[Libreoffice] [LibreOffice] [Patch] Fix for i#108228: Bool has negative sign when used in Writer formula expression

Fix for http://qa.openoffice.org/issues/show_bug.cgi?id=108228.

The problem behaviour occurs because the boolean expression "true"
evaluates to -1 rather than +1 in formulas in Writer. So if, for
example, you create a table formula in Writer, (Table->Formula) and
enter something like 1+(2==2), it evaluates to 0 rather than 2. It
turns out the reason for this is buried in sbxdef.hxx, where we have

// The numeric values of TRUE and FALSE
enum SbxBOOL { SbxFALSE = 0, SbxTRUE = -1 };

Bizarre, although I have very vague memories of Visual Basic defining
-1 to be true. Is that the reason? If it is supposed to be -1, someone
didn't get the memo, because struct SbxValues in sbxvar.hxx defines a
field "UINT16 nUShort", i.e. an unsigned int, which appears to be
where bools are stored. This is borne out by the code in sbxvalue.cxx
which has

SbxValue::PutBool( BOOL b )
    aRes.eType = SbxBOOL;
    aRes.nUShort = sal::static_int_cast< UINT16 >(b ? SbxTRUE : SbxFALSE);
    Put( aRes );

Weird - the cast changes the -1 to 65535. But wait! If we actually
look at the Put code, we have

SbxValue::Put( const SbxValues& rVal )
...
case SbxBOOL:           ImpPutBool( &p->aData, rVal.nInteger ); break;

i.e. we're now back to considering ints rather than uints, and since
SbxValues is defined as a union, the value we've stuffed into it looks
like -1 again if we try to pull an integer out of it. A lot of the
code to do with bools in SbxValues looks like this - it can't make up
its mind if the bool is supposed to be uint or an int, there are casts
everywhere, and it's a miracle it works. Or occasionally doesn't work,
according to the bug.

Lest someone think this bug is correct behaviour, (2==2) currently
gives 1 as expected, not -1; there's an explicit check in the output
in this case to get around the SbxTRUE = -1 thing. Anyway, this patch
fixes the bug, while leaving the whole SbxTRUE = -1 infrastructure
intact. Presumably it should be applied to master rather than 3.3,
since it's hardly an RC blocker :-P

Code contributed under MPL 1.1 / GPLv3+ / LGPLv3+ licenses.

Cheers,
Mattias

From cacb952d14de82625a93373d82c541810f2c38c5 Mon Sep 17 00:00:00 2001
From: Mattias Johnsson <m.t.johnsson@gmail.com>
Date: Wed, 8 Dec 2010 21:15:43 +1100
Subject: [PATCH] Fix i#108228 : bool has negative sign when used in formula expression

---
 sw/source/core/bastyp/calc.cxx |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/sw/source/core/bastyp/calc.cxx b/sw/source/core/bastyp/calc.cxx
index 9f4b77c..a2a2a1f 100644
--- a/sw/source/core/bastyp/calc.cxx
+++ b/sw/source/core/bastyp/calc.cxx
@@ -1726,7 +1726,7 @@ double SwSbxValue::GetDouble() const
 
 SwSbxValue& SwSbxValue::MakeDouble()
 {
-    if( SbxSTRING == GetType() )
+    if( GetType() == SbxSTRING  || GetType() == SbxBOOL )
         PutDouble( GetDouble() );
     return *this;
 }
-- 
1.7.1