/*
  * JPEG2000 image decoder
  * Copyright (c) 2007 Kamil Nowosad
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * JPEG2000 image decoder
  * @file
  * @author Kamil Nowosad
  */
 
 #include "avcodec.h"
 #include "bytestream.h"
 #include "j2k.h"
 #include "libavutil/common.h"
 
 #define JP2_SIG_TYPE    0x6A502020
 #define JP2_SIG_VALUE   0x0D0A870A
 #define JP2_CODESTREAM  0x6A703263
 
 #define HAD_COC 0x01
 #define HAD_QCC 0x02
 
 typedef struct {
    J2kComponent *comp;
    uint8_t properties[4];
    J2kCodingStyle codsty[4];
    J2kQuantStyle  qntsty[4];
 } J2kTile;
 
 typedef struct {
     AVCodecContext *avctx;
     AVFrame picture;
 
     int width, height; ///< image width and height
     int image_offset_x, image_offset_y;
     int tile_offset_x, tile_offset_y;
     uint8_t cbps[4]; ///< bits per sample in particular components
     uint8_t sgnd[4]; ///< if a component is signed
     uint8_t properties[4];
     int cdx[4], cdy[4];
     int precision;
     int ncomponents;
     int tile_width, tile_height; ///< tile size
     int numXtiles, numYtiles;
     int maxtilelen;
 
     J2kCodingStyle codsty[4];
     J2kQuantStyle  qntsty[4];
 

     const uint8_t *buf_start;
     const uint8_t *buf;
     const uint8_t *buf_end;

     int bit_index;
 
     int16_t curtileno;
 
     J2kTile *tile;
 } J2kDecoderContext;
 
 static int get_bits(J2kDecoderContext *s, int n)
 {
     int res = 0;
     if (s->buf_end - s->buf < ((n - s->bit_index) >> 8))
         return AVERROR(EINVAL);
     while (--n >= 0){
         res <<= 1;
         if (s->bit_index == 0){
             s->bit_index = 7 + (*s->buf != 0xff);
             s->buf++;
         }
         s->bit_index--;
         res |= (*s->buf >> s->bit_index) & 1;
     }
     return res;
 }
 
 static void j2k_flush(J2kDecoderContext *s)
 {
     if (*s->buf == 0xff)
         s->buf++;
     s->bit_index = 8;
     s->buf++;
 }
 #if 0
 void printcomp(J2kComponent *comp)
 {
     int i;
     for (i = 0; i < comp->y1 - comp->y0; i++)
         ff_j2k_printv(comp->data + i * (comp->x1 - comp->x0), comp->x1 - comp->x0);
 }
 
 static void nspaces(FILE *fd, int n)
 {
     while(n--) putc(' ', fd);
 }
 
 static void dump(J2kDecoderContext *s, FILE *fd)
 {
     int tileno, compno, reslevelno, bandno, precno;
     fprintf(fd, "XSiz = %d, YSiz = %d, tile_width = %d, tile_height = %d\n"
                 "numXtiles = %d, numYtiles = %d, ncomponents = %d\n"
                 "tiles:\n",
             s->width, s->height, s->tile_width, s->tile_height,
             s->numXtiles, s->numYtiles, s->ncomponents);
     for (tileno = 0; tileno < s->numXtiles * s->numYtiles; tileno++){
         J2kTile *tile = s->tile + tileno;
         nspaces(fd, 2);
         fprintf(fd, "tile %d:\n", tileno);
         for(compno = 0; compno < s->ncomponents; compno++){
             J2kComponent *comp = tile->comp + compno;
             nspaces(fd, 4);
             fprintf(fd, "component %d:\n", compno);
             nspaces(fd, 4);
             fprintf(fd, "x0 = %d, x1 = %d, y0 = %d, y1 = %d\n",
                         comp->x0, comp->x1, comp->y0, comp->y1);
             for(reslevelno = 0; reslevelno < codsty->nreslevels; reslevelno++){
                 J2kResLevel *reslevel = comp->reslevel + reslevelno;
                 nspaces(fd, 6);
                 fprintf(fd, "reslevel %d:\n", reslevelno);
                 nspaces(fd, 6);
                 fprintf(fd, "x0 = %d, x1 = %d, y0 = %d, y1 = %d, nbands = %d\n",
                         reslevel->x0, reslevel->x1, reslevel->y0,
                         reslevel->y1, reslevel->nbands);
                 for(bandno = 0; bandno < reslevel->nbands; bandno++){
                     J2kBand *band = reslevel->band + bandno;
                     nspaces(fd, 8);
                     fprintf(fd, "band %d:\n", bandno);
                     nspaces(fd, 8);
                     fprintf(fd, "x0 = %d, x1 = %d, y0 = %d, y1 = %d,"
                                 "codeblock_width = %d, codeblock_height = %d cblknx = %d cblkny = %d\n",
                                 band->x0, band->x1,
                                 band->y0, band->y1,
                                 band->codeblock_width, band->codeblock_height,
                                 band->cblknx, band->cblkny);
                     for (precno = 0; precno < reslevel->num_precincts_x * reslevel->num_precincts_y; precno++){
                         J2kPrec *prec = band->prec + precno;
                         nspaces(fd, 10);
                         fprintf(fd, "prec %d:\n", precno);
                         nspaces(fd, 10);
                         fprintf(fd, "xi0 = %d, xi1 = %d, yi0 = %d, yi1 = %d\n",
                                      prec->xi0, prec->xi1, prec->yi0, prec->yi1);
                     }
                 }
             }
         }
     }
 }
 #endif
 
 /** decode the value stored in node */
 static int tag_tree_decode(J2kDecoderContext *s, J2kTgtNode *node, int threshold)
 {
     J2kTgtNode *stack[30];
     int sp = -1, curval = 0;
 
     while(node && !node->vis){
         stack[++sp] = node;
         node = node->parent;
     }
 
     if (node)
         curval = node->val;
     else
         curval = stack[sp]->val;
 
     while(curval < threshold && sp >= 0){
         if (curval < stack[sp]->val)
             curval = stack[sp]->val;
         while (curval < threshold){
             int ret;
             if ((ret = get_bits(s, 1)) > 0){
                 stack[sp]->vis++;
                 break;
             } else if (!ret)
                 curval++;
             else
                 return ret;
         }
         stack[sp]->val = curval;
         sp--;
     }
     return curval;
 }
 
 /* marker segments */
 /** get sizes and offsets of image, tiles; number of components */
 static int get_siz(J2kDecoderContext *s)
 {
     int i, ret;
 
     if (s->buf_end - s->buf < 36)
         return AVERROR(EINVAL);
 
                         bytestream_get_be16(&s->buf); // Rsiz (skipped)
              s->width = bytestream_get_be32(&s->buf); // width
             s->height = bytestream_get_be32(&s->buf); // height
     s->image_offset_x = bytestream_get_be32(&s->buf); // X0Siz
     s->image_offset_y = bytestream_get_be32(&s->buf); // Y0Siz
 
         s->tile_width = bytestream_get_be32(&s->buf); // XTSiz
        s->tile_height = bytestream_get_be32(&s->buf); // YTSiz
      s->tile_offset_x = bytestream_get_be32(&s->buf); // XT0Siz
      s->tile_offset_y = bytestream_get_be32(&s->buf); // YT0Siz
        s->ncomponents = bytestream_get_be16(&s->buf); // CSiz
 

     if(s->tile_width<=0 || s->tile_height<=0)
         return AVERROR(EINVAL);
 

     if (s->buf_end - s->buf < 2 * s->ncomponents)
         return AVERROR(EINVAL);
 
     for (i = 0; i < s->ncomponents; i++){ // Ssiz_i XRsiz_i, YRsiz_i
         uint8_t x = bytestream_get_byte(&s->buf);
         s->cbps[i] = (x & 0x7f) + 1;
         s->precision = FFMAX(s->cbps[i], s->precision);

         s->sgnd[i] = !!(x & 0x80);

         s->cdx[i] = bytestream_get_byte(&s->buf);
         s->cdy[i] = bytestream_get_byte(&s->buf);
     }
 
     s->numXtiles = ff_j2k_ceildiv(s->width - s->tile_offset_x, s->tile_width);
     s->numYtiles = ff_j2k_ceildiv(s->height - s->tile_offset_y, s->tile_height);
 

     if(s->numXtiles * (uint64_t)s->numYtiles > INT_MAX/sizeof(J2kTile))
         return AVERROR(EINVAL);
 

     s->tile = av_mallocz(s->numXtiles * s->numYtiles * sizeof(J2kTile));
     if (!s->tile)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < s->numXtiles * s->numYtiles; i++){
         J2kTile *tile = s->tile + i;
 
         tile->comp = av_mallocz(s->ncomponents * sizeof(J2kComponent));
         if (!tile->comp)
             return AVERROR(ENOMEM);
     }
 
     s->avctx->width = s->width - s->image_offset_x;
     s->avctx->height = s->height - s->image_offset_y;
 
     switch(s->ncomponents){
         case 1: if (s->precision > 8) {
                     s->avctx->pix_fmt    = PIX_FMT_GRAY16;
                 } else s->avctx->pix_fmt = PIX_FMT_GRAY8;
                 break;
         case 3: if (s->precision > 8) {
                     s->avctx->pix_fmt    = PIX_FMT_RGB48;
                 } else s->avctx->pix_fmt = PIX_FMT_RGB24;
                 break;
         case 4: s->avctx->pix_fmt = PIX_FMT_BGRA; break;
     }
 
     if (s->picture.data[0])
         s->avctx->release_buffer(s->avctx, &s->picture);
 
     if ((ret = s->avctx->get_buffer(s->avctx, &s->picture)) < 0)
         return ret;
 
     s->picture.pict_type = FF_I_TYPE;
     s->picture.key_frame = 1;
 
     return 0;
 }
 
 /** get common part for COD and COC segments */
 static int get_cox(J2kDecoderContext *s, J2kCodingStyle *c)
 {
     if (s->buf_end - s->buf < 5)
         return AVERROR(EINVAL);
           c->nreslevels = bytestream_get_byte(&s->buf) + 1; // num of resolution levels - 1
      c->log2_cblk_width = bytestream_get_byte(&s->buf) + 2; // cblk width
     c->log2_cblk_height = bytestream_get_byte(&s->buf) + 2; // cblk height
 
     c->cblk_style = bytestream_get_byte(&s->buf);
     if (c->cblk_style != 0){ // cblk style

         av_log(s->avctx, AV_LOG_WARNING, "extra cblk styles %X\n", c->cblk_style);

     }
     c->transform = bytestream_get_byte(&s->buf); // transformation
     if (c->csty & J2K_CSTY_PREC) {
         int i;
         for (i = 0; i < c->nreslevels; i++)
             bytestream_get_byte(&s->buf);
     }
     return 0;
 }
 
 /** get coding parameters for a particular tile or whole image*/
 static int get_cod(J2kDecoderContext *s, J2kCodingStyle *c, uint8_t *properties)
 {
     J2kCodingStyle tmp;
     int compno;
 
     if (s->buf_end - s->buf < 5)
         return AVERROR(EINVAL);
 
     tmp.log2_prec_width  =
     tmp.log2_prec_height = 15;
 
     tmp.csty = bytestream_get_byte(&s->buf);
 
     if (bytestream_get_byte(&s->buf)){ // progression level
         av_log(s->avctx, AV_LOG_ERROR, "only LRCP progression supported\n");
         return -1;
     }
 
     tmp.nlayers = bytestream_get_be16(&s->buf);
         tmp.mct = bytestream_get_byte(&s->buf); // multiple component transformation
 
     get_cox(s, &tmp);
     for (compno = 0; compno < s->ncomponents; compno++){
         if (!(properties[compno] & HAD_COC))
             memcpy(c + compno, &tmp, sizeof(J2kCodingStyle));
     }
     return 0;
 }
 
 /** get coding parameters for a component in the whole image on a particular tile */
 static int get_coc(J2kDecoderContext *s, J2kCodingStyle *c, uint8_t *properties)
 {
     int compno;
 
     if (s->buf_end - s->buf < 2)
         return AVERROR(EINVAL);
 
     compno = bytestream_get_byte(&s->buf);
 
     c += compno;
     c->csty = bytestream_get_byte(&s->buf);
     get_cox(s, c);
 
     properties[compno] |= HAD_COC;
     return 0;
 }
 
 /** get common part for QCD and QCC segments */
 static int get_qcx(J2kDecoderContext *s, int n, J2kQuantStyle *q)
 {
     int i, x;
 
     if (s->buf_end - s->buf < 1)
         return AVERROR(EINVAL);
 
     x = bytestream_get_byte(&s->buf); // Sqcd
 
     q->nguardbits = x >> 5;
       q->quantsty = x & 0x1f;
 
     if (q->quantsty == J2K_QSTY_NONE){
         n -= 3;

         if (s->buf_end - s->buf < n || 32*3 < n)

             return AVERROR(EINVAL);
         for (i = 0; i < n; i++)
             q->expn[i] = bytestream_get_byte(&s->buf) >> 3;
     } else if (q->quantsty == J2K_QSTY_SI){
         if (s->buf_end - s->buf < 2)
             return AVERROR(EINVAL);
         x = bytestream_get_be16(&s->buf);
         q->expn[0] = x >> 11;
         q->mant[0] = x & 0x7ff;
         for (i = 1; i < 32 * 3; i++){
             int curexpn = FFMAX(0, q->expn[0] - (i-1)/3);
             q->expn[i] = curexpn;
             q->mant[i] = q->mant[0];
         }
     } else{
         n = (n - 3) >> 1;

         if (s->buf_end - s->buf < n || 32*3 < n)

             return AVERROR(EINVAL);
         for (i = 0; i < n; i++){
             x = bytestream_get_be16(&s->buf);
             q->expn[i] = x >> 11;
             q->mant[i] = x & 0x7ff;
         }
     }
     return 0;
 }
 
 /** get quantization parameters for a particular tile or a whole image */
 static int get_qcd(J2kDecoderContext *s, int n, J2kQuantStyle *q, uint8_t *properties)
 {
     J2kQuantStyle tmp;
     int compno;
 
     if (get_qcx(s, n, &tmp))
         return -1;
     for (compno = 0; compno < s->ncomponents; compno++)
         if (!(properties[compno] & HAD_QCC))
             memcpy(q + compno, &tmp, sizeof(J2kQuantStyle));
     return 0;
 }
 
 /** get quantization parameters for a component in the whole image on in a particular tile */
 static int get_qcc(J2kDecoderContext *s, int n, J2kQuantStyle *q, uint8_t *properties)
 {
     int compno;
 
     if (s->buf_end - s->buf < 1)
         return AVERROR(EINVAL);
 
     compno = bytestream_get_byte(&s->buf);
     properties[compno] |= HAD_QCC;
     return get_qcx(s, n-1, q+compno);
 }
 
 /** get start of tile segment */
 static uint8_t get_sot(J2kDecoderContext *s)
 {
     if (s->buf_end - s->buf < 4)
         return AVERROR(EINVAL);
 
     s->curtileno = bytestream_get_be16(&s->buf); ///< Isot

     if((unsigned)s->curtileno >= s->numXtiles * s->numYtiles){
         s->curtileno=0;
         return AVERROR(EINVAL);
     }

 
     s->buf += 4; ///< Psot (ignored)
 
     if (!bytestream_get_byte(&s->buf)){ ///< TPsot
         J2kTile *tile = s->tile + s->curtileno;
 
         /* copy defaults */
         memcpy(tile->codsty, s->codsty, s->ncomponents * sizeof(J2kCodingStyle));
         memcpy(tile->qntsty, s->qntsty, s->ncomponents * sizeof(J2kQuantStyle));
     }
     bytestream_get_byte(&s->buf); ///< TNsot
 
     return 0;
 }
 
 static int init_tile(J2kDecoderContext *s, int tileno)
 {
     int compno,
         tilex = tileno % s->numXtiles,
         tiley = tileno / s->numXtiles;
     J2kTile *tile = s->tile + tileno;
 
     if (!tile->comp)
         return AVERROR(ENOMEM);
     for (compno = 0; compno < s->ncomponents; compno++){
         J2kComponent *comp = tile->comp + compno;
         J2kCodingStyle *codsty = tile->codsty + compno;
         J2kQuantStyle  *qntsty = tile->qntsty + compno;
         int ret; // global bandno
 
         comp->coord[0][0] = FFMAX(tilex * s->tile_width + s->tile_offset_x, s->image_offset_x);
         comp->coord[0][1] = FFMIN((tilex+1)*s->tile_width + s->tile_offset_x, s->width);
         comp->coord[1][0] = FFMAX(tiley * s->tile_height + s->tile_offset_y, s->image_offset_y);
         comp->coord[1][1] = FFMIN((tiley+1)*s->tile_height + s->tile_offset_y, s->height);
 
         if (ret = ff_j2k_init_component(comp, codsty, qntsty, s->cbps[compno], s->cdx[compno], s->cdy[compno]))
             return ret;
     }
     return 0;
 }
 
 /** read the number of coding passes */
 static int getnpasses(J2kDecoderContext *s)
 {
     int num;
     if (!get_bits(s, 1))
         return 1;
     if (!get_bits(s, 1))
         return 2;
     if ((num = get_bits(s, 2)) != 3)
         return num < 0 ? num : 3 + num;
     if ((num = get_bits(s, 5)) != 31)
         return num < 0 ? num : 6 + num;
     num = get_bits(s, 7);
     return num < 0 ? num : 37 + num;
 }
 
 static int getlblockinc(J2kDecoderContext *s)
 {
     int res = 0, ret;
     while (ret = get_bits(s, 1)){
         if (ret < 0)
             return ret;
         res++;
     }
     return res;
 }
 
 static int decode_packet(J2kDecoderContext *s, J2kCodingStyle *codsty, J2kResLevel *rlevel, int precno,
                          int layno, uint8_t *expn, int numgbits)
 {
     int bandno, cblkny, cblknx, cblkno, ret;
 
     if (!(ret = get_bits(s, 1))){
         j2k_flush(s);
         return 0;
     } else if (ret < 0)
         return ret;
 
     for (bandno = 0; bandno < rlevel->nbands; bandno++){
         J2kBand *band = rlevel->band + bandno;
         J2kPrec *prec = band->prec + precno;
         int pos = 0;
 
         if (band->coord[0][0] == band->coord[0][1]
         ||  band->coord[1][0] == band->coord[1][1])
             continue;
 
         for (cblkny = prec->yi0; cblkny < prec->yi1; cblkny++)
             for(cblknx = prec->xi0, cblkno = cblkny * band->cblknx + cblknx; cblknx < prec->xi1; cblknx++, cblkno++, pos++){
                 J2kCblk *cblk = band->cblk + cblkno;
                 int incl, newpasses, llen;
 
                 if (cblk->npasses)
                     incl = get_bits(s, 1);
                 else
                     incl = tag_tree_decode(s, prec->cblkincl + pos, layno+1) == layno;
                 if (!incl)
                     continue;
                 else if (incl < 0)
                     return incl;
 
                 if (!cblk->npasses)
                     cblk->nonzerobits = expn[bandno] + numgbits - 1 - tag_tree_decode(s, prec->zerobits + pos, 100);
                 if ((newpasses = getnpasses(s)) < 0)
                     return newpasses;
                 if ((llen = getlblockinc(s)) < 0)
                     return llen;
                 cblk->lblock += llen;
                 if ((ret = get_bits(s, av_log2(newpasses) + cblk->lblock)) < 0)
                     return ret;
                 cblk->lengthinc = ret;
                 cblk->npasses += newpasses;
             }
     }
     j2k_flush(s);
 
     if (codsty->csty & J2K_CSTY_EPH) {
         if (AV_RB16(s->buf) == J2K_EPH) {
             s->buf += 2;
         } else {
             av_log(s->avctx, AV_LOG_ERROR, "EPH marker not found.\n");
         }
     }
 
     for (bandno = 0; bandno < rlevel->nbands; bandno++){
         J2kBand *band = rlevel->band + bandno;
         int yi, cblknw = band->prec[precno].xi1 - band->prec[precno].xi0;
         for (yi = band->prec[precno].yi0; yi < band->prec[precno].yi1; yi++){
             int xi;
             for (xi = band->prec[precno].xi0; xi < band->prec[precno].xi1; xi++){
                 J2kCblk *cblk = band->cblk + yi * cblknw + xi;
                 if (s->buf_end - s->buf < cblk->lengthinc)
                     return AVERROR(EINVAL);
                 bytestream_get_buffer(&s->buf, cblk->data, cblk->lengthinc);
                 cblk->length += cblk->lengthinc;
                 cblk->lengthinc = 0;
             }
         }
     }
     return 0;
 }
 
 static int decode_packets(J2kDecoderContext *s, J2kTile *tile)
 {
     int layno, reslevelno, compno, precno, ok_reslevel;
     s->bit_index = 8;
     for (layno = 0; layno < tile->codsty[0].nlayers; layno++){
         ok_reslevel = 1;
         for (reslevelno = 0; ok_reslevel; reslevelno++){
             ok_reslevel = 0;
             for (compno = 0; compno < s->ncomponents; compno++){
                 J2kCodingStyle *codsty = tile->codsty + compno;
                 J2kQuantStyle  *qntsty = tile->qntsty + compno;
                 if (reslevelno < codsty->nreslevels){
                     J2kResLevel *rlevel = tile->comp[compno].reslevel + reslevelno;
                     ok_reslevel = 1;
                     for (precno = 0; precno < rlevel->num_precincts_x * rlevel->num_precincts_y; precno++){
                         if (decode_packet(s, codsty, rlevel, precno, layno, qntsty->expn +
                                           (reslevelno ? 3*(reslevelno-1)+1 : 0), qntsty->nguardbits))
                             return -1;
                     }
                 }
             }
         }
     }
     return 0;
 }
 
 /* TIER-1 routines */

 static void decode_sigpass(J2kT1Context *t1, int width, int height, int bpno, int bandno, int bpass_csty_symbol,
                            int vert_causal_ctx_csty_symbol)

 {
     int mask = 3 << (bpno - 1), y0, x, y;
 
     for (y0 = 0; y0 < height; y0 += 4)
         for (x = 0; x < width; x++)
             for (y = y0; y < height && y < y0+4; y++){
                 if ((t1->flags[y+1][x+1] & J2K_T1_SIG_NB)
                 && !(t1->flags[y+1][x+1] & (J2K_T1_SIG | J2K_T1_VIS))){

                     int vert_causal_ctx_csty_loc_symbol = vert_causal_ctx_csty_symbol && (x == 3 && y == 3);
                     if (ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + ff_j2k_getnbctxno(t1->flags[y+1][x+1], bandno,
                                       vert_causal_ctx_csty_loc_symbol))){

                         int xorbit, ctxno = ff_j2k_getsgnctxno(t1->flags[y+1][x+1], &xorbit);

                         if (bpass_csty_symbol)
                              t1->data[y][x] = ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + ctxno) ? -mask : mask;
                         else
                              t1->data[y][x] = (ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + ctxno) ^ xorbit) ?
                                                -mask : mask;

 
                         ff_j2k_set_significant(t1, x, y, t1->data[y][x] < 0);
                     }
                     t1->flags[y+1][x+1] |= J2K_T1_VIS;
                 }
             }
 }
 
 static void decode_refpass(J2kT1Context *t1, int width, int height, int bpno)
 {
     int phalf, nhalf;
     int y0, x, y;
 
     phalf = 1 << (bpno - 1);
     nhalf = -phalf;
 
     for (y0 = 0; y0 < height; y0 += 4)
         for (x = 0; x < width; x++)
             for (y = y0; y < height && y < y0+4; y++){
                 if ((t1->flags[y+1][x+1] & (J2K_T1_SIG | J2K_T1_VIS)) == J2K_T1_SIG){
                     int ctxno = ff_j2k_getrefctxno(t1->flags[y+1][x+1]);
                     int r = ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + ctxno) ? phalf : nhalf;
                     t1->data[y][x] += t1->data[y][x] < 0 ? -r : r;
                     t1->flags[y+1][x+1] |= J2K_T1_REF;
                 }
             }
 }
 
 static void decode_clnpass(J2kDecoderContext *s, J2kT1Context *t1, int width, int height,
                            int bpno, int bandno, int seg_symbols)
 {
     int mask = 3 << (bpno - 1), y0, x, y, runlen, dec;
 
     for (y0 = 0; y0 < height; y0 += 4) {
         for (x = 0; x < width; x++){
             if (y0 + 3 < height && !(
             (t1->flags[y0+1][x+1] & (J2K_T1_SIG_NB | J2K_T1_VIS | J2K_T1_SIG)) ||
             (t1->flags[y0+2][x+1] & (J2K_T1_SIG_NB | J2K_T1_VIS | J2K_T1_SIG)) ||
             (t1->flags[y0+3][x+1] & (J2K_T1_SIG_NB | J2K_T1_VIS | J2K_T1_SIG)) ||
             (t1->flags[y0+4][x+1] & (J2K_T1_SIG_NB | J2K_T1_VIS | J2K_T1_SIG)))){
                 if (!ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + MQC_CX_RL))
                     continue;
                 runlen = ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + MQC_CX_UNI);
                 runlen = (runlen << 1) | ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + MQC_CX_UNI);
                 dec = 1;
             } else{
                 runlen = 0;
                 dec = 0;
             }
 
             for (y = y0 + runlen; y < y0 + 4 && y < height; y++){
                 if (!dec){
                     if (!(t1->flags[y+1][x+1] & (J2K_T1_SIG | J2K_T1_VIS)))

                         dec = ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + ff_j2k_getnbctxno(t1->flags[y+1][x+1],
                                                                                              bandno, 0));

                 }
                 if (dec){
                     int xorbit, ctxno = ff_j2k_getsgnctxno(t1->flags[y+1][x+1], &xorbit);
                     t1->data[y][x] = (ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + ctxno) ^ xorbit) ? -mask : mask;
                     ff_j2k_set_significant(t1, x, y, t1->data[y][x] < 0);
                 }
                 dec = 0;
                 t1->flags[y+1][x+1] &= ~J2K_T1_VIS;
             }
         }
     }
     if (seg_symbols) {
         int val;
         val = ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + MQC_CX_UNI);
         val = (val << 1) + ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + MQC_CX_UNI);
         val = (val << 1) + ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + MQC_CX_UNI);
         val = (val << 1) + ff_mqc_decode(&t1->mqc, t1->mqc.cx_states + MQC_CX_UNI);
         if (val != 0xa) {
             av_log(s->avctx, AV_LOG_ERROR,"Segmentation symbol value incorrect\n");
         }
     }
 }
 
 static int decode_cblk(J2kDecoderContext *s, J2kCodingStyle *codsty, J2kT1Context *t1, J2kCblk *cblk,
                        int width, int height, int bandpos)
 {

     int passno = cblk->npasses, pass_t = 2, bpno = cblk->nonzerobits - 1, y, clnpass_cnt = 0;

     int bpass_csty_symbol = J2K_CBLK_BYPASS & codsty->cblk_style;
     int vert_causal_ctx_csty_symbol = J2K_CBLK_VSC & codsty->cblk_style;

 
     for (y = 0; y < height+2; y++)
         memset(t1->flags[y], 0, (width+2)*sizeof(int));
 
     for (y = 0; y < height; y++)
         memset(t1->data[y], 0, width*sizeof(int));
 
     cblk->data[cblk->length] = 0xff;
     cblk->data[cblk->length+1] = 0xff;

     ff_mqc_initdec(&t1->mqc, cblk->data);

 
     while(passno--){
         switch(pass_t){

             case 0: decode_sigpass(t1, width, height, bpno+1, bandpos,
                                   bpass_csty_symbol && (clnpass_cnt >= 4), vert_causal_ctx_csty_symbol);

                     break;
             case 1: decode_refpass(t1, width, height, bpno+1);

                     if (bpass_csty_symbol && clnpass_cnt >= 4)
                         ff_mqc_initdec(&t1->mqc, cblk->data);

                     break;
             case 2: decode_clnpass(s, t1, width, height, bpno+1, bandpos,
                                    codsty->cblk_style & J2K_CBLK_SEGSYM);

                     clnpass_cnt = clnpass_cnt + 1;
                     if (bpass_csty_symbol && clnpass_cnt >= 4)
                        ff_mqc_initdec(&t1->mqc, cblk->data);

                     break;
         }
 
         pass_t++;
         if (pass_t == 3){
             bpno--;
             pass_t = 0;
         }
     }
     return 0;
 }
 
 static void mct_decode(J2kDecoderContext *s, J2kTile *tile)
 {
     int i, *src[3], i0, i1, i2, csize = 1;
 
     for (i = 0; i < 3; i++)
         src[i] = tile->comp[i].data;
 
     for (i = 0; i < 2; i++)
         csize *= tile->comp[0].coord[i][1] - tile->comp[0].coord[i][0];
 
     if (tile->codsty[0].transform == FF_DWT97){
         for (i = 0; i < csize; i++){
             i0 = *src[0] + (*src[2] * 46802 >> 16);
             i1 = *src[0] - (*src[1] * 22553 + *src[2] * 46802 >> 16);
             i2 = *src[0] + (116130 * *src[1] >> 16);
             *src[0]++ = i0;
             *src[1]++ = i1;
             *src[2]++ = i2;
         }
     } else{
         for (i = 0; i < csize; i++){
             i1 = *src[0] - (*src[2] + *src[1] >> 2);
             i0 = i1 + *src[2];
             i2 = i1 + *src[1];
             *src[0]++ = i0;
             *src[1]++ = i1;
             *src[2]++ = i2;
         }
     }
 }
 
 static int decode_tile(J2kDecoderContext *s, J2kTile *tile)
 {
     int compno, reslevelno, bandno;
     int x, y, *src[4];
     uint8_t *line;
     J2kT1Context t1;
 
     for (compno = 0; compno < s->ncomponents; compno++){
         J2kComponent *comp = tile->comp + compno;
         J2kCodingStyle *codsty = tile->codsty + compno;
 
         for (reslevelno = 0; reslevelno < codsty->nreslevels; reslevelno++){
             J2kResLevel *rlevel = comp->reslevel + reslevelno;
             for (bandno = 0; bandno < rlevel->nbands; bandno++){
                 J2kBand *band = rlevel->band + bandno;
                 int cblkx, cblky, cblkno=0, xx0, x0, xx1, y0, yy0, yy1, bandpos;
 
                 bandpos = bandno + (reslevelno > 0);
 
                 yy0 = bandno == 0 ? 0 : comp->reslevel[reslevelno-1].coord[1][1] - comp->reslevel[reslevelno-1].coord[1][0];
                 y0 = yy0;
                 yy1 = FFMIN(ff_j2k_ceildiv(band->coord[1][0] + 1, band->codeblock_height) * band->codeblock_height,
                             band->coord[1][1]) - band->coord[1][0] + yy0;
 
                 if (band->coord[0][0] == band->coord[0][1] || band->coord[1][0] == band->coord[1][1])
                     continue;
 
                 for (cblky = 0; cblky < band->cblkny; cblky++){
                     if (reslevelno == 0 || bandno == 1)
                         xx0 = 0;
                     else
                         xx0 = comp->reslevel[reslevelno-1].coord[0][1] - comp->reslevel[reslevelno-1].coord[0][0];
                     x0 = xx0;
                     xx1 = FFMIN(ff_j2k_ceildiv(band->coord[0][0] + 1, band->codeblock_width) * band->codeblock_width,
                                 band->coord[0][1]) - band->coord[0][0] + xx0;
 
                     for (cblkx = 0; cblkx < band->cblknx; cblkx++, cblkno++){
                         int y, x;
                         decode_cblk(s, codsty, &t1, band->cblk + cblkno, xx1 - xx0, yy1 - yy0, bandpos);
                         if (codsty->transform == FF_DWT53){
                             for (y = yy0; y < yy1; y+=s->cdy[compno]){
                                 int *ptr = t1.data[y-yy0];
                                 for (x = xx0; x < xx1; x+=s->cdx[compno]){
                                     comp->data[(comp->coord[0][1] - comp->coord[0][0]) * y + x] = *ptr++ >> 1;
                                 }
                             }
                         } else{
                             for (y = yy0; y < yy1; y+=s->cdy[compno]){
                                 int *ptr = t1.data[y-yy0];
                                 for (x = xx0; x < xx1; x+=s->cdx[compno]){
                                     int tmp = ((int64_t)*ptr++) * ((int64_t)band->stepsize) >> 13, tmp2;
                                     tmp2 = FFABS(tmp>>1) + FFABS(tmp&1);
                                     comp->data[(comp->coord[0][1] - comp->coord[0][0]) * y + x] = tmp < 0 ? -tmp2 : tmp2;
                                 }
                             }
                         }
                         xx0 = xx1;
                         xx1 = FFMIN(xx1 + band->codeblock_width, band->coord[0][1] - band->coord[0][0] + x0);
                     }
                     yy0 = yy1;
                     yy1 = FFMIN(yy1 + band->codeblock_height, band->coord[1][1] - band->coord[1][0] + y0);
                 }
             }
         }
         ff_j2k_dwt_decode(&comp->dwt, comp->data);
         src[compno] = comp->data;
     }
     if (tile->codsty[0].mct)
         mct_decode(s, tile);
 
     if (s->avctx->pix_fmt == PIX_FMT_BGRA) // RGBA -> BGRA
         FFSWAP(int *, src[0], src[2]);
 
     if (s->precision <= 8) {
         for (compno = 0; compno < s->ncomponents; compno++){
             y = tile->comp[compno].coord[1][0] - s->image_offset_y;
             line = s->picture.data[0] + y * s->picture.linesize[0];
             for (; y < tile->comp[compno].coord[1][1] - s->image_offset_y; y += s->cdy[compno]){
                 uint8_t *dst;
 
                 x = tile->comp[compno].coord[0][0] - s->image_offset_x;
                 dst = line + x * s->ncomponents + compno;
 
                 for (; x < tile->comp[compno].coord[0][1] - s->image_offset_x; x += s->cdx[compno]) {
                     *src[compno] += 1 << (s->cbps[compno]-1);
                     if (*src[compno] < 0)
                         *src[compno] = 0;
                     else if (*src[compno] >= (1 << s->cbps[compno]))
                         *src[compno] = (1 << s->cbps[compno]) - 1;
                     *dst = *src[compno]++;
                     dst += s->ncomponents;
                 }
                 line += s->picture.linesize[0];
             }
         }
     } else {
         for (compno = 0; compno < s->ncomponents; compno++) {
             y = tile->comp[compno].coord[1][0] - s->image_offset_y;
             line = s->picture.data[0] + y * s->picture.linesize[0];
             for (; y < tile->comp[compno].coord[1][1] - s->image_offset_y; y += s->cdy[compno]) {
                 uint16_t *dst;
                 x = tile->comp[compno].coord[0][0] - s->image_offset_x;
                 dst = line + (x * s->ncomponents + compno) * 2;
                 for (; x < tile->comp[compno].coord[0][1] - s->image_offset_x; x += s-> cdx[compno]) {
                     int32_t val;
                     val = *src[compno]++ << (16 - s->cbps[compno]);
                     val += 1 << 15;
                     val = av_clip(val, 0, (1 << 16) - 1);
                     *dst = val;
                     dst += s->ncomponents;
                 }
                 line += s->picture.linesize[0];
             }
         }
     }
     return 0;
 }
 
 static void cleanup(J2kDecoderContext *s)
 {
     int tileno, compno;
     for (tileno = 0; tileno < s->numXtiles * s->numYtiles; tileno++){
         for (compno = 0; compno < s->ncomponents; compno++){
             J2kComponent *comp = s->tile[tileno].comp + compno;
             J2kCodingStyle *codsty = s->tile[tileno].codsty + compno;
 
             ff_j2k_cleanup(comp, codsty);
         }
         av_freep(&s->tile[tileno].comp);
     }
     av_freep(&s->tile);
 }
 
 static int decode_codestream(J2kDecoderContext *s)
 {
     J2kCodingStyle *codsty = s->codsty;
     J2kQuantStyle  *qntsty = s->qntsty;
     uint8_t *properties = s->properties;
 
     for (;;){
         int marker, len, ret = 0;

         const uint8_t *oldbuf;

         if (s->buf_end - s->buf < 2){
             av_log(s->avctx, AV_LOG_ERROR, "Missing EOC\n");
             break;
         }
 
         marker = bytestream_get_be16(&s->buf);

         if(s->avctx->debug & FF_DEBUG_STARTCODE)

             av_log(s->avctx, AV_LOG_DEBUG, "marker 0x%.4X at pos 0x%tx\n", marker, s->buf - s->buf_start - 4);

         oldbuf = s->buf;
 
         if (marker == J2K_SOD){
             J2kTile *tile = s->tile + s->curtileno;
             if (ret = init_tile(s, s->curtileno))
                 return ret;
             if (ret = decode_packets(s, tile))
                 return ret;
             continue;
         }
         if (marker == J2K_EOC)
             break;
 
         if (s->buf_end - s->buf < 2)
             return AVERROR(EINVAL);
         len = bytestream_get_be16(&s->buf);
         switch(marker){
             case J2K_SIZ:
                 ret = get_siz(s); break;
             case J2K_COC:
                 ret = get_coc(s, codsty, properties); break;
             case J2K_COD:
                 ret = get_cod(s, codsty, properties); break;
             case J2K_QCC:
                 ret = get_qcc(s, len, qntsty, properties); break;
             case J2K_QCD:
                 ret = get_qcd(s, len, qntsty, properties); break;
             case J2K_SOT:
                 if (!(ret = get_sot(s))){
                     codsty = s->tile[s->curtileno].codsty;
                     qntsty = s->tile[s->curtileno].qntsty;
                     properties = s->tile[s->curtileno].properties;
                 }
                 break;
             case J2K_COM:
                 // the comment is ignored
                 s->buf += len - 2; break;
             default:

                 av_log(s->avctx, AV_LOG_ERROR, "unsupported marker 0x%.4X at pos 0x%tx\n", marker, s->buf - s->buf_start - 4);

                 s->buf += len - 2; break;
         }
         if (s->buf - oldbuf != len || ret){
             av_log(s->avctx, AV_LOG_ERROR, "error during processing marker segment %.4x\n", marker);
             return ret ? ret : -1;
         }
     }
     return 0;
 }
 
 static int jp2_find_codestream(J2kDecoderContext *s)
 {

     uint32_t atom_size;

     int found_codestream = 0, search_range = 10;
 
     // skip jpeg2k signature atom
     s->buf += 12;
 

     while(!found_codestream && search_range && s->buf_end - s->buf >= 8) {

         atom_size = AV_RB32(s->buf);
         if(AV_RB32(s->buf + 4) == JP2_CODESTREAM) {
             found_codestream = 1;
             s->buf += 8;
         } else {

             if (s->buf_end - s->buf < atom_size)
                 return 0;

             s->buf += atom_size;
             search_range--;
         }
     }
 
     if(found_codestream)
         return 1;
     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx,
                         void *data, int *data_size,
                         AVPacket *avpkt)
 {
     J2kDecoderContext *s = avctx->priv_data;
     AVFrame *picture = data;
     int tileno, ret;
 
     s->avctx = avctx;
     av_log(s->avctx, AV_LOG_DEBUG, "start\n");
 
     // init
     s->buf = s->buf_start = avpkt->data;
     s->buf_end = s->buf_start + avpkt->size;
     s->curtileno = -1;
 
     ff_j2k_init_tier1_luts();
 
     if (s->buf_end - s->buf < 2)
         return AVERROR(EINVAL);
 
     // check if the image is in jp2 format

     if(s->buf_end - s->buf >= 12 &&
        (AV_RB32(s->buf) == 12) && (AV_RB32(s->buf + 4) == JP2_SIG_TYPE) &&

        (AV_RB32(s->buf + 8) == JP2_SIG_VALUE)) {
         if(!jp2_find_codestream(s)) {
             av_log(avctx, AV_LOG_ERROR, "couldn't find jpeg2k codestream atom\n");
             return -1;
         }
     }
 
     if (bytestream_get_be16(&s->buf) != J2K_SOC){
         av_log(avctx, AV_LOG_ERROR, "SOC marker not present\n");
         return -1;
     }
     if (ret = decode_codestream(s))
         return ret;
 
     for (tileno = 0; tileno < s->numXtiles * s->numYtiles; tileno++)
         if (ret = decode_tile(s, s->tile + tileno))
             return ret;
 
     cleanup(s);
     av_log(s->avctx, AV_LOG_DEBUG, "end\n");
 
     *data_size = sizeof(AVPicture);
     *picture = s->picture;
 
     return s->buf - s->buf_start;
 }
 
 static av_cold int j2kdec_init(AVCodecContext *avctx)
 {
     J2kDecoderContext *s = avctx->priv_data;
 
     avcodec_get_frame_defaults((AVFrame*)&s->picture);
     avctx->coded_frame = (AVFrame*)&s->picture;
     return 0;
 }
 
 static av_cold int decode_end(AVCodecContext *avctx)
 {
     J2kDecoderContext *s = avctx->priv_data;
 
     if (s->picture.data[0])
         avctx->release_buffer(avctx, &s->picture);
 
     return 0;
 }
 
 AVCodec ff_jpeg2000_decoder = {
     "j2k",
     AVMEDIA_TYPE_VIDEO,
     CODEC_ID_JPEG2000,
     sizeof(J2kDecoderContext),
     j2kdec_init,
     NULL,
     decode_end,
     decode_frame,

     .capabilities = CODEC_CAP_EXPERIMENTAL,

     .long_name = NULL_IF_CONFIG_SMALL("JPEG 2000"),

     .pix_fmts =
         (enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_RGB24, -1}
 };