Refactor the block decode code to make it simpler.

Change-Id: I0f983cb821ad7ec6fbefe7895cb8124a8fa39df6

diff --git a/vp9/common/vp9_blockd.c b/vp9/common/vp9_blockd.c
index 7094a0118c02fb7435add29b600bfa5688674846..caec1dad580f6eacc800513e70d392b270ca64ee 100644 (file)
--- a/vp9/common/vp9_blockd.c
+++ b/vp9/common/vp9_blockd.c
@@ -50,39 +50,25 @@ void vp9_foreach_transformed_block_in_plane(
   const int num_4x4_w = num_4x4_blocks_wide_lookup[plane_bsize];
   const int num_4x4_h = num_4x4_blocks_high_lookup[plane_bsize];
   const int step = 1 << (tx_size << 1);
-  int i;
+  int i = 0, r, c;
 
   // If mb_to_right_edge is < 0 we are in a situation in which
   // the current block size extends into the UMV and we won't
   // visit the sub blocks that are wholly within the UMV.
-  if (xd->mb_to_right_edge < 0 || xd->mb_to_bottom_edge < 0) {
-    int r, c;
-
-    int max_blocks_wide = num_4x4_w;
-    int max_blocks_high = num_4x4_h;
-
-    // xd->mb_to_right_edge is in units of pixels * 8.  This converts
-    // it to 4x4 block sizes.
-    if (xd->mb_to_right_edge < 0)
-      max_blocks_wide += (xd->mb_to_right_edge >> (5 + pd->subsampling_x));
-
-    if (xd->mb_to_bottom_edge < 0)
-      max_blocks_high += (xd->mb_to_bottom_edge >> (5 + pd->subsampling_y));
-
-    i = 0;
-    // Unlike the normal case - in here we have to keep track of the
-    // row and column of the blocks we use so that we know if we are in
-    // the unrestricted motion border.
-    for (r = 0; r < num_4x4_h; r += (1 << tx_size)) {
-      for (c = 0; c < num_4x4_w; c += (1 << tx_size)) {
-        if (r < max_blocks_high && c < max_blocks_wide)
-          visit(plane, i, plane_bsize, tx_size, arg);
-        i += step;
-      }
+  const int max_blocks_wide = num_4x4_w + (xd->mb_to_right_edge >= 0 ? 0 :
+      xd->mb_to_right_edge >> (5 + pd->subsampling_x));
+  const int max_blocks_high = num_4x4_h + (xd->mb_to_bottom_edge >= 0 ? 0 :
+      xd->mb_to_bottom_edge >> (5 + pd->subsampling_x));
+
+  // Keep track of the row and column of the blocks we use so that we know
+  // if we are in the unrestricted motion border.
+  for (r = 0; r < max_blocks_high; r += (1 << tx_size)) {
+    for (c = 0; c < num_4x4_w; c += (1 << tx_size)) {
+      // Skip visiting the sub blocks that are wholly within the UMV.
+      if (c < max_blocks_wide)
+        visit(plane, i, plane_bsize, tx_size, arg);
+      i += step;
     }
-  } else {
-    for (i = 0; i < num_4x4_w * num_4x4_h; i += step)
-      visit(plane, i, plane_bsize, tx_size, arg);
   }
 }