text: /*
   *  Copyright (c) 2014 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 "vp9/encoder/vp9_context_tree.h"
  #include "vp9/encoder/vp9_encoder.h"
  
  static const BLOCK_SIZE square[] = {
    BLOCK_8X8,
    BLOCK_16X16,
    BLOCK_32X32,
    BLOCK_64X64,
  };
  
  static void alloc_mode_context(VP9_COMMON *cm, int num_4x4_blk,
                                 PICK_MODE_CONTEXT *ctx) {
    const int num_blk = (num_4x4_blk < 4 ? 4 : num_4x4_blk);
    const int num_pix = num_blk << 4;
    int i, k;
    ctx->num_4x4_blk = num_blk;
  
    CHECK_MEM_ERROR(cm, ctx->zcoeff_blk, vpx_calloc(num_blk, sizeof(uint8_t)));
    for (i = 0; i < MAX_MB_PLANE; ++i) {
      for (k = 0; k < 3; ++k) {
        CHECK_MEM_ERROR(cm, ctx->coeff[i][k],
                        vpx_memalign(32, num_pix * sizeof(*ctx->coeff[i][k])));
        CHECK_MEM_ERROR(cm, ctx->qcoeff[i][k],
                        vpx_memalign(32, num_pix * sizeof(*ctx->qcoeff[i][k])));
        CHECK_MEM_ERROR(cm, ctx->dqcoeff[i][k],
                        vpx_memalign(32, num_pix * sizeof(*ctx->dqcoeff[i][k])));
        CHECK_MEM_ERROR(cm, ctx->eobs[i][k],
                        vpx_memalign(32, num_blk * sizeof(*ctx->eobs[i][k])));
        ctx->coeff_pbuf[i][k] = ctx->coeff[i][k];
        ctx->qcoeff_pbuf[i][k] = ctx->qcoeff[i][k];
        ctx->dqcoeff_pbuf[i][k] = ctx->dqcoeff[i][k];
        ctx->eobs_pbuf[i][k] = ctx->eobs[i][k];
      }
    }
  }
  
  static void free_mode_context(PICK_MODE_CONTEXT *ctx) {
    int i, k;
    vpx_free(ctx->zcoeff_blk);
    ctx->zcoeff_blk = 0;
    for (i = 0; i < MAX_MB_PLANE; ++i) {
      for (k = 0; k < 3; ++k) {
        vpx_free(ctx->coeff[i][k]);
        ctx->coeff[i][k] = 0;
        vpx_free(ctx->qcoeff[i][k]);
        ctx->qcoeff[i][k] = 0;
        vpx_free(ctx->dqcoeff[i][k]);
        ctx->dqcoeff[i][k] = 0;
        vpx_free(ctx->eobs[i][k]);
        ctx->eobs[i][k] = 0;
      }
    }
  }
  
  static void alloc_tree_contexts(VP9_COMMON *cm, PC_TREE *tree,
                                  int num_4x4_blk) {
    alloc_mode_context(cm, num_4x4_blk, &tree->none);
    alloc_mode_context(cm, num_4x4_blk / 2, &tree->horizontal[0]);
    alloc_mode_context(cm, num_4x4_blk / 2, &tree->vertical[0]);
  
    if (num_4x4_blk > 4) {
      alloc_mode_context(cm, num_4x4_blk / 2, &tree->horizontal[1]);
      alloc_mode_context(cm, num_4x4_blk / 2, &tree->vertical[1]);
    } else {
      memset(&tree->horizontal[1], 0, sizeof(tree->horizontal[1]));
      memset(&tree->vertical[1], 0, sizeof(tree->vertical[1]));
    }
  }
  
  static void free_tree_contexts(PC_TREE *tree) {
    free_mode_context(&tree->none);
    free_mode_context(&tree->horizontal[0]);
    free_mode_context(&tree->horizontal[1]);
    free_mode_context(&tree->vertical[0]);
    free_mode_context(&tree->vertical[1]);
  }
  
  // This function sets up a tree of contexts such that at each square
  // partition level. There are contexts for none, horizontal, vertical, and
  // split.  Along with a block_size value and a selected block_size which
  // represents the state of our search.
  void vp9_setup_pc_tree(VP9_COMMON *cm, ThreadData *td) {
    int i, j;
    const int leaf_nodes = 64;
    const int tree_nodes = 64 + 16 + 4 + 1;
    int pc_tree_index = 0;
    PC_TREE *this_pc;
    PICK_MODE_CONTEXT *this_leaf;
    int square_index = 1;
    int nodes;
  
    vpx_free(td->leaf_tree);
    CHECK_MEM_ERROR(cm, td->leaf_tree,
                    vpx_calloc(leaf_nodes, sizeof(*td->leaf_tree)));
    vpx_free(td->pc_tree);
    CHECK_MEM_ERROR(cm, td->pc_tree,
                    vpx_calloc(tree_nodes, sizeof(*td->pc_tree)));
  
    this_pc = &td->pc_tree[0];
    this_leaf = &td->leaf_tree[0];
  
    // 4x4 blocks smaller than 8x8 but in the same 8x8 block share the same
    // context so we only need to allocate 1 for each 8x8 block.
    for (i = 0; i < leaf_nodes; ++i) alloc_mode_context(cm, 1, &td->leaf_tree[i]);
  
    // Sets up all the leaf nodes in the tree.
    for (pc_tree_index = 0; pc_tree_index < leaf_nodes; ++pc_tree_index) {
      PC_TREE *const tree = &td->pc_tree[pc_tree_index];
      tree->block_size = square[0];
      alloc_tree_contexts(cm, tree, 4);
      tree->leaf_split[0] = this_leaf++;
      for (j = 1; j < 4; j++) tree->leaf_split[j] = tree->leaf_split[0];
    }
  
    // Each node has 4 leaf nodes, fill each block_size level of the tree
    // from leafs to the root.
    for (nodes = 16; nodes > 0; nodes >>= 2) {
      for (i = 0; i < nodes; ++i) {
        PC_TREE *const tree = &td->pc_tree[pc_tree_index];
        alloc_tree_contexts(cm, tree, 4 << (2 * square_index));
        tree->block_size = square[square_index];
        for (j = 0; j < 4; j++) tree->split[j] = this_pc++;
        ++pc_tree_index;
      }
      ++square_index;
    }
    td->pc_root = &td->pc_tree[tree_nodes - 1];
    td->pc_root[0].none.best_mode_index = 2;
  }
  
  void vp9_free_pc_tree(ThreadData *td) {
    int i;
  
    if (td == NULL) return;
  
    if (td->leaf_tree != NULL) {
      // Set up all 4x4 mode contexts
      for (i = 0; i < 64; ++i) free_mode_context(&td->leaf_tree[i]);
      vpx_free(td->leaf_tree);
      td->leaf_tree = NULL;
    }
  
    if (td->pc_tree != NULL) {
      const int tree_nodes = 64 + 16 + 4 + 1;
      // Sets up all the leaf nodes in the tree.
      for (i = 0; i < tree_nodes; ++i) free_tree_contexts(&td->pc_tree[i]);
      vpx_free(td->pc_tree);
      td->pc_tree = NULL;
    }
  }
  