/*

 * QPEG codec

 * Copyright (c) 2004 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

 * QPEG codec.

 */

#include "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "decode.h"

#include "libavutil/attributes.h"

typedef struct QpegContext{

    AVCodecContext *avctx;

    AVFrame *ref;

    uint32_t pal[256];

    GetByteContext buffer;

} QpegContext;

static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,

                              int stride, int width, int height)

{

    int i;

    int code;

    int c0, c1;

    int run, copy;

    int filled = 0;

    int rows_to_go;

    rows_to_go = height;

    height--;

    dst = dst + height * stride;

    while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (rows_to_go > 0)) {

        code = bytestream2_get_byte(&qctx->buffer);

        run = copy = 0;

        if(code == 0xFC) /* end-of-picture code */

            break;

        if(code >= 0xF8) { /* very long run */

            c0 = bytestream2_get_byte(&qctx->buffer);

            c1 = bytestream2_get_byte(&qctx->buffer);

            run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;

        } else if (code >= 0xF0) { /* long run */

            c0 = bytestream2_get_byte(&qctx->buffer);

            run = ((code & 0xF) << 8) + c0 + 2;

        } else if (code >= 0xE0) { /* short run */

            run = (code & 0x1F) + 2;

        } else if (code >= 0xC0) { /* very long copy */

            c0 = bytestream2_get_byte(&qctx->buffer);

            c1 = bytestream2_get_byte(&qctx->buffer);

            copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;

        } else if (code >= 0x80) { /* long copy */

            c0 = bytestream2_get_byte(&qctx->buffer);

            copy = ((code & 0x7F) << 8) + c0 + 1;

        } else { /* short copy */

            copy = code + 1;

        }

        /* perform actual run or copy */

        if(run) {

            int p;

            p = bytestream2_get_byte(&qctx->buffer);

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

                int step = FFMIN(run - i, width - filled);

                memset(dst+filled, p, step);

                filled += step;

                i      += step - 1;

                if (filled >= width) {

                    filled = 0;

                    dst -= stride;

                    rows_to_go--;

                    while (run - i > width && rows_to_go > 0) {

                        memset(dst, p, width);

                        dst -= stride;

                        rows_to_go--;

                        i += width;

                    }

                    if(rows_to_go <= 0)

                        break;

                }

            }

        } else {

            if (bytestream2_get_bytes_left(&qctx->buffer) < copy)

                copy = bytestream2_get_bytes_left(&qctx->buffer);

            while (copy > 0) {

                int step = FFMIN(copy, width - filled);

                bytestream2_get_bufferu(&qctx->buffer, dst + filled, step);

                filled += step;

                copy -= step;

                if (filled >= width) {

                    filled = 0;

                    dst -= stride;

                    rows_to_go--;

                    if(rows_to_go <= 0)

                        break;

                }

            }

        }

    }

}

static const uint8_t qpeg_table_h[16] =

 { 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};

static const uint8_t qpeg_table_w[16] =

 { 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};

/* Decodes delta frames */

static void av_noinline qpeg_decode_inter(QpegContext *qctx, uint8_t *dst,

                              int stride, int width, int height,

                              int delta, const uint8_t *ctable,

                              uint8_t *refdata)

{

    int i, j;

    int code;

    int filled = 0;

    int orig_height;

    if (refdata) {

        /* copy prev frame */

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

            memcpy(dst + (i * stride), refdata + (i * stride), width);

    } else {

        refdata = dst;

    }

    orig_height = height;

    height--;

    dst = dst + height * stride;

    while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (height >= 0)) {

        code = bytestream2_get_byte(&qctx->buffer);

        if(delta) {

            /* motion compensation */

            while(bytestream2_get_bytes_left(&qctx->buffer) > 0 && (code & 0xF0) == 0xF0) {

                if(delta == 1) {

                    int me_idx;

                    int me_w, me_h, me_x, me_y;

                    uint8_t *me_plane;

                    int corr, val;

                    /* get block size by index */

                    me_idx = code & 0xF;

                    me_w = qpeg_table_w[me_idx];

                    me_h = qpeg_table_h[me_idx];

                    /* extract motion vector */

                    corr = bytestream2_get_byte(&qctx->buffer);

                    val = corr >> 4;

                    if(val > 7)

                        val -= 16;

                    me_x = val;

                    val = corr & 0xF;

                    if(val > 7)

                        val -= 16;

                    me_y = val;

                    /* check motion vector */

                    if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||

                       (height - me_y - me_h < 0) || (height - me_y >= orig_height) ||

                       (filled + me_w > width) || (height - me_h < 0))

                        av_log(qctx->avctx, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",

                               me_x, me_y, me_w, me_h, filled, height);

                    else {

                        /* do motion compensation */

                        me_plane = refdata + (filled + me_x) + (height - me_y) * stride;

                        for(j = 0; j < me_h; j++) {

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

                                dst[filled + i - (j * stride)] = me_plane[i - (j * stride)];

                        }

                    }

                }

                code = bytestream2_get_byte(&qctx->buffer);

            }

        }

        if(code == 0xE0) /* end-of-picture code */

            break;

        if(code > 0xE0) { /* run code: 0xE1..0xFF */

            int p;

            code &= 0x1F;

            p = bytestream2_get_byte(&qctx->buffer);

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

                dst[filled++] = p;

                if(filled >= width) {

                    filled = 0;

                    dst -= stride;

                    height--;

                    if (height < 0)

                        break;

                }

            }

        } else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */

            code &= 0x1F;

            if(code + 1 > bytestream2_get_bytes_left(&qctx->buffer))

                break;

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

                dst[filled++] = bytestream2_get_byte(&qctx->buffer);

                if(filled >= width) {

                    filled = 0;

                    dst -= stride;

                    height--;

                    if (height < 0)

                        break;

                }

            }

        } else if(code >= 0x80) { /* skip code: 0x80..0xBF */

            int skip;

            code &= 0x3F;

            /* codes 0x80 and 0x81 are actually escape codes,

               skip value minus constant is in the next byte */

            if(!code)

                skip = bytestream2_get_byte(&qctx->buffer) +  64;

            else if(code == 1)

                skip = bytestream2_get_byte(&qctx->buffer) + 320;

            else

                skip = code;

            filled += skip;

            while( filled >= width) {

                filled -= width;

                dst -= stride;

                height--;

                if(height < 0)

                    break;

            }

        } else {

            /* zero code treated as one-pixel skip */

            if(code) {

                dst[filled++] = ctable[code & 0x7F];

            }

            else

                filled++;

            if(filled >= width) {

                filled = 0;

                dst -= stride;

                height--;

            }

        }

    }

}

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

                        int *got_frame, AVPacket *avpkt)

{

    uint8_t ctable[128];

    QpegContext * const a = avctx->priv_data;

    AVFrame * const ref = a->ref;

    uint8_t* outdata;

    int delta, intra, ret;

    if (avpkt->size < 0x86) {

        av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

        return AVERROR_INVALIDDATA;

    }

    bytestream2_init(&a->buffer, avpkt->data, avpkt->size);

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

        return ret;

    outdata = p->data[0];

    bytestream2_skip(&a->buffer, 4);

    bytestream2_get_buffer(&a->buffer, ctable, 128);

    bytestream2_skip(&a->buffer, 1);

    delta = bytestream2_get_byte(&a->buffer);

    intra = delta == 0x10;

    if (intra) {

        qpeg_decode_intra(a, outdata, p->linesize[0], avctx->width, avctx->height);

    } else {

        qpeg_decode_inter(a, outdata, p->linesize[0], avctx->width, avctx->height, delta, ctable, ref->data[0]);

    }

    /* make the palette available on the way out */

    ff_copy_palette(a->pal, avpkt, avctx);

    memcpy(p->data[1], a->pal, AVPALETTE_SIZE);

    if ((ret = av_frame_replace(ref, p)) < 0)

        return ret;

    if (intra)

        p->flags |= AV_FRAME_FLAG_KEY;

    else

        p->flags &= ~AV_FRAME_FLAG_KEY;

    p->pict_type = intra ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;

    *got_frame      = 1;

    return avpkt->size;

}

static av_cold void decode_flush(AVCodecContext *avctx)

{

    QpegContext * const a = avctx->priv_data;

    int i, pal_size;

    const uint8_t *pal_src;

    av_frame_unref(a->ref);

    pal_size = FFMIN(1024U, avctx->extradata_size);

    pal_src = avctx->extradata + avctx->extradata_size - pal_size;

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

        a->pal[i] = 0xFFU<<24 | AV_RL32(pal_src+4*i);

}

static av_cold int decode_end(AVCodecContext *avctx)

{

    QpegContext * const a = avctx->priv_data;

    av_frame_free(&a->ref);

    return 0;

}

static av_cold int decode_init(AVCodecContext *avctx){

    QpegContext * const a = avctx->priv_data;

    a->avctx = avctx;

    avctx->pix_fmt= AV_PIX_FMT_PAL8;

    a->ref = av_frame_alloc();

    if (!a->ref)

        return AVERROR(ENOMEM);

    decode_flush(avctx);

    return 0;

}

const FFCodec ff_qpeg_decoder = {

    .p.name         = "qpeg",

    CODEC_LONG_NAME("Q-team QPEG"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_QPEG,

    .priv_data_size = sizeof(QpegContext),

    .init           = decode_init,

    .close          = decode_end,

    FF_CODEC_DECODE_CB(decode_frame),

    .flush          = decode_flush,

    .p.capabilities = AV_CODEC_CAP_DR1,

    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,

};