Odd width variation of scale down by 2 for subsampling

source/scale_common.cc

 /*
  *  Copyright 2013 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.
  */
 
@@ skipping 85 matching lines @@
     dst[1] = (s[2] + s[3] + t[2] + t[3] + 2) >> 2;
     dst += 2;
     s += 4;
     t += 4;
   }
   if (dst_width & 1) {
     dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
   }
 }
 
+void ScaleRowDown2Box_Odd_C(const uint8* src_ptr, ptrdiff_t src_stride,
+                            uint8* dst, int dst_width) {
+  const uint8* s = src_ptr;
+  const uint8* t = src_ptr + src_stride;
+  int x;
+  dst_width -= 1;
+  for (x = 0; x < dst_width - 1; x += 2) {
+    dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
+    dst[1] = (s[2] + s[3] + t[2] + t[3] + 2) >> 2;
+    dst += 2;
+    s += 4;
+    t += 4;
+  }
+  if (dst_width & 1) {
+    dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
+    dst += 1;
+    s += 2;
+    t += 2;
+  }
+  dst[0] = (s[0] + t[0] + 1) >> 1;
+}
+
 void ScaleRowDown2Box_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
                            uint16* dst, int dst_width) {
   const uint16* s = src_ptr;
   const uint16* t = src_ptr + src_stride;
   int x;
   for (x = 0; x < dst_width - 1; x += 2) {
     dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
     dst[1] = (s[2] + s[3] + t[2] + t[3] + 2) >> 2;
     dst += 2;
     s += 4;
@@ skipping 1004 matching lines @@
     *dx = -*dx;
     // src_width = -src_width;   // Caller must do this.
   }
 }
 #undef CENTERSTART
 
 #ifdef __cplusplus
 }  // extern "C"
 }  // namespace libyuv
 #endif