If image sizes are greater than 32768, fixed point stepping will overflow an…

If image sizes are greater than 32768, fixed point stepping will overflow an int. This CL changes the max size to 32768 and disables the test if larger.

BUG=libyuv:590
TESTED=LIBYUV_FLAGS=-1 LIBYUV_WIDTH=8192 LIBYUV_HEIGHT=16 out/Release/libyuv_unittest --gtest_filter=*
R=harryjin@google.com

Review URL: https://codereview.chromium.org/1947783002 .

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1586
+Version: 1587
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1586
+#define LIBYUV_VERSION 1587
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

unit_test/scale_argb_test.cc

@@ -28,6 +28,10 @@ static int ARGBTestFilter(int src_width, int src_height,
                           int dst_width, int dst_height,
                           FilterMode f, int benchmark_iterations,
                           int disable_cpu_flags, int benchmark_cpu_info) {
+  if (!SizeValid(src_width, src_height, dst_width, dst_height)) {
+    return 0;
+  }
+
   int i, j;
   const int b = 0;  // 128 to test for padding/stride.
   int64 src_argb_plane_size = (Abs(src_width) + b * 2) *
@@ -143,6 +147,10 @@ static int TileARGBScale(const uint8* src_argb, int src_stride_argb,
 static int ARGBClipTestFilter(int src_width, int src_height,
                               int dst_width, int dst_height,
                               FilterMode f, int benchmark_iterations) {
+  if (!SizeValid(src_width, src_height, dst_width, dst_height)) {
+    return 0;
+  }
+
   const int b = 128;
   int64 src_argb_plane_size = (Abs(src_width) + b * 2) *
       (Abs(src_height) + b * 2) * 4;

unit_test/scale_test.cc

@@ -25,6 +25,10 @@ static int TestFilter(int src_width, int src_height,
                       int dst_width, int dst_height,
                       FilterMode f, int benchmark_iterations,
                       int disable_cpu_flags, int benchmark_cpu_info) {
+  if (!SizeValid(src_width, src_height, dst_width, dst_height)) {
+    return 0;
+  }
+
   int i, j;
   const int b = 0;  // 128 to test for padding/stride.
   int src_width_uv = (Abs(src_width) + 1) >> 1;
@@ -148,6 +152,10 @@ static int TestFilter(int src_width, int src_height,
 static int TestFilter_16(int src_width, int src_height,
                          int dst_width, int dst_height,
                          FilterMode f, int benchmark_iterations) {
+  if (!SizeValid(src_width, src_height, dst_width, dst_height)) {
+    return 0;
+  }
+
   int i, j;
   const int b = 0;  // 128 to test for padding/stride.
   int src_width_uv = (Abs(src_width) + 1) >> 1;
@@ -274,8 +282,8 @@ static int TestFilter_16(int src_width, int src_height,
 // The following adjustments in dimensions ensure the scale factor will be
 // exactly achieved.
 // 2 is chroma subsample
-#define DX(x, nom, denom) static_cast<int>((Abs(x) / nom / 2) * nom * 2)
-#define SX(x, nom, denom) static_cast<int>((x / nom / 2) * denom * 2)
+#define DX(x, nom, denom) static_cast<int>(((Abs(x) / nom + 1) / 2) * nom * 2)
+#define SX(x, nom, denom) static_cast<int>(((x / nom + 1) / 2) * denom * 2)
 
 #define TEST_FACTOR1(name, filter, nom, denom, max_diff)                       \
     TEST_F(LibYUVScaleTest, ScaleDownBy##name##_##filter) {                    \

unit_test/unit_test.h

@@ -28,6 +28,32 @@ static __inline int Abs(int v) {
 
 #define OFFBY 0
 
+// Scaling uses 16.16 fixed point to step thru the source image, so a
+// maximum size of 32767.999 can be expressed.  32768 is valid because
+// the step is 1 beyond the image but not used.
+// Destination size is mainly constrained by valid scale step not the 
+// absolute size, so it may be possible to relax the destination size
+// constraint.
+// Source size is unconstrained for most specialized scalers.  e.g.
+// An image of 65536 scaled to half size would be valid.  The test 
+// could be relaxed for special scale factors.
+// If this test is removed, the scaling function should gracefully
+// fail with a return code.  The test could be changed to know that
+// libyuv failed in a controlled way.
+
+static const int kMaxWidth = 32768;
+static const int kMaxHeight = 32768;
+
+static inline bool SizeValid(int src_width, int src_height,
+                             int dst_width, int dst_height) {
+  if (src_width > kMaxWidth || src_height > kMaxHeight ||
+      dst_width > kMaxWidth || dst_height > kMaxHeight) {
+    printf("Warning - size too large to test.  Skipping\n");
+    return false;
+  }
+  return true;
+}
+
 #define align_buffer_page_end(var, size)                                       \
   uint8* var;                                                                  \
   uint8* var##_mem;                                                            \