loplugin:redundantcast improvements for floating-integer conversions

Change-Id: I63dbf18f144a792ae775fe6706da81657f790016
Reviewed-on: https://gerrit.libreoffice.org/54416
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
Tested-by: Stephan Bergmann <sbergman@redhat.com>

17 files changed, 80 insertions, 29 deletions

diff --git a/basic/source/comp/exprnode.cxx b/basic/source/comp/exprnode.cxx
index 55131fc1c14d..8d6db9bd88d8 100644
--- a/basic/source/comp/exprnode.cxx
+++ b/basic/source/comp/exprnode.cxx
@@ -155,7 +155,6 @@ void SbiExprNode::ConvertToIntConstIfPossible()
             double n;
             if( nVal >= SbxMININT && nVal <= SbxMAXINT && modf( nVal, &n ) == 0 )
             {
-                nVal = static_cast<double>(static_cast<short>(nVal));
                 eType = SbxINTEGER;
             }
         }
diff --git a/compilerplugins/clang/redundantcast.cxx b/compilerplugins/clang/redundantcast.cxx
index 0faadc5a541a..66b81941e579 100644
--- a/compilerplugins/clang/redundantcast.cxx
+++ b/compilerplugins/clang/redundantcast.cxx
@@ -248,6 +248,23 @@ bool RedundantCast::VisitImplicitCastExpr(const ImplicitCastExpr * expr) {
             }
         }
         break;
+    case CK_FloatingToIntegral:
+    case CK_IntegralToFloating:
+        if (auto e = dyn_cast<ExplicitCastExpr>(expr->getSubExpr()->IgnoreParenImpCasts())) {
+            if ((isa<CXXStaticCastExpr>(e) || isa<CXXFunctionalCastExpr>(e))
+                && (e->getSubExprAsWritten()->getType().getCanonicalType().getTypePtr()
+                    == expr->getType().getCanonicalType().getTypePtr()))
+            {
+                report(
+                    DiagnosticsEngine::Warning,
+                    ("suspicious %select{static_cast|functional cast}0 from %1 to %2, result is"
+                     " implicitly cast to %3"),
+                    e->getExprLoc())
+                    << isa<CXXFunctionalCastExpr>(e) << e->getSubExprAsWritten()->getType()
+                    << e->getTypeAsWritten() << expr->getType() << expr->getSourceRange();
+            }
+        }
+        break;
     default:
         break;
     }
diff --git a/compilerplugins/clang/test/redundantcast.cxx b/compilerplugins/clang/test/redundantcast.cxx
index 70fcdf3340cb..713a3be1433c 100644
--- a/compilerplugins/clang/test/redundantcast.cxx
+++ b/compilerplugins/clang/test/redundantcast.cxx
@@ -374,6 +374,15 @@ void testOverloadResolution() {
     (void) NonOverloadMemFn(&Overload::nonOverload); // expected-error {{redundant functional cast from 'void (Overload::*)()' to 'NonOverloadMemFn' (aka 'void (Overload::*)()') [loplugin:redundantcast]}}
 };
 
+void testIntermediaryStaticCast() {
+    int n = 0;
+    n = static_cast<double>(n); // expected-error {{suspicious static_cast from 'int' to 'double', result is implicitly cast to 'int' [loplugin:redundantcast]}}
+    n = double(n); // expected-error {{suspicious functional cast from 'int' to 'double', result is implicitly cast to 'int' [loplugin:redundantcast]}}
+    double d = 0.0;
+    d = static_cast<int>(d) + 1.0; // expected-error {{suspicious static_cast from 'double' to 'int', result is implicitly cast to 'double' [loplugin:redundantcast]}}
+    d = int(d) + 1.0; // expected-error {{suspicious functional cast from 'double' to 'int', result is implicitly cast to 'double' [loplugin:redundantcast]}}
+};
+
 int main() {
     testConstCast();
     testStaticCast();
@@ -382,6 +391,7 @@ int main() {
     testCStyleCastOfTemplateMethodResult(nullptr);
     testReinterpretConstCast();
     testDynamicCast();
+    testIntermediaryStaticCast();
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/connectivity/source/drivers/dbase/DTable.cxx b/connectivity/source/drivers/dbase/DTable.cxx
index 815d45ba4635..f0112d35a03e 100644
--- a/connectivity/source/drivers/dbase/DTable.cxx
+++ b/connectivity/source/drivers/dbase/DTable.cxx
@@ -134,9 +134,9 @@ void lcl_CalcJulDate(sal_Int32& _nJulianDate,sal_Int32& _nJulianTime, const css:
     } // if ( rDateTime.Year <= 0 )
     else
     {
-        _nJulianDate = static_cast<sal_Int32>( ((365.25 * iy0)
+        _nJulianDate = static_cast<sal_Int32>(365.25 * iy0)
             + static_cast<sal_Int32>(30.6001 * (im0 + 1))
-            + aDateTime.Day + 1720994));
+            + aDateTime.Day + 1720994;
     }
     double JD = _nJulianDate + 0.5;
     _nJulianDate = static_cast<sal_Int32>( JD + 0.5);
diff --git a/drawinglayer/source/primitive3d/sdrextrudeprimitive3d.cxx b/drawinglayer/source/primitive3d/sdrextrudeprimitive3d.cxx
index cf00f208b9b8..1921c71dac25 100644
--- a/drawinglayer/source/primitive3d/sdrextrudeprimitive3d.cxx
+++ b/drawinglayer/source/primitive3d/sdrextrudeprimitive3d.cxx
@@ -17,6 +17,10 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
 
+#include <sal/config.h>
+
+#include <cmath>
+
 #include <drawinglayer/primitive3d/sdrextrudeprimitive3d.hxx>
 #include <basegfx/matrix/b2dhommatrix.hxx>
 #include <basegfx/polygon/b2dpolygontools.hxx>
@@ -62,7 +66,7 @@ namespace drawinglayer
                     const double fFrontArea(basegfx::utils::getArea(aFirstPolygon));
                     const double fSqrtFrontArea(sqrt(fFrontArea));
                     double fRelativeTextureWidth = basegfx::fTools::equalZero(fSqrtFrontArea) ? 1.0 : fFrontLength / fSqrtFrontArea;
-                    fRelativeTextureWidth = static_cast<double>(static_cast<sal_uInt32>(fRelativeTextureWidth - 0.5));
+                    fRelativeTextureWidth = std::trunc(fRelativeTextureWidth - 0.5);
 
                     if(fRelativeTextureWidth < 1.0)
                     {
diff --git a/hwpfilter/source/hwpreader.cxx b/hwpfilter/source/hwpreader.cxx
index 2b5e5145ae5b..d1e3d8d36691 100644
--- a/hwpfilter/source/hwpreader.cxx
+++ b/hwpfilter/source/hwpreader.cxx
@@ -4399,21 +4399,21 @@ void HwpReader::makePictureDRAW(HWPDrawingObject *drawobj, Picture * hbox)
                                   NaturalSpline(n, tarr, yarr, yb, carr, darr);
                               }
 
-                              sprintf(buf, "M%d %dC%d %d", WTSM(static_cast<int>(xarr[0])), WTSM(static_cast<int>(yarr[0])),
-                                      WTSM(static_cast<int>(xarr[0] + xb[0]/3)), WTSM(static_cast<int>(yarr[0] + yb[0]/3)) );
+                              sprintf(buf, "M%d %dC%d %d", WTSM(xarr[0]), WTSM(yarr[0]),
+                                      WTSM(xarr[0] + xb[0]/3), WTSM(yarr[0] + yb[0]/3) );
                               oustr += ascii(buf);
 
                               for( i = 1 ; i < n  ; i++ ){
                                   if( i == n -1 ){
                                       sprintf(buf, " %d %d %d %dz",
-                                              WTSM(static_cast<int>(xarr[i] - xb[i]/3)), WTSM(static_cast<int>(yarr[i] - yb[i]/3)),
-                                              WTSM(static_cast<int>(xarr[i])), WTSM(static_cast<int>(yarr[i])) );
+                                              WTSM(xarr[i] - xb[i]/3), WTSM(yarr[i] - yb[i]/3),
+                                              WTSM(xarr[i]), WTSM(yarr[i]) );
                                   }
                                   else{
                                       sprintf(buf, " %d %d %d %d %d %d",
-                                              WTSM(static_cast<int>(xarr[i] - xb[i]/3)), WTSM(static_cast<int>(yarr[i] - yb[i]/3)),
-                                              WTSM(static_cast<int>(xarr[i])), WTSM(static_cast<int>(yarr[i])),
-                                              WTSM(static_cast<int>(xarr[i]) + xb[i]/3), WTSM(static_cast<int>(yarr[i] + yb[i]/3)) );
+                                              WTSM(xarr[i] - xb[i]/3), WTSM(yarr[i] - yb[i]/3),
+                                              WTSM(xarr[i]), WTSM(yarr[i]),
+                                              WTSM(xarr[i] + xb[i]/3), WTSM(yarr[i] + yb[i]/3) );
                                   }
 
                                   oustr += ascii(buf);
diff --git a/libreofficekit/qa/tilebench/tilebench.cxx b/libreofficekit/qa/tilebench/tilebench.cxx
index 3c62e2e36838..8bb41999f17c 100644
--- a/libreofficekit/qa/tilebench/tilebench.cxx
+++ b/libreofficekit/qa/tilebench/tilebench.cxx
@@ -155,7 +155,7 @@ int main( int argc, char* argv[] )
 
         // Estimate the maximum tiles based on the number of parts requested, if Writer.
         if (pDocument->getDocumentType() == LOK_DOCTYPE_TEXT)
-            max_tiles = static_cast<int>(ceil(max_parts * 16128. / nTilePixelHeight)) * ceil(static_cast<double>(nWidth) / nTilePixelWidth);
+            max_tiles = static_cast<int>(ceil(max_parts * 16128. / nTilePixelHeight) * ceil(static_cast<double>(nWidth) / nTilePixelWidth));
         fprintf(stderr, "Parts to render: %d, Total Parts: %d, Max parts: %d, Max tiles: %d\n", nParts, nTotalParts, max_parts, max_tiles);
 
         std::vector<unsigned char> vBuffer(nTilePixelWidth * nTilePixelHeight * 4);
@@ -210,7 +210,7 @@ int main( int argc, char* argv[] )
                 aTimes.emplace_back("render sub-regions at scale");
                 int nMaxTiles = max_tiles;
                 if (pDocument->getDocumentType() == LOK_DOCTYPE_TEXT)
-                    nMaxTiles = static_cast<int>(ceil(max_parts * 16128. / nTileTwipHeight)) * ceil(static_cast<double>(nWidth) / nTileTwipWidth);
+                    nMaxTiles = static_cast<int>(ceil(max_parts * 16128. / nTileTwipHeight) * ceil(static_cast<double>(nWidth) / nTileTwipWidth));
                 int nTiles = 0;
                 for (int nY = 0; nY < nHeight - 1; nY += nTileTwipHeight)
                 {
diff --git a/reportdesign/source/filter/xml/xmlControlProperty.cxx b/reportdesign/source/filter/xml/xmlControlProperty.cxx
index 7eae2645c985..c232a44d6019 100644
--- a/reportdesign/source/filter/xml/xmlControlProperty.cxx
+++ b/reportdesign/source/filter/xml/xmlControlProperty.cxx
@@ -19,6 +19,7 @@
 
 #include <sal/config.h>
 
+#include <cmath>
 #include <map>
 
 #include "xmlControlProperty.hxx"
@@ -271,7 +272,8 @@ Any OXMLControlProperty::convertString(const css::uno::Type& _rExpectedType, con
                     {
                         case TYPE_DATE:
                         {
-                            OSL_ENSURE((static_cast<sal_uInt32>(nValue)) - nValue == 0,
+                            double dummy;
+                            OSL_ENSURE(std::modf(nValue, &dummy) == 0,
                                 "OPropertyImport::convertString: a Date value with a fractional part?");
                             aReturn <<= implGetDate(nValue);
                         }
diff --git a/sal/rtl/random.cxx b/sal/rtl/random.cxx
index 158e8fff3cc5..c9269abb837b 100644
--- a/sal/rtl/random.cxx
+++ b/sal/rtl/random.cxx
@@ -17,6 +17,10 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
 
+#include <sal/config.h>
+
+#include <cmath>
+
 #include <sal/types.h>
 #include <osl/thread.h>
 #include <osl/thread.hxx>
@@ -81,8 +85,7 @@ static double data(RandomData_Impl *pImpl)
               (static_cast<double>(pImpl->m_nY) / 30269.0) +
               (static_cast<double>(pImpl->m_nZ) / 30307.0)   );
 
-    random -= static_cast<double>(static_cast<sal_uInt32>(random));
-    return random;
+    return std::modf(random, &random);
 }
 
 static bool initPool(RandomPool_Impl *pImpl)
diff --git a/sccomp/source/solver/SwarmSolver.cxx b/sccomp/source/solver/SwarmSolver.cxx
index dab7b648b8c0..2a549fb0e0a8 100644
--- a/sccomp/source/solver/SwarmSolver.cxx
+++ b/sccomp/source/solver/SwarmSolver.cxx
@@ -30,6 +30,7 @@
 #include <comphelper/propertycontainer.hxx>
 #include <comphelper/proparrhlp.hxx>
 
+#include <cmath>
 #include <vector>
 #include <limits>
 #include <chrono>
@@ -370,7 +371,7 @@ double SwarmSolver::clampVariable(size_t nVarIndex, double fValue)
     double fResult = std::max(std::min(fValue, rBound.upper), rBound.lower);
 
     if (mbInteger)
-        return sal_Int64(fResult);
+        return std::trunc(fResult);
 
     return fResult;
 }
@@ -389,7 +390,7 @@ double SwarmSolver::boundVariable(size_t nVarIndex, double fValue)
     }
 
     if (mbInteger)
-        return sal_Int64(fResult);
+        return std::trunc(fResult);
 
     return fResult;
 }
diff --git a/sd/source/filter/eppt/pptx-epptooxml.cxx b/sd/source/filter/eppt/pptx-epptooxml.cxx
index f33c62db57dd..13dd072460f0 100644
--- a/sd/source/filter/eppt/pptx-epptooxml.cxx
+++ b/sd/source/filter/eppt/pptx-epptooxml.cxx
@@ -1898,8 +1898,8 @@ bool PowerPointExport::WriteComments(sal_uInt32 nPageNum)
                                     FSEND);
 
                 pFS->singleElementNS(XML_p, XML_pos,
-                                     XML_x, I64S((static_cast<sal_Int64>(57600*aRealPoint2D.X + 1270)/2540.0)),
-                                     XML_y, I64S((static_cast<sal_Int64>(57600*aRealPoint2D.Y + 1270)/2540.0)),
+                                     XML_x, I64S(static_cast<sal_Int64>((57600*aRealPoint2D.X + 1270)/2540.0)),
+                                     XML_y, I64S(static_cast<sal_Int64>((57600*aRealPoint2D.Y + 1270)/2540.0)),
                                      FSEND);
 
                 pFS->startElementNS(XML_p, XML_text,
diff --git a/slideshow/source/engine/transitions/snakewipe.cxx b/slideshow/source/engine/transitions/snakewipe.cxx
index dd15d1238deb..b484f36cb8d7 100644
--- a/slideshow/source/engine/transitions/snakewipe.cxx
+++ b/slideshow/source/engine/transitions/snakewipe.cxx
@@ -17,6 +17,9 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
 
+#include <sal/config.h>
+
+#include <cmath>
 
 #include <osl/diagnose.h>
 #include <basegfx/matrix/b2dhommatrix.hxx>
@@ -87,7 +90,7 @@ SnakeWipe::SnakeWipe( sal_Int32 nElements, bool diagonal, bool flipOnYAxis )
     if (in) {
         const double sqrtArea2 = sqrt( t * m_sqrtElements * m_sqrtElements );
         const double edge = ::basegfx::pruneScaleValue(
-            static_cast<double>( static_cast<sal_Int32>(sqrtArea2) ) /
+            std::trunc(sqrtArea2) /
             m_sqrtElements );
 
         ::basegfx::B2DPolygon poly;
@@ -99,7 +102,8 @@ SnakeWipe::SnakeWipe( sal_Int32 nElements, bool diagonal, bool flipOnYAxis )
             res.append(poly);
         }
         const double a = (M_SQRT1_2 / m_sqrtElements);
-        const double d = (sqrtArea2 - static_cast<sal_Int32>(sqrtArea2));
+        double dummy;
+        const double d = std::modf(sqrtArea2, &dummy);
         const double len = (t * M_SQRT2 * d);
         const double height = ::basegfx::pruneScaleValue( M_SQRT1_2 / m_sqrtElements );
         poly.clear();
@@ -130,7 +134,7 @@ SnakeWipe::SnakeWipe( sal_Int32 nElements, bool diagonal, bool flipOnYAxis )
     {
         const double sqrtArea2 = sqrt( t * m_sqrtElements * m_sqrtElements );
         const double edge = ::basegfx::pruneScaleValue(
-            static_cast<double>( static_cast<sal_Int32>(sqrtArea2) ) /
+            std::trunc(sqrtArea2) /
             m_sqrtElements );
 
         ::basegfx::B2DPolygon poly;
@@ -143,7 +147,8 @@ SnakeWipe::SnakeWipe( sal_Int32 nElements, bool diagonal, bool flipOnYAxis )
             res.append(poly);
         }
         const double a = (M_SQRT1_2 / m_sqrtElements);
-        const double d = (sqrtArea2 - static_cast<sal_Int32>(sqrtArea2));
+        double dummy;
+        const double d = std::modf(sqrtArea2, &dummy);
         const double len = ((1.0 - t) * M_SQRT2 * d);
         const double height = ::basegfx::pruneScaleValue( M_SQRT1_2 / m_sqrtElements );
         poly.clear();
diff --git a/tools/source/generic/poly.cxx b/tools/source/generic/poly.cxx
index ce9dabefa37e..5b00e6bc56a3 100644
--- a/tools/source/generic/poly.cxx
+++ b/tools/source/generic/poly.cxx
@@ -1329,7 +1329,7 @@ void Polygon::ImplReduceEdges( tools::Polygon& rPoly, const double& rArea, sal_u
                         else if( fRelLen > 1.0 )
                             fRelLen = 1.0;
 
-                        if( ( static_cast<sal_uInt32>( ( ( fLenFact - 1.0 ) * 1000000.0 ) + 0.5 ) < fBound ) &&
+                        if( ( std::round( ( fLenFact - 1.0 ) * 1000000.0 ) < fBound ) &&
                             ( fabs( fGradB ) <= ( fRelLen * fBound * 0.01 ) ) )
                         {
                             bDeletePoint = true;
diff --git a/vcl/opengl/gdiimpl.cxx b/vcl/opengl/gdiimpl.cxx
index df4996a6ca09..6858a2adbae7 100644
--- a/vcl/opengl/gdiimpl.cxx
+++ b/vcl/opengl/gdiimpl.cxx
@@ -39,6 +39,7 @@
 #include <opengl/VertexUtils.hxx>
 #include <opengl/BufferObject.hxx>
 
+#include <cmath>
 #include <vector>
 
 #include <glm/gtc/type_ptr.hpp>
@@ -1071,7 +1072,7 @@ void OpenGLSalGraphicsImpl::DrawTransformedTexture(
     if( ixscale >= 2 && iyscale >= 2 )  // scale ratio less than 50%
     {
         areaScaling = true;
-        fastAreaScaling = ( ixscale == int( ixscale ) && iyscale == int( iyscale ));
+        fastAreaScaling = ( ixscale == std::trunc( ixscale ) && iyscale == std::trunc( iyscale ));
         // The generic case has arrays only up to 16 ratio downscaling and is performed in 2 passes,
         // when the ratio is in the 16-100 range, which is hopefully enough in practice, but protect
         // against buffer overflows in case such an extreme case happens (and in such case the precision
diff --git a/vcl/opengl/scale.cxx b/vcl/opengl/scale.cxx
index 433ad19f2e8b..a5280bf70817 100644
--- a/vcl/opengl/scale.cxx
+++ b/vcl/opengl/scale.cxx
@@ -19,6 +19,8 @@
 
 #include <sal/config.h>
 
+#include <cmath>
+
 #include <vcl/opengl/OpenGLHelper.hxx>
 
 #include <vcl/bitmap.hxx>
@@ -203,7 +205,7 @@ bool OpenGLSalBitmap::ImplScaleArea( const rtl::Reference< OpenGLContext > &xCon
 
     double ixscale = 1 / rScaleX;
     double iyscale = 1 / rScaleY;
-    bool fast = ( ixscale == int( ixscale ) && iyscale == int( iyscale )
+    bool fast = ( ixscale == std::trunc( ixscale ) && iyscale == std::trunc( iyscale )
         && int( nNewWidth * ixscale ) == mnWidth && int( nNewHeight * iyscale ) == mnHeight );
 
     bool bTwoPasses = false;
diff --git a/writerfilter/source/dmapper/DomainMapper_Impl.cxx b/writerfilter/source/dmapper/DomainMapper_Impl.cxx
index f2274f0c646a..7194879807fd 100644
--- a/writerfilter/source/dmapper/DomainMapper_Impl.cxx
+++ b/writerfilter/source/dmapper/DomainMapper_Impl.cxx
@@ -78,6 +78,7 @@
 
 #include <oox/token/tokens.hxx>
 
+#include <cmath>
 #include <map>
 #include <tuple>
 #include <unordered_map>
@@ -4586,7 +4587,8 @@ static util::DateTime lcl_dateTimeFromSerial(const double& dSerial)
     DateTime d(Date(30, 12, 1899));
     d.AddDays( static_cast<sal_Int32>(dSerial) );
 
-    double frac = dSerial - static_cast<sal_Int32>(dSerial);
+    double dummy;
+    double frac = std::modf(dSerial, &dummy);
     sal_uInt32 seconds = frac * secondsPerDay;
 
     util::DateTime date;
diff --git a/xmloff/source/forms/propertyimport.cxx b/xmloff/source/forms/propertyimport.cxx
index 0851edf31519..679f1d5b3154 100644
--- a/xmloff/source/forms/propertyimport.cxx
+++ b/xmloff/source/forms/propertyimport.cxx
@@ -17,6 +17,10 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
 
+#include <sal/config.h>
+
+#include <cmath>
+
 #include "propertyimport.hxx"
 
 #include <sax/tools/converter.hxx>
@@ -182,7 +186,8 @@ Any PropertyConversion::convertString( const css::uno::Type& _rExpectedType,
                 {
                     case TYPE_DATE:
                     {
-                        OSL_ENSURE((static_cast<sal_uInt32>(nValue)) - nValue == 0,
+                        double dummy;
+                        OSL_ENSURE(std::modf(nValue, &dummy) == 0,
                             "PropertyConversion::convertString: a Date value with a fractional part?");
                         aReturn <<= lcl_getDate(nValue);
                     }