text: /*
   * 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.
   */
  
  #ifndef AVCODEC_JPEGLS_H
  #define AVCODEC_JPEGLS_H
  
  #include "libavutil/common.h"
  #include "avcodec.h"
  #include "internal.h"
  
  #undef near /* This file uses struct member 'near' which in windows.h is defined as empty. */
  
  typedef struct JpeglsContext {
      AVCodecContext *avctx;
  } JpeglsContext;
  
  typedef struct JLSState {
      int T1, T2, T3;
      int A[367], B[367], C[365], N[367];
      int limit, reset, bpp, qbpp, maxval, range;
      int near, twonear;
      int run_index[4];
  } JLSState;
  
  /**
   * Calculate initial JPEG-LS parameters
   */
  void ff_jpegls_init_state(JLSState *state);
  
  /**
   * Calculate quantized gradient value, used for context determination
   */
  static inline int ff_jpegls_quantize(JLSState *s, int v)
  {
      if (v == 0)
          return 0;
      if (v < 0) {
          if (v <= -s->T3)
              return -4;
          if (v <= -s->T2)
              return -3;
          if (v <= -s->T1)
              return -2;
          if (v < -s->near)
              return -1;
          return 0;
      } else {
          if (v <= s->near)
              return 0;
          if (v < s->T1)
              return 1;
          if (v < s->T2)
              return 2;
          if (v < s->T3)
              return 3;
          return 4;
      }
  }
  
  /**
   * Calculate JPEG-LS codec values
   */
  void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
  
  static inline void ff_jpegls_downscale_state(JLSState *state, int Q)
  {
      if (state->N[Q] == state->reset) {
          state->A[Q] >>= 1;
          state->B[Q] >>= 1;
          state->N[Q] >>= 1;
      }
      state->N[Q]++;
  }
  
  static inline int ff_jpegls_update_state_regular(JLSState *state,
                                                   int Q, int err)
  {
      if(FFABS(err) > 0xFFFF)
          return -0x10000;
      state->A[Q] += FFABS(err);
      err         *= state->twonear;
      state->B[Q] += err;
  
      ff_jpegls_downscale_state(state, Q);
  
      if (state->B[Q] <= -state->N[Q]) {
          state->B[Q] = FFMAX(state->B[Q] + state->N[Q], 1 - state->N[Q]);
          if (state->C[Q] > -128)
              state->C[Q]--;
      } else if (state->B[Q] > 0) {
          state->B[Q] = FFMIN(state->B[Q] - state->N[Q], 0);
          if (state->C[Q] < 127)
              state->C[Q]++;
      }
  
      return err;
  }
  
  #define R(a, i)    (bits == 8 ?  ((uint8_t *)(a))[i]      :  ((uint16_t *)(a))[i])
  #define W(a, i, v) (bits == 8 ? (((uint8_t *)(a))[i] = v) : (((uint16_t *)(a))[i] = v))
  
  #endif /* AVCODEC_JPEGLS_H */
  