1 files changed, 76 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/desktop_capture/differ_block.cc b/third_party/libwebrtc/modules/desktop_capture/differ_block.cc
new file mode 100644
index 0000000000..c51d33e41e
--- /dev/null
+++ b/third_party/libwebrtc/modules/desktop_capture/differ_block.cc
@@ -0,0 +1,76 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/desktop_capture/differ_block.h"
+
+#include <string.h>
+
+#include "rtc_base/system/arch.h"
+#include "system_wrappers/include/cpu_features_wrapper.h"
+
+// This needs to be after rtc_base/system/arch.h which defines
+// architecture macros.
+#if defined(WEBRTC_ARCH_X86_FAMILY)
+#include "modules/desktop_capture/differ_vector_sse2.h"
+#endif
+
+namespace webrtc {
+
+namespace {
+
+bool VectorDifference_C(const uint8_t* image1, const uint8_t* image2) {
+  return memcmp(image1, image2, kBlockSize * kBytesPerPixel) != 0;
+}
+
+}  // namespace
+
+bool VectorDifference(const uint8_t* image1, const uint8_t* image2) {
+  static bool (*diff_proc)(const uint8_t*, const uint8_t*) = nullptr;
+
+  if (!diff_proc) {
+#if defined(WEBRTC_ARCH_X86_FAMILY)
+    bool have_sse2 = GetCPUInfo(kSSE2) != 0;
+    // For x86 processors, check if SSE2 is supported.
+    if (have_sse2 && kBlockSize == 32) {
+      diff_proc = &VectorDifference_SSE2_W32;
+    } else if (have_sse2 && kBlockSize == 16) {
+      diff_proc = &VectorDifference_SSE2_W16;
+    } else {
+      diff_proc = &VectorDifference_C;
+    }
+#else
+    // For other processors, always use C version.
+    // TODO(hclam): Implement a NEON version.
+    diff_proc = &VectorDifference_C;
+#endif
+  }
+
+  return diff_proc(image1, image2);
+}
+
+bool BlockDifference(const uint8_t* image1,
+                     const uint8_t* image2,
+                     int height,
+                     int stride) {
+  for (int i = 0; i < height; i++) {
+    if (VectorDifference(image1, image2)) {
+      return true;
+    }
+    image1 += stride;
+    image2 += stride;
+  }
+  return false;
+}
+
+bool BlockDifference(const uint8_t* image1, const uint8_t* image2, int stride) {
+  return BlockDifference(image1, image2, kBlockSize, stride);
+}
+
+}  // namespace webrtc