/*

 * Copyright (c) 2016, Alliance for Open Media. All rights reserved.

 *

 * This source code is subject to the terms of the BSD 2 Clause License and

 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License

 * was not distributed with this source code in the LICENSE file, you can

 * obtain it at www.aomedia.org/license/software. If the Alliance for Open

 * Media Patent License 1.0 was not distributed with this source code in the

 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.

 */

#include <assert.h>

#include "av1/common/cfl.h"

#include "av1/common/common.h"

#include "av1/common/entropy.h"

#include "av1/common/entropymode.h"

#include "av1/common/entropymv.h"

#include "av1/common/mvref_common.h"

#include "av1/common/pred_common.h"

#include "av1/common/reconinter.h"

#include "av1/common/reconintra.h"

#include "av1/common/seg_common.h"

#include "av1/common/warped_motion.h"

#include "av1/decoder/decodeframe.h"

#include "av1/decoder/decodemv.h"

#include "aom_dsp/aom_dsp_common.h"

#include "aom_ports/bitops.h"

#define ACCT_STR __func__

#define DEC_MISMATCH_DEBUG 0

static PREDICTION_MODE read_intra_mode(aom_reader *r, aom_cdf_prob *cdf) {

  return (PREDICTION_MODE)aom_read_symbol(r, cdf, INTRA_MODES, ACCT_STR);

}

static void read_cdef(AV1_COMMON *cm, aom_reader *r, MACROBLOCKD *const xd) {

  const int skip_txfm = xd->mi[0]->skip_txfm;

  if (cm->features.coded_lossless) return;

  if (cm->features.allow_intrabc) {

    assert(cm->cdef_info.cdef_bits == 0);

    return;

  }

  // At the start of a superblock, mark that we haven't yet read CDEF strengths

  // for any of the CDEF units contained in this superblock.

  const int sb_mask = (cm->seq_params->mib_size - 1);

  const int mi_row_in_sb = (xd->mi_row & sb_mask);

  const int mi_col_in_sb = (xd->mi_col & sb_mask);

  if (mi_row_in_sb == 0 && mi_col_in_sb == 0) {

    xd->cdef_transmitted[0] = xd->cdef_transmitted[1] =

        xd->cdef_transmitted[2] = xd->cdef_transmitted[3] = false;

  }

  // CDEF unit size is 64x64 irrespective of the superblock size.

  const int cdef_size = 1 << (6 - MI_SIZE_LOG2);

  // Find index of this CDEF unit in this superblock.

  const int index_mask = cdef_size;

  const int cdef_unit_row_in_sb = ((xd->mi_row & index_mask) != 0);

  const int cdef_unit_col_in_sb = ((xd->mi_col & index_mask) != 0);

  const int index = (cm->seq_params->sb_size == BLOCK_128X128)

                        ? cdef_unit_col_in_sb + 2 * cdef_unit_row_in_sb

                        : 0;

  // Read CDEF strength from the first non-skip coding block in this CDEF unit.

  if (!xd->cdef_transmitted[index] && !skip_txfm) {

    // CDEF strength for this CDEF unit needs to be read into the MB_MODE_INFO

    // of the 1st block in this CDEF unit.

    const int first_block_mask = ~(cdef_size - 1);

    CommonModeInfoParams *const mi_params = &cm->mi_params;

    const int grid_idx =

        get_mi_grid_idx(mi_params, xd->mi_row & first_block_mask,

                        xd->mi_col & first_block_mask);

    MB_MODE_INFO *const mbmi = mi_params->mi_grid_base[grid_idx];

    mbmi->cdef_strength =

        aom_read_literal(r, cm->cdef_info.cdef_bits, ACCT_STR);

    xd->cdef_transmitted[index] = true;

  }

}

static int read_delta_qindex(AV1_COMMON *cm, const MACROBLOCKD *xd,

                             aom_reader *r, MB_MODE_INFO *const mbmi) {

  int sign, abs, reduced_delta_qindex = 0;

  BLOCK_SIZE bsize = mbmi->bsize;

  const int b_col = xd->mi_col & (cm->seq_params->mib_size - 1);

  const int b_row = xd->mi_row & (cm->seq_params->mib_size - 1);

  const int read_delta_q_flag = (b_col == 0 && b_row == 0);

  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

  if ((bsize != cm->seq_params->sb_size || mbmi->skip_txfm == 0) &&

      read_delta_q_flag) {

    abs = aom_read_symbol(r, ec_ctx->delta_q_cdf, DELTA_Q_PROBS + 1, ACCT_STR);

    const int smallval = (abs < DELTA_Q_SMALL);

    if (!smallval) {

      const int rem_bits = aom_read_literal(r, 3, ACCT_STR) + 1;

      const int thr = (1 << rem_bits) + 1;

      abs = aom_read_literal(r, rem_bits, ACCT_STR) + thr;

    }

    if (abs) {

      sign = aom_read_bit(r, ACCT_STR);

    } else {

      sign = 1;

    }

    reduced_delta_qindex = sign ? -abs : abs;

  }

  return reduced_delta_qindex;

}

static int read_delta_lflevel(const AV1_COMMON *const cm, aom_reader *r,

                              aom_cdf_prob *const cdf,

                              const MB_MODE_INFO *const mbmi, int mi_col,

                              int mi_row) {

  int reduced_delta_lflevel = 0;

  const BLOCK_SIZE bsize = mbmi->bsize;

  const int b_col = mi_col & (cm->seq_params->mib_size - 1);

  const int b_row = mi_row & (cm->seq_params->mib_size - 1);

  const int read_delta_lf_flag = (b_col == 0 && b_row == 0);

  if ((bsize != cm->seq_params->sb_size || mbmi->skip_txfm == 0) &&

      read_delta_lf_flag) {

    int abs = aom_read_symbol(r, cdf, DELTA_LF_PROBS + 1, ACCT_STR);

    const int smallval = (abs < DELTA_LF_SMALL);

    if (!smallval) {

      const int rem_bits = aom_read_literal(r, 3, ACCT_STR) + 1;

      const int thr = (1 << rem_bits) + 1;

      abs = aom_read_literal(r, rem_bits, ACCT_STR) + thr;

    }

    const int sign = abs ? aom_read_bit(r, ACCT_STR) : 1;

    reduced_delta_lflevel = sign ? -abs : abs;

  }

  return reduced_delta_lflevel;

}

static UV_PREDICTION_MODE read_intra_mode_uv(FRAME_CONTEXT *ec_ctx,

                                             aom_reader *r,

                                             CFL_ALLOWED_TYPE cfl_allowed,

                                             PREDICTION_MODE y_mode) {

  const UV_PREDICTION_MODE uv_mode =

      aom_read_symbol(r, ec_ctx->uv_mode_cdf[cfl_allowed][y_mode],

                      UV_INTRA_MODES - !cfl_allowed, ACCT_STR);

  return uv_mode;

}

static uint8_t read_cfl_alphas(FRAME_CONTEXT *const ec_ctx, aom_reader *r,

                               int8_t *signs_out) {

  const int8_t joint_sign =

      aom_read_symbol(r, ec_ctx->cfl_sign_cdf, CFL_JOINT_SIGNS, "cfl:signs");

  uint8_t idx = 0;

  // Magnitudes are only coded for nonzero values

  if (CFL_SIGN_U(joint_sign) != CFL_SIGN_ZERO) {

    aom_cdf_prob *cdf_u = ec_ctx->cfl_alpha_cdf[CFL_CONTEXT_U(joint_sign)];

    idx = (uint8_t)aom_read_symbol(r, cdf_u, CFL_ALPHABET_SIZE, "cfl:alpha_u")

          << CFL_ALPHABET_SIZE_LOG2;

  }

  if (CFL_SIGN_V(joint_sign) != CFL_SIGN_ZERO) {

    aom_cdf_prob *cdf_v = ec_ctx->cfl_alpha_cdf[CFL_CONTEXT_V(joint_sign)];

    idx += (uint8_t)aom_read_symbol(r, cdf_v, CFL_ALPHABET_SIZE, "cfl:alpha_v");

  }

  *signs_out = joint_sign;

  return idx;

}

static INTERINTRA_MODE read_interintra_mode(MACROBLOCKD *xd, aom_reader *r,

                                            int size_group) {

  const INTERINTRA_MODE ii_mode = (INTERINTRA_MODE)aom_read_symbol(

      r, xd->tile_ctx->interintra_mode_cdf[size_group], INTERINTRA_MODES,

      ACCT_STR);

  return ii_mode;

}

static PREDICTION_MODE read_inter_mode(FRAME_CONTEXT *ec_ctx, aom_reader *r,

                                       int16_t ctx) {

  int16_t mode_ctx = ctx & NEWMV_CTX_MASK;

  int is_newmv, is_zeromv, is_refmv;

  is_newmv = aom_read_symbol(r, ec_ctx->newmv_cdf[mode_ctx], 2, ACCT_STR) == 0;

  if (is_newmv) return NEWMV;

  mode_ctx = (ctx >> GLOBALMV_OFFSET) & GLOBALMV_CTX_MASK;

  is_zeromv =

      aom_read_symbol(r, ec_ctx->zeromv_cdf[mode_ctx], 2, ACCT_STR) == 0;

  if (is_zeromv) return GLOBALMV;

  mode_ctx = (ctx >> REFMV_OFFSET) & REFMV_CTX_MASK;

  is_refmv = aom_read_symbol(r, ec_ctx->refmv_cdf[mode_ctx], 2, ACCT_STR) == 0;

  if (is_refmv)

    return NEARESTMV;

  else

    return NEARMV;

}

static void read_drl_idx(FRAME_CONTEXT *ec_ctx, DecoderCodingBlock *dcb,

                         MB_MODE_INFO *mbmi, aom_reader *r) {

  MACROBLOCKD *const xd = &dcb->xd;

  uint8_t ref_frame_type = av1_ref_frame_type(mbmi->ref_frame);

  mbmi->ref_mv_idx = 0;

  if (mbmi->mode == NEWMV || mbmi->mode == NEW_NEWMV) {

    for (int idx = 0; idx < 2; ++idx) {

      if (dcb->ref_mv_count[ref_frame_type] > idx + 1) {

        uint8_t drl_ctx = av1_drl_ctx(xd->weight[ref_frame_type], idx);

        int drl_idx = aom_read_symbol(r, ec_ctx->drl_cdf[drl_ctx], 2, ACCT_STR);

        mbmi->ref_mv_idx = idx + drl_idx;

        if (!drl_idx) return;

      }

    }

  }

  if (have_nearmv_in_inter_mode(mbmi->mode)) {

    // Offset the NEARESTMV mode.

    // TODO(jingning): Unify the two syntax decoding loops after the NEARESTMV

    // mode is factored in.

    for (int idx = 1; idx < 3; ++idx) {

      if (dcb->ref_mv_count[ref_frame_type] > idx + 1) {

        uint8_t drl_ctx = av1_drl_ctx(xd->weight[ref_frame_type], idx);

        int drl_idx = aom_read_symbol(r, ec_ctx->drl_cdf[drl_ctx], 2, ACCT_STR);

        mbmi->ref_mv_idx = idx + drl_idx - 1;

        if (!drl_idx) return;

      }

    }

  }

}

static MOTION_MODE read_motion_mode(AV1_COMMON *cm, MACROBLOCKD *xd,

                                    MB_MODE_INFO *mbmi, aom_reader *r) {

  if (cm->features.switchable_motion_mode == 0) return SIMPLE_TRANSLATION;

  if (mbmi->skip_mode) return SIMPLE_TRANSLATION;

  const MOTION_MODE last_motion_mode_allowed = motion_mode_allowed(

      xd->global_motion, xd, mbmi, cm->features.allow_warped_motion);

  int motion_mode;

  if (last_motion_mode_allowed == SIMPLE_TRANSLATION) return SIMPLE_TRANSLATION;

  if (last_motion_mode_allowed == OBMC_CAUSAL) {

    motion_mode =

        aom_read_symbol(r, xd->tile_ctx->obmc_cdf[mbmi->bsize], 2, ACCT_STR);

    return (MOTION_MODE)(SIMPLE_TRANSLATION + motion_mode);

  } else {

    motion_mode = aom_read_symbol(r, xd->tile_ctx->motion_mode_cdf[mbmi->bsize],

                                  MOTION_MODES, ACCT_STR);

    return (MOTION_MODE)(SIMPLE_TRANSLATION + motion_mode);

  }

}

static PREDICTION_MODE read_inter_compound_mode(MACROBLOCKD *xd, aom_reader *r,

                                                int16_t ctx) {

  const int mode =

      aom_read_symbol(r, xd->tile_ctx->inter_compound_mode_cdf[ctx],

                      INTER_COMPOUND_MODES, ACCT_STR);

  assert(is_inter_compound_mode(NEAREST_NEARESTMV + mode));

  return NEAREST_NEARESTMV + mode;

}

int av1_neg_deinterleave(int diff, int ref, int max) {

  if (!ref) return diff;

  if (ref >= (max - 1)) return max - diff - 1;

  if (2 * ref < max) {

    if (diff <= 2 * ref) {

      if (diff & 1)

        return ref + ((diff + 1) >> 1);

      else

        return ref - (diff >> 1);

    }

    return diff;

  } else {

    if (diff <= 2 * (max - ref - 1)) {

      if (diff & 1)

        return ref + ((diff + 1) >> 1);

      else

        return ref - (diff >> 1);

    }

    return max - (diff + 1);

  }

}

static int read_segment_id(AV1_COMMON *const cm, const MACROBLOCKD *const xd,

                           aom_reader *r, int skip) {

  int cdf_num;

  const uint8_t pred = av1_get_spatial_seg_pred(cm, xd, &cdf_num, 0);

  if (skip) return pred;

  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

  struct segmentation *const seg = &cm->seg;

  struct segmentation_probs *const segp = &ec_ctx->seg;

  aom_cdf_prob *pred_cdf = segp->spatial_pred_seg_cdf[cdf_num];

  const int coded_id = aom_read_symbol(r, pred_cdf, MAX_SEGMENTS, ACCT_STR);

  const int segment_id =

      av1_neg_deinterleave(coded_id, pred, seg->last_active_segid + 1);

  if (segment_id < 0 || segment_id > seg->last_active_segid) {

    aom_internal_error(xd->error_info, AOM_CODEC_CORRUPT_FRAME,

                       "Corrupted segment_ids");

  }

  return segment_id;

}

static int dec_get_segment_id(const AV1_COMMON *cm, const uint8_t *segment_ids,

                              int mi_offset, int x_mis, int y_mis) {

  int segment_id = INT_MAX;

  for (int y = 0; y < y_mis; y++)

    for (int x = 0; x < x_mis; x++)

      segment_id = AOMMIN(

          segment_id, segment_ids[mi_offset + y * cm->mi_params.mi_cols + x]);

  assert(segment_id >= 0 && segment_id < MAX_SEGMENTS);

  return segment_id;

}

static int read_intra_segment_id(AV1_COMMON *const cm,

                                 const MACROBLOCKD *const xd, BLOCK_SIZE bsize,

                                 aom_reader *r, int skip) {

  struct segmentation *const seg = &cm->seg;

  if (!seg->enabled) return 0;  // Default for disabled segmentation

  assert(seg->update_map && !seg->temporal_update);

  const CommonModeInfoParams *const mi_params = &cm->mi_params;

  const int mi_row = xd->mi_row;

  const int mi_col = xd->mi_col;

  const int mi_stride = cm->mi_params.mi_cols;

  const int mi_offset = mi_row * mi_stride + mi_col;

  const int bw = mi_size_wide[bsize];

  const int bh = mi_size_high[bsize];

  const int x_mis = AOMMIN(mi_params->mi_cols - mi_col, bw);

  const int y_mis = AOMMIN(mi_params->mi_rows - mi_row, bh);

  const int segment_id = read_segment_id(cm, xd, r, skip);

  set_segment_id(cm->cur_frame->seg_map, mi_offset, x_mis, y_mis, mi_stride,

                 segment_id);

  return segment_id;

}

static void copy_segment_id(const CommonModeInfoParams *const mi_params,

                            const uint8_t *last_segment_ids,

                            uint8_t *current_segment_ids, int mi_offset,

                            int x_mis, int y_mis) {

  const int stride = mi_params->mi_cols;

  if (last_segment_ids) {

    assert(last_segment_ids != current_segment_ids);

    for (int y = 0; y < y_mis; y++) {

      memcpy(&current_segment_ids[mi_offset + y * stride],

             &last_segment_ids[mi_offset + y * stride],

             sizeof(current_segment_ids[0]) * x_mis);

    }

  } else {

    for (int y = 0; y < y_mis; y++) {

      memset(&current_segment_ids[mi_offset + y * stride], 0,

             sizeof(current_segment_ids[0]) * x_mis);

    }

  }

}

static int get_predicted_segment_id(AV1_COMMON *const cm, int mi_offset,

                                    int x_mis, int y_mis) {

  return cm->last_frame_seg_map ? dec_get_segment_id(cm, cm->last_frame_seg_map,

                                                     mi_offset, x_mis, y_mis)

                                : 0;

}

static int read_inter_segment_id(AV1_COMMON *const cm, MACROBLOCKD *const xd,

                                 int preskip, aom_reader *r) {

  struct segmentation *const seg = &cm->seg;

  const CommonModeInfoParams *const mi_params = &cm->mi_params;

  MB_MODE_INFO *const mbmi = xd->mi[0];

  const int mi_row = xd->mi_row;

  const int mi_col = xd->mi_col;

  const int mi_offset = mi_row * mi_params->mi_cols + mi_col;

  const int bw = mi_size_wide[mbmi->bsize];

  const int bh = mi_size_high[mbmi->bsize];

  // TODO(slavarnway): move x_mis, y_mis into xd ?????

  const int x_mis = AOMMIN(mi_params->mi_cols - mi_col, bw);

  const int y_mis = AOMMIN(mi_params->mi_rows - mi_row, bh);

  if (!seg->enabled) return 0;  // Default for disabled segmentation

  if (!seg->update_map) {

    copy_segment_id(mi_params, cm->last_frame_seg_map, cm->cur_frame->seg_map,

                    mi_offset, x_mis, y_mis);

    return get_predicted_segment_id(cm, mi_offset, x_mis, y_mis);

  }

  uint8_t segment_id;

  const int mi_stride = cm->mi_params.mi_cols;

  if (preskip) {

    if (!seg->segid_preskip) return 0;

  } else {

    if (mbmi->skip_txfm) {

      if (seg->temporal_update) {

        mbmi->seg_id_predicted = 0;

      }

      segment_id = read_segment_id(cm, xd, r, 1);

      set_segment_id(cm->cur_frame->seg_map, mi_offset, x_mis, y_mis, mi_stride,

                     segment_id);

      return segment_id;

    }

  }

  if (seg->temporal_update) {

    const uint8_t ctx = av1_get_pred_context_seg_id(xd);

    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

    struct segmentation_probs *const segp = &ec_ctx->seg;

    aom_cdf_prob *pred_cdf = segp->pred_cdf[ctx];

    mbmi->seg_id_predicted = aom_read_symbol(r, pred_cdf, 2, ACCT_STR);

    if (mbmi->seg_id_predicted) {

      segment_id = get_predicted_segment_id(cm, mi_offset, x_mis, y_mis);

    } else {

      segment_id = read_segment_id(cm, xd, r, 0);

    }

  } else {

    segment_id = read_segment_id(cm, xd, r, 0);

  }

  set_segment_id(cm->cur_frame->seg_map, mi_offset, x_mis, y_mis, mi_stride,

                 segment_id);

  return segment_id;

}

static int read_skip_mode(AV1_COMMON *cm, const MACROBLOCKD *xd, int segment_id,

                          aom_reader *r) {

  if (!cm->current_frame.skip_mode_info.skip_mode_flag) return 0;

  if (segfeature_active(&cm->seg, segment_id, SEG_LVL_SKIP)) {

    return 0;

  }

  if (!is_comp_ref_allowed(xd->mi[0]->bsize)) return 0;

  if (segfeature_active(&cm->seg, segment_id, SEG_LVL_REF_FRAME) ||

      segfeature_active(&cm->seg, segment_id, SEG_LVL_GLOBALMV)) {

    // These features imply single-reference mode, while skip mode implies

    // compound reference. Hence, the two are mutually exclusive.

    // In other words, skip_mode is implicitly 0 here.

    return 0;

  }

  const int ctx = av1_get_skip_mode_context(xd);

  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

  const int skip_mode =

      aom_read_symbol(r, ec_ctx->skip_mode_cdfs[ctx], 2, ACCT_STR);

  return skip_mode;

}

static int read_skip_txfm(AV1_COMMON *cm, const MACROBLOCKD *xd, int segment_id,

                          aom_reader *r) {

  if (segfeature_active(&cm->seg, segment_id, SEG_LVL_SKIP)) {

    return 1;

  } else {

    const int ctx = av1_get_skip_txfm_context(xd);

    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

    const int skip_txfm =

        aom_read_symbol(r, ec_ctx->skip_txfm_cdfs[ctx], 2, ACCT_STR);

    return skip_txfm;

  }

}

// Merge the sorted list of cached colors(cached_colors[0...n_cached_colors-1])

// and the sorted list of transmitted colors(colors[n_cached_colors...n-1]) into

// one single sorted list(colors[...]).

static void merge_colors(uint16_t *colors, uint16_t *cached_colors,

                         int n_colors, int n_cached_colors) {

  if (n_cached_colors == 0) return;

  int cache_idx = 0, trans_idx = n_cached_colors;

  for (int i = 0; i < n_colors; ++i) {

    if (cache_idx < n_cached_colors &&

        (trans_idx >= n_colors ||

         cached_colors[cache_idx] <= colors[trans_idx])) {

      colors[i] = cached_colors[cache_idx++];

    } else {

      assert(trans_idx < n_colors);

      colors[i] = colors[trans_idx++];

    }

  }

}

static void read_palette_colors_y(MACROBLOCKD *const xd, int bit_depth,

                                  PALETTE_MODE_INFO *const pmi, aom_reader *r) {

  uint16_t color_cache[2 * PALETTE_MAX_SIZE];

  uint16_t cached_colors[PALETTE_MAX_SIZE];

  const int n_cache = av1_get_palette_cache(xd, 0, color_cache);

  const int n = pmi->palette_size[0];

  int idx = 0;

  for (int i = 0; i < n_cache && idx < n; ++i)

    if (aom_read_bit(r, ACCT_STR)) cached_colors[idx++] = color_cache[i];

  if (idx < n) {

    const int n_cached_colors = idx;

    pmi->palette_colors[idx++] = aom_read_literal(r, bit_depth, ACCT_STR);

    if (idx < n) {

      const int min_bits = bit_depth - 3;

      int bits = min_bits + aom_read_literal(r, 2, ACCT_STR);

      int range = (1 << bit_depth) - pmi->palette_colors[idx - 1] - 1;

      for (; idx < n; ++idx) {

        assert(range >= 0);

        const int delta = aom_read_literal(r, bits, ACCT_STR) + 1;

        pmi->palette_colors[idx] = clamp(pmi->palette_colors[idx - 1] + delta,

                                         0, (1 << bit_depth) - 1);

        range -= (pmi->palette_colors[idx] - pmi->palette_colors[idx - 1]);

        bits = AOMMIN(bits, aom_ceil_log2(range));

      }

    }

    merge_colors(pmi->palette_colors, cached_colors, n, n_cached_colors);

  } else {

    memcpy(pmi->palette_colors, cached_colors, n * sizeof(cached_colors[0]));

  }

}

static void read_palette_colors_uv(MACROBLOCKD *const xd, int bit_depth,

                                   PALETTE_MODE_INFO *const pmi,

                                   aom_reader *r) {

  const int n = pmi->palette_size[1];

  // U channel colors.

  uint16_t color_cache[2 * PALETTE_MAX_SIZE];

  uint16_t cached_colors[PALETTE_MAX_SIZE];

  const int n_cache = av1_get_palette_cache(xd, 1, color_cache);

  int idx = 0;

  for (int i = 0; i < n_cache && idx < n; ++i)

    if (aom_read_bit(r, ACCT_STR)) cached_colors[idx++] = color_cache[i];

  if (idx < n) {

    const int n_cached_colors = idx;

    idx += PALETTE_MAX_SIZE;

    pmi->palette_colors[idx++] = aom_read_literal(r, bit_depth, ACCT_STR);

    if (idx < PALETTE_MAX_SIZE + n) {

      const int min_bits = bit_depth - 3;

      int bits = min_bits + aom_read_literal(r, 2, ACCT_STR);

      int range = (1 << bit_depth) - pmi->palette_colors[idx - 1];

      for (; idx < PALETTE_MAX_SIZE + n; ++idx) {

        assert(range >= 0);

        const int delta = aom_read_literal(r, bits, ACCT_STR);

        pmi->palette_colors[idx] = clamp(pmi->palette_colors[idx - 1] + delta,

                                         0, (1 << bit_depth) - 1);

        range -= (pmi->palette_colors[idx] - pmi->palette_colors[idx - 1]);

        bits = AOMMIN(bits, aom_ceil_log2(range));

      }

    }

    merge_colors(pmi->palette_colors + PALETTE_MAX_SIZE, cached_colors, n,

                 n_cached_colors);

  } else {

    memcpy(pmi->palette_colors + PALETTE_MAX_SIZE, cached_colors,

           n * sizeof(cached_colors[0]));

  }

  // V channel colors.

  if (aom_read_bit(r, ACCT_STR)) {  // Delta encoding.

    const int min_bits_v = bit_depth - 4;

    const int max_val = 1 << bit_depth;

    int bits = min_bits_v + aom_read_literal(r, 2, ACCT_STR);

    pmi->palette_colors[2 * PALETTE_MAX_SIZE] =

        aom_read_literal(r, bit_depth, ACCT_STR);

    for (int i = 1; i < n; ++i) {

      int delta = aom_read_literal(r, bits, ACCT_STR);

      if (delta && aom_read_bit(r, ACCT_STR)) delta = -delta;

      int val = (int)pmi->palette_colors[2 * PALETTE_MAX_SIZE + i - 1] + delta;

      if (val < 0) val += max_val;

      if (val >= max_val) val -= max_val;

      pmi->palette_colors[2 * PALETTE_MAX_SIZE + i] = val;

    }

  } else {

    for (int i = 0; i < n; ++i) {

      pmi->palette_colors[2 * PALETTE_MAX_SIZE + i] =

          aom_read_literal(r, bit_depth, ACCT_STR);

    }

  }

}

static void read_palette_mode_info(AV1_COMMON *const cm, MACROBLOCKD *const xd,

                                   aom_reader *r) {

  const int num_planes = av1_num_planes(cm);

  MB_MODE_INFO *const mbmi = xd->mi[0];

  const BLOCK_SIZE bsize = mbmi->bsize;

  assert(av1_allow_palette(cm->features.allow_screen_content_tools, bsize));

  PALETTE_MODE_INFO *const pmi = &mbmi->palette_mode_info;

  const int bsize_ctx = av1_get_palette_bsize_ctx(bsize);

  if (mbmi->mode == DC_PRED) {

    const int palette_mode_ctx = av1_get_palette_mode_ctx(xd);

    const int modev = aom_read_symbol(

        r, xd->tile_ctx->palette_y_mode_cdf[bsize_ctx][palette_mode_ctx], 2,

        ACCT_STR);

    if (modev) {

      pmi->palette_size[0] =

          aom_read_symbol(r, xd->tile_ctx->palette_y_size_cdf[bsize_ctx],

                          PALETTE_SIZES, ACCT_STR) +

          2;

      read_palette_colors_y(xd, cm->seq_params->bit_depth, pmi, r);

    }

  }

  if (num_planes > 1 && mbmi->uv_mode == UV_DC_PRED && xd->is_chroma_ref) {

    const int palette_uv_mode_ctx = (pmi->palette_size[0] > 0);

    const int modev = aom_read_symbol(

        r, xd->tile_ctx->palette_uv_mode_cdf[palette_uv_mode_ctx], 2, ACCT_STR);

    if (modev) {

      pmi->palette_size[1] =

          aom_read_symbol(r, xd->tile_ctx->palette_uv_size_cdf[bsize_ctx],

                          PALETTE_SIZES, ACCT_STR) +

          2;

      read_palette_colors_uv(xd, cm->seq_params->bit_depth, pmi, r);

    }

  }

}

static int read_angle_delta(aom_reader *r, aom_cdf_prob *cdf) {

  const int sym = aom_read_symbol(r, cdf, 2 * MAX_ANGLE_DELTA + 1, ACCT_STR);

  return sym - MAX_ANGLE_DELTA;

}

static void read_filter_intra_mode_info(const AV1_COMMON *const cm,

                                        MACROBLOCKD *const xd, aom_reader *r) {

  MB_MODE_INFO *const mbmi = xd->mi[0];

  FILTER_INTRA_MODE_INFO *filter_intra_mode_info =

      &mbmi->filter_intra_mode_info;

  if (av1_filter_intra_allowed(cm, mbmi)) {

    filter_intra_mode_info->use_filter_intra = aom_read_symbol(

        r, xd->tile_ctx->filter_intra_cdfs[mbmi->bsize], 2, ACCT_STR);

    if (filter_intra_mode_info->use_filter_intra) {

      filter_intra_mode_info->filter_intra_mode = aom_read_symbol(

          r, xd->tile_ctx->filter_intra_mode_cdf, FILTER_INTRA_MODES, ACCT_STR);

    }

  } else {

    filter_intra_mode_info->use_filter_intra = 0;

  }

}

void av1_read_tx_type(const AV1_COMMON *const cm, MACROBLOCKD *xd, int blk_row,

                      int blk_col, TX_SIZE tx_size, aom_reader *r) {

  MB_MODE_INFO *mbmi = xd->mi[0];

  uint8_t *tx_type =

      &xd->tx_type_map[blk_row * xd->tx_type_map_stride + blk_col];

  *tx_type = DCT_DCT;

  // No need to read transform type if block is skipped.

  if (mbmi->skip_txfm ||

      segfeature_active(&cm->seg, mbmi->segment_id, SEG_LVL_SKIP))

    return;

  // No need to read transform type for lossless mode(qindex==0).

  const int qindex = xd->qindex[mbmi->segment_id];

  if (qindex == 0) return;

  const int inter_block = is_inter_block(mbmi);

  if (get_ext_tx_types(tx_size, inter_block, cm->features.reduced_tx_set_used) >

      1) {

    const TxSetType tx_set_type = av1_get_ext_tx_set_type(

        tx_size, inter_block, cm->features.reduced_tx_set_used);

    const int eset =

        get_ext_tx_set(tx_size, inter_block, cm->features.reduced_tx_set_used);

    // eset == 0 should correspond to a set with only DCT_DCT and

    // there is no need to read the tx_type

    assert(eset != 0);

    const TX_SIZE square_tx_size = txsize_sqr_map[tx_size];

    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

    if (inter_block) {

      *tx_type = av1_ext_tx_inv[tx_set_type][aom_read_symbol(

          r, ec_ctx->inter_ext_tx_cdf[eset][square_tx_size],

          av1_num_ext_tx_set[tx_set_type], ACCT_STR)];

    } else {

      const PREDICTION_MODE intra_mode =

          mbmi->filter_intra_mode_info.use_filter_intra

              ? fimode_to_intradir[mbmi->filter_intra_mode_info

                                       .filter_intra_mode]

              : mbmi->mode;

      *tx_type = av1_ext_tx_inv[tx_set_type][aom_read_symbol(

          r, ec_ctx->intra_ext_tx_cdf[eset][square_tx_size][intra_mode],

          av1_num_ext_tx_set[tx_set_type], ACCT_STR)];

    }

  }

}

static inline void read_mv(aom_reader *r, MV *mv, const MV *ref,

                           nmv_context *ctx, MvSubpelPrecision precision);

static inline int is_mv_valid(const MV *mv);

static inline int assign_dv(AV1_COMMON *cm, MACROBLOCKD *xd, int_mv *mv,

                            const int_mv *ref_mv, int mi_row, int mi_col,

                            BLOCK_SIZE bsize, aom_reader *r) {

  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

  read_mv(r, &mv->as_mv, &ref_mv->as_mv, &ec_ctx->ndvc, MV_SUBPEL_NONE);

  // DV should not have sub-pel.

  assert((mv->as_mv.col & 7) == 0);

  assert((mv->as_mv.row & 7) == 0);

  mv->as_mv.col = (mv->as_mv.col >> 3) * 8;

  mv->as_mv.row = (mv->as_mv.row >> 3) * 8;

  int valid = is_mv_valid(&mv->as_mv) &&

              av1_is_dv_valid(mv->as_mv, cm, xd, mi_row, mi_col, bsize,

                              cm->seq_params->mib_size_log2);

  return valid;

}

static void read_intrabc_info(AV1_COMMON *const cm, DecoderCodingBlock *dcb,

                              aom_reader *r) {

  MACROBLOCKD *const xd = &dcb->xd;

  MB_MODE_INFO *const mbmi = xd->mi[0];

  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

  mbmi->use_intrabc = aom_read_symbol(r, ec_ctx->intrabc_cdf, 2, ACCT_STR);

  if (mbmi->use_intrabc) {

    BLOCK_SIZE bsize = mbmi->bsize;

    mbmi->mode = DC_PRED;

    mbmi->uv_mode = UV_DC_PRED;

    mbmi->interp_filters = av1_broadcast_interp_filter(BILINEAR);

    mbmi->motion_mode = SIMPLE_TRANSLATION;

    int16_t inter_mode_ctx[MODE_CTX_REF_FRAMES];

    int_mv ref_mvs[INTRA_FRAME + 1][MAX_MV_REF_CANDIDATES];

    av1_find_mv_refs(cm, xd, mbmi, INTRA_FRAME, dcb->ref_mv_count,

                     xd->ref_mv_stack, xd->weight, ref_mvs, /*global_mvs=*/NULL,

                     inter_mode_ctx);

    int_mv nearestmv, nearmv;

    av1_find_best_ref_mvs(0, ref_mvs[INTRA_FRAME], &nearestmv, &nearmv, 0);

    int_mv dv_ref = nearestmv.as_int == 0 ? nearmv : nearestmv;

    if (dv_ref.as_int == 0)

      av1_find_ref_dv(&dv_ref, &xd->tile, cm->seq_params->mib_size, xd->mi_row);

    // Ref DV should not have sub-pel.

    int valid_dv = (dv_ref.as_mv.col & 7) == 0 && (dv_ref.as_mv.row & 7) == 0;

    dv_ref.as_mv.col = (dv_ref.as_mv.col >> 3) * 8;

    dv_ref.as_mv.row = (dv_ref.as_mv.row >> 3) * 8;

    valid_dv = valid_dv && assign_dv(cm, xd, &mbmi->mv[0], &dv_ref, xd->mi_row,

                                     xd->mi_col, bsize, r);

    if (!valid_dv) {

      // Intra bc motion vectors are not valid - signal corrupt frame

      aom_internal_error(xd->error_info, AOM_CODEC_CORRUPT_FRAME,

                         "Invalid intrabc dv");

    }

  }

}

// If delta q is present, reads delta_q index.

// Also reads delta_q loop filter levels, if present.

static void read_delta_q_params(AV1_COMMON *const cm, MACROBLOCKD *const xd,

                                aom_reader *r) {

  DeltaQInfo *const delta_q_info = &cm->delta_q_info;

  if (delta_q_info->delta_q_present_flag) {

    MB_MODE_INFO *const mbmi = xd->mi[0];

    xd->current_base_qindex +=

        read_delta_qindex(cm, xd, r, mbmi) * delta_q_info->delta_q_res;

    /* Normative: Clamp to [1,MAXQ] to not interfere with lossless mode */

    xd->current_base_qindex = clamp(xd->current_base_qindex, 1, MAXQ);

    FRAME_CONTEXT *const ec_ctx = xd->tile_ctx;

    if (delta_q_info->delta_lf_present_flag) {

      const int mi_row = xd->mi_row;

      const int mi_col = xd->mi_col;

      if (delta_q_info->delta_lf_multi) {

        const int frame_lf_count =

            av1_num_planes(cm) > 1 ? FRAME_LF_COUNT : FRAME_LF_COUNT - 2;

        for (int lf_id = 0; lf_id < frame_lf_count; ++lf_id) {

          const int tmp_lvl =

              xd->delta_lf[lf_id] +

              read_delta_lflevel(cm, r, ec_ctx->delta_lf_multi_cdf[lf_id], mbmi,

                                 mi_col, mi_row) *

                  delta_q_info->delta_lf_res;

          mbmi->delta_lf[lf_id] = xd->delta_lf[lf_id] =

              clamp(tmp_lvl, -MAX_LOOP_FILTER, MAX_LOOP_FILTER);

        }

      } else {

        const int tmp_lvl = xd->delta_lf_from_base +

                            read_delta_lflevel(cm, r, ec_ctx->delta_lf_cdf,

                                               mbmi, mi_col, mi_row) *

                                delta_q_info->delta_lf_res;

        mbmi->delta_lf_from_base = xd->delta_lf_from_base =

            clamp(tmp_lvl, -MAX_LOOP_FILTER, MAX_LOOP_FILTER);

      }

    }

  }

}

static void read_intra_frame_mode_info(AV1_COMMON *const cm,

                                       DecoderCodingBlock *dcb, aom_reader *r) {

  MACROBLOCKD *const xd = &dcb->xd;

  MB_MODE_INFO *const mbmi = xd->mi[0];

  const MB_MODE_INFO *above_mi = xd->above_mbmi;

  const MB_MODE_INFO *left_mi = xd->left_mbmi;

  const BLOCK_SIZE bsize = mbmi->bsize;

  struct segmentation *const seg = &cm->seg;

  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;

  if (seg->segid_preskip)

    mbmi->segment_id = read_intra_segment_id(cm, xd, bsize, r, 0);

  mbmi->skip_txfm = read_skip_txfm(cm, xd, mbmi->segment_id, r);

  if (!seg->segid_preskip)

    mbmi->segment_id = read_intra_segment_id(cm, xd, bsize, r, mbmi->skip_txfm);

  read_cdef(cm, r, xd);

  read_delta_q_params(cm, xd, r);

  mbmi->current_qindex = xd->current_base_qindex;

  mbmi->ref_frame[0] = INTRA_FRAME;

  mbmi->ref_frame[1] = NONE_FRAME;

  mbmi->palette_mode_info.palette_size[0] = 0;

  mbmi->palette_mode_info.palette_size[1] = 0;

  mbmi->filter_intra_mode_info.use_filter_intra = 0;

  const int mi_row = xd->mi_row;

  const int mi_col = xd->mi_col;

  xd->above_txfm_context = cm->above_contexts.txfm[xd->tile.tile_row] + mi_col;

  xd->left_txfm_context =

      xd->left_txfm_context_buffer + (mi_row & MAX_MIB_MASK);

  if (av1_allow_intrabc(cm)) {

    read_intrabc_info(cm, dcb, r);

    if (is_intrabc_block(mbmi)) return;

  }

  mbmi->mode = read_intra_mode(r, get_y_mode_cdf(ec_ctx, above_mi, left_mi));

  const int use_angle_delta = av1_use_angle_delta(bsize);

  mbmi->angle_delta[PLANE_TYPE_Y] =

      (use_angle_delta && av1_is_directional_mode(mbmi->mode))

          ? read_angle_delta(r, ec_ctx->angle_delta_cdf[mbmi->mode - V_PRED])

          : 0;

  if (!cm->seq_params->monochrome && xd->is_chroma_ref) {

    mbmi->uv_mode =

        read_intra_mode_uv(ec_ctx, r, is_cfl_allowed(xd), mbmi->mode);

    if (mbmi->uv_mode == UV_CFL_PRED) {

      mbmi->cfl_alpha_idx = read_cfl_alphas(ec_ctx, r, &mbmi->cfl_alpha_signs);

    }

    const PREDICTION_MODE intra_mode = get_uv_mode(mbmi->uv_mode);

    mbmi->angle_delta[PLANE_TYPE_UV] =

        (use_angle_delta && av1_is_directional_mode(intra_mode))

            ? read_angle_delta(r, ec_ctx->angle_delta_cdf[intra_mode - V_PRED])

            : 0;

  } else {

    // Avoid decoding angle_info if there is no chroma prediction

    mbmi->uv_mode = UV_DC_PRED;

  }

  xd->cfl.store_y = store_cfl_required(cm, xd);

  if (av1_allow_palette(cm->features.allow_screen_content_tools, bsize))

    read_palette_mode_info(cm, xd, r);

  read_filter_intra_mode_info(cm, xd, r);

}