/*
  * JPEG-LS common code
  * Copyright (c) 2003 Michael Niedermayer
  * Copyright (c) 2006 Konstantin Shishkov
  *
  * 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
  */
 
 /**

  * @file

  * JPEG-LS common code.
  */
 

 #include "internal.h"

 #include "jpegls.h"
 

 void ff_jpegls_init_state(JLSState *state)
 {

     int i;
 
     state->twonear = state->near * 2 + 1;

     state->range   = (state->maxval + state->twonear - 1) / state->twonear + 1;

 
     // QBPP = ceil(log2(RANGE))

     for (state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++)
         ;

     state->bpp   = FFMAX(av_log2(state->maxval) + 1, 2);

     state->limit = 2*(state->bpp + FFMAX(state->bpp, 8)) - state->qbpp;

     for (i = 0; i < 367; i++) {

         state->A[i] = FFMAX(state->range + 32 >> 6, 2);

         state->N[i] = 1;
     }
 }
 
 /**
  * Custom value clipping function used in T1, T2, T3 calculation
  */

 static inline int iso_clip(int v, int vmin, int vmax)
 {
     if (v > vmax || v < vmin)
         return vmin;
     else
         return v;

 }
 

 void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all)
 {
     const int basic_t1 = 3;
     const int basic_t2 = 7;
     const int basic_t3 = 21;

     int factor;
 

     if (s->maxval == 0 || reset_all)
         s->maxval = (1 << s->bpp) - 1;

     if (s->maxval >= 128) {

         factor = FFMIN(s->maxval, 4095) + 128 >> 8;

         if (s->T1 == 0 || reset_all)
             s->T1 = iso_clip(factor * (basic_t1 - 2) + 2 + 3 * s->near,
                              s->near + 1, s->maxval);
         if (s->T2 == 0 || reset_all)
             s->T2 = iso_clip(factor * (basic_t2 - 3) + 3 + 5 * s->near,
                              s->T1, s->maxval);
         if (s->T3 == 0 || reset_all)
             s->T3 = iso_clip(factor * (basic_t3 - 4) + 4 + 7 * s->near,
                              s->T2, s->maxval);
     } else {
         factor = 256 / (s->maxval + 1);

         if (s->T1 == 0 || reset_all)
             s->T1 = iso_clip(FFMAX(2, basic_t1 / factor + 3 * s->near),
                              s->near + 1, s->maxval);
         if (s->T2 == 0 || reset_all)
             s->T2 = iso_clip(FFMAX(3, basic_t2 / factor + 5 * s->near),
                              s->T1, s->maxval);
         if (s->T3 == 0 || reset_all)
             s->T3 = iso_clip(FFMAX(4, basic_t3 / factor + 7 * s->near),
                              s->T2, s->maxval);

     }
 

     if (s->reset == 0 || reset_all)
         s->reset = 64;

     ff_dlog(NULL, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3);

 }