/*

 * VMware Screen Codec (VMnc) decoder

 * Copyright (c) 2006 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

 * VMware Screen Codec (VMnc) decoder

 * As Alex Beregszaszi discovered, this is effectively RFB data dump

 */

#include "libavutil/common.h"

#include "libavutil/mem.h"

#include "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

#include "bytestream.h"

enum EncTypes {

    MAGIC_WMVd = 0x574D5664,

    MAGIC_WMVe,

    MAGIC_WMVf,

    MAGIC_WMVg,

    MAGIC_WMVh,

    MAGIC_WMVi,

    MAGIC_WMVj

};

enum HexTile_Flags {

    HT_RAW =  1, // tile is raw

    HT_BKG =  2, // background color is present

    HT_FG  =  4, // foreground color is present

    HT_SUB =  8, // subrects are present

    HT_CLR = 16  // each subrect has own color

};

/*

 * Decoder context

 */

typedef struct VmncContext {

    AVCodecContext *avctx;

    AVFrame *pic;

    int bpp;

    int bpp2;

    int bigendian;

    uint8_t pal[768];

    int width, height;

    GetByteContext gb;

    /* cursor data */

    int cur_w, cur_h;

    int cur_x, cur_y;

    int cur_hx, cur_hy;

    uint8_t *curbits, *curmask;

    uint8_t *screendta;

} VmncContext;

/* read pixel value from stream */

static av_always_inline int vmnc_get_pixel(GetByteContext *gb, int bpp, int be)

{

    switch (bpp * 2 + be) {

    case 2:

    case 3:

        return bytestream2_get_byte(gb);

    case 4:

        return bytestream2_get_le16(gb);

    case 5:

        return bytestream2_get_be16(gb);

    case 8:

        return bytestream2_get_le32(gb);

    case 9:

        return bytestream2_get_be32(gb);

    default: return 0;

    }

}

static void load_cursor(VmncContext *c)

{

    int i, j, p;

    const int bpp   = c->bpp2;

    uint8_t *dst8   =             c->curbits;

    uint16_t *dst16 = (uint16_t *)c->curbits;

    uint32_t *dst32 = (uint32_t *)c->curbits;

    for (j = 0; j < c->cur_h; j++) {

        for (i = 0; i < c->cur_w; i++) {

            p = vmnc_get_pixel(&c->gb, bpp, c->bigendian);

            if (bpp == 1)

                *dst8++ = p;

            if (bpp == 2)

                *dst16++ = p;

            if (bpp == 4)

                *dst32++ = p;

        }

    }

    dst8  =            c->curmask;

    dst16 = (uint16_t*)c->curmask;

    dst32 = (uint32_t*)c->curmask;

    for (j = 0; j < c->cur_h; j++) {

        for (i = 0; i < c->cur_w; i++) {

            p = vmnc_get_pixel(&c->gb, bpp, c->bigendian);

            if (bpp == 1)

                *dst8++ = p;

            if (bpp == 2)

                *dst16++ = p;

            if (bpp == 4)

                *dst32++ = p;

        }

    }

}

static void put_cursor(uint8_t *dst, int stride, VmncContext *c, int dx, int dy)

{

    int i, j;

    int w, h, x, y;

    w = c->cur_w;

    if (c->width < c->cur_x + c->cur_w)

        w = c->width - c->cur_x;

    h = c->cur_h;

    if (c->height < c->cur_y + c->cur_h)

        h = c->height - c->cur_y;

    x = c->cur_x;

    y = c->cur_y;

    if (x < 0) {

        w += x;

        x  = 0;

    }

    if (y < 0) {

        h += y;

        y  = 0;

    }

    if ((w < 1) || (h < 1))

        return;

    dst += x * c->bpp2 + y * stride;

    if (c->bpp2 == 1) {

        uint8_t *cd = c->curbits, *msk = c->curmask;

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

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

                dst[i] = (dst[i] & cd[i]) ^ msk[i];

            msk += c->cur_w;

            cd  += c->cur_w;

            dst += stride;

        }

    } else if (c->bpp2 == 2) {

        uint16_t *cd = (uint16_t*)c->curbits, *msk = (uint16_t*)c->curmask;

        uint16_t *dst2;

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

            dst2 = (uint16_t*)dst;

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

                dst2[i] = (dst2[i] & cd[i]) ^ msk[i];

            msk += c->cur_w;

            cd  += c->cur_w;

            dst += stride;

        }

    } else if (c->bpp2 == 4) {

        uint32_t *cd = (uint32_t*)c->curbits, *msk = (uint32_t*)c->curmask;

        uint32_t *dst2;

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

            dst2 = (uint32_t*)dst;

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

                dst2[i] = (dst2[i] & cd[i]) ^ msk[i];

            msk += c->cur_w;

            cd  += c->cur_w;

            dst += stride;

        }

    }

}

/* fill rectangle with given color */

static av_always_inline void paint_rect(uint8_t *dst, int dx, int dy,

                                        int w, int h, int color,

                                        int bpp, int stride)

{

    int i, j;

    dst += dx * bpp + dy * stride;

    if (bpp == 1) {

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

            memset(dst, color, w);

            dst += stride;

        }

    } else if (bpp == 2) {

        uint16_t *dst2;

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

            dst2 = (uint16_t*)dst;

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

                *dst2++ = color;

            dst += stride;

        }

    } else if (bpp == 4) {

        uint32_t *dst2;

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

            dst2 = (uint32_t*)dst;

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

                dst2[i] = color;

            dst += stride;

        }

    }

}

static av_always_inline void paint_raw(uint8_t *dst, int w, int h,

                                       GetByteContext *gb, int bpp,

                                       int be, int stride)

{

    int i, j, p;

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

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

            p = vmnc_get_pixel(gb, bpp, be);

            switch (bpp) {

            case 1:

                dst[i] = p;

                break;

            case 2:

                ((uint16_t*)dst)[i] = p;

                break;

            case 4:

                ((uint32_t*)dst)[i] = p;

                break;

            }

        }

        dst += stride;

    }

}

static int decode_hextile(VmncContext *c, uint8_t* dst, GetByteContext *gb,

                          int w, int h, int stride)

{

    int i, j, k;

    int bg = 0, fg = 0, rects, color, flags, xy, wh;

    const int bpp = c->bpp2;

    uint8_t *dst2;

    int bw = 16, bh = 16;

    for (j = 0; j < h; j += 16) {

        dst2 = dst;

        bw   = 16;

        if (j + 16 > h)

            bh = h - j;

        for (i = 0; i < w; i += 16, dst2 += 16 * bpp) {

            if (bytestream2_get_bytes_left(gb) <= 0) {

                av_log(c->avctx, AV_LOG_ERROR, "Premature end of data!\n");

                return AVERROR_INVALIDDATA;

            }

            if (i + 16 > w)

                bw = w - i;

            flags = bytestream2_get_byte(gb);

            if (flags & HT_RAW) {

                if (bytestream2_get_bytes_left(gb) < bw * bh * bpp) {

                    av_log(c->avctx, AV_LOG_ERROR, "Premature end of data!\n");

                    return AVERROR_INVALIDDATA;

                }

                paint_raw(dst2, bw, bh, gb, bpp, c->bigendian, stride);

            } else {

                if (flags & HT_BKG)

                    bg = vmnc_get_pixel(gb, bpp, c->bigendian);

                if (flags & HT_FG)

                    fg = vmnc_get_pixel(gb, bpp, c->bigendian);

                rects = 0;

                if (flags & HT_SUB)

                    rects = bytestream2_get_byte(gb);

                color = !!(flags & HT_CLR);

                paint_rect(dst2, 0, 0, bw, bh, bg, bpp, stride);

                if (bytestream2_get_bytes_left(gb) < rects * (color * bpp + 2)) {

                    av_log(c->avctx, AV_LOG_ERROR, "Premature end of data!\n");

                    return AVERROR_INVALIDDATA;

                }

                for (k = 0; k < rects; k++) {

                    int rect_x, rect_y, rect_w, rect_h;

                    if (color)

                        fg = vmnc_get_pixel(gb, bpp, c->bigendian);

                    xy = bytestream2_get_byte(gb);

                    wh = bytestream2_get_byte(gb);

                    rect_x = xy >> 4;

                    rect_y = xy & 0xF;

                    rect_w = (wh >> 4) + 1;

                    rect_h = (wh & 0xF) + 1;

                    if (rect_x + rect_w > w - i || rect_y + rect_h > h - j) {

                        av_log(c->avctx, AV_LOG_ERROR, "Rectangle outside picture\n");

                        return AVERROR_INVALIDDATA;

                    }

                    paint_rect(dst2, rect_x, rect_y,

                               rect_w, rect_h, fg, bpp, stride);

                }

            }

        }

        dst += stride * 16;

    }

    return 0;

}

static void reset_buffers(VmncContext *c)

{

    av_freep(&c->curbits);

    av_freep(&c->curmask);

    av_freep(&c->screendta);

    c->cur_w = c->cur_h = 0;

    c->cur_hx = c->cur_hy = 0;

}

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

                        int *got_frame, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size       = avpkt->size;

    VmncContext * const c = avctx->priv_data;

    GetByteContext *gb = &c->gb;

    uint8_t *outptr;

    int dx, dy, w, h, depth, enc, chunks, res, size_left, ret;

    bytestream2_init(gb, buf, buf_size);

    bytestream2_skip(gb, 2);

    chunks = bytestream2_get_be16(gb);

    if (12LL * chunks > bytestream2_get_bytes_left(gb))

        return AVERROR_INVALIDDATA;

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

        return ret;

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

    c->pic->pict_type = AV_PICTURE_TYPE_P;

    // restore screen after cursor

    if (c->screendta) {

        int i;

        w = c->cur_w;

        if (c->width < c->cur_x + w)

            w = c->width - c->cur_x;

        h = c->cur_h;

        if (c->height < c->cur_y + h)

            h = c->height - c->cur_y;

        dx = c->cur_x;

        if (dx < 0) {

            w += dx;

            dx = 0;

        }

        dy = c->cur_y;

        if (dy < 0) {

            h += dy;

            dy = 0;

        }

        if ((w > 0) && (h > 0)) {

            outptr = c->pic->data[0] + dx * c->bpp2 + dy * c->pic->linesize[0];

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

                memcpy(outptr, c->screendta + i * c->cur_w * c->bpp2,

                       w * c->bpp2);

                outptr += c->pic->linesize[0];

            }

        }

    }

    while (chunks--) {

        if (bytestream2_get_bytes_left(gb) < 12) {

            av_log(avctx, AV_LOG_ERROR, "Premature end of data!\n");

            return -1;

        }

        dx  = bytestream2_get_be16(gb);

        dy  = bytestream2_get_be16(gb);

        w   = bytestream2_get_be16(gb);

        h   = bytestream2_get_be16(gb);

        enc = bytestream2_get_be32(gb);

        if ((dx + w > c->width) || (dy + h > c->height)) {

            av_log(avctx, AV_LOG_ERROR,

                    "Incorrect frame size: %ix%i+%ix%i of %ix%i\n",

                    w, h, dx, dy, c->width, c->height);

            return AVERROR_INVALIDDATA;

        }

        outptr = c->pic->data[0] + dx * c->bpp2 + dy * c->pic->linesize[0];

        size_left = bytestream2_get_bytes_left(gb);

        switch (enc) {

        case MAGIC_WMVd: // cursor

            if (w*(int64_t)h*c->bpp2 > INT_MAX/2 - 2) {

                av_log(avctx, AV_LOG_ERROR, "dimensions too large\n");

                return AVERROR_INVALIDDATA;

            }

            if (size_left < 2 + w * h * c->bpp2 * 2) {

                av_log(avctx, AV_LOG_ERROR,

                       "Premature end of data! (need %i got %i)\n",

                       2 + w * h * c->bpp2 * 2, size_left);

                return AVERROR_INVALIDDATA;

            }

            bytestream2_skip(gb, 2);

            c->cur_w  = w;

            c->cur_h  = h;

            c->cur_hx = dx;

            c->cur_hy = dy;

            if ((c->cur_hx > c->cur_w) || (c->cur_hy > c->cur_h)) {

                av_log(avctx, AV_LOG_ERROR,

                       "Cursor hot spot is not in image: "

                       "%ix%i of %ix%i cursor size\n",

                       c->cur_hx, c->cur_hy, c->cur_w, c->cur_h);

                c->cur_hx = c->cur_hy = 0;

            }

            if (c->cur_w * c->cur_h >= INT_MAX / c->bpp2) {

                reset_buffers(c);

                return AVERROR(EINVAL);

            } else {

                int screen_size = c->cur_w * c->cur_h * c->bpp2;

                if ((ret = av_reallocp(&c->curbits, screen_size)) < 0 ||

                    (ret = av_reallocp(&c->curmask, screen_size)) < 0 ||

                    (ret = av_reallocp(&c->screendta, screen_size)) < 0) {

                    reset_buffers(c);

                    return ret;

                }

            }

            load_cursor(c);

            break;

        case MAGIC_WMVe: // unknown

            bytestream2_skip(gb, 2);

            break;

        case MAGIC_WMVf: // update cursor position

            c->cur_x = dx - c->cur_hx;

            c->cur_y = dy - c->cur_hy;

            break;

        case MAGIC_WMVg: // unknown

            bytestream2_skip(gb, 10);

            break;

        case MAGIC_WMVh: // unknown

            bytestream2_skip(gb, 4);

            break;

        case MAGIC_WMVi: // ServerInitialization struct

            c->pic->flags |= AV_FRAME_FLAG_KEY;

            c->pic->pict_type = AV_PICTURE_TYPE_I;

            depth = bytestream2_get_byte(gb);

            if (depth != c->bpp) {

                av_log(avctx, AV_LOG_INFO,

                       "Depth mismatch. Container %i bpp, "

                       "Frame data: %i bpp\n",

                       c->bpp, depth);

            }

            bytestream2_skip(gb, 1);

            c->bigendian = bytestream2_get_byte(gb);

            if (c->bigendian & (~1)) {

                av_log(avctx, AV_LOG_INFO,

                       "Invalid header: bigendian flag = %i\n", c->bigendian);

                return AVERROR_INVALIDDATA;

            }

            //skip the rest of pixel format data

            bytestream2_skip(gb, 13);

            break;

        case MAGIC_WMVj: // unknown

            bytestream2_skip(gb, 2);

            break;

        case 0x00000000: // raw rectangle data

            if (size_left < w * h * c->bpp2) {

                av_log(avctx, AV_LOG_ERROR,

                       "Premature end of data! (need %i got %i)\n",

                       w * h * c->bpp2, size_left);

                return AVERROR_INVALIDDATA;

            }

            paint_raw(outptr, w, h, gb, c->bpp2, c->bigendian,

                      c->pic->linesize[0]);

            break;

        case 0x00000005: // HexTile encoded rectangle

            res = decode_hextile(c, outptr, gb, w, h, c->pic->linesize[0]);

            if (res < 0)

                return res;

            break;

        default:

            av_log(avctx, AV_LOG_ERROR, "Unsupported block type 0x%08X\n", enc);

            chunks = 0; // leave chunks decoding loop

        }

    }

    if (c->screendta) {

        int i;

        // save screen data before painting cursor

        w = c->cur_w;

        if (c->width < c->cur_x + w)

            w = c->width - c->cur_x;

        h = c->cur_h;

        if (c->height < c->cur_y + h)

            h = c->height - c->cur_y;

        dx = c->cur_x;

        if (dx < 0) {

            w += dx;

            dx = 0;

        }

        dy = c->cur_y;

        if (dy < 0) {

            h += dy;

            dy = 0;

        }

        if ((w > 0) && (h > 0)) {

            outptr = c->pic->data[0] + dx * c->bpp2 + dy * c->pic->linesize[0];

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

                memcpy(c->screendta + i * c->cur_w * c->bpp2, outptr,

                       w * c->bpp2);

                outptr += c->pic->linesize[0];

            }

            outptr = c->pic->data[0];

            put_cursor(outptr, c->pic->linesize[0], c, c->cur_x, c->cur_y);

        }

    }

    *got_frame = 1;

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

        return ret;

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

    return buf_size;

}

static av_cold int decode_init(AVCodecContext *avctx)

{

    VmncContext * const c = avctx->priv_data;

    c->avctx  = avctx;

    c->width  = avctx->width;

    c->height = avctx->height;

    c->bpp    = avctx->bits_per_coded_sample;

    switch (c->bpp) {

    case 8:

        avctx->pix_fmt = AV_PIX_FMT_PAL8;

        break;

    case 16:

        avctx->pix_fmt = AV_PIX_FMT_RGB555;

        break;

    case 24:

        /* 24 bits is not technically supported, but some clients might

         * mistakenly set it, so let's assume they actually meant 32 bits */

        c->bpp = 32;

    case 32:

        avctx->pix_fmt = AV_PIX_FMT_0RGB32;

        break;

    default:

        av_log(avctx, AV_LOG_ERROR, "Unsupported bitdepth %i\n", c->bpp);

        return AVERROR_INVALIDDATA;

    }

    c->bpp2 = c->bpp / 8;

    c->pic = av_frame_alloc();

    if (!c->pic)

        return AVERROR(ENOMEM);

    return 0;

}

static av_cold int decode_end(AVCodecContext *avctx)

{

    VmncContext * const c = avctx->priv_data;

    av_frame_free(&c->pic);

    av_freep(&c->curbits);

    av_freep(&c->curmask);

    av_freep(&c->screendta);

    return 0;

}

const FFCodec ff_vmnc_decoder = {

    .p.name         = "vmnc",

    CODEC_LONG_NAME("VMware Screen Codec / VMware Video"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_VMNC,

    .priv_data_size = sizeof(VmncContext),

    .init           = decode_init,

    .close          = decode_end,

    FF_CODEC_DECODE_CB(decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

};