libvpx: Pull from upstream

source/libvpx/vp9/common/vp9_treecoder.c

-/*
- *  Copyright (c) 2010 The WebM 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.
- */
-
-
-#include <assert.h>
-
-#include "./vpx_config.h"
-#include "vp9/common/vp9_treecoder.h"
-
-static void tree2tok(struct vp9_token *const p, vp9_tree t,
-                    int i, int v, int l) {
-  v += v;
-  ++l;
-
-  do {
-    const vp9_tree_index j = t[i++];
-
-    if (j <= 0) {
-      p[-j].value = v;
-      p[-j].len = l;
-    } else {
-      tree2tok(p, t, j, v, l);
-    }
-  } while (++v & 1);
-}
-
-void vp9_tokens_from_tree(struct vp9_token *p, vp9_tree t) {
-  tree2tok(p, t, 0, 0, 0);
-}
-
-void vp9_tokens_from_tree_offset(struct vp9_token *p, vp9_tree t,
-                                 int offset) {
-  tree2tok(p - offset, t, 0, 0, 0);
-}
-
-static unsigned int convert_distribution(unsigned int i,
-                                         vp9_tree tree,
-                                         vp9_prob probs[],
-                                         unsigned int branch_ct[][2],
-                                         const unsigned int num_events[],
-                                         unsigned int tok0_offset) {
-  unsigned int left, right;
-
-  if (tree[i] <= 0) {
-    left = num_events[-tree[i] - tok0_offset];
-  } else {
-    left = convert_distribution(tree[i], tree, probs, branch_ct,
-                                num_events, tok0_offset);
-  }
-  if (tree[i + 1] <= 0)
-    right = num_events[-tree[i + 1] - tok0_offset];
-  else
-    right = convert_distribution(tree[i + 1], tree, probs, branch_ct,
-                                 num_events, tok0_offset);
-
-  probs[i>>1] = get_binary_prob(left, right);
-  branch_ct[i>>1][0] = left;
-  branch_ct[i>>1][1] = right;
-  return left + right;
-}
-
-void vp9_tree_probs_from_distribution(vp9_tree tree, vp9_prob probs[/* n-1 */],
-                                      unsigned int branch_ct[/* n-1 */][2],
-                                      const unsigned int num_events[/* n */],
-                                      unsigned int tok0_offset) {
-  convert_distribution(0, tree, probs, branch_ct, num_events, tok0_offset);
-}