/*

 * 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 <stddef.h>

#include "libavutil/internal.h"

#include "libavutil/intmath.h"

#include "libavutil/log.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);

}