vmnc.c

mediastreamer2是开源的网络传输媒体流的库

/*
 * 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 vmnc.c
 * VMware Screen Codec (VMnc) decoder
 * As Alex Beregszaszi discovered, this is effectively RFB data dump
 */

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

#include "avcodec.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;

    /* 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(const uint8_t* buf, int bpp, int be) {
    switch(bpp * 2 + be) {
    case 2:
    case 3: return *buf;
    case 4: return AV_RL16(buf);
    case 5: return AV_RB16(buf);
    case 8: return AV_RL32(buf);
    case 9: return AV_RB32(buf);
    default: return 0;
    }
}

static void load_cursor(VmncContext *c, const uint8_t *src)
{
    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(src, bpp, c->bigendian);
            src += bpp;
            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(src, bpp, c->bigendian);
            src += bpp;
            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, const uint8_t* src, 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(src, bpp, be);
            src += bpp;
            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, const uint8_t* src, int ssize, 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;
    const uint8_t *ssrc=src;

    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(src - ssrc >= ssize) {
                av_log(c->avctx, AV_LOG_ERROR, "Premature end of data!\n");
                return -1;
            }
            if(i + 16 > w) bw = w - i;
            flags = *src++;
            if(flags & HT_RAW) {
                if(src - ssrc > ssize - bw * bh * bpp) {
                    av_log(c->avctx, AV_LOG_ERROR, "Premature end of data!\n");
                    return -1;
                }
                paint_raw(dst2, bw, bh, src, bpp, c->bigendian, stride);
                src += bw * bh * bpp;
            } else {
                if(flags & HT_BKG) {
                    bg = vmnc_get_pixel(src, bpp, c->bigendian); src += bpp;
                }
                if(flags & HT_FG) {
                    fg = vmnc_get_pixel(src, bpp, c->bigendian); src += bpp;
                }
                rects = 0;
                if(flags & HT_SUB)
                    rects = *src++;