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/*

 * Beam Software VB decoder

 * Copyright (c) 2007 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

 * VB Video decoder

 */

#include 

#include 

#include "avcodec.h"

#include "bytestream.h"

#include "internal.h"

enum VBFlags {

    VB_HAS_GMC     = 0x01,

    VB_HAS_AUDIO   = 0x04,

    VB_HAS_VIDEO   = 0x08,

    VB_HAS_PALETTE = 0x10,

    VB_HAS_LENGTH  = 0x20

};

typedef struct VBDecContext {

    AVCodecContext *avctx;

    uint8_t *frame, *prev_frame;

    uint32_t pal[AVPALETTE_COUNT];

    GetByteContext stream;

} VBDecContext;

static const uint16_t vb_patterns[64] = {

    0x0660, 0xFF00, 0xCCCC, 0xF000, 0x8888, 0x000F, 0x1111, 0xFEC8,

    0x8CEF, 0x137F, 0xF731, 0xC800, 0x008C, 0x0013, 0x3100, 0xCC00,

    0x00CC, 0x0033, 0x3300, 0x0FF0, 0x6666, 0x00F0, 0x0F00, 0x2222,

    0x4444, 0xF600, 0x8CC8, 0x006F, 0x1331, 0x318C, 0xC813, 0x33CC,

    0x6600, 0x0CC0, 0x0066, 0x0330, 0xF900, 0xC88C, 0x009F, 0x3113,

    0x6000, 0x0880, 0x0006, 0x0110, 0xCC88, 0xFC00, 0x00CF, 0x88CC,

    0x003F, 0x1133, 0x3311, 0xF300, 0x6FF6, 0x0603, 0x08C6, 0x8C63,

    0xC631, 0x6310, 0xC060, 0x0136, 0x136C, 0x36C8, 0x6C80, 0x324C

};

static void vb_decode_palette(VBDecContext *c, int data_size)

{

    int start, size, i;

    start = bytestream2_get_byte(&c->stream);

    size  = (bytestream2_get_byte(&c->stream) - 1) & 0xFF;

    if (start + size > 255) {

        av_log(c->avctx, AV_LOG_ERROR, "Palette change runs beyond entry 256\n");

        return;

    }

    if (size*3+2 > data_size) {

        av_log(c->avctx, AV_LOG_ERROR, "Palette data runs beyond chunk size\n");

        return;

    }

    for (i = start; i <= start + size; i++)

        c->pal[i] = 0xFFU << 24 | bytestream2_get_be24(&c->stream);

}

static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)

{

    return buf >= start && buf < end;

}

static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)

{

    return buf >= start && (buf + 4) <= end;

}

static int vb_decode_framedata(VBDecContext *c, int offset)

{

    GetByteContext g;

    uint8_t *prev, *cur;

    int blk, blocks, t, blk2;

    int blocktypes = 0;

    int x, y, a, b;

    int pattype, pattern;

    const int width = c->avctx->width;

    uint8_t *pstart = c->prev_frame;

    uint8_t *pend   = c->prev_frame + width*c->avctx->height;

    g = c->stream;

    prev = c->prev_frame + offset;

    cur  = c->frame;

    blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);

    blk2   = 0;

    for (blk = 0; blk < blocks; blk++) {

        if (!(blk & 3)) {

            blocktypes = bytestream2_get_byte(&g);

        }

        switch (blocktypes & 0xC0) {

        case 0x00: //skip

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

                if (check_line(prev + y*width, pstart, pend))

                    memcpy(cur + y*width, prev + y*width, 4);

                else

                    memset(cur + y*width, 0, 4);

            break;

        case 0x40:

            t = bytestream2_get_byte(&g);

            if (!t) { //raw block

                if (bytestream2_get_bytes_left(&g) < 16) {

                    av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");

                    return AVERROR_INVALIDDATA;

                }

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

                    bytestream2_get_buffer(&g, cur + y * width, 4);

            } else { // motion compensation

                x = ((t & 0xF)^8) - 8;

                y = ((t >> 4) ^8) - 8;

                t = x + y*width;

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

                    if (check_line(prev + t + y*width, pstart, pend))

                        memcpy(cur + y*width, prev + t + y*width, 4);

                    else

                        memset(cur + y*width, 0, 4);

            }

            break;

        case 0x80: // fill

            t = bytestream2_get_byte(&g);

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

                memset(cur + y*width, t, 4);

            break;

        case 0xC0: // pattern fill

            t       = bytestream2_get_byte(&g);

            pattype = t >> 6;

            pattern = vb_patterns[t & 0x3F];

            switch (pattype) {

            case 0:

                a = bytestream2_get_byte(&g);

                b = bytestream2_get_byte(&g);

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

                    for (x = 0; x < 4; x++, pattern >>= 1)

                        cur[x + y*width] = (pattern & 1) ? b : a;

                break;

            case 1:

                pattern = ~pattern;

            case 2:

                a = bytestream2_get_byte(&g);

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

                    for (x = 0; x < 4; x++, pattern >>= 1)

                        if (pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))

                            cur[x + y*width] = prev[x + y*width];

                        else

                            cur[x + y*width] = a;

                break;

            case 3:

                av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n", blk);

                return AVERROR_INVALIDDATA;

            }

            break;

        }

        blocktypes <<= 2;

        cur  += 4;

        prev += 4;

        blk2++;

        if (blk2 == (width >> 2)) {

            blk2  = 0;

            cur  += width * 3;

            prev += width * 3;

        }

    }

    return 0;

}

static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,

                        AVPacket *avpkt)

{

    VBDecContext * const c = avctx->priv_data;

    AVFrame *frame         = data;

    uint8_t *outptr, *srcptr;

    int i, j, ret;

    int flags;

    uint32_t size;

    int offset = 0;

    bytestream2_init(&c->stream, avpkt->data, avpkt->size);

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

        return ret;

    flags = bytestream2_get_le16(&c->stream);

    if (flags & VB_HAS_GMC) {

        i = (int16_t)bytestream2_get_le16(&c->stream);

        j = (int16_t)bytestream2_get_le16(&c->stream);

        offset = i + j * avctx->width;

    }

    if (flags & VB_HAS_VIDEO) {

        size = bytestream2_get_le32(&c->stream);

        if(size > bytestream2_get_bytes_left(&c->stream)+4 || size<4){

            av_log(avctx, AV_LOG_ERROR, "Frame size invalid\n");

            return -1;

        }

        vb_decode_framedata(c, offset);

        bytestream2_skip(&c->stream, size - 4);

    }

    if (flags & VB_HAS_PALETTE) {

        size = bytestream2_get_le32(&c->stream);

        vb_decode_palette(c, size);

    }

    memcpy(frame->data[1], c->pal, AVPALETTE_SIZE);

    frame->palette_has_changed = flags & VB_HAS_PALETTE;

    outptr = frame->data[0];

    srcptr = c->frame;

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

        memcpy(outptr, srcptr, avctx->width);

        srcptr += avctx->width;

        outptr += frame->linesize[0];

    }

    FFSWAP(uint8_t*, c->frame, c->prev_frame);

    *got_frame = 1;

    /* always report that the buffer was completely consumed */

    return avpkt->size;

}

static av_cold int decode_init(AVCodecContext *avctx)

{

    VBDecContext * const c = avctx->priv_data;

    c->avctx       = avctx;

    avctx->pix_fmt = AV_PIX_FMT_PAL8;

    c->frame      = av_mallocz(avctx->width * avctx->height);

    c->prev_frame = av_mallocz(avctx->width * avctx->height);

    return 0;

}

static av_cold int decode_end(AVCodecContext *avctx)

{

    VBDecContext *c = avctx->priv_data;

    av_freep(&c->frame);

    av_freep(&c->prev_frame);

    return 0;

}

AVCodec ff_vb_decoder = {

    .name           = "vb",

    .long_name      = NULL_IF_CONFIG_SMALL("Beam Software VB"),

    .type           = AVMEDIA_TYPE_VIDEO,

    .id             = AV_CODEC_ID_VB,

    .priv_data_size = sizeof(VBDecContext),

    .init           = decode_init,

    .close          = decode_end,

    .decode         = decode_frame,

    .capabilities   = CODEC_CAP_DR1,

};