/********************************************************************

 *                                                                  *

 * THIS FILE IS PART OF THE OggTheora SOFTWARE CODEC SOURCE CODE.   *

 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *

 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *

 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *

 *                                                                  *

 * THE Theora SOURCE CODE IS COPYRIGHT (C) 2002-2009,2025           *

 * by the Xiph.Org Foundation and contributors                      *

 * https://www.xiph.org/                                            *

 *                                                                  *

 ********************************************************************

  function:

 ********************************************************************/

#include <stdlib.h>

#include <string.h>

#include "state.h"

#if defined(OC_DUMP_IMAGES)

# include <stdio.h>

# include "png.h"

# include "zlib.h"

#endif

/*The function used to fill in the chroma plane motion vectors for a macro

   block when 4 different motion vectors are specified in the luma plane.

  This version is for use with chroma decimated in the X and Y directions

   (4:2:0).

  _cbmvs: The chroma block-level motion vectors to fill in.

  _lbmvs: The luma block-level motion vectors.*/

static void oc_set_chroma_mvs00(oc_mv _cbmvs[4],const oc_mv _lbmvs[4]){

  int dx;

  int dy;

  dx=OC_MV_X(_lbmvs[0])+OC_MV_X(_lbmvs[1])

   +OC_MV_X(_lbmvs[2])+OC_MV_X(_lbmvs[3]);

  dy=OC_MV_Y(_lbmvs[0])+OC_MV_Y(_lbmvs[1])

   +OC_MV_Y(_lbmvs[2])+OC_MV_Y(_lbmvs[3]);

  _cbmvs[0]=OC_MV(OC_DIV_ROUND_POW2(dx,2,2),OC_DIV_ROUND_POW2(dy,2,2));

}

/*The function used to fill in the chroma plane motion vectors for a macro

   block when 4 different motion vectors are specified in the luma plane.

  This version is for use with chroma decimated in the Y direction.

  _cbmvs: The chroma block-level motion vectors to fill in.

  _lbmvs: The luma block-level motion vectors.*/

static void oc_set_chroma_mvs01(oc_mv _cbmvs[4],const oc_mv _lbmvs[4]){

  int dx;

  int dy;

  dx=OC_MV_X(_lbmvs[0])+OC_MV_X(_lbmvs[2]);

  dy=OC_MV_Y(_lbmvs[0])+OC_MV_Y(_lbmvs[2]);

  _cbmvs[0]=OC_MV(OC_DIV_ROUND_POW2(dx,1,1),OC_DIV_ROUND_POW2(dy,1,1));

  dx=OC_MV_X(_lbmvs[1])+OC_MV_X(_lbmvs[3]);

  dy=OC_MV_Y(_lbmvs[1])+OC_MV_Y(_lbmvs[3]);

  _cbmvs[1]=OC_MV(OC_DIV_ROUND_POW2(dx,1,1),OC_DIV_ROUND_POW2(dy,1,1));

}

/*The function used to fill in the chroma plane motion vectors for a macro

   block when 4 different motion vectors are specified in the luma plane.

  This version is for use with chroma decimated in the X direction (4:2:2).

  _cbmvs: The chroma block-level motion vectors to fill in.

  _lbmvs: The luma block-level motion vectors.*/

static void oc_set_chroma_mvs10(oc_mv _cbmvs[4],const oc_mv _lbmvs[4]){

  int dx;

  int dy;

  dx=OC_MV_X(_lbmvs[0])+OC_MV_X(_lbmvs[1]);

  dy=OC_MV_Y(_lbmvs[0])+OC_MV_Y(_lbmvs[1]);

  _cbmvs[0]=OC_MV(OC_DIV_ROUND_POW2(dx,1,1),OC_DIV_ROUND_POW2(dy,1,1));

  dx=OC_MV_X(_lbmvs[2])+OC_MV_X(_lbmvs[3]);

  dy=OC_MV_Y(_lbmvs[2])+OC_MV_Y(_lbmvs[3]);

  _cbmvs[2]=OC_MV(OC_DIV_ROUND_POW2(dx,1,1),OC_DIV_ROUND_POW2(dy,1,1));

}

/*The function used to fill in the chroma plane motion vectors for a macro

   block when 4 different motion vectors are specified in the luma plane.

  This version is for use with no chroma decimation (4:4:4).

  _cbmvs: The chroma block-level motion vectors to fill in.

  _lmbmv: The luma macro-block level motion vector to fill in for use in

           prediction.

  _lbmvs: The luma block-level motion vectors.*/

static void oc_set_chroma_mvs11(oc_mv _cbmvs[4],const oc_mv _lbmvs[4]){

  _cbmvs[0]=_lbmvs[0];

  _cbmvs[1]=_lbmvs[1];

  _cbmvs[2]=_lbmvs[2];

  _cbmvs[3]=_lbmvs[3];

}

/*A table of functions used to fill in the chroma plane motion vectors for a

   macro block when 4 different motion vectors are specified in the luma

   plane.*/

const oc_set_chroma_mvs_func OC_SET_CHROMA_MVS_TABLE[TH_PF_NFORMATS]={

  (oc_set_chroma_mvs_func)oc_set_chroma_mvs00,

  (oc_set_chroma_mvs_func)oc_set_chroma_mvs01,

  (oc_set_chroma_mvs_func)oc_set_chroma_mvs10,

  (oc_set_chroma_mvs_func)oc_set_chroma_mvs11

};

/*Returns the fragment index of the top-left block in a macro block.

  This can be used to test whether or not the whole macro block is valid.

  _sb_map: The super block map.

  _quadi:  The quadrant number.

  Return: The index of the fragment of the upper left block in the macro

   block, or -1 if the block lies outside the coded frame.*/

static ptrdiff_t oc_sb_quad_top_left_frag(oc_sb_map_quad _sb_map[4],int _quadi){

  /*It so happens that under the Hilbert curve ordering described below, the

     upper-left block in each macro block is at index 0, except in macro block

     3, where it is at index 2.*/

  return _sb_map[_quadi][_quadi&_quadi<<1];

}

/*Fills in the mapping from block positions to fragment numbers for a single

   color plane.

  This function also fills in the "valid" flag of each quadrant in the super

   block flags.

  _sb_maps:  The array of super block maps for the color plane.

  _sb_flags: The array of super block flags for the color plane.

  _frag0:    The index of the first fragment in the plane.

  _hfrags:   The number of horizontal fragments in a coded frame.

  _vfrags:   The number of vertical fragments in a coded frame.*/

static void oc_sb_create_plane_mapping(oc_sb_map _sb_maps[],

 oc_sb_flags _sb_flags[],ptrdiff_t _frag0,int _hfrags,int _vfrags){

  /*Contains the (macro_block,block) indices for a 4x4 grid of

     fragments.

    The pattern is a 4x4 Hilbert space-filling curve.

    A Hilbert curve has the nice property that as the curve grows larger, its

     fractal dimension approaches 2.

    The intuition is that nearby blocks in the curve are also close spatially,

     with the previous element always an immediate neighbor, so that runs of

     blocks should be well correlated.*/

  static const int SB_MAP[4][4][2]={

    {{0,0},{0,1},{3,2},{3,3}},

    {{0,3},{0,2},{3,1},{3,0}},

    {{1,0},{1,3},{2,0},{2,3}},

    {{1,1},{1,2},{2,1},{2,2}}

  };

  ptrdiff_t  yfrag;

  unsigned   sbi;

  int        y;

  sbi=0;

  yfrag=_frag0;

  for(y=0;;y+=4){

    int imax;

    int x;

    /*Figure out how many columns of blocks in this super block lie within the

       image.*/

    imax=_vfrags-y;

    if(imax>4)imax=4;

    else if(imax<=0)break;

    for(x=0;;x+=4,sbi++){

      ptrdiff_t xfrag;

      int       jmax;

      int       quadi;

      int       i;

      /*Figure out how many rows of blocks in this super block lie within the

         image.*/

      jmax=_hfrags-x;

      if(jmax>4)jmax=4;

      else if(jmax<=0)break;

      /*By default, set all fragment indices to -1.*/

      memset(_sb_maps[sbi],0xFF,sizeof(_sb_maps[sbi]));

      /*Fill in the fragment map for this super block.*/

      xfrag=yfrag+x;

      for(i=0;i<imax;i++){

        int j;

        for(j=0;j<jmax;j++){

          _sb_maps[sbi][SB_MAP[i][j][0]][SB_MAP[i][j][1]]=xfrag+j;

        }

        xfrag+=_hfrags;

      }

      /*Mark which quadrants of this super block lie within the image.*/

      for(quadi=0;quadi<4;quadi++){

        _sb_flags[sbi].quad_valid|=

         (oc_sb_quad_top_left_frag(_sb_maps[sbi],quadi)>=0)<<quadi;

      }

    }

    yfrag+=_hfrags<<2;

  }

}

/*Fills in the Y plane fragment map for a macro block given the fragment

   coordinates of its upper-left hand corner.

  _mb_map:    The macro block map to fill.

  _fplane: The description of the Y plane.

  _xfrag0: The X location of the upper-left hand fragment in the luma plane.

  _yfrag0: The Y location of the upper-left hand fragment in the luma plane.*/

static void oc_mb_fill_ymapping(oc_mb_map_plane _mb_map[3],

 const oc_fragment_plane *_fplane,int _xfrag0,int _yfrag0){

  int i;

  int j;

  for(i=0;i<2;i++)for(j=0;j<2;j++){

    _mb_map[0][i<<1|j]=(_yfrag0+i)*(ptrdiff_t)_fplane->nhfrags+_xfrag0+j;

  }

}

/*Fills in the chroma plane fragment maps for a macro block.

  This version is for use with chroma decimated in the X and Y directions

   (4:2:0).

  _mb_map:  The macro block map to fill.

  _fplanes: The descriptions of the fragment planes.

  _xfrag0:  The X location of the upper-left hand fragment in the luma plane.

  _yfrag0:  The Y location of the upper-left hand fragment in the luma plane.*/

static void oc_mb_fill_cmapping00(oc_mb_map_plane _mb_map[3],

 const oc_fragment_plane _fplanes[3],int _xfrag0,int _yfrag0){

  ptrdiff_t fragi;

  _xfrag0>>=1;

  _yfrag0>>=1;

  fragi=_yfrag0*(ptrdiff_t)_fplanes[1].nhfrags+_xfrag0;

  _mb_map[1][0]=fragi+_fplanes[1].froffset;

  _mb_map[2][0]=fragi+_fplanes[2].froffset;

}

/*Fills in the chroma plane fragment maps for a macro block.

  This version is for use with chroma decimated in the Y direction.

  _mb_map:  The macro block map to fill.

  _fplanes: The descriptions of the fragment planes.

  _xfrag0:  The X location of the upper-left hand fragment in the luma plane.

  _yfrag0:  The Y location of the upper-left hand fragment in the luma plane.*/

static void oc_mb_fill_cmapping01(oc_mb_map_plane _mb_map[3],

 const oc_fragment_plane _fplanes[3],int _xfrag0,int _yfrag0){

  ptrdiff_t fragi;

  int       j;

  _yfrag0>>=1;

  fragi=_yfrag0*(ptrdiff_t)_fplanes[1].nhfrags+_xfrag0;

  for(j=0;j<2;j++){

    _mb_map[1][j]=fragi+_fplanes[1].froffset;

    _mb_map[2][j]=fragi+_fplanes[2].froffset;

    fragi++;

  }

}

/*Fills in the chroma plane fragment maps for a macro block.

  This version is for use with chroma decimated in the X direction (4:2:2).

  _mb_map:  The macro block map to fill.

  _fplanes: The descriptions of the fragment planes.

  _xfrag0:  The X location of the upper-left hand fragment in the luma plane.

  _yfrag0:  The Y location of the upper-left hand fragment in the luma plane.*/

static void oc_mb_fill_cmapping10(oc_mb_map_plane _mb_map[3],

 const oc_fragment_plane _fplanes[3],int _xfrag0,int _yfrag0){

  ptrdiff_t fragi;

  int       i;

  _xfrag0>>=1;

  fragi=_yfrag0*(ptrdiff_t)_fplanes[1].nhfrags+_xfrag0;

  for(i=0;i<2;i++){

    _mb_map[1][i<<1]=fragi+_fplanes[1].froffset;

    _mb_map[2][i<<1]=fragi+_fplanes[2].froffset;

    fragi+=_fplanes[1].nhfrags;

  }

}

/*Fills in the chroma plane fragment maps for a macro block.

  This version is for use with no chroma decimation (4:4:4).

  This uses the already filled-in luma plane values.

  _mb_map:  The macro block map to fill.

  _fplanes: The descriptions of the fragment planes.

  _xfrag0:  The X location of the upper-left hand fragment in the luma plane.

  _yfrag0:  The Y location of the upper-left hand fragment in the luma plane.*/

static void oc_mb_fill_cmapping11(oc_mb_map_plane _mb_map[3],

 const oc_fragment_plane _fplanes[3],int _xfrag0,int _yfrag0){

  int k;

  (void)_xfrag0;

  (void)_yfrag0;

  for(k=0;k<4;k++){

    _mb_map[1][k]=_mb_map[0][k]+_fplanes[1].froffset;

    _mb_map[2][k]=_mb_map[0][k]+_fplanes[2].froffset;

  }

}

/*The function type used to fill in the chroma plane fragment maps for a

   macro block.

  _mb_map:  The macro block map to fill.

  _fplanes: The descriptions of the fragment planes.

  _xfrag0:  The X location of the upper-left hand fragment in the luma plane.

  _yfrag0:  The Y location of the upper-left hand fragment in the luma plane.*/

typedef void (*oc_mb_fill_cmapping_func)(oc_mb_map_plane _mb_map[3],

 const oc_fragment_plane _fplanes[3],int _xfrag0,int _yfrag0);

/*A table of functions used to fill in the chroma plane fragment maps for a

   macro block for each type of chrominance decimation.*/

static const oc_mb_fill_cmapping_func OC_MB_FILL_CMAPPING_TABLE[4]={

  oc_mb_fill_cmapping00,

  oc_mb_fill_cmapping01,

  oc_mb_fill_cmapping10,

  oc_mb_fill_cmapping11

};

/*Fills in the mapping from macro blocks to their corresponding fragment

   numbers in each plane.

  _mb_maps:   The list of macro block maps.

  _mb_modes:  The list of macro block modes; macro blocks completely outside

               the coded region are marked invalid.

  _fplanes:   The descriptions of the fragment planes.

  _pixel_fmt: The chroma decimation type.*/

static void oc_mb_create_mapping(oc_mb_map _mb_maps[],

 signed char _mb_modes[],const oc_fragment_plane _fplanes[3],int _pixel_fmt){

  oc_mb_fill_cmapping_func  mb_fill_cmapping;

  unsigned                  sbi;

  int                       y;

  mb_fill_cmapping=OC_MB_FILL_CMAPPING_TABLE[_pixel_fmt];

  /*Loop through the luma plane super blocks.*/

  for(sbi=y=0;y<_fplanes[0].nvfrags;y+=4){

    int x;

    for(x=0;x<_fplanes[0].nhfrags;x+=4,sbi++){

      int ymb;

      /*Loop through the macro blocks in each super block in display order.*/

      for(ymb=0;ymb<2;ymb++){

        int xmb;

        for(xmb=0;xmb<2;xmb++){

          unsigned mbi;

          int      mbx;

          int      mby;

          mbi=sbi<<2|OC_MB_MAP[ymb][xmb];

          mbx=x|xmb<<1;

          mby=y|ymb<<1;

          /*Initialize fragment indices to -1.*/

          memset(_mb_maps[mbi],0xFF,sizeof(_mb_maps[mbi]));

          /*Make sure this macro block is within the encoded region.*/

          if(mbx>=_fplanes[0].nhfrags||mby>=_fplanes[0].nvfrags){

            _mb_modes[mbi]=OC_MODE_INVALID;

            continue;

          }

          /*Fill in the fragment indices for the luma plane.*/

          oc_mb_fill_ymapping(_mb_maps[mbi],_fplanes,mbx,mby);

          /*Fill in the fragment indices for the chroma planes.*/

          (*mb_fill_cmapping)(_mb_maps[mbi],_fplanes,mbx,mby);

        }

      }

    }

  }

}

/*Marks the fragments which fall all or partially outside the displayable

   region of the frame.

  _state: The Theora state containing the fragments to be marked.*/

static void oc_state_border_init(oc_theora_state *_state){

  oc_fragment       *frag;

  oc_fragment       *yfrag_end;

  oc_fragment       *xfrag_end;

  oc_fragment_plane *fplane;

  int                crop_x0;

  int                crop_y0;

  int                crop_xf;

  int                crop_yf;

  int                pli;

  int                y;

  int                x;

  /*The method we use here is slow, but the code is dead simple and handles

     all the special cases easily.

    We only ever need to do it once.*/

  /*Loop through the fragments, marking those completely outside the

     displayable region and constructing a border mask for those that straddle

     the border.*/

  _state->nborders=0;

  yfrag_end=frag=_state->frags;

  for(pli=0;pli<3;pli++){

    fplane=_state->fplanes+pli;

    /*Set up the cropping rectangle for this plane.*/

    crop_x0=_state->info.pic_x;

    crop_xf=_state->info.pic_x+_state->info.pic_width;

    crop_y0=_state->info.pic_y;

    crop_yf=_state->info.pic_y+_state->info.pic_height;

    if(pli>0){

      if(!(_state->info.pixel_fmt&1)){

        crop_x0=crop_x0>>1;

        crop_xf=crop_xf+1>>1;

      }

      if(!(_state->info.pixel_fmt&2)){

        crop_y0=crop_y0>>1;

        crop_yf=crop_yf+1>>1;

      }

    }

    y=0;

    for(yfrag_end+=fplane->nfrags;frag<yfrag_end;y+=8){

      x=0;

      for(xfrag_end=frag+fplane->nhfrags;frag<xfrag_end;frag++,x+=8){

        /*First check to see if this fragment is completely outside the

           displayable region.*/

        /*Note the special checks for an empty cropping rectangle.

          This guarantees that if we count a fragment as straddling the

           border below, at least one pixel in the fragment will be inside

           the displayable region.*/

        if(x+8<=crop_x0||crop_xf<=x||y+8<=crop_y0||crop_yf<=y||

         crop_x0>=crop_xf||crop_y0>=crop_yf){

          frag->invalid=1;

        }

        /*Otherwise, check to see if it straddles the border.*/

        else if(x<crop_x0&&crop_x0<x+8||x<crop_xf&&crop_xf<x+8||

         y<crop_y0&&crop_y0<y+8||y<crop_yf&&crop_yf<y+8){

          ogg_uint64_t mask;

          int         npixels;

          int         i;

          mask=npixels=0;

          for(i=0;i<8;i++){

            int j;

            for(j=0;j<8;j++){

              if(x+j>=crop_x0&&x+j<crop_xf&&y+i>=crop_y0&&y+i<crop_yf){

                mask|=(ogg_uint64_t)1<<(i<<3|j);

                npixels++;

              }

            }

          }

          /*Search the fragment array for border info with the same pattern.

            In general, there will be at most 8 different patterns (per

             plane).*/

          for(i=0;;i++){

            if(i>=_state->nborders){

              _state->nborders++;

              _state->borders[i].mask=mask;

              _state->borders[i].npixels=npixels;

            }

            else if(_state->borders[i].mask!=mask)continue;

            frag->borderi=i;

            break;

          }

        }

        else frag->borderi=-1;

      }

    }

  }

}

static int oc_state_frarray_init(oc_theora_state *_state){

  int       yhfrags;

  int       yvfrags;

  int       chfrags;

  int       cvfrags;

  ptrdiff_t yfrags;

  ptrdiff_t cfrags;

  ptrdiff_t nfrags;

  unsigned  yhsbs;

  unsigned  yvsbs;

  unsigned  chsbs;

  unsigned  cvsbs;

  unsigned  ysbs;

  unsigned  csbs;

  unsigned  nsbs;

  size_t    nmbs;

  int       hdec;

  int       vdec;

  int       pli;

  /*Figure out the number of fragments in each plane.*/

  /*These parameters have already been validated to be multiples of 16.*/

  yhfrags=_state->info.frame_width>>3;

  yvfrags=_state->info.frame_height>>3;

  hdec=!(_state->info.pixel_fmt&1);

  vdec=!(_state->info.pixel_fmt&2);

  chfrags=yhfrags+hdec>>hdec;

  cvfrags=yvfrags+vdec>>vdec;

  yfrags=yhfrags*(ptrdiff_t)yvfrags;

  cfrags=chfrags*(ptrdiff_t)cvfrags;

  nfrags=yfrags+2*cfrags;

  /*Figure out the number of super blocks in each plane.*/

  yhsbs=yhfrags+3>>2;

  yvsbs=yvfrags+3>>2;

  chsbs=chfrags+3>>2;

  cvsbs=cvfrags+3>>2;

  ysbs=yhsbs*yvsbs;

  csbs=chsbs*cvsbs;

  nsbs=ysbs+2*csbs;

  nmbs=(size_t)ysbs<<2;

  /*Check for overflow.

    We support the ridiculous upper limits of the specification (1048560 by

     1048560, or 3 TB frames) if the target architecture has 64-bit pointers,

     but for those with 32-bit pointers (or smaller!) we have to check.

    If the caller wants to prevent denial-of-service by imposing a more

     reasonable upper limit on the size of attempted allocations, they must do

     so themselves; we have no platform independent way to determine how much

     system memory there is nor an application-independent way to decide what a

     "reasonable" allocation is.*/

  if(yfrags/yhfrags!=yvfrags||2*cfrags<cfrags||nfrags<yfrags||

   ysbs/yhsbs!=yvsbs||2*csbs<csbs||nsbs<ysbs||nmbs>>2!=ysbs){

    return TH_EIMPL;

  }

  /*Initialize the fragment array.*/

  _state->fplanes[0].nhfrags=yhfrags;

  _state->fplanes[0].nvfrags=yvfrags;

  _state->fplanes[0].froffset=0;

  _state->fplanes[0].nfrags=yfrags;

  _state->fplanes[0].nhsbs=yhsbs;

  _state->fplanes[0].nvsbs=yvsbs;

  _state->fplanes[0].sboffset=0;

  _state->fplanes[0].nsbs=ysbs;

  _state->fplanes[1].nhfrags=_state->fplanes[2].nhfrags=chfrags;

  _state->fplanes[1].nvfrags=_state->fplanes[2].nvfrags=cvfrags;

  _state->fplanes[1].froffset=yfrags;

  _state->fplanes[2].froffset=yfrags+cfrags;

  _state->fplanes[1].nfrags=_state->fplanes[2].nfrags=cfrags;

  _state->fplanes[1].nhsbs=_state->fplanes[2].nhsbs=chsbs;

  _state->fplanes[1].nvsbs=_state->fplanes[2].nvsbs=cvsbs;

  _state->fplanes[1].sboffset=ysbs;

  _state->fplanes[2].sboffset=ysbs+csbs;

  _state->fplanes[1].nsbs=_state->fplanes[2].nsbs=csbs;

  _state->nfrags=nfrags;

  _state->frags=_ogg_calloc(nfrags,sizeof(*_state->frags));

  _state->frag_mvs=_ogg_malloc(nfrags*sizeof(*_state->frag_mvs));

  _state->nsbs=nsbs;

  _state->sb_maps=_ogg_malloc(nsbs*sizeof(*_state->sb_maps));

  _state->sb_flags=_ogg_calloc(nsbs,sizeof(*_state->sb_flags));

  _state->nhmbs=yhsbs<<1;

  _state->nvmbs=yvsbs<<1;

  _state->nmbs=nmbs;

  _state->mb_maps=_ogg_calloc(nmbs,sizeof(*_state->mb_maps));

  _state->mb_modes=_ogg_calloc(nmbs,sizeof(*_state->mb_modes));

  _state->coded_fragis=_ogg_malloc(nfrags*sizeof(*_state->coded_fragis));

  if(_state->frags==NULL||_state->frag_mvs==NULL||_state->sb_maps==NULL||

   _state->sb_flags==NULL||_state->mb_maps==NULL||_state->mb_modes==NULL||

   _state->coded_fragis==NULL){

    return TH_EFAULT;

  }

  /*Create the mapping from super blocks to fragments.*/

  for(pli=0;pli<3;pli++){

    oc_fragment_plane *fplane;

    fplane=_state->fplanes+pli;

    oc_sb_create_plane_mapping(_state->sb_maps+fplane->sboffset,

     _state->sb_flags+fplane->sboffset,fplane->froffset,

     fplane->nhfrags,fplane->nvfrags);

  }

  /*Create the mapping from macro blocks to fragments.*/

  oc_mb_create_mapping(_state->mb_maps,_state->mb_modes,

   _state->fplanes,_state->info.pixel_fmt);

  /*Initialize the invalid and borderi fields of each fragment.*/

  oc_state_border_init(_state);

  return 0;

}

static void oc_state_frarray_clear(oc_theora_state *_state){

  _ogg_free(_state->coded_fragis);

  _ogg_free(_state->mb_modes);

  _ogg_free(_state->mb_maps);

  _ogg_free(_state->sb_flags);

  _ogg_free(_state->sb_maps);

  _ogg_free(_state->frag_mvs);

  _ogg_free(_state->frags);

}

/*Initializes the buffers used for reconstructed frames.

  These buffers are padded with 16 extra pixels on each side, to allow

   unrestricted motion vectors without special casing the boundary.

  If chroma is decimated in either direction, the padding is reduced by a

   factor of 2 on the appropriate sides.

  _nrefs: The number of reference buffers to init; must be in the range 3...6.*/

static int oc_state_ref_bufs_init(oc_theora_state *_state,int _nrefs){

  th_info       *info;

  unsigned char *ref_frame_data;

  size_t         ref_frame_data_sz;

  size_t         ref_frame_sz;

  size_t         yplane_sz;

  size_t         cplane_sz;

  int            yhstride;

  int            yheight;

  int            chstride;

  int            cheight;

  ptrdiff_t      align;

  ptrdiff_t      yoffset;

  ptrdiff_t      coffset;

  ptrdiff_t     *frag_buf_offs;

  ptrdiff_t      fragi;

  int            hdec;

  int            vdec;

  int            rfi;

  int            pli;

  if(_nrefs<3||_nrefs>6)return TH_EINVAL;

  info=&_state->info;

  /*Compute the image buffer parameters for each plane.*/

  hdec=!(info->pixel_fmt&1);

  vdec=!(info->pixel_fmt&2);

  yhstride=info->frame_width+2*OC_UMV_PADDING;

  yheight=info->frame_height+2*OC_UMV_PADDING;

  /*Require 16-byte aligned rows in the chroma planes.*/

  chstride=(yhstride>>hdec)+15&~15;

  cheight=yheight>>vdec;

  yplane_sz=yhstride*(size_t)yheight;

  cplane_sz=chstride*(size_t)cheight;

  yoffset=OC_UMV_PADDING+OC_UMV_PADDING*(ptrdiff_t)yhstride;

  coffset=(OC_UMV_PADDING>>hdec)+(OC_UMV_PADDING>>vdec)*(ptrdiff_t)chstride;

  /*Although we guarantee the rows of the chroma planes are a multiple of 16

     bytes, the initial padding on the first row may only be 8 bytes.

    Compute the offset needed to the actual image data to a multiple of 16.*/

  align=-coffset&15;

  ref_frame_sz=yplane_sz+2*cplane_sz+16;

  ref_frame_data_sz=_nrefs*ref_frame_sz;

  /*Check for overflow.

    The same caveats apply as for oc_state_frarray_init().*/

  if(yplane_sz/yhstride!=(size_t)yheight||2*cplane_sz+16<cplane_sz||

   ref_frame_sz<yplane_sz||ref_frame_data_sz/_nrefs!=ref_frame_sz){

    return TH_EIMPL;

  }

  ref_frame_data=oc_aligned_malloc(ref_frame_data_sz,16);

  frag_buf_offs=_state->frag_buf_offs=

   _ogg_malloc(_state->nfrags*sizeof(*frag_buf_offs));

  if(ref_frame_data==NULL||frag_buf_offs==NULL){

    _ogg_free(frag_buf_offs);

    oc_aligned_free(ref_frame_data);

    return TH_EFAULT;

  }

  /*Set up the width, height and stride for the image buffers.*/

  _state->ref_frame_bufs[0][0].width=info->frame_width;

  _state->ref_frame_bufs[0][0].height=info->frame_height;

  _state->ref_frame_bufs[0][0].stride=yhstride;

  _state->ref_frame_bufs[0][1].width=_state->ref_frame_bufs[0][2].width=

   info->frame_width>>hdec;

  _state->ref_frame_bufs[0][1].height=_state->ref_frame_bufs[0][2].height=

   info->frame_height>>vdec;

  _state->ref_frame_bufs[0][1].stride=_state->ref_frame_bufs[0][2].stride=

   chstride;

  for(rfi=1;rfi<_nrefs;rfi++){

    memcpy(_state->ref_frame_bufs[rfi],_state->ref_frame_bufs[0],

     sizeof(_state->ref_frame_bufs[0]));

  }

  _state->ref_frame_handle=ref_frame_data;

  /*Set up the data pointers for the image buffers.*/

  for(rfi=0;rfi<_nrefs;rfi++){

    _state->ref_frame_bufs[rfi][0].data=ref_frame_data+yoffset;

    ref_frame_data+=yplane_sz+align;

    _state->ref_frame_bufs[rfi][1].data=ref_frame_data+coffset;

    ref_frame_data+=cplane_sz;

    _state->ref_frame_bufs[rfi][2].data=ref_frame_data+coffset;

    ref_frame_data+=cplane_sz+(16-align);

    /*Flip the buffer upside down.

      This allows us to decode Theora's bottom-up frames in their natural

       order, yet return a top-down buffer with a positive stride to the user.*/

    oc_ycbcr_buffer_flip(_state->ref_frame_bufs[rfi],

     _state->ref_frame_bufs[rfi]);

  }

  _state->ref_ystride[0]=-yhstride;

  _state->ref_ystride[1]=_state->ref_ystride[2]=-chstride;

  /*Initialize the fragment buffer offsets.*/

  ref_frame_data=_state->ref_frame_bufs[0][0].data;

  fragi=0;

  for(pli=0;pli<3;pli++){

    th_img_plane      *iplane;

    oc_fragment_plane *fplane;

    unsigned char     *vpix;

    ptrdiff_t          stride;

    ptrdiff_t          vfragi_end;

    int                nhfrags;

    iplane=_state->ref_frame_bufs[0]+pli;

    fplane=_state->fplanes+pli;

    vpix=iplane->data;

    vfragi_end=fplane->froffset+fplane->nfrags;

    nhfrags=fplane->nhfrags;

    stride=iplane->stride;

    while(fragi<vfragi_end){

      ptrdiff_t      hfragi_end;

      unsigned char *hpix;

      hpix=vpix;

      for(hfragi_end=fragi+nhfrags;fragi<hfragi_end;fragi++){

        frag_buf_offs[fragi]=hpix-ref_frame_data;

        hpix+=8;

      }

      vpix+=stride*8;

    }

  }

  /*Initialize the reference frame pointers and indices.*/

  _state->ref_frame_idx[OC_FRAME_GOLD]=

   _state->ref_frame_idx[OC_FRAME_PREV]=

   _state->ref_frame_idx[OC_FRAME_GOLD_ORIG]=

   _state->ref_frame_idx[OC_FRAME_PREV_ORIG]=

   _state->ref_frame_idx[OC_FRAME_SELF]=

   _state->ref_frame_idx[OC_FRAME_IO]=-1;

  _state->ref_frame_data[OC_FRAME_GOLD]=

   _state->ref_frame_data[OC_FRAME_PREV]=

   _state->ref_frame_data[OC_FRAME_GOLD_ORIG]=

   _state->ref_frame_data[OC_FRAME_PREV_ORIG]=

   _state->ref_frame_data[OC_FRAME_SELF]=

   _state->ref_frame_data[OC_FRAME_IO]=NULL;

  return 0;

}

static void oc_state_ref_bufs_clear(oc_theora_state *_state){

  _ogg_free(_state->frag_buf_offs);

  oc_aligned_free(_state->ref_frame_handle);

}

void oc_state_accel_init_c(oc_theora_state *_state){

  _state->cpu_flags=0;

#if defined(OC_STATE_USE_VTABLE)

  _state->opt_vtable.frag_copy=oc_frag_copy_c;

  _state->opt_vtable.frag_copy_list=oc_frag_copy_list_c;

  _state->opt_vtable.frag_recon_intra=oc_frag_recon_intra_c;

  _state->opt_vtable.frag_recon_inter=oc_frag_recon_inter_c;

  _state->opt_vtable.frag_recon_inter2=oc_frag_recon_inter2_c;

  _state->opt_vtable.idct8x8=oc_idct8x8_c;

  _state->opt_vtable.state_frag_recon=oc_state_frag_recon_c;

  _state->opt_vtable.loop_filter_init=oc_loop_filter_init_c;

  _state->opt_vtable.state_loop_filter_frag_rows=

   oc_state_loop_filter_frag_rows_c;

  _state->opt_vtable.restore_fpu=oc_restore_fpu_c;

#endif

  _state->opt_data.dct_fzig_zag=OC_FZIG_ZAG;

}

int oc_state_init(oc_theora_state *_state,const th_info *_info,int _nrefs){

  int ret;

  /*First validate the parameters.*/

  if(_info==NULL)return TH_EFAULT;

  /*The width and height of the encoded frame must be multiples of 16.

    They must also, when divided by 16, fit into a 16-bit unsigned integer.

    The displayable frame offset coordinates must fit into an 8-bit unsigned

     integer.

    Note that the offset Y in the API is specified on the opposite side from

     how it is specified in the bitstream, because the Y axis is flipped in

     the bitstream.

    The displayable frame must fit inside the encoded frame.

    The color space must be one known by the encoder.

    The framerate ratio must not contain a zero value.*/

  if((_info->frame_width&0xF)||(_info->frame_height&0xF)||

   _info->frame_width<=0||_info->frame_width>=0x100000||

   _info->frame_height<=0||_info->frame_height>=0x100000||

   _info->pic_x+_info->pic_width>_info->frame_width||

   _info->pic_y+_info->pic_height>_info->frame_height||

   _info->pic_x>255||_info->frame_height-_info->pic_height-_info->pic_y>255||

   /*Note: the following <0 comparisons may generate spurious warnings on

      platforms where enums are unsigned.

     We could cast them to unsigned and just use the following >= comparison,

      but there are a number of compilers which will mis-optimize this.

     It's better to live with the spurious warnings.*/

   _info->colorspace<0||_info->colorspace>=TH_CS_NSPACES||

   _info->pixel_fmt<0||_info->pixel_fmt>=TH_PF_NFORMATS||

   _info->fps_numerator<1||_info->fps_denominator<1){

    return TH_EINVAL;

  }

  memset(_state,0,sizeof(*_state));

  memcpy(&_state->info,_info,sizeof(*_info));

  /*Invert the sense of pic_y to match Theora's right-handed coordinate

     system.*/

  _state->info.pic_y=_info->frame_height-_info->pic_height-_info->pic_y;

  _state->frame_type=OC_UNKWN_FRAME;

  oc_state_accel_init(_state);

  ret=oc_state_frarray_init(_state);

  if(ret>=0)ret=oc_state_ref_bufs_init(_state,_nrefs);

  if(ret<0){

    oc_state_frarray_clear(_state);

    return ret;

  }

  /*If the keyframe_granule_shift is out of range, use the maximum allowable

     value.*/

  if(_info->keyframe_granule_shift<0||_info->keyframe_granule_shift>31){

    _state->info.keyframe_granule_shift=31;

  }

  _state->keyframe_num=0;

  _state->curframe_num=-1;

  /*3.2.0 streams mark the frame index instead of the frame count.

    This was changed with stream version 3.2.1 to conform to other Ogg

     codecs.

    We add an extra bias when computing granule positions for new streams.*/

  _state->granpos_bias=TH_VERSION_CHECK(_info,3,2,1);

  return 0;

}

void oc_state_clear(oc_theora_state *_state){

  oc_state_ref_bufs_clear(_state);

  oc_state_frarray_clear(_state);

}

/*Duplicates the pixels on the border of the image plane out into the

   surrounding padding for use by unrestricted motion vectors.

  This function only adds the left and right borders, and only for the fragment

   rows specified.

  _refi: The index of the reference buffer to pad.

  _pli:  The color plane.

  _y0:   The Y coordinate of the first row to pad.

  _yend: The Y coordinate of the row to stop padding at.*/

void oc_state_borders_fill_rows(oc_theora_state *_state,int _refi,int _pli,

 int _y0,int _yend){

  th_img_plane  *iplane;

  unsigned char *apix;

  unsigned char *bpix;

  unsigned char *epix;

  int            stride;

  int            hpadding;

  hpadding=OC_UMV_PADDING>>(_pli!=0&&!(_state->info.pixel_fmt&1));

  iplane=_state->ref_frame_bufs[_refi]+_pli;

  stride=iplane->stride;

  apix=iplane->data+_y0*(ptrdiff_t)stride;

  bpix=apix+iplane->width-1;

  epix=iplane->data+_yend*(ptrdiff_t)stride;

  /*Note the use of != instead of <, which allows the stride to be negative.*/

  while(apix!=epix){

    memset(apix-hpadding,apix[0],hpadding);

    memset(bpix+1,bpix[0],hpadding);

    apix+=stride;

    bpix+=stride;

  }

}

/*Duplicates the pixels on the border of the image plane out into the

   surrounding padding for use by unrestricted motion vectors.

  This function only adds the top and bottom borders, and must be called after

   the left and right borders are added.

  _refi:      The index of the reference buffer to pad.

  _pli:       The color plane.*/

void oc_state_borders_fill_caps(oc_theora_state *_state,int _refi,int _pli){

  th_img_plane  *iplane;

  unsigned char *apix;

  unsigned char *bpix;

  unsigned char *epix;

  int            stride;

  int            hpadding;

  int            vpadding;

  int            fullw;

  hpadding=OC_UMV_PADDING>>(_pli!=0&&!(_state->info.pixel_fmt&1));

  vpadding=OC_UMV_PADDING>>(_pli!=0&&!(_state->info.pixel_fmt&2));

  iplane=_state->ref_frame_bufs[_refi]+_pli;

  stride=iplane->stride;

  fullw=iplane->width+(hpadding<<1);

  apix=iplane->data-hpadding;

  bpix=iplane->data+(iplane->height-1)*(ptrdiff_t)stride-hpadding;

  epix=apix-stride*(ptrdiff_t)vpadding;

  while(apix!=epix){

    memcpy(apix-stride,apix,fullw);

    memcpy(bpix+stride,bpix,fullw);

    apix-=stride;

    bpix+=stride;

  }

}

/*Duplicates the pixels on the border of the given reference image out into

   the surrounding padding for use by unrestricted motion vectors.

  _state: The context containing the reference buffers.

  _refi:  The index of the reference buffer to pad.*/

void oc_state_borders_fill(oc_theora_state *_state,int _refi){

  int pli;

  for(pli=0;pli<3;pli++){

    oc_state_borders_fill_rows(_state,_refi,pli,0,

     _state->ref_frame_bufs[_refi][pli].height);

    oc_state_borders_fill_caps(_state,_refi,pli);

  }

}

/*Determines the offsets in an image buffer to use for motion compensation.

  _state:   The Theora state the offsets are to be computed with.

  _offsets: Returns the offset for the buffer(s).

            _offsets[0] is always set.

            _offsets[1] is set if the motion vector has non-zero fractional

             components.

  _pli:     The color plane index.

  _mv:      The motion vector.

  Return: The number of offsets returned: 1 or 2.*/

int oc_state_get_mv_offsets(const oc_theora_state *_state,int _offsets[2],

 int _pli,oc_mv _mv){

  /*Here is a brief description of how Theora handles motion vectors:

    Motion vector components are specified to half-pixel accuracy in

     undecimated directions of each plane, and quarter-pixel accuracy in

     decimated directions.

    Integer parts are extracted by dividing (not shifting) by the

     appropriate amount, with truncation towards zero.

    These integer values are used to calculate the first offset.

    If either of the fractional parts are non-zero, then a second offset is

     computed.

    No third or fourth offsets are computed, even if both components have

     non-zero fractional parts.

    The second offset is computed by dividing (not shifting) by the

     appropriate amount, always truncating _away_ from zero.*/

#if 0

  /*This version of the code doesn't use any tables, but is slower.*/

  int ystride;

  int xprec;

  int yprec;

  int xfrac;

  int yfrac;

  int offs;

  int dx;

  int dy;

  ystride=_state->ref_ystride[_pli];

  /*These two variables decide whether we are in half- or quarter-pixel

     precision in each component.*/

  xprec=1+(_pli!=0&&!(_state->info.pixel_fmt&1));

  yprec=1+(_pli!=0&&!(_state->info.pixel_fmt&2));

  dx=OC_MV_X(_mv);

  dy=OC_MV_Y(_mv);

  /*These two variables are either 0 if all the fractional bits are zero or -1

     if any of them are non-zero.*/

  xfrac=OC_SIGNMASK(-(dx&(xprec|1)));

  yfrac=OC_SIGNMASK(-(dy&(yprec|1)));

  offs=(dx>>xprec)+(dy>>yprec)*ystride;

  if(xfrac||yfrac){

    int xmask;

    int ymask;

    xmask=OC_SIGNMASK(dx);

    ymask=OC_SIGNMASK(dy);

    yfrac&=ystride;

    _offsets[0]=offs-(xfrac&xmask)+(yfrac&ymask);

    _offsets[1]=offs-(xfrac&~xmask)+(yfrac&~ymask);

    return 2;

  }

  else{

    _offsets[0]=offs;

    return 1;

  }

#else

  /*Using tables simplifies the code, and there's enough arithmetic to hide the

     latencies of the memory references.*/

  static const signed char OC_MVMAP[2][64]={

    {

          -15,-15,-14,-14,-13,-13,-12,-12,-11,-11,-10,-10, -9, -9, -8,

       -8, -7, -7, -6, -6, -5, -5, -4, -4, -3, -3, -2, -2, -1, -1,  0,

        0,  0,  1,  1,  2,  2,  3,  3,  4,  4,  5,  5,  6,  6,  7,  7,

        8,  8,  9,  9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15

    },

    {

           -7, -7, -7, -7, -6, -6, -6, -6, -5, -5, -5, -5, -4, -4, -4,

       -4, -3, -3, -3, -3, -2, -2, -2, -2, -1, -1, -1, -1,  0,  0,  0,

        0,  0,  0,  0,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  3,

        4,  4,  4,  4,  5,  5,  5,  5,  6,  6,  6,  6,  7,  7,  7,  7

    }

  };

  static const signed char OC_MVMAP2[2][64]={

    {

        -1, 0,-1,  0,-1, 0,-1,  0,-1, 0,-1,  0,-1, 0,-1,

      0,-1, 0,-1,  0,-1, 0,-1,  0,-1, 0,-1,  0,-1, 0,-1,

      0, 1, 0, 1,  0, 1, 0, 1,  0, 1, 0, 1,  0, 1, 0, 1,

      0, 1, 0, 1,  0, 1, 0, 1,  0, 1, 0, 1,  0, 1, 0, 1

    },

    {

        -1,-1,-1,  0,-1,-1,-1,  0,-1,-1,-1,  0,-1,-1,-1,

      0,-1,-1,-1,  0,-1,-1,-1,  0,-1,-1,-1,  0,-1,-1,-1,

      0, 1, 1, 1,  0, 1, 1, 1,  0, 1, 1, 1,  0, 1, 1, 1,

      0, 1, 1, 1,  0, 1, 1, 1,  0, 1, 1, 1,  0, 1, 1, 1

    }

  };

  int ystride;

  int qpx;

  int qpy;

  int mx;

  int my;

  int mx2;

  int my2;

  int offs;

  int dx;

  int dy;

  ystride=_state->ref_ystride[_pli];

  qpy=_pli!=0&&!(_state->info.pixel_fmt&2);

  dx=OC_MV_X(_mv);

  dy=OC_MV_Y(_mv);

  my=OC_MVMAP[qpy][dy+31];

  my2=OC_MVMAP2[qpy][dy+31];

  qpx=_pli!=0&&!(_state->info.pixel_fmt&1);

  mx=OC_MVMAP[qpx][dx+31];

  mx2=OC_MVMAP2[qpx][dx+31];

  offs=my*ystride+mx;

  if(mx2||my2){

    _offsets[1]=offs+my2*ystride+mx2;

    _offsets[0]=offs;

    return 2;

  }

  _offsets[0]=offs;

  return 1;

#endif

}

void oc_state_frag_recon_c(const oc_theora_state *_state,ptrdiff_t _fragi,

 int _pli,ogg_int16_t _dct_coeffs[128],int _last_zzi,ogg_uint16_t _dc_quant){

  unsigned char *dst;

  ptrdiff_t      frag_buf_off;

  int            ystride;

  int            refi;

  /*Apply the inverse transform.*/

  /*Special case only having a DC component.*/

  if(_last_zzi<2){

    ogg_int16_t p;

    int         ci;

    /*We round this dequant product (and not any of the others) because there's

       no iDCT rounding.*/

    p=(ogg_int16_t)(_dct_coeffs[0]*(ogg_int32_t)_dc_quant+15>>5);

    /*LOOP VECTORIZES.*/

    for(ci=0;ci<64;ci++)_dct_coeffs[64+ci]=p;

  }

  else{

    /*First, dequantize the DC coefficient.*/

    _dct_coeffs[0]=(ogg_int16_t)(_dct_coeffs[0]*(int)_dc_quant);

    oc_idct8x8(_state,_dct_coeffs+64,_dct_coeffs,_last_zzi);

  }

  /*Fill in the target buffer.*/

  frag_buf_off=_state->frag_buf_offs[_fragi];

  refi=_state->frags[_fragi].refi;

  ystride=_state->ref_ystride[_pli];

  dst=_state->ref_frame_data[OC_FRAME_SELF]+frag_buf_off;

  if(refi==OC_FRAME_SELF)oc_frag_recon_intra(_state,dst,ystride,_dct_coeffs+64);

  else{

    const unsigned char *ref;

    int                  mvoffsets[2];

    ref=_state->ref_frame_data[refi]+frag_buf_off;

    if(oc_state_get_mv_offsets(_state,mvoffsets,_pli,

     _state->frag_mvs[_fragi])>1){

      oc_frag_recon_inter2(_state,

       dst,ref+mvoffsets[0],ref+mvoffsets[1],ystride,_dct_coeffs+64);

    }

    else{

      oc_frag_recon_inter(_state,dst,ref+mvoffsets[0],ystride,_dct_coeffs+64);

    }

  }

}

static void loop_filter_h(unsigned char *_pix,int _ystride,signed char *_bv){

  int y;

  _pix-=2;

  for(y=0;y<8;y++){

    int f;

    f=_pix[0]-_pix[3]+3*(_pix[2]-_pix[1]);

    /*The _bv array is used to compute the function

      f=OC_CLAMPI(OC_MINI(-_2flimit-f,0),f,OC_MAXI(_2flimit-f,0));

      where _2flimit=_state->loop_filter_limits[_state->qis[0]]<<1;*/

    f=*(_bv+(f+4>>3));

    _pix[1]=OC_CLAMP255(_pix[1]+f);

    _pix[2]=OC_CLAMP255(_pix[2]-f);

    _pix+=_ystride;

  }

}

static void loop_filter_v(unsigned char *_pix,int _ystride,signed char *_bv){

  int x;

  _pix-=_ystride*2;

  for(x=0;x<8;x++){