fdo#81356: convert Fraction to boost::rational<long> - wip

* Added rational util functions used by Fraction class not
available in the boost::rational class.
* Replaced usage of Fraction by boost::rational<long>
* Removed code that relies on:
1. fraction.IsValid() -- rational only allow valid values, ie
denominator() != 0
2. rational.denominator() == 0 -- always false
3. rational.denominator() < 0 -- always false but implementation
detail: http://www.boost.org/doc/libs/release/libs/rational/rational.html#Internal%20representation
* Simplified code that relies on:
1. rational.denominator() != 0 -- always true
* BUGS EXIST because Fraction allows the creation of invalid values but
boost::rational throws the exception boost::bad_rational

Change-Id: I84970a4956afb3f91ac0c8f726547466319420f9
Reviewed-on: https://gerrit.libreoffice.org/11551
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>

1 files changed, 101 insertions, 0 deletions

diff --git a/tools/qa/cppunit/test_rational.cxx b/tools/qa/cppunit/test_rational.cxx
new file mode 100644
index 000000000000..e503c1c5d38d
--- /dev/null
+++ b/tools/qa/cppunit/test_rational.cxx
@@ -0,0 +1,101 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * 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/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <sal/types.h>
+#include <cppunit/TestFixture.h>
+#include <cppunit/extensions/HelperMacros.h>
+
+#include <rtl/math.hxx>
+#include <tools/rational.hxx>
+
+namespace tools
+{
+
+class RationalTest : public CppUnit::TestFixture
+{
+public:
+
+    void testReduceInaccurate()
+    {
+        const boost::rational<long> aFract(1082130431,1073741824);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #1 not approximately equal to 1.007812499068677",
+                                rtl::math::approxEqual(boost::rational_cast<double>(aFract),1.007812499068677) );
+
+        boost::rational<long> aFract2( aFract );
+        rational_ReduceInaccurate(aFract2, 8);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #2 not 1",
+                                aFract2.numerator() == 1 &&
+                                aFract2.denominator() == 1 );
+
+        boost::rational<long> aFract3( 0x7AAAAAAA, 0x35555555 );
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #3 cancellation wrong",
+                                aFract3.numerator() == 0x7AAAAAAA &&
+                                aFract3.denominator() == 0x35555555 );
+        rational_ReduceInaccurate(aFract3, 30);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #3 ReduceInaccurate errorneously cut precision",
+                                aFract3.numerator() == 0x7AAAAAAA &&
+                                aFract3.denominator() == 0x35555555 );
+
+        rational_ReduceInaccurate(aFract3, 29);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #3 reduce to 29 bits failed",
+                                aFract3.numerator() == 0x3D555555 &&
+                                aFract3.denominator() == 0x1AAAAAAA );
+
+        rational_ReduceInaccurate(aFract3, 9);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #3 reduce to 9 bits failed",
+                                aFract3.numerator() == 0x0147 &&
+                                aFract3.denominator() == 0x008E );
+
+        rational_ReduceInaccurate(aFract3, 1);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #3 reduce to 1 bit failed",
+                                aFract3.numerator() == 2 &&
+                                aFract3.denominator() == 1 );
+
+        rational_ReduceInaccurate(aFract3, 0);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #3 reduce to 0 bits failed",
+                                aFract3.numerator() == 2 &&
+                                aFract3.denominator() == 1 );
+
+#if SAL_TYPES_SIZEOFLONG == 8
+        boost::rational<long> aFract4(0x7AAAAAAAAAAAAAAA, 0x3555555555555555);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #4 cancellation wrong",
+                                aFract4.numerator() == 0x7AAAAAAAAAAAAAAA &&
+                                aFract4.denominator() == 0x3555555555555555 );
+        rational_ReduceInaccurate(aFract4, 62);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #4 ReduceInaccurate errorneously cut precision",
+                                aFract4.numerator() == 0x7AAAAAAAAAAAAAAA &&
+                                aFract4.denominator() == 0x3555555555555555 );
+
+        rational_ReduceInaccurate(aFract4, 61);
+        CPPUNIT_ASSERT_MESSAGE( "Fraction #4 ReduceInaccurate reduce to 61 bit failed",
+                                aFract4.numerator() == 0x3D55555555555555 &&
+                                aFract4.denominator() == 0x1AAAAAAAAAAAAAAA );
+#endif
+    }
+
+    CPPUNIT_TEST_SUITE(RationalTest);
+    CPPUNIT_TEST(testReduceInaccurate);
+    CPPUNIT_TEST_SUITE_END();
+};
+
+
+CPPUNIT_TEST_SUITE_REGISTRATION(RationalTest);
+} // namespace tools
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */