add ADD xfermode
safely handle (don't draw) if the size of SkMask exceeds 31bits
git-svn-id: http://skia.googlecode.com/svn/trunk@159 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index 93b5d4e..e3e5c49 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -911,11 +911,16 @@
return;
}
}
+
mask.fFormat = SkMask::kA8_Format;
mask.fRowBytes = SkAlign4(mask.fBounds.width());
+ size_t size = mask.computeImageSize();
+ if (0 == size) {
+ // the mask is too big to allocated, draw nothing
+ return;
+ }
// allocate (and clear) our temp buffer to hold the transformed bitmap
- size_t size = mask.computeImageSize();
SkAutoMalloc storage(size);
mask.fImage = (uint8_t*)storage.get();
memset(mask.fImage, 0, size);
@@ -2350,7 +2355,12 @@
if (SkMask::kComputeBoundsAndRenderImage_CreateMode == mode) {
mask->fFormat = SkMask::kA8_Format;
mask->fRowBytes = mask->fBounds.width();
- mask->fImage = SkMask::AllocImage(mask->computeImageSize());
+ size_t size = mask->computeImageSize();
+ if (0 == size) {
+ // we're too big to allocate the mask, abort
+ return false;
+ }
+ mask->fImage = SkMask::AllocImage(size);
memset(mask->fImage, 0, mask->computeImageSize());
}
diff --git a/src/core/SkMask.cpp b/src/core/SkMask.cpp
index b237639..337204b 100644
--- a/src/core/SkMask.cpp
+++ b/src/core/SkMask.cpp
@@ -15,19 +15,30 @@
** limitations under the License.
*/
+#include "Sk64.h"
#include "SkMask.h"
-size_t SkMask::computeImageSize() const
-{
- return fBounds.height() * fRowBytes;
+/** returns the product if it is positive and fits in 31 bits. Otherwise this
+ returns 0.
+ */
+static int32_t safeMul32(int32_t a, int32_t b) {
+ Sk64 size;
+ size.setMul(a, b);
+ if (size.is32() && size.isPos()) {
+ return size.get32();
+ }
+ return 0;
}
-size_t SkMask::computeTotalImageSize() const
-{
- size_t size = this->computeImageSize();
+size_t SkMask::computeImageSize() const {
+ return safeMul32(fBounds.height(), fRowBytes);
+}
- if (fFormat == SkMask::k3D_Format)
- size *= 3;
+size_t SkMask::computeTotalImageSize() const {
+ size_t size = this->computeImageSize();
+ if (fFormat == SkMask::k3D_Format) {
+ size = safeMul32(size, 3);
+ }
return size;
}
diff --git a/src/core/SkXfermode.cpp b/src/core/SkXfermode.cpp
index 7c336c2..9514bfa 100644
--- a/src/core/SkXfermode.cpp
+++ b/src/core/SkXfermode.cpp
@@ -45,6 +45,16 @@
}
#endif
+static unsigned saturated_add(unsigned a, unsigned b) {
+ SkASSERT(a <= 255);
+ SkASSERT(b <= 255);
+ unsigned sum = a + b;
+ if (sum > 255) {
+ sum = 255;
+ }
+ return sum;
+}
+
///////////////////////////////////////////////////////////////////////////////
bool SkXfermode::asCoeff(Coeff* src, Coeff* dst) {
@@ -500,6 +510,14 @@
return SkPackARGB32(a, r, g, b);
}
+static SkPMColor add_modeproc(SkPMColor src, SkPMColor dst) {
+ unsigned a = saturated_add(SkGetPackedA32(src), SkGetPackedA32(dst));
+ unsigned r = saturated_add(SkGetPackedR32(src), SkGetPackedR32(dst));
+ unsigned g = saturated_add(SkGetPackedG32(src), SkGetPackedG32(dst));
+ unsigned b = saturated_add(SkGetPackedB32(src), SkGetPackedB32(dst));
+ return SkPackARGB32(a, r, g, b);
+}
+
///////////////////////////////////////////////////////////////////////////////
class SkClearXfermode : public SkProcCoeffXfermode {
@@ -701,6 +719,8 @@
SkXfermode::Coeff fDC;
};
+#define CANNOT_USE_COEFF SkXfermode::Coeff(-1)
+
static const ProcCoeff gProcCoeffs[] = {
{ clear_modeproc, SkXfermode::kZero_Coeff, SkXfermode::kZero_Coeff },
{ src_modeproc, SkXfermode::kOne_Coeff, SkXfermode::kZero_Coeff },
@@ -714,12 +734,11 @@
{ srcatop_modeproc, SkXfermode::kDA_Coeff, SkXfermode::kISA_Coeff },
{ dstatop_modeproc, SkXfermode::kIDA_Coeff, SkXfermode::kSA_Coeff },
{ xor_modeproc, SkXfermode::kIDA_Coeff, SkXfermode::kISA_Coeff },
- // these two can't be represented as coefficients
- { darken_modeproc, SkXfermode::Coeff(-1), SkXfermode::Coeff(-1) },
- { lighten_modeproc, SkXfermode::Coeff(-1), SkXfermode::Coeff(-1) },
- // these can use coefficients
+ { darken_modeproc, CANNOT_USE_COEFF, CANNOT_USE_COEFF },
+ { lighten_modeproc, CANNOT_USE_COEFF, CANNOT_USE_COEFF },
{ mult_modeproc, SkXfermode::kZero_Coeff, SkXfermode::kSC_Coeff },
- { screen_modeproc, SkXfermode::kOne_Coeff, SkXfermode::kISC_Coeff }
+ { screen_modeproc, SkXfermode::kOne_Coeff, SkXfermode::kISC_Coeff },
+ { add_modeproc, CANNOT_USE_COEFF, CANNOT_USE_COEFF }
};
SkXfermode* SkPorterDuff::CreateXfermode(SkPorterDuff::Mode mode) {
diff --git a/src/effects/SkBlurMask.cpp b/src/effects/SkBlurMask.cpp
index 416eda4..8c7c64e 100644
--- a/src/effects/SkBlurMask.cpp
+++ b/src/effects/SkBlurMask.cpp
@@ -234,10 +234,15 @@
if (src.fImage)
{
+ size_t dstSize = dst->computeImageSize();
+ if (0 == dstSize) {
+ return false; // too big to allocate, abort
+ }
+
int sw = src.fBounds.width();
int sh = src.fBounds.height();
const uint8_t* sp = src.fImage;
- uint8_t* dp = SkMask::AllocImage(dst->computeImageSize());
+ uint8_t* dp = SkMask::AllocImage(dstSize);
SkAutoTCallVProc<uint8_t, SkMask_FreeImage> autoCall(dp);
@@ -258,7 +263,11 @@
// the blur into it (applying the src)
if (style == kInner_Style)
{
- dst->fImage = SkMask::AllocImage(src.computeImageSize());
+ size_t srcSize = src.computeImageSize();
+ if (0 == srcSize) {
+ return false; // too big to allocate, abort
+ }
+ dst->fImage = SkMask::AllocImage(srcSize);
merge_src_with_blur(dst->fImage, sp, sw, sh,
dp + rx + ry*dst->fBounds.width(),
dst->fBounds.width());
diff --git a/src/effects/SkEmbossMaskFilter.cpp b/src/effects/SkEmbossMaskFilter.cpp
index fcfad9d..67c8024 100644
--- a/src/effects/SkEmbossMaskFilter.cpp
+++ b/src/effects/SkEmbossMaskFilter.cpp
@@ -88,7 +88,9 @@
{
uint8_t* alphaPlane = dst->fImage;
size_t planeSize = dst->computeImageSize();
-
+ if (0 == planeSize) {
+ return false; // too big to allocate, abort
+ }
dst->fImage = SkMask::AllocImage(planeSize * 3);
memcpy(dst->fImage, alphaPlane, planeSize);
SkMask::FreeImage(alphaPlane);
diff --git a/src/effects/SkKernel33MaskFilter.cpp b/src/effects/SkKernel33MaskFilter.cpp
index a30ea4a..429e120 100644
--- a/src/effects/SkKernel33MaskFilter.cpp
+++ b/src/effects/SkKernel33MaskFilter.cpp
@@ -19,6 +19,9 @@
dst->fRowBytes = dst->fBounds.width();
size_t size = dst->computeImageSize();
+ if (0 == size) {
+ return false; // too big to allocate, abort
+ }
dst->fImage = SkMask::AllocImage(size);
const int h = src.fBounds.height();
diff --git a/src/effects/SkLayerRasterizer.cpp b/src/effects/SkLayerRasterizer.cpp
index ad16ea8..5aa883d 100644
--- a/src/effects/SkLayerRasterizer.cpp
+++ b/src/effects/SkLayerRasterizer.cpp
@@ -108,8 +108,12 @@
{
mask->fFormat = SkMask::kA8_Format;
mask->fRowBytes = mask->fBounds.width();
- mask->fImage = SkMask::AllocImage(mask->computeImageSize());
- memset(mask->fImage, 0, mask->computeImageSize());
+ size_t size = mask->computeImageSize();
+ if (0 == size) {
+ return false; // too big to allocate, abort
+ }
+ mask->fImage = SkMask::AllocImage(size);
+ memset(mask->fImage, 0, size);
}
if (SkMask::kJustComputeBounds_CreateMode != mode)