Define Chromoting's differ block size in one (and only one) place.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/7511014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@95475 0039d316-1c4b-4281-b951-d872f2087c98

remoting/host/differ.cc

@@ -105,7 +105,7 @@ void Differ::MarkDirtyBlocks(const void* prev_buffer, const void* curr_buffer) {
     for (int x = 0; x < x_full_blocks; x++) {
       *diff_info = DiffPartialBlock(prev_block, curr_block,
                                     bytes_per_row_,
-                                    kBlockWidth, partial_row_height);
+                                    kBlockSize, partial_row_height);
       prev_block += block_x_offset;
       curr_block += block_x_offset;
       diff_info += sizeof(DiffInfo);

remoting/host/differ.h

@@ -16,10 +16,6 @@ namespace remoting {
 
 typedef uint8 DiffInfo;
 
-// Size (in pixels) of each square block used for diffing.
-// This must be a multiple of sizeof(uint64).
-static const int kBlockSize = 32;
-
 class Differ {
  public:
   // Create a differ that operates on bitmaps with the specified width, height

remoting/host/differ_block.cc

@@ -11,9 +11,9 @@
 namespace remoting {
 
 int BlockDifference_C(const uint8* image1, const uint8* image2, int stride) {
-  int width_bytes = kBlockWidth * kBytesPerPixel;
+  int width_bytes = kBlockSize * kBytesPerPixel;
 
-  for (int y = 0; y < kBlockHeight; y++) {
+  for (int y = 0; y < kBlockSize; y++) {
     if (memcmp(image1, image2, width_bytes) != 0)
       return 1;
     image1 += stride;
@@ -32,9 +32,9 @@ int BlockDifference(const uint8* image1, const uint8* image2, int stride) {
     diff_proc = &BlockDifference_C;
 #else
     // For x86 processors, check if SSE2 is supported.
-    if (media::hasSSE2() && kBlockWidth == 32)
+    if (media::hasSSE2() && kBlockSize == 32)
       diff_proc = &BlockDifference_SSE2_W32;
-    else if (media::hasSSE2() && kBlockWidth == 16)
+    else if (media::hasSSE2() && kBlockSize == 16)
       diff_proc = &BlockDifference_SSE2_W16;
     else
       diff_proc = &BlockDifference_C;

remoting/host/differ_block.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -9,9 +9,11 @@
 
 namespace remoting {
 
-// Block size and format (BGRA 32 bit) are fixed.
-static const int kBlockWidth = 32;
-static const int kBlockHeight = 32;
+// Size (in pixels) of each square block used for diffing.
+// This must be a multiple of sizeof(uint64)/8.
+static const int kBlockSize = 32;
+
+// Format: BGRA 32 bit.
 static const int kBytesPerPixel = 4;
 
 // Low level functions to compare 2 blocks of pixels.

remoting/host/differ_block_sse2.cc

@@ -20,7 +20,7 @@ extern int BlockDifference_SSE2_W16(const uint8* image1, const uint8* image2,
   __m128i v0;
   __m128i v1;
   __m128i sad;
-  for (int y = 0; y < kBlockHeight; ++y) {
+  for (int y = 0; y < kBlockSize; ++y) {
     const __m128i* i1 = reinterpret_cast<const __m128i*>(image1);
     const __m128i* i2 = reinterpret_cast<const __m128i*>(image2);
     v0 = _mm_loadu_si128(i1);
@@ -59,7 +59,7 @@ extern int BlockDifference_SSE2_W32(const uint8* image1, const uint8* image2,
   __m128i v0;
   __m128i v1;
   __m128i sad;
-  for (int y = 0; y < kBlockHeight; ++y) {
+  for (int y = 0; y < kBlockSize; ++y) {
     const __m128i* i1 = reinterpret_cast<const __m128i*>(image1);
     const __m128i* i2 = reinterpret_cast<const __m128i*>(image2);
     v0 = _mm_loadu_si128(i1);

remoting/host/differ_block_unittest.cc

@@ -25,7 +25,7 @@ class EncodeDoneHandler
 };
 
 // Memory buffer large enough for 2 blocks aligned to 16 bytes.
-static const int kSizeOfBlock = kBlockHeight * kBlockWidth * kBytesPerPixel;
+static const int kSizeOfBlock = kBlockSize * kBlockSize * kBytesPerPixel;
 uint8 block_buffer[kSizeOfBlock * 2 + 16];
 
 void PrepareBuffers(uint8* &block1, uint8* &block2) {
@@ -43,7 +43,7 @@ TEST(BlockDifferenceTestSame, BlockDifference) {
 
   // These blocks should match.
   for (int i = 0; i < kTimesToRun; ++i) {
-    int result = BlockDifference(block1, block2, kBlockWidth * kBytesPerPixel);
+    int result = BlockDifference(block1, block2, kBlockSize * kBytesPerPixel);
     EXPECT_EQ(0, result);
   }
 }
@@ -55,7 +55,7 @@ TEST(BlockDifferenceTestLast, BlockDifference) {
   block2[kSizeOfBlock-2] += 1;
 
   for (int i = 0; i < kTimesToRun; ++i) {
-    int result = BlockDifference(block1, block2, kBlockWidth * kBytesPerPixel);
+    int result = BlockDifference(block1, block2, kBlockSize * kBytesPerPixel);
     EXPECT_EQ(1, result);
   }
 }
@@ -67,7 +67,7 @@ TEST(BlockDifferenceTestMid, BlockDifference) {
   block2[kSizeOfBlock/2+1] += 1;
 
   for (int i = 0; i < kTimesToRun; ++i) {
-    int result = BlockDifference(block1, block2, kBlockWidth * kBytesPerPixel);
+    int result = BlockDifference(block1, block2, kBlockSize * kBytesPerPixel);
     EXPECT_EQ(1, result);
   }
 }
@@ -79,7 +79,7 @@ TEST(BlockDifferenceTestFirst, BlockDifference) {
   block2[0] += 1;
 
   for (int i = 0; i < kTimesToRun; ++i) {
-    int result = BlockDifference(block1, block2, kBlockWidth * kBytesPerPixel);
+    int result = BlockDifference(block1, block2, kBlockSize * kBytesPerPixel);
     EXPECT_EQ(1, result);
   }
 }