Adding vp9_rb_read_signed_literal function.

Change-Id: I30ea91561ffac7e5065ba41b2d3ab7dedb720593

vp9/decoder/vp9_decodframe.c

@@ -512,29 +512,21 @@ static void setup_loopfilter(VP9D_COMP *pbi, struct vp9_read_bit_buffer *rb) {
     if (xd->mode_ref_lf_delta_update) {
       int i;
 
-      for (i = 0; i < MAX_REF_LF_DELTAS; i++) {
-        if (vp9_rb_read_bit(rb)) {
-          const int value = vp9_rb_read_literal(rb, 6);
-          xd->ref_lf_deltas[i] = vp9_rb_read_bit(rb) ? -value : value;
-        }
-      }
+      for (i = 0; i < MAX_REF_LF_DELTAS; i++)
+        if (vp9_rb_read_bit(rb))
+          xd->ref_lf_deltas[i] = vp9_rb_read_signed_literal(rb, 6);
 
-      for (i = 0; i < MAX_MODE_LF_DELTAS; i++) {
-        if (vp9_rb_read_bit(rb)) {
-          const int value = vp9_rb_read_literal(rb, 6);
-          xd->mode_lf_deltas[i] = vp9_rb_read_bit(rb) ? -value : value;
-        }
-      }
+      for (i = 0; i < MAX_MODE_LF_DELTAS; i++)
+        if (vp9_rb_read_bit(rb))
+          xd->mode_lf_deltas[i] = vp9_rb_read_signed_literal(rb, 6);
     }
   }
 }
 
 static int read_delta_q(struct vp9_read_bit_buffer *rb, int *delta_q) {
   const int old = *delta_q;
-  if (vp9_rb_read_bit(rb)) {
-    const int value = vp9_rb_read_literal(rb, 4);
-    *delta_q = vp9_rb_read_bit(rb) ? -value : value;
-  }
+  if (vp9_rb_read_bit(rb))
+    *delta_q = vp9_rb_read_signed_literal(rb, 4);
   return old != *delta_q;
 }
 

vp9/decoder/vp9_read_bit_buffer.h

@@ -51,4 +51,10 @@ static int vp9_rb_read_literal(struct vp9_read_bit_buffer *rb, int bits) {
   return value;
 }
 
+static int vp9_rb_read_signed_literal(struct vp9_read_bit_buffer *rb,
+                                      int bits) {
+  const int value = vp9_rb_read_literal(rb, bits);
+  return vp9_rb_read_bit(rb) ? -value : value;
+}
+
 #endif  // VP9_READ_BIT_BUFFER_