src/decoders/fuji_compressed.cpp

/* -*- C++ -*-
 * File: libraw_fuji_compressed.cpp
 * Copyright (C) 2016-2019 Alexey Danilchenko
 *
 * Adopted to LibRaw by Alex Tutubalin, lexa@lexa.ru
 * LibRaw Fujifilm/compressed decoder

LibRaw is free software; you can redistribute it and/or modify
it under the terms of the one of two licenses as you choose:

1. GNU LESSER GENERAL PUBLIC LICENSE version 2.1
   (See file LICENSE.LGPL provided in LibRaw distribution archive for details).

2. COMMON DEVELOPMENT AND DISTRIBUTION LICENSE (CDDL) Version 1.0
   (See file LICENSE.CDDL provided in LibRaw distribution archive for details).

 */

#include "../../internal/libraw_cxx_defs.h"

#ifdef _abs
#undef _abs
#undef _min
#undef _max
#endif
#define _abs(x) (((int)(x) ^ ((int)(x) >> 31)) - ((int)(x) >> 31))
#define _min(a, b) ((a) < (b) ? (a) : (b))
#define _max(a, b) ((a) > (b) ? (a) : (b))

struct int_pair
{
  int value1;
  int value2;
};

enum _xt_lines
{
  _R0 = 0,
  _R1,
  _R2,
  _R3,
  _R4,
  _G0,
  _G1,
  _G2,
  _G3,
  _G4,
  _G5,
  _G6,
  _G7,
  _B0,
  _B1,
  _B2,
  _B3,
  _B4,
  _ltotal
};

struct fuji_compressed_block
{
  int cur_bit;            // current bit being read (from left to right)
  int cur_pos;            // current position in a buffer
  INT64 cur_buf_offset;   // offset of this buffer in a file
  unsigned max_read_size; // Amount of data to be read
  int cur_buf_size;       // buffer size
  uchar *cur_buf;         // currently read block
  int fillbytes;          // Counter to add extra byte for block size N*16
  LibRaw_abstract_datastream *input;
  struct int_pair grad_even[3][41]; // tables of gradients
  struct int_pair grad_odd[3][41];
  ushort *linealloc;
  ushort *linebuf[_ltotal];
};

void LibRaw::init_fuji_compr(struct fuji_compressed_params *info)
{
  int cur_val;
  int8_t *qt;

  if ((libraw_internal_data.unpacker_data.fuji_block_width % 3 &&
       libraw_internal_data.unpacker_data.fuji_raw_type == 16) ||
      (libraw_internal_data.unpacker_data.fuji_block_width & 1 &&
       libraw_internal_data.unpacker_data.fuji_raw_type == 0))
    derror();

  info->q_table =
      (int8_t *)malloc(2 << libraw_internal_data.unpacker_data.fuji_bits);
  merror(info->q_table, "init_fuji_compr()");

  if (libraw_internal_data.unpacker_data.fuji_raw_type == 16)
    info->line_width =
        (libraw_internal_data.unpacker_data.fuji_block_width * 2) / 3;
  else
    info->line_width = libraw_internal_data.unpacker_data.fuji_block_width >> 1;

  info->q_point[0] = 0;
  info->q_point[1] = 0x12;
  info->q_point[2] = 0x43;
  info->q_point[3] = 0x114;
  info->q_point[4] = (1 << libraw_internal_data.unpacker_data.fuji_bits) - 1;
  info->min_value = 0x40;

  cur_val = -info->q_point[4];
  for (qt = info->q_table; cur_val <= info->q_point[4]; ++qt, ++cur_val)
  {
    if (cur_val <= -info->q_point[3])
      *qt = -4;
    else if (cur_val <= -info->q_point[2])
      *qt = -3;
    else if (cur_val <= -info->q_point[1])
      *qt = -2;
    else if (cur_val < 0)
      *qt = -1;
    else if (cur_val == 0)
      *qt = 0;
    else if (cur_val < info->q_point[1])
      *qt = 1;
    else if (cur_val < info->q_point[2])
      *qt = 2;
    else if (cur_val < info->q_point[3])
      *qt = 3;
    else
      *qt = 4;
  }

  // populting gradients
  info->total_values = (1 << libraw_internal_data.unpacker_data.fuji_bits);
  info->raw_bits = libraw_internal_data.unpacker_data.fuji_bits;
  info->max_bits = 4 * info->raw_bits;
  info->maxDiff = info->total_values >> 6;
}

#define XTRANS_BUF_SIZE 0x10000

static inline void fuji_fill_buffer(struct fuji_compressed_block *info)
{
  if (info->cur_pos >= info->cur_buf_size)
  {
    info->cur_pos = 0;
    info->cur_buf_offset += info->cur_buf_size;
#ifdef LIBRAW_USE_OPENMP
#pragma omp critical
#endif
    {
#ifndef LIBRAW_USE_OPENMP
      info->input->lock();
#endif
      info->input->seek(info->cur_buf_offset, SEEK_SET);
      info->cur_buf_size = info->input->read(
          info->cur_buf, 1, _min(info->max_read_size, XTRANS_BUF_SIZE));
#ifndef LIBRAW_USE_OPENMP
      info->input->unlock();
#endif
      if (info->cur_buf_size < 1) // nothing read
      {
        if (info->fillbytes > 0)
        {
          int ls = _max(1, _min(info->fillbytes, XTRANS_BUF_SIZE));
          memset(info->cur_buf, 0, ls);
          info->fillbytes -= ls;
        }
        else
          throw LIBRAW_EXCEPTION_IO_EOF;
      }
      info->max_read_size -= info->cur_buf_size;
    }
  }
}

void LibRaw::init_fuji_block(struct fuji_compressed_block *info,
                             const struct fuji_compressed_params *params,
                             INT64 raw_offset, unsigned dsize)
{
  info->linealloc =
      (ushort *)calloc(sizeof(ushort), _ltotal * (params->line_width + 2));
  merror(info->linealloc, "init_fuji_block()");

  INT64 fsize = libraw_internal_data.internal_data.input->size();
  info->max_read_size =
      _min(unsigned(fsize - raw_offset), dsize); // Data size may be incorrect?
  info->fillbytes = 1;

  info->input = libraw_internal_data.internal_data.input;
  info->linebuf[_R0] = info->linealloc;
  for (int i = _R1; i <= _B4; i++)
    info->linebuf[i] = info->linebuf[i - 1] + params->line_width + 2;

  // init buffer
  info->cur_buf = (uchar *)malloc(XTRANS_BUF_SIZE);
  merror(info->cur_buf, "init_fuji_block()");
  info->cur_bit = 0;
  info->cur_pos = 0;
  info->cur_buf_offset = raw_offset;
  for (int j = 0; j < 3; j++)
    for (int i = 0; i < 41; i++)
    {
      info->grad_even[j][i].value1 = params->maxDiff;
      info->grad_even[j][i].value2 = 1;
      info->grad_odd[j][i].value1 = params->maxDiff;
      info->grad_odd[j][i].value2 = 1;
    }

  info->cur_buf_size = 0;
  fuji_fill_buffer(info);
}

void LibRaw::copy_line_to_xtrans(struct fuji_compressed_block *info,
                                 int cur_line, int cur_block,
                                 int cur_block_width)
{
  ushort *lineBufB[3];
  ushort *lineBufG[6];
  ushort *lineBufR[3];
  unsigned pixel_count;
  ushort *line_buf;
  int index;

  int offset = libraw_internal_data.unpacker_data.fuji_block_width * cur_block +
               6 * imgdata.sizes.raw_width * cur_line;
  ushort *raw_block_data = imgdata.rawdata.raw_image + offset;
  int row_count = 0;

  for (int i = 0; i < 3; i++)
  {
    lineBufR[i] = info->linebuf[_R2 + i] + 1;
    lineBufB[i] = info->linebuf[_B2 + i] + 1;
  }
  for (int i = 0; i < 6; i++)
    lineBufG[i] = info->linebuf[_G2 + i] + 1;

  while (row_count < 6)
  {
    pixel_count = 0;
    while (pixel_count < (unsigned)cur_block_width)
    {
      switch (imgdata.idata.xtrans_abs[row_count][(pixel_count % 6)])
      {
      case 0: // red
        line_buf = lineBufR[row_count >> 1];
        break;
      case 1:  // green
      default: // to make static analyzer happy
        line_buf = lineBufG[row_count];
        break;
      case 2: // blue
        line_buf = lineBufB[row_count >> 1];
        break;
      }

      index = (((pixel_count * 2 / 3) & 0x7FFFFFFE) | ((pixel_count % 3) & 1)) +
              ((pixel_count % 3) >> 1);
      raw_block_data[pixel_count] = line_buf[index];

      ++pixel_count;
    }
    ++row_count;
    raw_block_data += imgdata.sizes.raw_width;
  }
}

void LibRaw::copy_line_to_bayer(struct fuji_compressed_block *info,
                                int cur_line, int cur_block,
                                int cur_block_width)
{
  ushort *lineBufB[3];
  ushort *lineBufG[6];
  ushort *lineBufR[3];
  unsigned pixel_count;
  ushort *line_buf;

  int fuji_bayer[2][2];
  for (int r = 0; r < 2; r++)
    for (int c = 0; c < 2; c++)
      fuji_bayer[r][c] = FC(r, c); // We'll downgrade G2 to G below

  int offset = libraw_internal_data.unpacker_data.fuji_block_width * cur_block +
               6 * imgdata.sizes.raw_width * cur_line;
  ushort *raw_block_data = imgdata.rawdata.raw_image + offset;
  int row_count = 0;

  for (int i = 0; i < 3; i++)
  {
    lineBufR[i] = info->linebuf[_R2 + i] + 1;
    lineBufB[i] = info->linebuf[_B2 + i] + 1;
  }
  for (int i = 0; i < 6; i++)
    lineBufG[i] = info->linebuf[_G2 + i] + 1;

  while (row_count < 6)
  {
    pixel_count = 0;
    while (pixel_count < (unsigned)cur_block_width)
    {
      switch (fuji_bayer[row_count & 1][pixel_count & 1])
      {
      case 0: // red
        line_buf = lineBufR[row_count >> 1];
        break;
      case 1:  // green
      case 3:  // second green
      default: // to make static analyzer happy
        line_buf = lineBufG[row_count];
        break;
      case 2: // blue
        line_buf = lineBufB[row_count >> 1];
        break;
      }

      raw_block_data[pixel_count] = line_buf[pixel_count >> 1];
      ++pixel_count;
    }
    ++row_count;
    raw_block_data += imgdata.sizes.raw_width;
  }
}

#define fuji_quant_gradient(i, v1, v2)                                         \
  (9 * i->q_table[i->q_point[4] + (v1)] + i->q_table[i->q_point[4] + (v2)])

static inline void fuji_zerobits(struct fuji_compressed_block *info, int *count)
{
  uchar zero = 0;
  *count = 0;
  while (zero == 0)
  {
    zero = (info->cur_buf[info->cur_pos] >> (7 - info->cur_bit)) & 1;
    info->cur_bit++;
    info->cur_bit &= 7;
    if (!info->cur_bit)
    {
      ++info->cur_pos;
      fuji_fill_buffer(info);
    }
    if (zero)
      break;
    ++*count;
  }
}

static inline void fuji_read_code(struct fuji_compressed_block *info, int *data,
                                  int bits_to_read)
{
  uchar bits_left = bits_to_read;
  uchar bits_left_in_byte = 8 - (info->cur_bit & 7);
  *data = 0;
  if (!bits_to_read)
    return;
  if (bits_to_read >= bits_left_in_byte)
  {
    do
    {
      *data <<= bits_left_in_byte;
      bits_left -= bits_left_in_byte;
      *data |= info->cur_buf[info->cur_pos] & ((1 << bits_left_in_byte) - 1);
      ++info->cur_pos;
      fuji_fill_buffer(info);
      bits_left_in_byte = 8;
    } while (bits_left >= 8);
  }
  if (!bits_left)
  {
    info->cur_bit = (8 - (bits_left_in_byte & 7)) & 7;
    return;
  }
  *data <<= bits_left;
  bits_left_in_byte -= bits_left;
  *data |= ((1 << bits_left) - 1) &
           ((unsigned)info->cur_buf[info->cur_pos] >> bits_left_in_byte);
  info->cur_bit = (8 - (bits_left_in_byte & 7)) & 7;
}

static inline int bitDiff(int value1, int value2)
{
  int decBits = 0;
  if (value2 < value1)
    while (decBits <= 14 && (value2 << ++decBits) < value1)
      ;
  return decBits;
}

static inline int
fuji_decode_sample_even(struct fuji_compressed_block *info,
                        const struct fuji_compressed_params *params,
                        ushort *line_buf, int pos, struct int_pair *grads)
{
  int interp_val = 0;
  // ushort decBits;
  int errcnt = 0;

  int sample = 0, code = 0;
  ushort *line_buf_cur = line_buf + pos;
  int Rb = line_buf_cur[-2 - params->line_width];
  int Rc = line_buf_cur[-3 - params->line_width];
  int Rd = line_buf_cur[-1 - params->line_width];
  int Rf = line_buf_cur[-4 - 2 * params->line_width];

  int grad, gradient, diffRcRb, diffRfRb, diffRdRb;

  grad = fuji_quant_gradient(params, Rb - Rf, Rc - Rb);
  gradient = _abs(grad);
  diffRcRb = _abs(Rc - Rb);
  diffRfRb = _abs(Rf - Rb);
  diffRdRb = _abs(Rd - Rb);

  if (diffRcRb > diffRfRb && diffRcRb > diffRdRb)
    interp_val = Rf + Rd + 2 * Rb;
  else if (diffRdRb > diffRcRb && diffRdRb > diffRfRb)
    interp_val = Rf + Rc + 2 * Rb;
  else
    interp_val = Rd + Rc + 2 * Rb;

  fuji_zerobits(info, &sample);

  if (sample < params->max_bits - params->raw_bits - 1)
  {
    int decBits = bitDiff(grads[gradient].value1, grads[gradient].value2);
    fuji_read_code(info, &code, decBits);
    code += sample << decBits;
  }
  else
  {
    fuji_read_code(info, &code, params->raw_bits);
    code++;
  }

  if (code < 0 || code >= params->total_values)
    errcnt++;

  if (code & 1)
    code = -1 - code / 2;
  else
    code /= 2;

  grads[gradient].value1 += _abs(code);
  if (grads[gradient].value2 == params->min_value)
  {
    grads[gradient].value1 >>= 1;
    grads[gradient].value2 >>= 1;
  }
  grads[gradient].value2++;
  if (grad < 0)
    interp_val = (interp_val >> 2) - code;
  else
    interp_val = (interp_val >> 2) + code;
  if (interp_val < 0)
    interp_val += params->total_values;
  else if (interp_val > params->q_point[4])
    interp_val -= params->total_values;

  if (interp_val >= 0)
    line_buf_cur[0] = _min(interp_val, params->q_point[4]);
  else
    line_buf_cur[0] = 0;
  return errcnt;
}

static inline int
fuji_decode_sample_odd(struct fuji_compressed_block *info,
                       const struct fuji_compressed_params *params,
                       ushort *line_buf, int pos, struct int_pair *grads)
{
  int interp_val = 0;
  int errcnt = 0;

  int sample = 0, code = 0;
  ushort *line_buf_cur = line_buf + pos;
  int Ra = line_buf_cur[-1];
  int Rb = line_buf_cur[-2 - params->line_width];
  int Rc = line_buf_cur[-3 - params->line_width];
  int Rd = line_buf_cur[-1 - params->line_width];
  int Rg = line_buf_cur[1];

  int grad, gradient;

  grad = fuji_quant_gradient(params, Rb - Rc, Rc - Ra);
  gradient = _abs(grad);

  if ((Rb > Rc && Rb > Rd) || (Rb < Rc && Rb < Rd))
    interp_val = (Rg + Ra + 2 * Rb) >> 2;
  else
    interp_val = (Ra + Rg) >> 1;

  fuji_zerobits(info, &sample);

  if (sample < params->max_bits - params->raw_bits - 1)
  {
    int decBits = bitDiff(grads[gradient].value1, grads[gradient].value2);
    fuji_read_code(info, &code, decBits);
    code += sample << decBits;
  }
  else
  {
    fuji_read_code(info, &code, params->raw_bits);
    code++;
  }

  if (code < 0 || code >= params->total_values)
    errcnt++;

  if (code & 1)
    code = -1 - code / 2;
  else
    code /= 2;

  grads[gradient].value1 += _abs(code);
  if (grads[gradient].value2 == params->min_value)
  {
    grads[gradient].value1 >>= 1;
    grads[gradient].value2 >>= 1;
  }
  grads[gradient].value2++;
  if (grad < 0)
    interp_val -= code;
  else
    interp_val += code;
  if (interp_val < 0)
    interp_val += params->total_values;
  else if (interp_val > params->q_point[4])
    interp_val -= params->total_values;

  if (interp_val >= 0)
    line_buf_cur[0] = _min(interp_val, params->q_point[4]);
  else
    line_buf_cur[0] = 0;
  return errcnt;
}

static void fuji_decode_interpolation_even(int line_width, ushort *line_buf,
                                           int pos)
{
  ushort *line_buf_cur = line_buf + pos;
  int Rb = line_buf_cur[-2 - line_width];
  int Rc = line_buf_cur[-3 - line_width];
  int Rd = line_buf_cur[-1 - line_width];
  int Rf = line_buf_cur[-4 - 2 * line_width];
  int diffRcRb = _abs(Rc - Rb);
  int diffRfRb = _abs(Rf - Rb);
  int diffRdRb = _abs(Rd - Rb);
  if (diffRcRb > diffRfRb && diffRcRb > diffRdRb)
    *line_buf_cur = (Rf + Rd + 2 * Rb) >> 2;
  else if (diffRdRb > diffRcRb && diffRdRb > diffRfRb)
    *line_buf_cur = (Rf + Rc + 2 * Rb) >> 2;
  else
    *line_buf_cur = (Rd + Rc + 2 * Rb) >> 2;
}

static void fuji_extend_generic(ushort *linebuf[_ltotal], int line_width,
                                int start, int end)
{
  for (int i = start; i <= end; i++)
  {
    linebuf[i][0] = linebuf[i - 1][1];
    linebuf[i][line_width + 1] = linebuf[i - 1][line_width];
  }
}

static void fuji_extend_red(ushort *linebuf[_ltotal], int line_width)
{
  fuji_extend_generic(linebuf, line_width, _R2, _R4);
}

static void fuji_extend_green(ushort *linebuf[_ltotal], int line_width)
{
  fuji_extend_generic(linebuf, line_width, _G2, _G7);
}

static void fuji_extend_blue(ushort *linebuf[_ltotal], int line_width)
{
  fuji_extend_generic(linebuf, line_width, _B2, _B4);
}

void LibRaw::xtrans_decode_block(struct fuji_compressed_block *info,
                                 const struct fuji_compressed_params *params,
                                 int cur_line)
{
  int r_even_pos = 0, r_odd_pos = 1;
  int g_even_pos = 0, g_odd_pos = 1;
  int b_even_pos = 0, b_odd_pos = 1;

  int errcnt = 0;

  const int line_width = params->line_width;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      fuji_decode_interpolation_even(line_width, info->linebuf[_R2] + 1,
                                     r_even_pos);
      r_even_pos += 2;
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G2] + 1,
                                        g_even_pos, info->grad_even[0]);
      g_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_R2] + 1,
                                       r_odd_pos, info->grad_odd[0]);
      r_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G2] + 1,
                                       g_odd_pos, info->grad_odd[0]);
      g_odd_pos += 2;
    }
  }

  fuji_extend_red(info->linebuf, line_width);
  fuji_extend_green(info->linebuf, line_width);

  g_even_pos = 0, g_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G3] + 1,
                                        g_even_pos, info->grad_even[1]);
      g_even_pos += 2;
      fuji_decode_interpolation_even(line_width, info->linebuf[_B2] + 1,
                                     b_even_pos);
      b_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G3] + 1,
                                       g_odd_pos, info->grad_odd[1]);
      g_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_B2] + 1,
                                       b_odd_pos, info->grad_odd[1]);
      b_odd_pos += 2;
    }
  }

  fuji_extend_green(info->linebuf, line_width);
  fuji_extend_blue(info->linebuf, line_width);

  r_even_pos = 0, r_odd_pos = 1;
  g_even_pos = 0, g_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      if (r_even_pos & 3)
        errcnt += fuji_decode_sample_even(info, params, info->linebuf[_R3] + 1,
                                          r_even_pos, info->grad_even[2]);
      else
        fuji_decode_interpolation_even(line_width, info->linebuf[_R3] + 1,
                                       r_even_pos);
      r_even_pos += 2;
      fuji_decode_interpolation_even(line_width, info->linebuf[_G4] + 1,
                                     g_even_pos);
      g_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_R3] + 1,
                                       r_odd_pos, info->grad_odd[2]);
      r_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G4] + 1,
                                       g_odd_pos, info->grad_odd[2]);
      g_odd_pos += 2;
    }
  }

  fuji_extend_red(info->linebuf, line_width);
  fuji_extend_green(info->linebuf, line_width);

  g_even_pos = 0, g_odd_pos = 1;
  b_even_pos = 0, b_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G5] + 1,
                                        g_even_pos, info->grad_even[0]);
      g_even_pos += 2;
      if ((b_even_pos & 3) == 2)
        fuji_decode_interpolation_even(line_width, info->linebuf[_B3] + 1,
                                       b_even_pos);
      else
        errcnt += fuji_decode_sample_even(info, params, info->linebuf[_B3] + 1,
                                          b_even_pos, info->grad_even[0]);
      b_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G5] + 1,
                                       g_odd_pos, info->grad_odd[0]);
      g_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_B3] + 1,
                                       b_odd_pos, info->grad_odd[0]);
      b_odd_pos += 2;
    }
  }

  fuji_extend_green(info->linebuf, line_width);
  fuji_extend_blue(info->linebuf, line_width);

  r_even_pos = 0, r_odd_pos = 1;
  g_even_pos = 0, g_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      if ((r_even_pos & 3) == 2)
        fuji_decode_interpolation_even(line_width, info->linebuf[_R4] + 1,
                                       r_even_pos);
      else
        errcnt += fuji_decode_sample_even(info, params, info->linebuf[_R4] + 1,
                                          r_even_pos, info->grad_even[1]);
      r_even_pos += 2;
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G6] + 1,
                                        g_even_pos, info->grad_even[1]);
      g_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_R4] + 1,
                                       r_odd_pos, info->grad_odd[1]);
      r_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G6] + 1,
                                       g_odd_pos, info->grad_odd[1]);
      g_odd_pos += 2;
    }
  }

  fuji_extend_red(info->linebuf, line_width);
  fuji_extend_green(info->linebuf, line_width);

  g_even_pos = 0, g_odd_pos = 1;
  b_even_pos = 0, b_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      fuji_decode_interpolation_even(line_width, info->linebuf[_G7] + 1,
                                     g_even_pos);
      g_even_pos += 2;
      if (b_even_pos & 3)
        errcnt += fuji_decode_sample_even(info, params, info->linebuf[_B4] + 1,
                                          b_even_pos, info->grad_even[2]);
      else
        fuji_decode_interpolation_even(line_width, info->linebuf[_B4] + 1,
                                       b_even_pos);
      b_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G7] + 1,
                                       g_odd_pos, info->grad_odd[2]);
      g_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_B4] + 1,
                                       b_odd_pos, info->grad_odd[2]);
      b_odd_pos += 2;
    }
  }

  fuji_extend_green(info->linebuf, line_width);
  fuji_extend_blue(info->linebuf, line_width);

  if (errcnt)
    derror();
}

void LibRaw::fuji_bayer_decode_block(
    struct fuji_compressed_block *info,
    const struct fuji_compressed_params *params, int cur_line)
{
  int r_even_pos = 0, r_odd_pos = 1;
  int g_even_pos = 0, g_odd_pos = 1;
  int b_even_pos = 0, b_odd_pos = 1;

  int errcnt = 0;

  const int line_width = params->line_width;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_R2] + 1,
                                        r_even_pos, info->grad_even[0]);
      r_even_pos += 2;
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G2] + 1,
                                        g_even_pos, info->grad_even[0]);
      g_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_R2] + 1,
                                       r_odd_pos, info->grad_odd[0]);
      r_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G2] + 1,
                                       g_odd_pos, info->grad_odd[0]);
      g_odd_pos += 2;
    }
  }

  fuji_extend_red(info->linebuf, line_width);
  fuji_extend_green(info->linebuf, line_width);

  g_even_pos = 0, g_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G3] + 1,
                                        g_even_pos, info->grad_even[1]);
      g_even_pos += 2;
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_B2] + 1,
                                        b_even_pos, info->grad_even[1]);
      b_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G3] + 1,
                                       g_odd_pos, info->grad_odd[1]);
      g_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_B2] + 1,
                                       b_odd_pos, info->grad_odd[1]);
      b_odd_pos += 2;
    }
  }

  fuji_extend_green(info->linebuf, line_width);
  fuji_extend_blue(info->linebuf, line_width);

  r_even_pos = 0, r_odd_pos = 1;
  g_even_pos = 0, g_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_R3] + 1,
                                        r_even_pos, info->grad_even[2]);
      r_even_pos += 2;
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G4] + 1,
                                        g_even_pos, info->grad_even[2]);
      g_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_R3] + 1,
                                       r_odd_pos, info->grad_odd[2]);
      r_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G4] + 1,
                                       g_odd_pos, info->grad_odd[2]);
      g_odd_pos += 2;
    }
  }

  fuji_extend_red(info->linebuf, line_width);
  fuji_extend_green(info->linebuf, line_width);

  g_even_pos = 0, g_odd_pos = 1;
  b_even_pos = 0, b_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G5] + 1,
                                        g_even_pos, info->grad_even[0]);
      g_even_pos += 2;
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_B3] + 1,
                                        b_even_pos, info->grad_even[0]);
      b_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G5] + 1,
                                       g_odd_pos, info->grad_odd[0]);
      g_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_B3] + 1,
                                       b_odd_pos, info->grad_odd[0]);
      b_odd_pos += 2;
    }
  }

  fuji_extend_green(info->linebuf, line_width);
  fuji_extend_blue(info->linebuf, line_width);

  r_even_pos = 0, r_odd_pos = 1;
  g_even_pos = 0, g_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_R4] + 1,
                                        r_even_pos, info->grad_even[1]);
      r_even_pos += 2;
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G6] + 1,
                                        g_even_pos, info->grad_even[1]);
      g_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_R4] + 1,
                                       r_odd_pos, info->grad_odd[1]);
      r_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G6] + 1,
                                       g_odd_pos, info->grad_odd[1]);
      g_odd_pos += 2;
    }
  }

  fuji_extend_red(info->linebuf, line_width);
  fuji_extend_green(info->linebuf, line_width);

  g_even_pos = 0, g_odd_pos = 1;
  b_even_pos = 0, b_odd_pos = 1;

  while (g_even_pos < line_width || g_odd_pos < line_width)
  {
    if (g_even_pos < line_width)
    {
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_G7] + 1,
                                        g_even_pos, info->grad_even[2]);
      g_even_pos += 2;
      errcnt += fuji_decode_sample_even(info, params, info->linebuf[_B4] + 1,
                                        b_even_pos, info->grad_even[2]);
      b_even_pos += 2;
    }
    if (g_even_pos > 8)
    {
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_G7] + 1,
                                       g_odd_pos, info->grad_odd[2]);
      g_odd_pos += 2;
      errcnt += fuji_decode_sample_odd(info, params, info->linebuf[_B4] + 1,
                                       b_odd_pos, info->grad_odd[2]);
      b_odd_pos += 2;
    }
  }

  fuji_extend_green(info->linebuf, line_width);
  fuji_extend_blue(info->linebuf, line_width);

  if (errcnt)
    derror();
}

void LibRaw::fuji_decode_strip(const struct fuji_compressed_params *info_common,
                               int cur_block, INT64 raw_offset, unsigned dsize)
{
  int cur_block_width, cur_line;
  unsigned line_size;
  struct fuji_compressed_block info;

  init_fuji_block(&info, info_common, raw_offset, dsize);
  line_size = sizeof(ushort) * (info_common->line_width + 2);

  cur_block_width = libraw_internal_data.unpacker_data.fuji_block_width;
  if (cur_block + 1 == libraw_internal_data.unpacker_data.fuji_total_blocks)
  {
    cur_block_width =
        imgdata.sizes.raw_width -
        (libraw_internal_data.unpacker_data.fuji_block_width * cur_block);
    /* Old code, may get incorrect results on GFX50, but luckily large optical
    black cur_block_width = imgdata.sizes.raw_width %
    libraw_internal_data.unpacker_data.fuji_block_width;
    */
  }

  struct i_pair
  {
    int a, b;
  };
  const i_pair mtable[6] = {{_R0, _R3}, {_R1, _R4}, {_G0, _G6},
                            {_G1, _G7}, {_B0, _B3}, {_B1, _B4}},
               ztable[3] = {{_R2, 3}, {_G2, 6}, {_B2, 3}};
  for (cur_line = 0;
       cur_line < libraw_internal_data.unpacker_data.fuji_total_lines;
       cur_line++)
  {
    if (libraw_internal_data.unpacker_data.fuji_raw_type == 16)
      xtrans_decode_block(&info, info_common, cur_line);
    else
      fuji_bayer_decode_block(&info, info_common, cur_line);

    // copy data from line buffers and advance
    for (int i = 0; i < 6; i++)
      memcpy(info.linebuf[mtable[i].a], info.linebuf[mtable[i].b], line_size);

    if (libraw_internal_data.unpacker_data.fuji_raw_type == 16)
      copy_line_to_xtrans(&info, cur_line, cur_block, cur_block_width);
    else
      copy_line_to_bayer(&info, cur_line, cur_block, cur_block_width);

    for (int i = 0; i < 3; i++)
    {
      memset(info.linebuf[ztable[i].a], 0, ztable[i].b * line_size);
      info.linebuf[ztable[i].a][0] = info.linebuf[ztable[i].a - 1][1];
      info.linebuf[ztable[i].a][info_common->line_width + 1] =
          info.linebuf[ztable[i].a - 1][info_common->line_width];
    }
  }

  // release data
  free(info.linealloc);
  free(info.cur_buf);
}

void LibRaw::fuji_compressed_load_raw()
{
  struct fuji_compressed_params common_info;
  int cur_block;
  unsigned *block_sizes;
  INT64 raw_offset, *raw_block_offsets;
  // struct fuji_compressed_block info;

  init_fuji_compr(&common_info);

  // read block sizes
  block_sizes = (unsigned *)malloc(
      sizeof(unsigned) * libraw_internal_data.unpacker_data.fuji_total_blocks);
  merror(block_sizes, "fuji_compressed_load_raw()");
  raw_block_offsets = (INT64 *)malloc(
      sizeof(INT64) * libraw_internal_data.unpacker_data.fuji_total_blocks);
  merror(raw_block_offsets, "fuji_compressed_load_raw()");

  raw_offset =
      sizeof(unsigned) * libraw_internal_data.unpacker_data.fuji_total_blocks;
  if (raw_offset & 0xC)
    raw_offset += 0x10 - (raw_offset & 0xC);

  raw_offset += libraw_internal_data.unpacker_data.data_offset;

  libraw_internal_data.internal_data.input->seek(
      libraw_internal_data.unpacker_data.data_offset, SEEK_SET);
  libraw_internal_data.internal_data.input->read(
      block_sizes, 1,
      sizeof(unsigned) * libraw_internal_data.unpacker_data.fuji_total_blocks);

  raw_block_offsets[0] = raw_offset;
  // calculating raw block offsets
  for (cur_block = 0;
       cur_block < libraw_internal_data.unpacker_data.fuji_total_blocks;
       cur_block++)
  {
    unsigned bsize = sgetn(4, (uchar *)(block_sizes + cur_block));
    block_sizes[cur_block] = bsize;
  }

  for (cur_block = 1;
       cur_block < libraw_internal_data.unpacker_data.fuji_total_blocks;
       cur_block++)
    raw_block_offsets[cur_block] =
        raw_block_offsets[cur_block - 1] + block_sizes[cur_block - 1];

  fuji_decode_loop(&common_info,
                   libraw_internal_data.unpacker_data.fuji_total_blocks,
                   raw_block_offsets, block_sizes);

  free(block_sizes);
  free(raw_block_offsets);
  free(common_info.q_table);
}

void LibRaw::fuji_decode_loop(const struct fuji_compressed_params *common_info,
                              int count, INT64 *raw_block_offsets,
                              unsigned *block_sizes)
{
  int cur_block;
#ifdef LIBRAW_USE_OPENMP
#pragma omp parallel for private(cur_block)
#endif
  for (cur_block = 0; cur_block < count; cur_block++)
  {
    fuji_decode_strip(common_info, cur_block, raw_block_offsets[cur_block],
                      block_sizes[cur_block]);
  }
}

void LibRaw::parse_fuji_compressed_header()
{
  unsigned signature, version, h_raw_type, h_raw_bits, h_raw_height,
      h_raw_rounded_width, h_raw_width, h_block_size, h_blocks_in_row,
      h_total_lines;

  uchar header[16];

  libraw_internal_data.internal_data.input->seek(
      libraw_internal_data.unpacker_data.data_offset, SEEK_SET);
  libraw_internal_data.internal_data.input->read(header, 1, sizeof(header));

  // read all header
  signature = sgetn(2, header);
  version = header[2];
  h_raw_type = header[3];
  h_raw_bits = header[4];
  h_raw_height = sgetn(2, header + 5);
  h_raw_rounded_width = sgetn(2, header + 7);
  h_raw_width = sgetn(2, header + 9);
  h_block_size = sgetn(2, header + 11);
  h_blocks_in_row = header[13];
  h_total_lines = sgetn(2, header + 14);

  // general validation
  if (signature != 0x4953 || version != 1 || h_raw_height > 0x3000 ||
      h_raw_height < 6 || h_raw_height % 6 || h_block_size < 1 ||
      h_raw_width > 0x3000 || h_raw_width < 0x300 || h_raw_width % 24 ||
      h_raw_rounded_width > 0x3000 || h_raw_rounded_width < h_block_size ||
      h_raw_rounded_width % h_block_size ||
      h_raw_rounded_width - h_raw_width >= h_block_size ||
      h_block_size != 0x300 || h_blocks_in_row > 0x10 || h_blocks_in_row == 0 ||
      h_blocks_in_row != h_raw_rounded_width / h_block_size ||
      h_total_lines > 0x800 || h_total_lines == 0 ||
      h_total_lines != h_raw_height / 6 ||
      (h_raw_bits != 12 && h_raw_bits != 14 && h_raw_bits != 16) ||
      (h_raw_type != 16 && h_raw_type != 0))
    return;

  // modify data
  libraw_internal_data.unpacker_data.fuji_total_lines = h_total_lines;
  libraw_internal_data.unpacker_data.fuji_total_blocks = h_blocks_in_row;
  libraw_internal_data.unpacker_data.fuji_block_width = h_block_size;
  libraw_internal_data.unpacker_data.fuji_bits = h_raw_bits;
  libraw_internal_data.unpacker_data.fuji_raw_type = h_raw_type;
  imgdata.sizes.raw_width = h_raw_width;
  imgdata.sizes.raw_height = h_raw_height;
  libraw_internal_data.unpacker_data.data_offset += 16;
  load_raw = &LibRaw::fuji_compressed_load_raw;
}

#undef _abs
#undef _min