unroll code for early returns, no logic changed intended

(cherry picked from commit 218179ddbffbc4d4a1e96dfaeebca19cffda5f9c)

Change-Id: Ic1cc63a5fe3ad2c949f91c395c00f5f99bd7602a
(cherry picked from commit ea08f30d999af015390c6767310e2462e7f33711)

1 files changed, 97 insertions, 99 deletions

diff --git a/vcl/headless/svpbmp.cxx b/vcl/headless/svpbmp.cxx
index 94f795539011..ef175e8838f3 100644
--- a/vcl/headless/svpbmp.cxx
+++ b/vcl/headless/svpbmp.cxx
@@ -53,119 +53,117 @@ BitmapBuffer* ImplCreateDIB(
         || nBitCount == 32)
         && "Unsupported BitCount!");
 
+    if (!rSize.Width() || !rSize.Height())
+        return nullptr;
+
     BitmapBuffer* pDIB = nullptr;
 
-    if( rSize.Width() && rSize.Height() )
+    try
     {
-        try
+        pDIB = new BitmapBuffer;
+    }
+    catch (const std::bad_alloc&)
+    {
+        pDIB = nullptr;
+    }
+
+    if(!pDIB)
+        return nullptr;
+
+    const sal_uInt16 nColors = ( nBitCount <= 8 ) ? ( 1 << nBitCount ) : 0;
+
+    switch (nBitCount)
+    {
+        case 1:
+            pDIB->mnFormat = ScanlineFormat::N1BitLsbPal;
+            break;
+        case 4:
+            pDIB->mnFormat = ScanlineFormat::N4BitMsnPal;
+            break;
+        case 8:
+            pDIB->mnFormat = ScanlineFormat::N8BitPal;
+            break;
+        case 16:
         {
-            pDIB = new BitmapBuffer;
+#ifdef OSL_BIGENDIAN
+            pDIB->mnFormat= ScanlineFormat::N16BitTcMsbMask;
+#else
+            pDIB->mnFormat= ScanlineFormat::N16BitTcLsbMask;
+#endif
+            ColorMaskElement aRedMask(0xf800);
+            aRedMask.CalcMaskShift();
+            ColorMaskElement aGreenMask(0x07e0);
+            aGreenMask.CalcMaskShift();
+            ColorMaskElement aBlueMask(0x001f);
+            aBlueMask.CalcMaskShift();
+            pDIB->maColorMask = ColorMask(aRedMask, aGreenMask, aBlueMask);
+            break;
         }
-        catch (const std::bad_alloc&)
+        default:
+            nBitCount = 32;
+            SAL_FALLTHROUGH;
+        case 32:
         {
-            pDIB = nullptr;
+            pDIB->mnFormat = SVP_CAIRO_FORMAT;
+            break;
         }
+    }
 
-        if( pDIB )
+    pDIB->mnFormat |= ScanlineFormat::TopDown;
+    pDIB->mnWidth = rSize.Width();
+    pDIB->mnHeight = rSize.Height();
+    long nScanlineBase;
+    bool bFail = o3tl::checked_multiply<long>(pDIB->mnWidth, nBitCount, nScanlineBase);
+    if (bFail)
+    {
+        SAL_WARN("vcl.gdi", "checked multiply failed");
+        delete pDIB;
+        return nullptr;
+     }
+     pDIB->mnScanlineSize = AlignedWidth4Bytes(nScanlineBase);
+     if (pDIB->mnScanlineSize < nScanlineBase/8)
+     {
+         SAL_WARN("vcl.gdi", "scanline calculation wraparound");
+         delete pDIB;
+         return nullptr;
+     }
+     pDIB->mnBitCount = nBitCount;
+
+    if( nColors )
+    {
+        pDIB->maPalette = rPal;
+        pDIB->maPalette.SetEntryCount( nColors );
+    }
+
+    try
+    {
+        size_t size;
+        bFail = o3tl::checked_multiply<size_t>(pDIB->mnHeight, pDIB->mnScanlineSize, size);
+        SAL_WARN_IF(bFail, "vcl.gdi", "checked multiply failed");
+        if (bFail)
         {
-            const sal_uInt16 nColors = ( nBitCount <= 8 ) ? ( 1 << nBitCount ) : 0;
-
-            switch (nBitCount)
-            {
-                case 1:
-                    pDIB->mnFormat = ScanlineFormat::N1BitLsbPal;
-                    break;
-                case 4:
-                    pDIB->mnFormat = ScanlineFormat::N4BitMsnPal;
-                    break;
-                case 8:
-                    pDIB->mnFormat = ScanlineFormat::N8BitPal;
-                    break;
-                case 16:
-                {
-#ifdef OSL_BIGENDIAN
-                    pDIB->mnFormat= ScanlineFormat::N16BitTcMsbMask;
-#else
-                    pDIB->mnFormat= ScanlineFormat::N16BitTcLsbMask;
-#endif
-                    ColorMaskElement aRedMask(0xf800);
-                    aRedMask.CalcMaskShift();
-                    ColorMaskElement aGreenMask(0x07e0);
-                    aGreenMask.CalcMaskShift();
-                    ColorMaskElement aBlueMask(0x001f);
-                    aBlueMask.CalcMaskShift();
-                    pDIB->maColorMask = ColorMask(aRedMask, aGreenMask, aBlueMask);
-                    break;
-                }
-                default:
-                    nBitCount = 32;
-                    SAL_FALLTHROUGH;
-                case 32:
-                {
-                    pDIB->mnFormat = SVP_CAIRO_FORMAT;
-                    break;
-                }
-            }
-
-            pDIB->mnFormat |= ScanlineFormat::TopDown;
-            pDIB->mnWidth = rSize.Width();
-            pDIB->mnHeight = rSize.Height();
-            long nScanlineBase;
-            bool bFail = o3tl::checked_multiply<long>(pDIB->mnWidth, nBitCount, nScanlineBase);
-            if (bFail)
-            {
-                SAL_WARN("vcl.gdi", "checked multiply failed");
-                delete pDIB;
-                return nullptr;
-            }
-            pDIB->mnScanlineSize = AlignedWidth4Bytes(nScanlineBase);
-            if (pDIB->mnScanlineSize < nScanlineBase/8)
-            {
-                SAL_WARN("vcl.gdi", "scanline calculation wraparound");
-                delete pDIB;
-                return nullptr;
-            }
-            pDIB->mnBitCount = nBitCount;
-
-            if( nColors )
-            {
-                pDIB->maPalette = rPal;
-                pDIB->maPalette.SetEntryCount( nColors );
-            }
-
-            try
-            {
-                size_t size;
-                bFail = o3tl::checked_multiply<size_t>(pDIB->mnHeight, pDIB->mnScanlineSize, size);
-                SAL_WARN_IF(bFail, "vcl.gdi", "checked multiply failed");
-                if (bFail)
-                {
-                    delete pDIB;
-                    return nullptr;
-                }
-
-                pDIB->mpBits = new sal_uInt8[size];
+            delete pDIB;
+            return nullptr;
+        }
+
+        pDIB->mpBits = new sal_uInt8[size];
 #ifdef __SANITIZE_ADDRESS__
-                if (!pDIB->mpBits)
-                {   // can only happen with ASAN allocator_may_return_null=1
-                    delete pDIB;
-                    pDIB = nullptr;
-                }
-                else
+        if (!pDIB->mpBits)
+        {   // can only happen with ASAN allocator_may_return_null=1
+            delete pDIB;
+            pDIB = nullptr;
+        }
+        else
 #endif
-                {
-                    std::memset(pDIB->mpBits, 0, size);
-                }
-            }
-            catch (const std::bad_alloc&)
-            {
-                delete pDIB;
-                pDIB = nullptr;
-            }
+        {
+            std::memset(pDIB->mpBits, 0, size);
         }
     }
-    else
+    catch (const std::bad_alloc&)
+    {
+        delete pDIB;
         pDIB = nullptr;
+    }
 
     return pDIB;
 }