hplx_hor_synthesis_by_lifting.c

JPEG2000实现的源码

      right_ext = symmetric_extension_type(1,(src_cols+dst_cols)&1,
                                           the_stage&1,1);
    }
  else
    { /* Extension for odd tap filters. */
      pos_support-=src_offset;
      neg_support+=src_offset;
      taps += src_offset;
      left_ext = (src_on_left_boundary)?0:1;
      right_ext = (src_on_right_boundary)?0:1;
    }

  /* Perform extensions, alternating between left and right extension
     until we are done. */
  sp = src; dp = sp + src_cols - 1;
  pos_support += dst_cols - src_cols;
  for (n=p=1; (n <= neg_support) || (p <= pos_support); )
    {
      int did_something;

      did_something = 0;
      if (n <= neg_support)
        { /* Still need extension on the left. */
          if (left_ext)
            { /* Half-point extension. */
              if (n <= (src_cols+p-1))
                { sp[-n] = sp[n-1]*left_ext; n++; did_something = 1; }
            }
          else
            { /* Nice case for odd length filters; should always work. */
              if (n < (src_cols+p-1))
                { sp[-n] = sp[n]; n++; did_something = 1; }
            }
        }
      if (p <= pos_support)
        { /* Still need extension on the right. */
          if (right_ext)
            { /* Half-point extension. */
              if (p <= (src_cols+n-1))
                { dp[p] = dp[-p+1]*right_ext; p++; did_something = 1; }
            }
          else
            { /* Whole-point extension. */
              if (p < (src_cols+n-1))
                { dp[p] = dp[-p]; p++; did_something = 1; }
            }
        }
      assert(did_something);
    }
  pos_support -= dst_cols - src_cols;

  /* Apply lifting step.  Note that `taps' points to "centre" of support. */

  offset = (1<<downshift) >> 1;
  if (skip_first)
    { dst_cols--; dst++; src++; }
  if (skip_last)
    { dst_cols--; }
  for (; dst_cols > 0; dst_cols--, src++, dst++)
    {
      for (sum=0, n=-neg_support; n <= pos_support; n++)
        sum += src[n] * taps[n];
      *dst -= (ifc_int)((sum+offset) >> downshift);
    }
}

/*****************************************************************************/
/* STATIC                     undo_1d_float_lifting                          */
/*****************************************************************************/

static void
  undo_1d_float_lifting(hplx_hor_synthesis_by_lifting_ref self)

 /* Undoes the sequence of floating point lifting steps on the
    two branch buffers in the `self->branch_buf_float' array.  Also takes
    care of frames where necessary. */

{
  float *src_bufs[2], *work_bufs[2], *sp, *dp, scale;
  int b, n, remaining_cols, frame_cols, first_col_idx;
  int frame_idx;

  /* Set up the `src_bufs' and `work_bufs' arrays first. */

  for (b=0; b < ((hplx_synthesis_stage_ref) self)->horiz_limit; b++)
    {
      src_bufs[b] = work_bufs[b] = self->branch_buf_float[b];
      if (self->num_frames > 1)
        {
          if (self->frame_work_buf_float[b] == NULL)
            {
              self->frame_work_buf_float[b] = (float *)
                local_malloc(XFORM_HBUF_KEY,
                             sizeof(float)*((self->frame_cols>>1)+
                             self->neg_extend+self->pos_extend + 2));
              self->frame_work_buf_float[b] += self->neg_extend;
            }
          work_bufs[b] = self->frame_work_buf_float[b];
        }
    }

  /* Now for the main processing loop. */

  frame_cols = self->first_frame_cols;
  remaining_cols = self->tile_width;
  assert(remaining_cols > 0);
  first_col_idx = self->first_idx;
  for (frame_idx=0; frame_idx < self->num_frames; frame_idx++)
    {
      int special_first, special_last, ovlp_left, ovlp_right;
      int left_boundary_odd, right_boundary_odd;
      int subseq_cols[2]; /* even and odd sub-sequence lengths. */

      left_boundary_odd = first_col_idx & 1;
      right_boundary_odd = (first_col_idx+frame_cols-1) & 1;
      subseq_cols[0] = (frame_cols+1-left_boundary_odd) >> 1;
      subseq_cols[1] = (frame_cols+left_boundary_odd) >> 1;
      special_first = special_last = ovlp_left = ovlp_right = 0;
      if (frame_idx > 0)
        { /* Internal left boundary. */
          special_first = 1;
          if (left_boundary_odd)
            { ovlp_left = 1; subseq_cols[0]++; left_boundary_odd = 0; }
        }
      else if (self->base.sso_ext && !left_boundary_odd)
        special_first = 1; /* Use SSO-DWT style extension. */
      if (frame_idx < (self->num_frames-1))
        { /* Internal right boundary. */
          special_last = 1;
          if (right_boundary_odd)
            { ovlp_right = 1; subseq_cols[0]++; right_boundary_odd = 0; }
        }
      else if (self->base.sso_ext && !right_boundary_odd)
        special_last = 1; /* Use SSO-DWT style extension. */
      if (self->num_frames > 1)
        { /* Transfer input to `work_bufs', including overlap samples */
          for (b=0; b < ((hplx_synthesis_stage_ref) self)->horiz_limit; b++)
            {
              for (sp=src_bufs[b]-(ovlp_left&(1-b)), dp=work_bufs[b],
                   n=subseq_cols[b]; n > 0; n--)
                *(dp++) = *(sp++);
            }
        }
      if ((subseq_cols[0]+subseq_cols[1]) > 1)
        { /* If there is only 1 sample in the frame, we have nothing to do. */
          for (b=0; b < ((hplx_synthesis_stage_ref) self)->horiz_limit; b++)
            {
              scale = self->branch_scale[b];
              for (sp=work_bufs[b], n=subseq_cols[b]; n > 0; n--)
                *(sp++) *= scale;
            }
          for (n=self->num_steps-1; n >= 0; n--)
            {
              int src_seq, dst_seq;
              int src_offset; /* First src index - first dst index */

              src_seq = n & 1; dst_seq = (n+1) & 1;
              src_offset = (src_seq&1)?(-left_boundary_odd):left_boundary_odd;
              undo_float_step(n,self->neg_supports[n],self->pos_supports[n],
                              self->float_taps[n],
                              work_bufs[src_seq],work_bufs[dst_seq],
                              subseq_cols[src_seq],subseq_cols[dst_seq],
                              src_offset,left_boundary_odd^dst_seq,
                              right_boundary_odd^dst_seq,
                              special_first&src_seq,special_last&src_seq,
                              self->step_dc_gains[n]);
            }
        }
      if (self->num_frames > 1)
        { /* Transfer output from `work_bufs', excluding overlap samples */
          subseq_cols[0] -= ovlp_left+ovlp_right;
          for (b=0; b < ((hplx_synthesis_stage_ref) self)->horiz_limit; b++)
            {
              for (dp=src_bufs[b], sp=work_bufs[b]+(ovlp_left&(1-b)),
                   n=subseq_cols[b]; n > 0; n--)
                *(dp++) = *(sp++);
              src_bufs[b] += subseq_cols[b];
            }
        }
      first_col_idx += frame_cols;
      remaining_cols -= frame_cols;
      frame_cols = self->frame_cols;
      if (frame_cols > remaining_cols)
        frame_cols = remaining_cols;
    }
}

/*****************************************************************************/
/* STATIC                        undo_1d_int_lifting                         */
/*****************************************************************************/

static void
  undo_1d_int_lifting(hplx_hor_synthesis_by_lifting_ref self)

 /* Undoes the sequence of floating point lifting steps on the
    two branch buffers in the `self->branch_buf_int' array.  Also takes
    care of frames where necessary. */

{
  ifc_int *src_bufs[2], *work_bufs[2], *sp, *dp;
  int b, n, remaining_cols, frame_cols, first_col_idx;
  int frame_idx;

  /* Set up the `src_bufs' and `work_bufs' arrays first. */

  for (b=0; b < ((hplx_synthesis_stage_ref) self)->horiz_limit; b++)
    {
      src_bufs[b] = work_bufs[b] = self->branch_buf_int[b];
      if (self->num_frames > 1)
        {
          if (self->frame_work_buf_int[b] == NULL)
            {
              self->frame_work_buf_int[b] = (ifc_int *)
                local_malloc(XFORM_HBUF_KEY,
                             sizeof(ifc_int)*((self->frame_cols>>1)+
                             self->neg_extend+self->pos_extend + 2));
              self->frame_work_buf_int[b] += self->neg_extend;
            }
          work_bufs[b] = self->frame_work_buf_int[b];
        }
    }

  /* Now for the main processing loop. */

  frame_cols = self->first_frame_cols;
  remaining_cols = self->tile_width;
  assert(remaining_cols > 0);
  first_col_idx = self->first_idx;
  for (frame_idx=0; frame_idx < self->num_frames; frame_idx++)
    {
      int special_first, special_last, ovlp_left, ovlp_right;
      int left_boundary_odd, right_boundary_odd;
      int subseq_cols[2]; /* even and odd sub-sequence lengths. */

      left_boundary_odd = first_col_idx & 1;
      right_boundary_odd = (first_col_idx+frame_cols-1) & 1;
      subseq_cols[0] = (frame_cols+1-left_boundary_odd) >> 1;
      subseq_cols[1] = (frame_cols+left_boundary_odd) >> 1;
      special_first = special_last = ovlp_left = ovlp_right = 0;
      if (frame_idx > 0)
        { /* Internal left boundary. */
          special_first = 1;
          if (left_boundary_odd)
            { ovlp_left = 1; subseq_cols[0]++; left_boundary_odd = 0; }
        }
      else if (self->base.sso_ext && !left_boundary_odd)
        special_first = 1; /* Use SSO-DWT style extension. */
      if (frame_idx < (self->num_frames-1))
        { /* Internal right boundary. */
          special_last = 1;
          if (right_boundary_odd)
            { ovlp_right = 1; subseq_cols[0]++; right_boundary_odd = 0; }
        }
      else if (self->base.sso_ext && !right_boundary_odd)
        special_last = 1; /* Use SSO-DWT style extension. */
      if (self->num_frames > 1)
        { /* Transfer input to `work_bufs', including overlap samples */
          for (b=0; b < ((hplx_synthesis_stage_ref) self)->horiz_limit; b++)
            {
              for (sp=src_bufs[b]-(ovlp_left&(1-b)), dp=work_bufs[b],
                   n=subseq_cols[b]; n > 0; n--)
                *(dp++) = *(sp++);
            }
        }
      if ((subseq_cols[0]+subseq_cols[1]) > 1)
        { /* If there is only 1 sample in the frame, we have nothing to do. */
          for (n=self->num_steps-1; n >= 0; n--)
            {
              int src_seq, dst_seq;
              int src_offset; /* First src index - first dst index */

              src_seq = n & 1; dst_seq = (n+1) & 1;
              src_offset = (src_seq&1)?(-left_boundary_odd):left_boundary_odd;
              undo_int_step(n,self->neg_supports[n],self->pos_supports[n],
                            self->int_taps[n],self->int_downshifts[n],
                            work_bufs[src_seq],work_bufs[dst_seq],
                            subseq_cols[src_seq],subseq_cols[dst_seq],
                            src_offset,left_boundary_odd^dst_seq,
                            right_boundary_odd^dst_seq,
                            special_first&src_seq,special_last&src_seq);
            }
        }

      /* Fix for single sample discrepancy between VM8.5 and FDIS */
      else if ((frame_cols == 1) && (left_boundary_odd))
        {
          for (sp=work_bufs[1], n=subseq_cols[1]; n > 0; n--)
            *(sp++) >>= 1;
        }

      if (self->num_frames > 1)
        { /* Transfer output from `work_bufs', excluding overlap samples */
          subseq_cols[0] -= ovlp_left+ovlp_right;
          for (b=0; b < ((hplx_synthesis_stage_ref) self)->horiz_limit; b++)
            {
              for (dp=src_bufs[b], sp=work_bufs[b]+(ovlp_left&(1-b)),
                   n=subseq_cols[b]; n > 0; n--)
                *(dp++) = *(sp++);
              src_bufs[b] += subseq_cols[b];
            }
        }
      first_col_idx += frame_cols;
      remaining_cols -= frame_cols;
      frame_cols = self->frame_cols;
      if (frame_cols > remaining_cols)
        frame_cols = remaining_cols;
    }
}