1 files changed, 74 insertions, 0 deletions
diff --git a/media/libyuv/libyuv/source/compare_common.cc b/media/libyuv/libyuv/source/compare_common.cc
new file mode 100644
index 0000000000..d1cab8d2b4
--- /dev/null
+++ b/media/libyuv/libyuv/source/compare_common.cc
@@ -0,0 +1,74 @@
+/*
+ *  Copyright 2012 The LibYuv 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 "libyuv/basic_types.h"
+
+#include "libyuv/compare_row.h"
+
+#ifdef __cplusplus
+namespace libyuv {
+extern "C" {
+#endif
+
+// Hakmem method for hamming distance.
+uint32_t HammingDistance_C(const uint8_t* src_a,
+                           const uint8_t* src_b,
+                           int count) {
+  uint32_t diff = 0u;
+
+  int i;
+  for (i = 0; i < count - 3; i += 4) {
+    uint32_t x = *((const uint32_t*)src_a) ^ *((const uint32_t*)src_b);
+    uint32_t u = x - ((x >> 1) & 0x55555555);
+    u = ((u >> 2) & 0x33333333) + (u & 0x33333333);
+    diff += ((((u + (u >> 4)) & 0x0f0f0f0f) * 0x01010101) >> 24);
+    src_a += 4;
+    src_b += 4;
+  }
+
+  for (; i < count; ++i) {
+    uint32_t x = *src_a ^ *src_b;
+    uint32_t u = x - ((x >> 1) & 0x55);
+    u = ((u >> 2) & 0x33) + (u & 0x33);
+    diff += (u + (u >> 4)) & 0x0f;
+    src_a += 1;
+    src_b += 1;
+  }
+
+  return diff;
+}
+
+uint32_t SumSquareError_C(const uint8_t* src_a,
+                          const uint8_t* src_b,
+                          int count) {
+  uint32_t sse = 0u;
+  int i;
+  for (i = 0; i < count; ++i) {
+    int diff = src_a[i] - src_b[i];
+    sse += (uint32_t)(diff * diff);
+  }
+  return sse;
+}
+
+// hash seed of 5381 recommended.
+// Internal C version of HashDjb2 with int sized count for efficiency.
+uint32_t HashDjb2_C(const uint8_t* src, int count, uint32_t seed) {
+  uint32_t hash = seed;
+  int i;
+  for (i = 0; i < count; ++i) {
+    hash += (hash << 5) + src[i];
+  }
+  return hash;
+}
+
+#ifdef __cplusplus
+}  // extern "C"
+}  // namespace libyuv
+#endif