Checking structure sizes before reading them from memory to avoid overflowing the buffer's stream.

tests/MatrixTest.cpp

Index: tests/MatrixTest.cpp
diff --git a/tests/MatrixTest.cpp b/tests/MatrixTest.cpp
index 07eacb6f444ac414391ba52ced766d4c143d19c3..53a4ac170e0731c7bf1e8b25d9fa38fdf5c0946c 100644
--- a/tests/MatrixTest.cpp
+++ b/tests/MatrixTest.cpp
@@ -10,6 +10,8 @@
 #include "SkMatrix.h"
 #include "SkMatrixUtils.h"
 #include "SkRandom.h"
+#include "SkReader32.h"
+#include "SkWriter32.h"
 
 static bool nearly_equal_scalar(SkScalar a, SkScalar b) {
     // Note that we get more compounded error for multiple operations when
@@ -112,19 +114,26 @@ static void test_matrix_recttorect(skiatest::Reporter* reporter) {
 
 static void test_flatten(skiatest::Reporter* reporter, const SkMatrix& m) {
     // add 100 in case we have a bug, I don't want to kill my stack in the test
-    char buffer[SkMatrix::kMaxFlattenSize + 100];
-    uint32_t size1 = m.writeToMemory(NULL);
-    uint32_t size2 = m.writeToMemory(buffer);
+    static const uint32_t kBufferSize = SkWriter32::MaxWriteMatrixSize() + 100;
+    char buffer[kBufferSize];
+    SkWriter32 writer(SkWriter32::MaxWriteMatrixSize(), buffer, kBufferSize);
+    uint32_t size1 = writer.writeMatrixSize(m);
+    writer.writeMatrix(m);
+    uint32_t size2 = writer.bytesWritten();
     REPORTER_ASSERT(reporter, size1 == size2);
-    REPORTER_ASSERT(reporter, size1 <= SkMatrix::kMaxFlattenSize);
+    REPORTER_ASSERT(reporter, size1 <= SkWriter32::MaxWriteMatrixSize());
 
     SkMatrix m2;
-    uint32_t size3 = m2.readFromMemory(buffer);
+    SkReader32 reader(buffer, kBufferSize);
+    reader.readMatrix(&m2);
+    uint32_t size3 = reader.offset();
     REPORTER_ASSERT(reporter, size1 == size3);
     REPORTER_ASSERT(reporter, are_equal(reporter, m, m2));
 
-    char buffer2[SkMatrix::kMaxFlattenSize + 100];
-    size3 = m2.writeToMemory(buffer2);
+    char buffer2[kBufferSize];
+    SkWriter32 writer2(SkWriter32::MaxWriteMatrixSize(), buffer2, kBufferSize);
+    writer2.writeMatrix(m2);
+    size3 = writer2.bytesWritten();
     REPORTER_ASSERT(reporter, size1 == size3);
     REPORTER_ASSERT(reporter, memcmp(buffer, buffer2, size1) == 0);
 }