[reactos] 01/01: [WIN32K] CreateDIBPalette SEH Simplification #3758 CORE-17626

[Joachim Henze]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=c596fd3ef6933c9eec95a4...

commit c596fd3ef6933c9eec95a47c807d01d3776bbcc0
Author:     Joachim Henze [e-mail]
AuthorDate: Wed Jun 23 19:59:42 2021 +0200
Commit:     Joachim Henze [e-mail]
CommitDate: Wed Jun 23 19:59:42 2021 +0200

[WIN32K] CreateDIBPalette SEH Simplification #3758 CORE-17626

Enter an SEH2_TRY one time and do all testing within it instead of entering the SEH_TRY multiple times.

The commit is an addendum to 0.4.15-dev-2734-g 514147776a7e70636911033ab6c89779b2c8ee1e

Thanks to patches author Doug-Lyons

This is 1:1 the final approved content of #3758, but I committed
    by hand and closed the PR to avoid squash+rebase.
---
 win32ss/gdi/ntgdi/dibobj.c | 41 +++++++++++++++++------------------------
 1 file changed, 17 insertions(+), 24 deletions(-)

diff --git a/win32ss/gdi/ntgdi/dibobj.c b/win32ss/gdi/ntgdi/dibobj.c
index 1ae6e8affa9..acd8da28d23 100644
--- a/win32ss/gdi/ntgdi/dibobj.c
+++ b/win32ss/gdi/ntgdi/dibobj.c
@@ -45,8 +45,6 @@ CreateDIBPalette(
 {
     PPALETTE ppal;
     ULONG i, cBitsPixel, cColors;
-    RGBQUAD rgb;
-    NTSTATUS Status;

if (pbmi->bmiHeader.biSize < sizeof(BITMAPINFOHEADER))
     {
@@ -129,34 +127,29 @@ CreateDIBPalette(
         {
             /* The colors are an array of RGBQUAD values */
             RGBQUAD *prgb = (RGBQUAD*)((PCHAR)pbmi + pbmi->bmiHeader.biSize);
+            RGBQUAD colors[256] = {0};

// FIXME: do we need to handle PALETTEINDEX / PALETTERGB macro?

-            /* Loop all color indices in the DIB */
-            for (i = 0; i < cColors; i++)
+            /* Use SEH to verify we can READ prgb[] succesfully */
+            _SEH2_TRY
             {
-                /* User SEH to verify READ success */
-                Status = STATUS_SUCCESS;
-                _SEH2_TRY
-                {
-                    rgb = prgb[i];
-                }
-                _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
-                {
-                    Status = _SEH2_GetExceptionCode();
-                    /* On Read Failure, put zero in Palette */
-                    PALETTE_vSetRGBColorForIndex(ppal, i, 0);
-                }
-                _SEH2_END
+                RtlCopyMemory(colors, prgb, cColors * sizeof(colors[0]));
+            }
+            _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
+            {
+              /* Do Nothing */
+            }
+            _SEH2_END;

-                if(NT_SUCCESS(Status))
-                {
-                    /* Get the color value and translate it to a COLORREF */
-                    COLORREF crColor = RGB(rgb.rgbRed, rgb.rgbGreen, rgb.rgbBlue);
+            for (i = 0; i < cColors; ++i)
+            {
+                /* Get the color value and translate it to a COLORREF */
+                COLORREF crColor = RGB(colors[i].rgbRed, colors[i].rgbGreen, colors[i].rgbBlue);
+
+                /* Set the RGB value in the palette */
+                PALETTE_vSetRGBColorForIndex(ppal, i, crColor);

-                    /* Set the RGB value in the palette */
-                    PALETTE_vSetRGBColorForIndex(ppal, i, crColor);
-                }
             }
         }
         else