/*

 * Packed Animation File video decoder

 * Copyright (c) 2012 Paul B Mahol

 *

 * 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/imgutils.h"

#include "libavutil/mem.h"

#include "avcodec.h"

#include "bytestream.h"

#include "copy_block.h"

#include "codec_internal.h"

#include "decode.h"

static const uint8_t block_sequences[16][8] = {

    { 0, 0, 0, 0, 0, 0, 0, 0 },

    { 2, 0, 0, 0, 0, 0, 0, 0 },

    { 5, 7, 0, 0, 0, 0, 0, 0 },

    { 5, 0, 0, 0, 0, 0, 0, 0 },

    { 6, 0, 0, 0, 0, 0, 0, 0 },

    { 5, 7, 5, 7, 0, 0, 0, 0 },

    { 5, 7, 5, 0, 0, 0, 0, 0 },

    { 5, 7, 6, 0, 0, 0, 0, 0 },

    { 5, 5, 0, 0, 0, 0, 0, 0 },

    { 3, 0, 0, 0, 0, 0, 0, 0 },

    { 6, 6, 0, 0, 0, 0, 0, 0 },

    { 2, 4, 0, 0, 0, 0, 0, 0 },

    { 2, 4, 5, 7, 0, 0, 0, 0 },

    { 2, 4, 5, 0, 0, 0, 0, 0 },

    { 2, 4, 6, 0, 0, 0, 0, 0 },

    { 2, 4, 5, 7, 5, 7, 0, 0 },

};

typedef struct PAFVideoDecContext {

    AVFrame  *pic;

    GetByteContext gb;

    int width;

    int height;

    int current_frame;

    uint8_t *frame[4];

    int dirty[4];

    int frame_size;

    int video_size;

    uint8_t *opcodes;

} PAFVideoDecContext;

static av_cold int paf_video_close(AVCodecContext *avctx)

{

    PAFVideoDecContext *c = avctx->priv_data;

    int i;

    av_frame_free(&c->pic);

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

        av_freep(&c->frame[i]);

    return 0;

}

static av_cold int paf_video_init(AVCodecContext *avctx)

{

    PAFVideoDecContext *c = avctx->priv_data;

    int i;

    int ret;

    c->width  = avctx->width;

    c->height = avctx->height;

    if (avctx->height & 3 || avctx->width & 3) {

        av_log(avctx, AV_LOG_ERROR,

               "width %d and height %d must be multiplie of 4.\n",

               avctx->width, avctx->height);

        return AVERROR_INVALIDDATA;

    }

    avctx->pix_fmt = AV_PIX_FMT_PAL8;

    ret = av_image_check_size2(avctx->width, FFALIGN(avctx->height, 256), avctx->max_pixels, avctx->pix_fmt, 0, avctx);

    if (ret < 0)

        return ret;

    c->pic = av_frame_alloc();

    if (!c->pic)

        return AVERROR(ENOMEM);

    c->frame_size = avctx->width * FFALIGN(avctx->height, 256);

    c->video_size = avctx->width * avctx->height;

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

        c->frame[i] = av_mallocz(c->frame_size);

        if (!c->frame[i])

            return AVERROR(ENOMEM);

    }

    return 0;

}

static void read4x4block(PAFVideoDecContext *c, uint8_t *dst, int width)

{

    int i;

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

        bytestream2_get_buffer(&c->gb, dst, 4);

        dst += width;

    }

}

static void copy_color_mask(uint8_t *dst, int width, uint8_t mask, uint8_t color)

{

    int i;

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

        if (mask & (1 << 7 - i))

            dst[i] = color;

        if (mask & (1 << 3 - i))

            dst[width + i] = color;

    }

}

static void copy_src_mask(uint8_t *dst, int width, uint8_t mask, const uint8_t *src)

{

    int i;

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

        if (mask & (1 << 7 - i))

            dst[i] = src[i];

        if (mask & (1 << 3 - i))

            dst[width + i] = src[width + i];

    }

}

static void set_src_position(PAFVideoDecContext *c,

                             const uint8_t **p,

                             const uint8_t **pend)

{

    int val  = bytestream2_get_be16(&c->gb);

    int page = val >> 14;

    int x    = (val & 0x7F);

    int y    = ((val >> 7) & 0x7F);

    *p    = c->frame[page] + x * 2 + y * 2 * c->width;

    *pend = c->frame[page] + c->frame_size;

}

static int decode_0(PAFVideoDecContext *c, const uint8_t *pkt, uint8_t code)

{

    uint32_t opcode_size, offset;

    uint8_t *dst, *dend, mask = 0, color = 0;

    const uint8_t *src, *send, *opcodes;

    int i, j, op = 0;

    i = bytestream2_get_byte(&c->gb);

    if (i) {

        if (code & 0x10) {

            int align;

            align = bytestream2_tell(&c->gb) & 3;

            if (align)

                bytestream2_skip(&c->gb, 4 - align);

        }

        do {

            int page, val, x, y;

            val    = bytestream2_get_be16(&c->gb);

            page   = val >> 14;

            x      = (val & 0x7F) * 2;

            y      = ((val >> 7) & 0x7F) * 2;

            dst    = c->frame[page] + x + y * c->width;

            dend   = c->frame[page] + c->frame_size;

            offset = (x & 0x7F) * 2;

            j      = bytestream2_get_le16(&c->gb) + offset;

            if (bytestream2_get_bytes_left(&c->gb) < (j - offset) * 16)

                return AVERROR_INVALIDDATA;

            c->dirty[page] = 1;

            do {

                offset++;

                if (dst + 3 * c->width + 4 > dend)

                    return AVERROR_INVALIDDATA;

                read4x4block(c, dst, c->width);

                if ((offset & 0x3F) == 0)

                    dst += c->width * 3;

                dst += 4;

            } while (offset < j);

        } while (--i);

    }

    dst  = c->frame[c->current_frame];

    dend = c->frame[c->current_frame] + c->frame_size;

    do {

        set_src_position(c, &src, &send);

        if ((src + 3 * c->width + 4 > send) ||

            (dst + 3 * c->width + 4 > dend) ||

            bytestream2_get_bytes_left(&c->gb) < 4)

            return AVERROR_INVALIDDATA;

        copy_block4(dst, src, c->width, c->width, 4);

        i++;

        if ((i & 0x3F) == 0)

            dst += c->width * 3;

        dst += 4;

    } while (i < c->video_size / 16);

    opcode_size = bytestream2_get_le16(&c->gb);

    bytestream2_skip(&c->gb, 2);

    if (bytestream2_get_bytes_left(&c->gb) < opcode_size)

        return AVERROR_INVALIDDATA;

    opcodes = pkt + bytestream2_tell(&c->gb);

    bytestream2_skipu(&c->gb, opcode_size);

    dst = c->frame[c->current_frame];

    for (i = 0; i < c->height; i += 4, dst += c->width * 3)

        for (j = 0; j < c->width; j += 4, dst += 4) {

            int opcode, k = 0;

            if (op > opcode_size)

                return AVERROR_INVALIDDATA;

            if (j & 4) {

                opcode = opcodes[op] & 15;

                op++;

            } else {

                opcode = opcodes[op] >> 4;

            }

            while (block_sequences[opcode][k]) {

                offset = c->width * 2;

                code   = block_sequences[opcode][k++];

                switch (code) {

                case 2:

                    offset = 0;

                    av_fallthrough;

                case 3:

                    color = bytestream2_get_byte(&c->gb);

                    av_fallthrough;

                case 4:

                    mask = bytestream2_get_byte(&c->gb);

                    copy_color_mask(dst + offset, c->width, mask, color);

                    break;

                case 5:

                    offset = 0;

                    av_fallthrough;

                case 6:

                    set_src_position(c, &src, &send);

                    av_fallthrough;

                case 7:

                    if (src + offset + c->width + 4 > send)

                        return AVERROR_INVALIDDATA;

                    mask = bytestream2_get_byte(&c->gb);

                    copy_src_mask(dst + offset, c->width, mask, src + offset);

                    break;

                }

            }

        }

    return 0;

}

static int paf_video_decode(AVCodecContext *avctx, AVFrame *rframe,

                            int *got_frame, AVPacket *pkt)

{

    PAFVideoDecContext *c = avctx->priv_data;

    uint8_t code, *dst, *end;

    int i, frame, ret;

    if (pkt->size < 2)

        return AVERROR_INVALIDDATA;

    bytestream2_init(&c->gb, pkt->data, pkt->size);

    code = bytestream2_get_byte(&c->gb);

    if ((code & 0xF) > 4 || (code & 0xF) == 3) {

        avpriv_request_sample(avctx, "unknown/invalid code");

        return AVERROR_INVALIDDATA;

    }

    if ((code & 0xF) == 0 &&

        c->video_size / 32 - (int64_t)bytestream2_get_bytes_left(&c->gb) > c->video_size / 32 * (int64_t)avctx->discard_damaged_percentage / 100)

        return AVERROR_INVALIDDATA;

    if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)

        return ret;

    if (code & 0x20) {  // frame is keyframe

        memset(c->pic->data[1], 0, AVPALETTE_SIZE);

        c->current_frame  = 0;

        c->pic->flags |= AV_FRAME_FLAG_KEY;

        c->pic->pict_type = AV_PICTURE_TYPE_I;

    } else {

        c->pic->flags &= ~AV_FRAME_FLAG_KEY;

        c->pic->pict_type = AV_PICTURE_TYPE_P;

    }

    if (code & 0x40) {  // palette update

        uint32_t *out = (uint32_t *)c->pic->data[1];

        int index, count;

        index = bytestream2_get_byte(&c->gb);

        count = bytestream2_get_byte(&c->gb) + 1;

        if (index + count > 256)

            return AVERROR_INVALIDDATA;

        if (bytestream2_get_bytes_left(&c->gb) < 3 * count)

            return AVERROR_INVALIDDATA;

        out += index;

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

            unsigned r, g, b;

            r = bytestream2_get_byteu(&c->gb);

            r = r << 2 | r >> 4;

            g = bytestream2_get_byteu(&c->gb);

            g = g << 2 | g >> 4;

            b = bytestream2_get_byteu(&c->gb);

            b = b << 2 | b >> 4;

            *out++ = (0xFFU << 24) | (r << 16) | (g << 8) | b;

        }

    }

    c->dirty[c->current_frame] = 1;

    if (code & 0x20)

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

            if (c->dirty[i])

                memset(c->frame[i], 0, c->frame_size);

            c->dirty[i] = 0;

        }

    switch (code & 0x0F) {

    case 0:

        /* Block-based motion compensation using 4x4 blocks with either

         * horizontal or vertical vectors; might incorporate VQ as well. */

        if ((ret = decode_0(c, pkt->data, code)) < 0)

            return ret;

        break;

    case 1:

        /* Uncompressed data. This mode specifies that (width * height) bytes

         * should be copied directly from the encoded buffer into the output. */

        dst = c->frame[c->current_frame];

        // possibly chunk length data

        bytestream2_skip(&c->gb, 2);

        if (bytestream2_get_bytes_left(&c->gb) < c->video_size)

            return AVERROR_INVALIDDATA;

        bytestream2_get_bufferu(&c->gb, dst, c->video_size);

        break;

    case 2:

        /* Copy reference frame: Consume the next byte in the stream as the

         * reference frame (which should be 0, 1, 2, or 3, and should not be

         * the same as the current frame number). */

        frame = bytestream2_get_byte(&c->gb);

        if (frame > 3)

            return AVERROR_INVALIDDATA;

        if (frame != c->current_frame)

            memcpy(c->frame[c->current_frame], c->frame[frame], c->frame_size);

        break;

    case 4:

        /* Run length encoding.*/

        dst = c->frame[c->current_frame];

        end = dst + c->video_size;

        bytestream2_skip(&c->gb, 2);

        while (dst < end) {

            int8_t code;

            int count;

            if (bytestream2_get_bytes_left(&c->gb) < 2)

                return AVERROR_INVALIDDATA;

            code  = bytestream2_get_byteu(&c->gb);

            count = FFABS(code) + 1;

            if (dst + count > end)

                return AVERROR_INVALIDDATA;

            if (code < 0)

                memset(dst, bytestream2_get_byteu(&c->gb), count);

            else

                bytestream2_get_buffer(&c->gb, dst, count);

            dst += count;

        }

        break;

    default:

        av_assert0(0);

    }

    av_image_copy_plane(c->pic->data[0], c->pic->linesize[0],

                        c->frame[c->current_frame], c->width,

                        c->width, c->height);

    c->current_frame = (c->current_frame + 1) & 3;

    if ((ret = av_frame_ref(rframe, c->pic)) < 0)

        return ret;

    *got_frame = 1;

    return pkt->size;

}

const FFCodec ff_paf_video_decoder = {

    .p.name         = "paf_video",

    CODEC_LONG_NAME("Amazing Studio Packed Animation File Video"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_PAF_VIDEO,

    .priv_data_size = sizeof(PAFVideoDecContext),

    .init           = paf_video_init,

    .close          = paf_video_close,

    FF_CODEC_DECODE_CB(paf_video_decode),

    .p.capabilities = AV_CODEC_CAP_DR1,

    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,

};