/*

 * Copyright (c) 2017, 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 "av1/decoder/decodetxb.h"

#include "aom_ports/mem.h"

#include "av1/common/idct.h"

#include "av1/common/scan.h"

#include "av1/common/txb_common.h"

#include "av1/decoder/decodemv.h"

#define ACCT_STR __func__

static int read_golomb(MACROBLOCKD *xd, aom_reader *r) {

  int x = 1;

  int length = 0;

  int i = 0;

  while (!i) {

    i = aom_read_bit(r, ACCT_STR);

    ++length;

    if (length > 20) {

      aom_internal_error(xd->error_info, AOM_CODEC_CORRUPT_FRAME,

                         "Invalid length in read_golomb");

      break;

    }

  }

  for (i = 0; i < length - 1; ++i) {

    x <<= 1;

    x += aom_read_bit(r, ACCT_STR);

  }

  return x - 1;

}

static inline int rec_eob_pos(const int eob_token, const int extra) {

  int eob = av1_eob_group_start[eob_token];

  if (eob > 2) {

    eob += extra;

  }

  return eob;

}

static inline int get_dqv(const int16_t *dequant, int coeff_idx,

                          const qm_val_t *iqmatrix) {

  int dqv = dequant[!!coeff_idx];

  if (iqmatrix != NULL)

    dqv =

        ((iqmatrix[coeff_idx] * dqv) + (1 << (AOM_QM_BITS - 1))) >> AOM_QM_BITS;

  return dqv;

}

static inline void read_coeffs_reverse_2d(aom_reader *r, TX_SIZE tx_size,

                                          int start_si, int end_si,

                                          const int16_t *scan, int bhl,

                                          uint8_t *levels,

                                          base_cdf_arr base_cdf,

                                          br_cdf_arr br_cdf) {

  for (int c = end_si; c >= start_si; --c) {

    const int pos = scan[c];

    const int coeff_ctx = get_lower_levels_ctx_2d(levels, pos, bhl, tx_size);

    const int nsymbs = 4;

    int level = aom_read_symbol(r, base_cdf[coeff_ctx], nsymbs, ACCT_STR);

    if (level > NUM_BASE_LEVELS) {

      const int br_ctx = get_br_ctx_2d(levels, pos, bhl);

      aom_cdf_prob *cdf = br_cdf[br_ctx];

      for (int idx = 0; idx < COEFF_BASE_RANGE; idx += BR_CDF_SIZE - 1) {

        const int k = aom_read_symbol(r, cdf, BR_CDF_SIZE, ACCT_STR);

        level += k;

        if (k < BR_CDF_SIZE - 1) break;

      }

    }

    levels[get_padded_idx(pos, bhl)] = level;

  }

}

static inline void read_coeffs_reverse(aom_reader *r, TX_SIZE tx_size,

                                       TX_CLASS tx_class, int start_si,

                                       int end_si, const int16_t *scan, int bhl,

                                       uint8_t *levels, base_cdf_arr base_cdf,

                                       br_cdf_arr br_cdf) {

  for (int c = end_si; c >= start_si; --c) {

    const int pos = scan[c];

    const int coeff_ctx =

        get_lower_levels_ctx(levels, pos, bhl, tx_size, tx_class);

    const int nsymbs = 4;

    int level = aom_read_symbol(r, base_cdf[coeff_ctx], nsymbs, ACCT_STR);

    if (level > NUM_BASE_LEVELS) {

      const int br_ctx = get_br_ctx(levels, pos, bhl, tx_class);

      aom_cdf_prob *cdf = br_cdf[br_ctx];

      for (int idx = 0; idx < COEFF_BASE_RANGE; idx += BR_CDF_SIZE - 1) {

        const int k = aom_read_symbol(r, cdf, BR_CDF_SIZE, ACCT_STR);

        level += k;

        if (k < BR_CDF_SIZE - 1) break;

      }

    }

    levels[get_padded_idx(pos, bhl)] = level;

  }

}

static uint8_t read_coeffs_txb(const AV1_COMMON *const cm,

                               DecoderCodingBlock *dcb, aom_reader *const r,

                               const int blk_row, const int blk_col,

                               const int plane, const TXB_CTX *const txb_ctx,

                               const TX_SIZE tx_size) {

  MACROBLOCKD *const xd = &dcb->xd;

  FRAME_CONTEXT *const ec_ctx = xd->tile_ctx;

  const int32_t max_value = (1 << (7 + xd->bd)) - 1;

  const int32_t min_value = -(1 << (7 + xd->bd));

  const TX_SIZE txs_ctx = get_txsize_entropy_ctx(tx_size);

  const PLANE_TYPE plane_type = get_plane_type(plane);

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

  struct macroblockd_plane *const pd = &xd->plane[plane];

  const int16_t *const dequant = pd->seg_dequant_QTX[mbmi->segment_id];

  tran_low_t *const tcoeffs = dcb->dqcoeff_block[plane] + dcb->cb_offset[plane];

  const int shift = av1_get_tx_scale(tx_size);

  const int bhl = get_txb_bhl(tx_size);

  const int width = get_txb_wide(tx_size);

  const int height = get_txb_high(tx_size);

  int cul_level = 0;

  int dc_val = 0;

  uint8_t levels_buf[TX_PAD_2D];

  uint8_t *const levels = set_levels(levels_buf, height);

  const int all_zero = aom_read_symbol(

      r, ec_ctx->txb_skip_cdf[txs_ctx][txb_ctx->txb_skip_ctx], 2, ACCT_STR);

  eob_info *eob_data = dcb->eob_data[plane] + dcb->txb_offset[plane];

  uint16_t *const eob = &(eob_data->eob);

  uint16_t *const max_scan_line = &(eob_data->max_scan_line);

  *max_scan_line = 0;

  *eob = 0;

#if CONFIG_INSPECTION

  if (plane == 0) {

    const int txk_type_idx =

        av1_get_txk_type_index(mbmi->bsize, blk_row, blk_col);

    mbmi->tx_skip[txk_type_idx] = all_zero;

  }

#endif

  if (all_zero) {

    *max_scan_line = 0;

    if (plane == 0) {

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

    }

    return 0;

  }

  if (plane == AOM_PLANE_Y) {

    // only y plane's tx_type is transmitted

    av1_read_tx_type(cm, xd, blk_row, blk_col, tx_size, r);

  }

  const TX_TYPE tx_type =

      av1_get_tx_type(xd, plane_type, blk_row, blk_col, tx_size,

                      cm->features.reduced_tx_set_used);

  const TX_CLASS tx_class = tx_type_to_class[tx_type];

  const qm_val_t *iqmatrix =

      av1_get_iqmatrix(&cm->quant_params, xd, plane, tx_size, tx_type);

  const SCAN_ORDER *const scan_order = get_scan(tx_size, tx_type);

  const int16_t *const scan = scan_order->scan;

  int eob_extra = 0;

  int eob_pt = 1;

  const int eob_multi_size = txsize_log2_minus4[tx_size];

  const int eob_multi_ctx = (tx_class == TX_CLASS_2D) ? 0 : 1;

  switch (eob_multi_size) {

    case 0:

      eob_pt =

          aom_read_symbol(r, ec_ctx->eob_flag_cdf16[plane_type][eob_multi_ctx],

                          5, ACCT_STR) +

          1;

      break;

    case 1:

      eob_pt =

          aom_read_symbol(r, ec_ctx->eob_flag_cdf32[plane_type][eob_multi_ctx],

                          6, ACCT_STR) +

          1;

      break;

    case 2:

      eob_pt =

          aom_read_symbol(r, ec_ctx->eob_flag_cdf64[plane_type][eob_multi_ctx],

                          7, ACCT_STR) +

          1;

      break;

    case 3:

      eob_pt =

          aom_read_symbol(r, ec_ctx->eob_flag_cdf128[plane_type][eob_multi_ctx],

                          8, ACCT_STR) +

          1;

      break;

    case 4:

      eob_pt =

          aom_read_symbol(r, ec_ctx->eob_flag_cdf256[plane_type][eob_multi_ctx],

                          9, ACCT_STR) +

          1;

      break;

    case 5:

      eob_pt =

          aom_read_symbol(r, ec_ctx->eob_flag_cdf512[plane_type][eob_multi_ctx],

                          10, ACCT_STR) +

          1;

      break;

    case 6:

    default:

      eob_pt = aom_read_symbol(

                   r, ec_ctx->eob_flag_cdf1024[plane_type][eob_multi_ctx], 11,

                   ACCT_STR) +

               1;

      break;

  }

  const int eob_offset_bits = av1_eob_offset_bits[eob_pt];

  if (eob_offset_bits > 0) {

    const int eob_ctx = eob_pt - 3;

    int bit = aom_read_symbol(

        r, ec_ctx->eob_extra_cdf[txs_ctx][plane_type][eob_ctx], 2, ACCT_STR);

    if (bit) {

      eob_extra += (1 << (eob_offset_bits - 1));

    }

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

      bit = aom_read_bit(r, ACCT_STR);

      if (bit) {

        eob_extra += (1 << (eob_offset_bits - 1 - i));

      }

    }

  }

  *eob = rec_eob_pos(eob_pt, eob_extra);

  if (*eob > 1) {

    memset(levels_buf, 0,

           sizeof(*levels_buf) *

               ((height + TX_PAD_HOR) * (width + TX_PAD_VER) + TX_PAD_END));

  }

  {

    // Read the non-zero coefficient with scan index eob-1

    // TODO(angiebird): Put this into a function

    const int c = *eob - 1;

    const int pos = scan[c];

    const int coeff_ctx = get_lower_levels_ctx_eob(bhl, width, c);

    const int nsymbs = 3;

    aom_cdf_prob *cdf =

        ec_ctx->coeff_base_eob_cdf[txs_ctx][plane_type][coeff_ctx];

    int level = aom_read_symbol(r, cdf, nsymbs, ACCT_STR) + 1;

    if (level > NUM_BASE_LEVELS) {

      const int br_ctx = get_br_ctx_eob(pos, bhl, tx_class);

      cdf = ec_ctx->coeff_br_cdf[AOMMIN(txs_ctx, TX_32X32)][plane_type][br_ctx];

      for (int idx = 0; idx < COEFF_BASE_RANGE; idx += BR_CDF_SIZE - 1) {

        const int k = aom_read_symbol(r, cdf, BR_CDF_SIZE, ACCT_STR);

        level += k;

        if (k < BR_CDF_SIZE - 1) break;

      }

    }

    levels[get_padded_idx(pos, bhl)] = level;

  }

  if (*eob > 1) {

    base_cdf_arr base_cdf = ec_ctx->coeff_base_cdf[txs_ctx][plane_type];

    br_cdf_arr br_cdf =

        ec_ctx->coeff_br_cdf[AOMMIN(txs_ctx, TX_32X32)][plane_type];

    if (tx_class == TX_CLASS_2D) {

      read_coeffs_reverse_2d(r, tx_size, 1, *eob - 1 - 1, scan, bhl, levels,

                             base_cdf, br_cdf);

      read_coeffs_reverse(r, tx_size, tx_class, 0, 0, scan, bhl, levels,

                          base_cdf, br_cdf);

    } else {

      read_coeffs_reverse(r, tx_size, tx_class, 0, *eob - 1 - 1, scan, bhl,

                          levels, base_cdf, br_cdf);

    }

  }

  for (int c = 0; c < *eob; ++c) {

    const int pos = scan[c];

    uint8_t sign;

    tran_low_t level = levels[get_padded_idx(pos, bhl)];

    if (level) {

      *max_scan_line = AOMMAX(*max_scan_line, pos);

      if (c == 0) {

        const int dc_sign_ctx = txb_ctx->dc_sign_ctx;

        sign = aom_read_symbol(r, ec_ctx->dc_sign_cdf[plane_type][dc_sign_ctx],

                               2, ACCT_STR);

      } else {

        sign = aom_read_bit(r, ACCT_STR);

      }

      if (level >= MAX_BASE_BR_RANGE) {

        level += read_golomb(xd, r);

      }

      if (c == 0) dc_val = sign ? -level : level;

      // Bitmasking to clamp level to valid range:

      //   The valid range for 8/10/12 bit vdieo is at most 14/16/18 bit

      level &= 0xfffff;

      cul_level += level;

      tran_low_t dq_coeff;

      // Bitmasking to clamp dq_coeff to valid range:

      //   The valid range for 8/10/12 bit video is at most 17/19/21 bit

      dq_coeff =

          (tran_low_t)((int64_t)level * get_dqv(dequant, scan[c], iqmatrix) &

                       0xffffff);

      dq_coeff = dq_coeff >> shift;

      if (sign) {

        dq_coeff = -dq_coeff;

      }

      tcoeffs[pos] = clamp(dq_coeff, min_value, max_value);

    }

  }

  cul_level = AOMMIN(COEFF_CONTEXT_MASK, cul_level);

  // DC value

  set_dc_sign(&cul_level, dc_val);

  return cul_level;

}

void av1_read_coeffs_txb(const AV1_COMMON *const cm, DecoderCodingBlock *dcb,

                         aom_reader *const r, const int plane, const int row,

                         const int col, const TX_SIZE tx_size) {

#if TXCOEFF_TIMER

  struct aom_usec_timer timer;

  aom_usec_timer_start(&timer);

#endif

  MACROBLOCKD *const xd = &dcb->xd;

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

  struct macroblockd_plane *const pd = &xd->plane[plane];

  const BLOCK_SIZE bsize = mbmi->bsize;

  assert(bsize < BLOCK_SIZES_ALL);

  const BLOCK_SIZE plane_bsize =

      get_plane_block_size(bsize, pd->subsampling_x, pd->subsampling_y);

  TXB_CTX txb_ctx;

  get_txb_ctx(plane_bsize, tx_size, plane, pd->above_entropy_context + col,

              pd->left_entropy_context + row, &txb_ctx);

  const uint8_t cul_level =

      read_coeffs_txb(cm, dcb, r, row, col, plane, &txb_ctx, tx_size);

  av1_set_entropy_contexts(xd, pd, plane, plane_bsize, tx_size, cul_level, col,

                           row);

  if (is_inter_block(mbmi)) {

    const PLANE_TYPE plane_type = get_plane_type(plane);

    // tx_type will be read out in av1_read_coeffs_txb_facade

    const TX_TYPE tx_type = av1_get_tx_type(xd, plane_type, row, col, tx_size,

                                            cm->features.reduced_tx_set_used);

    if (plane == 0) {

      const int txw = tx_size_wide_unit[tx_size];

      const int txh = tx_size_high_unit[tx_size];

      // The 16x16 unit is due to the constraint from tx_64x64 which sets the

      // maximum tx size for chroma as 32x32. Coupled with 4x1 transform block

      // size, the constraint takes effect in 32x16 / 16x32 size too. To solve

      // the intricacy, cover all the 16x16 units inside a 64 level transform.

      if (txw == tx_size_wide_unit[TX_64X64] ||

          txh == tx_size_high_unit[TX_64X64]) {

        const int tx_unit = tx_size_wide_unit[TX_16X16];

        const int stride = xd->tx_type_map_stride;

        for (int idy = 0; idy < txh; idy += tx_unit) {

          for (int idx = 0; idx < txw; idx += tx_unit) {

            xd->tx_type_map[(row + idy) * stride + col + idx] = tx_type;

          }

        }

      }

    }

  }

#if TXCOEFF_TIMER

  aom_usec_timer_mark(&timer);

  const int64_t elapsed_time = aom_usec_timer_elapsed(&timer);

  cm->txcoeff_timer += elapsed_time;

  ++cm->txb_count;

#endif

}