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

tests/MatrixTest.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "Test.h"
 #include "SkMath.h"
 #include "SkMatrix.h"
@@ skipping 94 matching lines @@
 
     dst = src;
     dst.fRight = src.fRight * 2;
     matrix.setRectToRect(src, dst, SkMatrix::kFill_ScaleToFit);
     REPORTER_ASSERT(reporter, SkMatrix::kScale_Mask == matrix.getType());
     REPORTER_ASSERT(reporter, matrix.rectStaysRect());
 }
 
 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 size_t kBufferSize = SkMatrix::kMaxFlattenSize + 100;
+    char buffer[kBufferSize];
+    size_t size1 = m.writeToMemory(NULL);
+    size_t size2 = m.writeToMemory(buffer);
     REPORTER_ASSERT(reporter, size1 == size2);
     REPORTER_ASSERT(reporter, size1 <= SkMatrix::kMaxFlattenSize);
 
     SkMatrix m2;
-    uint32_t size3 = m2.readFromMemory(buffer);
+    size_t size3 = m2.readFromMemory(buffer, kBufferSize);
     REPORTER_ASSERT(reporter, size1 == size3);
     REPORTER_ASSERT(reporter, are_equal(reporter, m, m2));
 
-    char buffer2[SkMatrix::kMaxFlattenSize + 100];
+    char buffer2[kBufferSize];
     size3 = m2.writeToMemory(buffer2);
     REPORTER_ASSERT(reporter, size1 == size3);
     REPORTER_ASSERT(reporter, memcmp(buffer, buffer2, size1) == 0);
 }
 
 static void test_matrix_max_stretch(skiatest::Reporter* reporter) {
     SkMatrix identity;
     identity.reset();
     REPORTER_ASSERT(reporter, SK_Scalar1 == identity.getMaxStretch());
 
@@ skipping 661 matching lines @@
 
     test_matrix_max_stretch(reporter);
     test_matrix_is_similarity(reporter);
     test_matrix_recttorect(reporter);
     test_matrix_decomposition(reporter);
     test_matrix_homogeneous(reporter);
 }
 
 #include "TestClassDef.h"
 DEFINE_TESTCLASS("Matrix", MatrixTestClass, TestMatrix)