/*
 * JPEG-LS decoder
 * Copyright (c) 2003 Michael Niedermayer
 * Copyright (c) 2006 Konstantin Shishkov
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * JPEG-LS decoder.
 */

#include "avcodec.h"
#include "get_bits.h"
#include "golomb.h"
#include "mathops.h"
#include "mjpeg.h"
#include "mjpegdec.h"
#include "jpegls.h"
#include "jpeglsdec.h"

/*
 * Uncomment this to significantly speed up decoding of broken JPEG-LS
 * (or test broken JPEG-LS decoder) and slow down ordinary decoding a bit.
 *
 * There is no Golomb code with length >= 32 bits possible, so check and
 * avoid situation of 32 zeros, Libav Golomb decoder is painfully slow
 * on this errors.
 */
//#define JLS_BROKEN

/**
 * Decode LSE block with initialization parameters
 */
int ff_jpegls_decode_lse(MJpegDecodeContext *s)
{
    int id;

    skip_bits(&s->gb, 16);  /* length: FIXME: verify field validity */
    id = get_bits(&s->gb, 8);

    switch (id) {
    case 1:
        s->maxval = get_bits(&s->gb, 16);
        s->t1     = get_bits(&s->gb, 16);
        s->t2     = get_bits(&s->gb, 16);
        s->t3     = get_bits(&s->gb, 16);
        s->reset  = get_bits(&s->gb, 16);

//        ff_jpegls_reset_coding_parameters(s, 0);
        //FIXME quant table?
        break;
    case 2:
    case 3:
        av_log(s->avctx, AV_LOG_ERROR, "palette not supported\n");
        return -1;
    case 4:
        av_log(s->avctx, AV_LOG_ERROR, "oversize image not supported\n");
        return -1;
    default:
        av_log(s->avctx, AV_LOG_ERROR, "invalid id %d\n", id);
        return -1;
    }
    av_dlog(s->avctx, "ID=%i, T=%i,%i,%i\n", id, s->t1, s->t2, s->t3);

    return 0;
}

/**
 * Get context-dependent Golomb code, decode it and update context
 */
static inline int ls_get_code_regular(GetBitContext *gb, JLSState *state, int Q)
{
    int k, ret;

    for (k = 0; (state->N[Q] << k) < state->A[Q]; k++)
        ;

#ifdef JLS_BROKEN
    if (!show_bits_long(gb, 32))
        return -1;
#endif
    ret = get_ur_golomb_jpegls(gb, k, state->limit, state->qbpp);

    /* decode mapped error */
    if (ret & 1)
        ret = -(ret + 1 >> 1);
    else
        ret >>= 1;

    /* for NEAR=0, k=0 and 2*B[Q] <= - N[Q] mapping is reversed */
    if (!state->near && !k && (2 * state->B[Q] <= -state->N[Q]))
        ret = -(ret + 1);

    ret = ff_jpegls_update_state_regular(state, Q, ret);

    return ret;
}

/**
 * Get Golomb code, decode it and update state for run termination
 */
static inline int ls_get_code_runterm(GetBitContext *gb, JLSState *state,
                                      int RItype, int limit_add)
{
    int k, ret, temp, map;
    int Q = 365 + RItype;

    temp = state->A[Q];
    if (RItype)
        temp += state->N[Q] >> 1;

    for (k = 0; (state->N[Q] << k) < temp; k++)
        ;

#ifdef JLS_BROKEN
    if (!show_bits_long(gb, 32))
        return -1;
#endif
    ret = get_ur_golomb_jpegls(gb, k, state->limit - limit_add - 1,
                               state->qbpp);

    /* decode mapped error */
    map = 0;
    if (!k && (RItype || ret) && (2 * state->B[Q] < state->N[Q]))
        map = 1;
    ret += RItype + map;

    if (ret & 1) {
        ret = map - (ret + 1 >> 1);
        state->B[Q]++;
    } else {
        ret = ret >> 1;
    }

    /* update state */
    state->A[Q] += FFABS(ret) - RItype;
    ret         *= state->twonear;
    ff_jpegls_downscale_state(state, Q);

    return ret;
}

/**
 * Decode one line of image
 */
static inline void ls_decode_line(JLSState *state, MJpegDecodeContext *s,
                                  void *last, void *dst, int last2, int w,
                                  int stride, int comp, int bits)
{
    int i, x = 0;
    int Ra, Rb, Rc, Rd;
    int D0, D1, D2;

    while (x < w) {
        int err, pred;

        /* compute gradients */
        Ra = x ? R(dst, x - stride) : R(last, x);
        Rb = R(last, x);
        Rc = x ? R(last, x - stride) : last2;
        Rd = (x >= w - stride) ? R(last, x) : R(last, x + stride);
        D0 = Rd - Rb;
        D1 = Rb - Rc;
        D2 = Rc - Ra;
        /* run mode */
        if ((FFABS(D0) <= state->near) &&
            (FFABS(D1) <= state->near) &&
            (FFABS(D2) <= state->near)) {
            int r;
            int RItype;

            /* decode full runs while available */
            while (get_bits1(&s->gb)) {
                int r;
                r = 1 << ff_log2_run[state->run_index[comp]];
                if (x + r * stride > w)
                    r = (w - x) / stride;
                for (i = 0; i < r; i++) {
                    W(dst, x, Ra);
                    x += stride;
                }
                /* if EOL reached, we stop decoding */
                if (r != 1 << ff_log2_run[state->run_index[comp]])
                    return;
                if (state->run_index[comp] < 31)
                    state->run_index[comp]++;
                if (x + stride > w)
                    return;
            }
            /* decode aborted run */
            r = ff_log2_run[state->run_index[comp]];
            if (r)
                r = get_bits_long(&s->gb, r);
            for (i = 0; i < r; i++) {
                W(dst, x, Ra);
                x += stride;
            }

            /* decode run termination value */
            Rb     = R(last, x);
            RItype = (FFABS(Ra - Rb) <= state->near) ? 1 : 0;
            err    = ls_get_code_runterm(&s->gb, state, RItype,
                                         ff_log2_run[state->run_index[comp]]);
            if (state->run_index[comp])
                state->run_index[comp]--;

            if (state->near && RItype) {
                pred = Ra + err;
            } else {
                if (Rb < Ra)
                    pred = Rb - err;
                else
                    pred = Rb + err;
            }
        } else { /* regular mode */
            int context, sign;

            context = ff_jpegls_quantize(state, D0) * 81 +
                      ff_jpegls_quantize(state, D1) *  9 +
                      ff_jpegls_quantize(state, D2);
            pred    = mid_pred(Ra, Ra + Rb - Rc, Rb);

            if (context < 0) {
                context = -context;
                sign    = 1;
            } else {
                sign = 0;
            }

            if (sign) {
                pred = av_clip(pred - state->C[context], 0, state->maxval);
                err  = -ls_get_code_regular(&s->gb, state, context);
            } else {
                pred = av_clip(pred + state->C[context], 0, state->maxval);
                err  = ls_get_code_regular(&s->gb, state, context);
            }

            /* we have to do something more for near-lossless coding */
            pred += err;
        }
        if (state->near) {
            if (pred < -state->near)
                pred += state->range * state->twonear;
            else if (pred > state->maxval + state->near)
                pred -= state->range * state->twonear;
            pred = av_clip(pred, 0, state->maxval);
        }

        pred &= state->maxval;
        W(dst, x, pred);
        x += stride;
    }
}

int ff_jpegls_decode_picture(MJpegDecodeContext *s, int near,
                             int point_transform, int ilv)
{
    int i, t = 0;
    uint8_t *zero, *last, *cur;
    JLSState *state;
    int off = 0, stride = 1, width, shift;

    zero = av_mallocz(s->picture_ptr->linesize[0]);
    last = zero;
    cur  = s->picture_ptr->data[0];

    state = av_mallocz(sizeof(JLSState));
    /* initialize JPEG-LS state from JPEG parameters */
    state->near   = near;
    state->bpp    = (s->bits < 2) ? 2 : s->bits;
    state->maxval = s->maxval;
    state->T1     = s->t1;
    state->T2     = s->t2;
    state->T3     = s->t3;
    state->reset  = s->reset;
    ff_jpegls_reset_coding_parameters(state, 0);
    ff_jpegls_init_state(state);

    if (s->bits <= 8)
        shift = point_transform + (8 - s->bits);
    else
        shift = point_transform + (16 - s->bits);

    av_dlog(s->avctx,
            "JPEG-LS params: %ix%i NEAR=%i MV=%i T(%i,%i,%i) "
            "RESET=%i, LIMIT=%i, qbpp=%i, RANGE=%i\n",
            s->width, s->height, state->near, state->maxval,
            state->T1, state->T2, state->T3,
            state->reset, state->limit, state->qbpp, state->range);
    av_dlog(s->avctx, "JPEG params: ILV=%i Pt=%i BPP=%i, scan = %i\n",
            ilv, point_transform, s->bits, s->cur_scan);
    if (ilv == 0) { /* separate planes */
        off    = s->cur_scan - 1;
        stride = (s->nb_components > 1) ? 3 : 1;
        width  = s->width * stride;
        cur   += off;
        for (i = 0; i < s->height; i++) {
            if (s->bits <= 8) {
                ls_decode_line(state, s, last, cur, t, width, stride, off, 8);
                t = last[0];
            } else {
                ls_decode_line(state, s, last, cur, t, width, stride, off, 16);
                t = *((uint16_t *)last);
            }
            last = cur;
            cur += s->picture_ptr->linesize[0];

            if (s->restart_interval && !--s->restart_count) {
                align_get_bits(&s->gb);
                skip_bits(&s->gb, 16); /* skip RSTn */
            }
        }
    } else if (ilv == 1) { /* line interleaving */
        int j;
        int Rc[3] = { 0, 0, 0 };
        memset(cur, 0, s->picture_ptr->linesize[0]);
        width = s->width * 3;
        for (i = 0; i < s->height; i++) {
            for (j = 0; j < 3; j++) {
                ls_decode_line(state, s, last + j, cur + j,
                               Rc[j], width, 3, j, 8);
                Rc[j] = last[j];

                if (s->restart_interval && !--s->restart_count) {
                    align_get_bits(&s->gb);
                    skip_bits(&s->gb, 16); /* skip RSTn */
                }
            }
            last = cur;
            cur += s->picture_ptr->linesize[0];
        }
    } else if (ilv == 2) { /* sample interleaving */
        av_log(s->avctx, AV_LOG_ERROR,
               "Sample interleaved images are not supported.\n");
        av_free(state);
        av_free(zero);
        return -1;
    }

    if (shift) { /* we need to do point transform or normalize samples */
        int x, w;

        w = s->width * s->nb_components;

        if (s->bits <= 8) {
            uint8_t *src = s->picture_ptr->data[0];

            for (i = 0; i < s->height; i++) {
                for (x = off; x < w; x += stride)
                    src[x] <<= shift;
                src += s->picture_ptr->linesize[0];
            }
        } else {
            uint16_t *src = (uint16_t *)s->picture_ptr->data[0];

            for (i = 0; i < s->height; i++) {
                for (x = 0; x < w; x++)
                    src[x] <<= shift;
                src += s->picture_ptr->linesize[0] / 2;
            }
        }
    }
    av_free(state);
    av_free(zero);

    return 0;
}

AVCodec ff_jpegls_decoder = {
    .name           = "jpegls",
    .long_name      = NULL_IF_CONFIG_SMALL("JPEG-LS"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_JPEGLS,
    .priv_data_size = sizeof(MJpegDecodeContext),
    .init           = ff_mjpeg_decode_init,
    .close          = ff_mjpeg_decode_end,
    .decode         = ff_mjpeg_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
};