From 82e5665f74351f700ba2b22af6d5d71cb8505073 Mon Sep 17 00:00:00 2001
From: James Zern <jzern@google.com>
Date: Sun, 27 Jul 2014 14:57:50 -0700
Subject: [PATCH] vp9_subexp: remove vp9_compute_update_table()

makes update_bits[] a constant table

Change-Id: If105bf0522487f54a31e12a7cc73aa24671b19d4
---
 vp9/encoder/vp9_bitstream.c |  2 --
 vp9/encoder/vp9_subexp.c    | 37 ++++++++++++++++++-------------------
 vp9/encoder/vp9_subexp.h    |  3 ---
 3 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/vp9/encoder/vp9_bitstream.c b/vp9/encoder/vp9_bitstream.c
index 841b465..e00c3d5 100644
--- a/vp9/encoder/vp9_bitstream.c
+++ b/vp9/encoder/vp9_bitstream.c
@@ -1208,8 +1208,6 @@ void vp9_pack_bitstream(VP9_COMP *cpi, uint8_t *dest, size_t *size) {
   uncompressed_hdr_size = vp9_rb_bytes_written(&wb);
   data += uncompressed_hdr_size;
 
-  vp9_compute_update_table();
-
   vp9_clear_system_state();
 
   first_part_size = write_compressed_header(cpi, data);
diff --git a/vp9/encoder/vp9_subexp.c b/vp9/encoder/vp9_subexp.c
index 9796d64..530b592 100644
--- a/vp9/encoder/vp9_subexp.c
+++ b/vp9/encoder/vp9_subexp.c
@@ -16,7 +16,24 @@
 
 #define vp9_cost_upd256  ((int)(vp9_cost_one(upd) - vp9_cost_zero(upd)))
 
-static int update_bits[255];
+static const int update_bits[255] = {
+   5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,
+   6,  6,  6,  6,  6,  6,  6,  6,  6,  6,  6,  6,  6,  6,  6,  6,
+   8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,
+   8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,
+  10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
+  10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
+  10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
+  10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
+  10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
+  11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
+  11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
+  11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
+  11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
+  11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
+  11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
+  11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,  0,
+};
 
 static int recenter_nonneg(int v, int m) {
   if (v > (m << 1))
@@ -61,18 +78,6 @@ static int remap_prob(int v, int m) {
   return i;
 }
 
-static int count_term_subexp(int word) {
-  if (word < 16)
-    return 5;
-  if (word < 32)
-    return 6;
-  if (word < 64)
-    return 8;
-  if (word < 129)
-    return 10;
-  return 11;
-}
-
 static int prob_diff_update_cost(vp9_prob newp, vp9_prob oldp) {
   int delp = remap_prob(newp, oldp);
   return update_bits[delp] * 256;
@@ -111,12 +116,6 @@ void vp9_write_prob_diff_update(vp9_writer *w, vp9_prob newp, vp9_prob oldp) {
   encode_term_subexp(w, delp);
 }
 
-void vp9_compute_update_table() {
-  int i;
-  for (i = 0; i < 254; i++)
-    update_bits[i] = count_term_subexp(i);
-}
-
 int vp9_prob_diff_update_savings_search(const unsigned int *ct,
                                         vp9_prob oldp, vp9_prob *bestp,
                                         vp9_prob upd) {
diff --git a/vp9/encoder/vp9_subexp.h b/vp9/encoder/vp9_subexp.h
index 8e9c0c6..8e02a1d 100644
--- a/vp9/encoder/vp9_subexp.h
+++ b/vp9/encoder/vp9_subexp.h
@@ -16,9 +16,6 @@
 extern "C" {
 #endif
 
-void vp9_compute_update_table();
-
-
 void vp9_write_prob_diff_update(vp9_writer *w,
                                 vp9_prob newp, vp9_prob oldp);
 
-- 
2.7.4