/*

 * Winnov WNV1 codec

 * Copyright (c) 2005 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

 * Winnov WNV1 codec.

 */

#include "libavutil/thread.h"

#define BITSTREAM_READER_LE

#include "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

#include "get_bits.h"

static const uint8_t code_tab[16][2] = {

    {  7, 1 }, {  8, 3 }, {  6, 3 }, { 9, 4 }, {  5, 4 }, { 10, 5 }, {  4, 5 },

    { 11, 6 }, {  3, 6 }, { 12, 7 }, { 2, 7 }, { 13, 8 }, {  1, 8 }, { 14, 9 },

    {  0, 9 }, { 15, 8 }

};

#define CODE_VLC_BITS 9

static VLCElem code_vlc[1 << CODE_VLC_BITS];

/* returns modified base_value */

static inline int wnv1_get_code(GetBitContext *gb, int shift, int base_value)

{

    int v = get_vlc2(gb, code_vlc, CODE_VLC_BITS, 1);

    if (v == 8)

        return get_bits(gb, 8 - shift) << shift;

    else

        return base_value + v * (1 << shift);

}

static int decode_frame(AVCodecContext *avctx, AVFrame *p,

                        int *got_frame, AVPacket *avpkt)

{

    const uint8_t *buf    = avpkt->data;

    int buf_size          = avpkt->size;

    GetBitContext gb;

    unsigned char *Y,*U,*V;

    int i, j, ret, shift;

    int prev_y = 0, prev_u = 0, prev_v = 0;

    if (buf_size < 8 + avctx->height * (avctx->width/2)/8) {

        av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);

        return AVERROR_INVALIDDATA;

    }

    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)

        return ret;

    if ((ret = init_get_bits8(&gb, buf + 8, buf_size - 8)) < 0)

        return ret;

    if (buf[2] >> 4 == 6)

        shift = 2;

    else {

        shift = 8 - (buf[2] >> 4);

        if (shift > 4) {

            avpriv_request_sample(avctx,

                                  "Unknown WNV1 frame header value %i",

                                  buf[2] >> 4);

            shift = 4;

        }

        if (shift < 1) {

            avpriv_request_sample(avctx,

                                  "Unknown WNV1 frame header value %i",

                                  buf[2] >> 4);

            shift = 1;

        }

    }

    Y = p->data[0];

    U = p->data[1];

    V = p->data[2];

    for (j = 0; j < avctx->height; j++) {

        for (i = 0; i < avctx->width / 2; i++) {

            Y[i * 2] = wnv1_get_code(&gb, shift, prev_y);

            prev_u = U[i] = wnv1_get_code(&gb, shift, prev_u);

            prev_y = Y[(i * 2) + 1] = wnv1_get_code(&gb, shift, Y[i * 2]);

            prev_v = V[i] = wnv1_get_code(&gb, shift, prev_v);

        }

        Y += p->linesize[0];

        U += p->linesize[1];

        V += p->linesize[2];

    }

    *got_frame      = 1;

    return buf_size;

}

static av_cold void wnv1_init_static(void)

{

    VLC_INIT_STATIC_TABLE_FROM_LENGTHS(code_vlc, CODE_VLC_BITS, 16,

                                       &code_tab[0][1], 2,

                                       &code_tab[0][0], 2, 1,

                                       -7, VLC_INIT_OUTPUT_LE);

}

static av_cold int decode_init(AVCodecContext *avctx)

{

    static AVOnce init_static_once = AV_ONCE_INIT;

    if (avctx->width <= 1)

        return AVERROR_INVALIDDATA;

    avctx->pix_fmt = AV_PIX_FMT_YUV422P;

    ff_thread_once(&init_static_once, wnv1_init_static);

    return 0;

}

const FFCodec ff_wnv1_decoder = {

    .p.name         = "wnv1",

    CODEC_LONG_NAME("Winnov WNV1"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_WNV1,

    .init           = decode_init,

    FF_CODEC_DECODE_CB(decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

};