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// Copyright (c) 2010 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.
#include "remoting/host/differ_block.h"
#include "build/build_config.h"
#include "media/base/cpu_features.h"
#include "remoting/host/differ_block_internal.h"
namespace remoting {
int BlockDifference_C(const uint8* image1, const uint8* image2, int stride) {
// Number of uint64s in each row of the block.
// This must be an integral number.
int int64s_per_row = (kBlockWidth * kBytesPerPixel) / sizeof(uint64);
for (int y = 0; y < kBlockHeight; y++) {
const uint64* prev = reinterpret_cast<const uint64*>(image1);
const uint64* curr = reinterpret_cast<const uint64*>(image2);
// Check each row in uint64-sized chunks.
// Note that this check may straddle multiple pixels. This is OK because
// we're interested in identifying whether or not there was change - we
// don't care what the actual change is.
for (int x = 0; x < int64s_per_row; x++) {
if (*prev++ != *curr++) {
return 1;
}
}
image1 += stride;
image2 += stride;
}
return 0;
}
int BlockDifference(const uint8* image1, const uint8* image2, int stride) {
static int (*diff_proc)(const uint8*, const uint8*, int) = NULL;
if (!diff_proc) {
#if defined(ARCH_CPU_ARM_FAMILY)
// For ARM processors, always use C version.
// TODO(hclam): Implement a NEON version.
diff_proc = &BlockDifference_C;
#else
// For x86 processors, check if SSE2 is supported.
if (media::hasSSE2() && kBlockWidth == 32)
diff_proc = &BlockDifference_SSE2_W32;
else if (media::hasSSE2() && kBlockWidth == 16)
diff_proc = &BlockDifference_SSE2_W16;
else
diff_proc = &BlockDifference_C;
#endif
}
return diff_proc(image1, image2, stride);
}
} // namespace remoting
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