/*
  * 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 <stdio.h>
 #include <stdlib.h>
 

 #include "libavutil/common.h"

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"

 #include "internal.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++) {

                     if (color)
                         fg = vmnc_get_pixel(gb, bpp, c->bigendian);
                     xy = bytestream2_get_byte(gb);
                     wh = bytestream2_get_byte(gb);

                     if (   (xy >> 4) + (wh >> 4) + 1 > w - i
                         || (xy & 0xF) + (wh & 0xF)+1 > h - j) {
                         av_log(c->avctx, AV_LOG_ERROR, "Rectangle outside picture\n");
                         return AVERROR_INVALIDDATA;
                     }

                     paint_rect(dst2, xy >> 4, xy & 0xF,
                                (wh>>4)+1, (wh & 0xF)+1, 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, void *data, 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;

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

         return ret;

     bytestream2_init(gb, buf, buf_size);
 

     c->pic->key_frame = 0;
     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];

             }
         }
     }

     bytestream2_skip(gb, 2);
     chunks = bytestream2_get_be16(gb);

     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);

         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->key_frame = 1;
             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 ((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;

             }

             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

             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;

             }

             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(data, 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;
     c->bpp2   = c->bpp / 8;

     switch (c->bpp) {

     case 8:

         avctx->pix_fmt = AV_PIX_FMT_PAL8;

         break;
     case 16:

         avctx->pix_fmt = AV_PIX_FMT_RGB555;

         break;
     case 32:

         avctx->pix_fmt = AV_PIX_FMT_RGB32;

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

         return AVERROR_INVALIDDATA;

     }
 

     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;
 }
 

 AVCodec ff_vmnc_decoder = {

     .name           = "vmnc",

     .long_name      = NULL_IF_CONFIG_SMALL("VMware Screen Codec / VMware Video"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_VMNC,

     .priv_data_size = sizeof(VmncContext),
     .init           = decode_init,
     .close          = decode_end,
     .decode         = decode_frame,
     .capabilities   = CODEC_CAP_DR1,

 };