Refactor subpel_search_method setting

Change-Id: I35f7aa260a2b4bdf71c69d00aa2a547cd28aea3a

av1/encoder/speed_features.c

diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index 2e9ecfc..95a6060 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -2148,23 +2148,22 @@
   rt_sf->check_globalmv_on_single_ref = true;
 }
 
+static fractional_mv_step_fp
+    *const fractional_mv_search[SUBPEL_SEARCH_METHODS] = {
+      av1_find_best_sub_pixel_tree,             // SUBPEL_TREE = 0
+      av1_find_best_sub_pixel_tree_pruned,      // SUBPEL_TREE_PRUNED = 1
+      av1_find_best_sub_pixel_tree_pruned_more  // SUBPEL_TREE_PRUNED_MORE = 2
+    };
+
 // Populate appropriate sub-pel search method based on speed feature and user
 // specified settings
 static void set_subpel_search_method(
     MotionVectorSearchParams *mv_search_params,
     unsigned int motion_vector_unit_test,
-    SUBPEL_SEARCH_METHODS subpel_search_method) {
-  if (subpel_search_method == SUBPEL_TREE) {
-    mv_search_params->find_fractional_mv_step = av1_find_best_sub_pixel_tree;
-  } else if (subpel_search_method == SUBPEL_TREE_PRUNED) {
-    mv_search_params->find_fractional_mv_step =
-        av1_find_best_sub_pixel_tree_pruned;
-  } else if (subpel_search_method == SUBPEL_TREE_PRUNED_MORE) {
-    mv_search_params->find_fractional_mv_step =
-        av1_find_best_sub_pixel_tree_pruned_more;
-  } else {
-    assert(0);
-  }
+    SUBPEL_SEARCH_METHOD subpel_search_method) {
+  assert(subpel_search_method <= SUBPEL_TREE_PRUNED_MORE);
+  mv_search_params->find_fractional_mv_step =
+      fractional_mv_search[subpel_search_method];
 
   // This is only used in motion vector unit test.
   if (motion_vector_unit_test == 1)

av1/encoder/speed_features.h

diff --git a/av1/encoder/speed_features.h b/av1/encoder/speed_features.h
index bef24c1..e2acf52 100644
--- a/av1/encoder/speed_features.h
+++ b/av1/encoder/speed_features.h
@@ -134,7 +134,8 @@
   SUBPEL_TREE = 0,
   SUBPEL_TREE_PRUNED = 1,       // Prunes 1/2-pel searches
   SUBPEL_TREE_PRUNED_MORE = 2,  // Prunes 1/2-pel searches more aggressively
-} UENUM1BYTE(SUBPEL_SEARCH_METHODS);
+  SUBPEL_SEARCH_METHODS
+} UENUM1BYTE(SUBPEL_SEARCH_METHOD);
 
 enum {
   // Try the full image with different values.
@@ -762,7 +763,7 @@
   // logarithmic search that keeps stepping at 1/2 pixel units until
   // you stop getting a gain, and then goes on to 1/4 and repeats
   // the same process. Along the way it skips many diagonals.
-  SUBPEL_SEARCH_METHODS subpel_search_method;
+  SUBPEL_SEARCH_METHOD subpel_search_method;
 
   // Maximum number of steps in logarithmic subpel search before giving up.
   int subpel_iters_per_step;