Fix buffer overrun, bit overrun and add a test.
BUG=539691
Review URL: https://codereview.chromium.org/1453163002
diff --git a/tests/BlitMaskClip.cpp b/tests/BlitMaskClip.cpp
new file mode 100644
index 0000000..a3bce17
--- /dev/null
+++ b/tests/BlitMaskClip.cpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBlitter.h"
+#include "SkMask.h"
+#include "Test.h"
+
+class TestBlitter : public SkBlitter {
+public:
+ TestBlitter(SkIRect bounds, skiatest::Reporter* reporter)
+ : fBounds(bounds)
+ , fReporter(reporter) { }
+
+ void blitH(int x, int y, int width) override {
+
+ REPORTER_ASSERT(fReporter, x >= fBounds.fLeft && x < fBounds.fRight);
+ REPORTER_ASSERT(fReporter, y >= fBounds.fTop && y < fBounds.fBottom);
+ int right = x + width;
+ REPORTER_ASSERT(fReporter, right > fBounds.fLeft && right <= fBounds.fRight);
+ }
+
+private:
+ SkIRect fBounds;
+ skiatest::Reporter* fReporter;
+};
+
+
+// Exercise all clips compared with different widths of bitMask. Make sure that no buffer
+// overruns happen.
+DEF_TEST(BlitAndClip, reporter) {
+ const int originX = 100;
+ const int originY = 100;
+ for (int width = 1; width <= 32; width++) {
+ const int height = 2;
+ int rowBytes = (width + 7) >> 3;
+ uint8_t* bits = new uint8_t[rowBytes * height];
+
+ SkIRect b = {originX, originY, originX + width, originY + height};
+
+ SkMask mask;
+ mask.fFormat = SkMask::kBW_Format;
+ mask.fBounds = b;
+ mask.fImage = (uint8_t*)bits;
+ mask.fRowBytes = rowBytes;
+
+ TestBlitter tb(mask.fBounds, reporter);
+
+ for (int top = b.fTop; top < b.fBottom; top++) {
+ for (int bottom = top + 1; bottom <= b.fBottom; bottom++) {
+ for (int left = b.fLeft; left < b.fRight; left++) {
+ for (int right = left + 1; right <= b.fRight; right++) {
+ SkIRect clipRect = {left, top, right, bottom};
+ tb.blitMask(mask, clipRect);
+ }
+ }
+ }
+ }
+
+ delete [] bits;
+ }
+}