/*

 * Escape 130 video decoder

 * Copyright (C) 2008 Eli Friedman (eli.friedman <at> gmail.com)

 *

 * 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

 */

#include "libavutil/attributes.h"

#include "libavutil/mem.h"

#define BITSTREAM_READER_LE

#include "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

#include "get_bits.h"

typedef struct Escape130Context {

    uint8_t *old_y_avg;

    uint8_t *new_y, *old_y;

    uint8_t *new_u, *old_u;

    uint8_t *new_v, *old_v;

    uint8_t *buf1, *buf2;

    int     linesize[3];

} Escape130Context;

static const uint8_t offset_table[] = { 2, 4, 10, 20 };

static const int8_t sign_table[64][4] = {

    {  0,  0,  0,  0 },

    { -1,  1,  0,  0 },

    {  1, -1,  0,  0 },

    { -1,  0,  1,  0 },

    { -1,  1,  1,  0 },

    {  0, -1,  1,  0 },

    {  1, -1,  1,  0 },

    { -1, -1,  1,  0 },

    {  1,  0, -1,  0 },

    {  0,  1, -1,  0 },

    {  1,  1, -1,  0 },

    { -1,  1, -1,  0 },

    {  1, -1, -1,  0 },

    { -1,  0,  0,  1 },

    { -1,  1,  0,  1 },

    {  0, -1,  0,  1 },

    {  0,  0,  0,  0 },

    {  1, -1,  0,  1 },

    { -1, -1,  0,  1 },

    { -1,  0,  1,  1 },

    { -1,  1,  1,  1 },

    {  0, -1,  1,  1 },

    {  1, -1,  1,  1 },

    { -1, -1,  1,  1 },

    {  0,  0, -1,  1 },

    {  1,  0, -1,  1 },

    { -1,  0, -1,  1 },

    {  0,  1, -1,  1 },

    {  1,  1, -1,  1 },

    { -1,  1, -1,  1 },

    {  0, -1, -1,  1 },

    {  1, -1, -1,  1 },

    {  0,  0,  0,  0 },

    { -1, -1, -1,  1 },

    {  1,  0,  0, -1 },

    {  0,  1,  0, -1 },

    {  1,  1,  0, -1 },

    { -1,  1,  0, -1 },

    {  1, -1,  0, -1 },

    {  0,  0,  1, -1 },

    {  1,  0,  1, -1 },

    { -1,  0,  1, -1 },

    {  0,  1,  1, -1 },

    {  1,  1,  1, -1 },

    { -1,  1,  1, -1 },

    {  0, -1,  1, -1 },

    {  1, -1,  1, -1 },

    { -1, -1,  1, -1 },

    {  0,  0,  0,  0 },

    {  1,  0, -1, -1 },

    {  0,  1, -1, -1 },

    {  1,  1, -1, -1 },

    { -1,  1, -1, -1 },

    {  1, -1, -1, -1 }

};

static const int8_t luma_adjust[] = { -4, -3, -2, -1, 1, 2, 3, 4 };

static const int8_t chroma_adjust[2][8] = {

    { 1, 1, 0, -1, -1, -1,  0,  1 },

    { 0, 1, 1,  1,  0, -1, -1, -1 }

};

static const uint8_t chroma_vals[] = {

     20,  28,  36,  44,  52,  60,  68,  76,

     84,  92, 100, 106, 112, 116, 120, 124,

    128, 132, 136, 140, 144, 150, 156, 164,

    172, 180, 188, 196, 204, 212, 220, 228

};

static av_cold int escape130_decode_init(AVCodecContext *avctx)

{

    Escape130Context *s = avctx->priv_data;

    avctx->pix_fmt = AV_PIX_FMT_YUV420P;

    if ((avctx->width & 1) || (avctx->height & 1)) {

        av_log(avctx, AV_LOG_ERROR,

               "Dimensions should be a multiple of two.\n");

        return AVERROR_INVALIDDATA;

    }

    s->old_y_avg = av_malloc(avctx->width * avctx->height / 4);

    s->buf1      = av_malloc(avctx->width * avctx->height * 3 / 2);

    s->buf2      = av_malloc(avctx->width * avctx->height * 3 / 2);

    if (!s->old_y_avg || !s->buf1 || !s->buf2) {

        av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");

        return AVERROR(ENOMEM);

    }

    s->linesize[0] = avctx->width;

    s->linesize[1] =

    s->linesize[2] = avctx->width / 2;

    s->new_y = s->buf1;

    s->new_u = s->new_y + avctx->width * avctx->height;

    s->new_v = s->new_u + avctx->width * avctx->height / 4;

    s->old_y = s->buf2;

    s->old_u = s->old_y + avctx->width * avctx->height;

    s->old_v = s->old_u + avctx->width * avctx->height / 4;

    memset(s->old_y, 0,    avctx->width * avctx->height);

    memset(s->old_u, 0x10, avctx->width * avctx->height / 4);

    memset(s->old_v, 0x10, avctx->width * avctx->height / 4);

    return 0;

}

static av_cold int escape130_decode_close(AVCodecContext *avctx)

{

    Escape130Context *s = avctx->priv_data;

    av_freep(&s->old_y_avg);

    av_freep(&s->buf1);

    av_freep(&s->buf2);

    return 0;

}

static int decode_skip_count(GetBitContext* gb)

{

    int value;

    if (get_bits_left(gb) < 1+3)

        return -1;

    value = get_bits1(gb);

    if (value)

        return 0;

    value = get_bits(gb, 3);

    if (value)

        return value;

    value = get_bits(gb, 8);

    if (value)

        return value + 7;

    value = get_bits(gb, 15);

    if (value)

        return value + 262;

    return -1;

}

static int escape130_decode_frame(AVCodecContext *avctx, AVFrame *pic,

                                  int *got_frame, AVPacket *avpkt)

{

    int buf_size        = avpkt->size;

    Escape130Context *s = avctx->priv_data;

    GetBitContext gb;

    int ret;

    uint8_t *old_y, *old_cb, *old_cr,

            *new_y, *new_cb, *new_cr;

    uint8_t *dstY, *dstU, *dstV;

    unsigned old_y_stride, old_cb_stride, old_cr_stride,

             new_y_stride, new_cb_stride, new_cr_stride;

    unsigned total_blocks = avctx->width * avctx->height / 4,

             block_index, block_x = 0;

    unsigned y[4] = { 0 }, cb = 0x10, cr = 0x10;

    int skip = -1, y_avg = 0, i, j;

    uint8_t *ya = s->old_y_avg;

    // first 16 bytes are header; no useful information in here

    if (buf_size <= 16) {

        av_log(avctx, AV_LOG_ERROR, "Insufficient frame data\n");

        return AVERROR_INVALIDDATA;

    }

    if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)

        return ret;

    skip_bits_long(&gb, 16 * 8);

    new_y  = s->new_y;

    new_cb = s->new_u;

    new_cr = s->new_v;

    new_y_stride  = s->linesize[0];

    new_cb_stride = s->linesize[1];

    new_cr_stride = s->linesize[2];

    old_y  = s->old_y;

    old_cb = s->old_u;

    old_cr = s->old_v;

    old_y_stride  = s->linesize[0];

    old_cb_stride = s->linesize[1];

    old_cr_stride = s->linesize[2];

    for (block_index = 0; block_index < total_blocks; block_index++) {

        // Note that this call will make us skip the rest of the blocks

        // if the frame ends prematurely.

        if (skip == -1)

            skip = decode_skip_count(&gb);

        if (skip == -1) {

            av_log(avctx, AV_LOG_ERROR, "Error decoding skip value\n");

            return AVERROR_INVALIDDATA;

        }

        if (skip) {

            y[0] = old_y[0];

            y[1] = old_y[1];

            y[2] = old_y[old_y_stride];

            y[3] = old_y[old_y_stride + 1];

            y_avg = ya[0];

            cb = old_cb[0];

            cr = old_cr[0];

        } else {

            if (get_bits1(&gb)) {

                unsigned sign_selector       = get_bits(&gb, 6);

                unsigned difference_selector = get_bits(&gb, 2);

                y_avg = 2 * get_bits(&gb, 5);

                for (i = 0; i < 4; i++) {

                    y[i] = av_clip(y_avg + offset_table[difference_selector] *

                                   sign_table[sign_selector][i], 0, 63);

                }

            } else if (get_bits1(&gb)) {

                if (get_bits1(&gb)) {

                    y_avg = get_bits(&gb, 6);

                } else {

                    unsigned adjust_index = get_bits(&gb, 3);

                    y_avg = (y_avg + luma_adjust[adjust_index]) & 63;

                }

                for (i = 0; i < 4; i++)

                    y[i] = y_avg;

            }

            if (get_bits1(&gb)) {

                if (get_bits1(&gb)) {

                    cb = get_bits(&gb, 5);

                    cr = get_bits(&gb, 5);

                } else {

                    unsigned adjust_index = get_bits(&gb, 3);

                    cb = (cb + chroma_adjust[0][adjust_index]) & 31;

                    cr = (cr + chroma_adjust[1][adjust_index]) & 31;

                }

            }

        }

        *ya++ = y_avg;

        new_y[0]                = y[0];

        new_y[1]                = y[1];

        new_y[new_y_stride]     = y[2];

        new_y[new_y_stride + 1] = y[3];

        *new_cb = cb;

        *new_cr = cr;

        old_y += 2;

        old_cb++;

        old_cr++;

        new_y += 2;

        new_cb++;

        new_cr++;

        block_x++;

        if (block_x * 2 == avctx->width) {

            block_x = 0;

            old_y  += old_y_stride * 2  - avctx->width;

            old_cb += old_cb_stride     - avctx->width / 2;

            old_cr += old_cr_stride     - avctx->width / 2;

            new_y  += new_y_stride * 2  - avctx->width;

            new_cb += new_cb_stride     - avctx->width / 2;

            new_cr += new_cr_stride     - avctx->width / 2;

        }

        skip--;

    }

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

        return ret;

    new_y  = s->new_y;

    new_cb = s->new_u;

    new_cr = s->new_v;

    dstY   = pic->data[0];

    dstU   = pic->data[1];

    dstV   = pic->data[2];

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

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

            dstY[i] = new_y[i] << 2;

        dstY  += pic->linesize[0];

        new_y += new_y_stride;

    }

    for (j = 0; j < avctx->height / 2; j++) {

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

            dstU[i] = chroma_vals[new_cb[i]];

            dstV[i] = chroma_vals[new_cr[i]];

        }

        dstU   += pic->linesize[1];

        dstV   += pic->linesize[2];

        new_cb += new_cb_stride;

        new_cr += new_cr_stride;

    }

    ff_dlog(avctx, "Frame data: provided %d bytes, used %d bytes\n",

            buf_size, get_bits_count(&gb) >> 3);

    FFSWAP(uint8_t*, s->old_y, s->new_y);

    FFSWAP(uint8_t*, s->old_u, s->new_u);

    FFSWAP(uint8_t*, s->old_v, s->new_v);

    *got_frame = 1;

    return buf_size;

}

const FFCodec ff_escape130_decoder = {

    .p.name         = "escape130",

    CODEC_LONG_NAME("Escape 130"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_ESCAPE130,

    .priv_data_size = sizeof(Escape130Context),

    .init           = escape130_decode_init,

    .close          = escape130_decode_close,

    FF_CODEC_DECODE_CB(escape130_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,

};