commit 1fbf760a123ab45834bceed36047c7d240f78262
author wjmaclean@chromium.org <wjmaclean@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Wed Apr 13 13:31:06 2011 +0000
committer wjmaclean@chromium.org <wjmaclean@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Wed Apr 13 13:31:06 2011 +0000
tree c246c08ca8247ab514be66dc4ea222e4811b5d57
parent 521e34e2912d835ab1b33a06cb8fb416510d7c53

Fix SkFixed overflows in SkFixedSquare, SkGradientShader.

Return SK_FixedMax when overflow occurs.

git-svn-id: http://skia.googlecode.com/svn/trunk@1117 2bbb7eff-a529-9590-31e7-b0007b416f81

src/effects/SkGradientShader.cpp

diff --git a/src/effects/SkGradientShader.cpp b/src/effects/SkGradientShader.cpp
index dca87b0..f43cf4b 100644
--- a/src/effects/SkGradientShader.cpp
+++ b/src/effects/SkGradientShader.cpp
@@ -1096,7 +1096,10 @@
             else if (proc == mirror_tileproc)
             {
                 do {
-                    SkFixed dist = SkFixedSqrt(SkFixedSquare(fx) + SkFixedSquare(fy));
+                    SkFixed magnitudeSquared = SkFixedSquare(fx) + SkFixedSquare(fy);
+                    if (magnitudeSquared < 0) // Overflow.
+                        magnitudeSquared = SK_FixedMax;
+                    SkFixed dist = SkFixedSqrt(magnitudeSquared);
                     unsigned fi = mirror_tileproc(dist);
                     SkASSERT(fi <= 0xFFFF);
                     *dstC++ = cache[fi >> (16 - kCache32Bits)];
@@ -1108,7 +1111,10 @@
             {
                 SkASSERT(proc == repeat_tileproc);
                 do {
-                    SkFixed dist = SkFixedSqrt(SkFixedSquare(fx) + SkFixedSquare(fy));
+                    SkFixed magnitudeSquared = SkFixedSquare(fx) + SkFixedSquare(fy);
+                    if (magnitudeSquared < 0) // Overflow.
+                        magnitudeSquared = SK_FixedMax;
+                    SkFixed dist = SkFixedSqrt(magnitudeSquared);
                     unsigned fi = repeat_tileproc(dist);
                     SkASSERT(fi <= 0xFFFF);
                     *dstC++ = cache[fi >> (16 - kCache32Bits)];