[Boost-commit] svn:boost r83103 - in trunk: boost/multiprecision/cpp_int libs/multiprecision/test

Subject: [Boost-commit] svn:boost r83103 - in trunk: boost/multiprecision/cpp_int libs/multiprecision/test
From: john_at_[hidden]
Date: 2013-02-23 12:22:19

Author: johnmaddock
Date: 2013-02-23 12:22:18 EST (Sat, 23 Feb 2013)
New Revision: 83103
URL: http://svn.boost.org/trac/boost/changeset/83103

Log:
Fix bug in subtraction routine that leads to -0 rather than 0.
Add test cases.
Fixes #8145.
Text files modified: 
   trunk/boost/multiprecision/cpp_int/add.hpp      |     4 ++++                                    
   trunk/libs/multiprecision/test/test_cpp_int.cpp |    40 ++++++++++++++++++++++++++++++++++++++++
   2 files changed, 44 insertions(+), 0 deletions(-)

Modified: trunk/boost/multiprecision/cpp_int/add.hpp
==============================================================================
--- trunk/boost/multiprecision/cpp_int/add.hpp	(original)
+++ trunk/boost/multiprecision/cpp_int/add.hpp	2013-02-23 12:22:18 EST (Sat, 23 Feb 2013)
@@ -223,6 +223,10 @@
 #endif
          result.sign(a.sign());
       }
+      else if((result.size() == 1) && (*pr == 0))
+      {
+         result.sign(false); // zero is unsigned.
+      }
    }
    else if(result.size() == 1)
    {

Modified: trunk/libs/multiprecision/test/test_cpp_int.cpp
==============================================================================
--- trunk/libs/multiprecision/test/test_cpp_int.cpp	(original)
+++ trunk/libs/multiprecision/test/test_cpp_int.cpp	2013-02-23 12:22:18 EST (Sat, 23 Feb 2013)
@@ -418,6 +418,46 @@
       a = a - ull;
       BOOST_CHECK_EQUAL(a, test_type("0x12345600012434ffffffff0000000000000000"));
 #endif
+      //
+      // Now check that things which should be zero really are
+      // https://svn.boost.org/trac/boost/ticket/8145:
+      //
+      a = -1;
+      a += 1;
+      BOOST_CHECK_EQUAL(a, 0);
+      a = 1;
+      a += -1;
+      BOOST_CHECK_EQUAL(a, 0);
+      a = -1;
+      a += test_type(1);
+      BOOST_CHECK_EQUAL(a, 0);
+      a = 1;
+      a += test_type(-1);
+      BOOST_CHECK_EQUAL(a, 0);
+      a = test_type("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
+      a -= test_type("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
+      BOOST_CHECK_EQUAL(a, 0);
+      a = -test_type("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
+      a += test_type("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
+      BOOST_CHECK_EQUAL(a, 0);
+      a = 2;
+      a *= 0;
+      BOOST_CHECK_EQUAL(a, 0);
+      a = -2;
+      a *= 0;
+      BOOST_CHECK_EQUAL(a, 0);
+      a = 2;
+      a *= test_type(0);
+      BOOST_CHECK_EQUAL(a, 0);
+      a = -2;
+      a *= test_type(0);
+      BOOST_CHECK_EQUAL(a, 0);
+      a = -2;
+      a /= 50;
+      BOOST_CHECK_EQUAL(a, 0);
+      a = -test_type("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
+      a /= (1 + test_type("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"));
+      BOOST_CHECK_EQUAL(a, 0);
    }
 
    void test()