streambuf.hpp>
 #include <detail/serialization/xlsx_producer.hpp>
 #include <detail/serialization/zstream.hpp>
+#include <detail/numeric_utils.hpp>
 #include <xlnt/cell/cell.hpp>
 #include <xlnt/cell/hyperlink.hpp>
 #include <xlnt/packaging/manifest.hpp>
 #include <xlnt/utils/path.hpp>
 #include <xlnt/utils/scoped_enum_hash.hpp>
-#include <xlnt/utils/serialisation_utils.hpp>
 #include <xlnt/workbook/workbook.hpp>
 #include <xlnt/workbook/workbook_view.hpp>
 #include <xlnt/worksheet/header_footer.hpp>