Shared TDE VNC library sources
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libtdevnc/libvncserver/zrleencodetemplate.c

273 lines
6.9 KiB

/*
* Copyright (C) 2002 RealVNC Ltd. All Rights Reserved.
* Copyright (C) 2003 Sun Microsystems, Inc.
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
/*
* Before including this file, you must define a number of CPP macros.
*
* BPP should be 8, 16 or 32 depending on the bits per pixel.
* GET_IMAGE_INTO_BUF should be some code which gets a rectangle of pixel data
* into the given buffer. EXTRA_ARGS can be defined to pass any other
* arguments needed by GET_IMAGE_INTO_BUF.
*
* Note that the buf argument to ZRLE_ENCODE needs to be at least one pixel
* bigger than the largest tile of pixel data, since the ZRLE encoding
* algorithm writes to the position one past the end of the pixel data.
*/
#include "zrleoutstream.h"
#include "zrlepalettehelper.h"
#include <assert.h>
/* __RFB_CONCAT2 concatenates its two arguments. __RFB_CONCAT2E does the same
but also expands its arguments if they are macros */
#ifndef __RFB_CONCAT2E
#define __RFB_CONCAT2(a,b) a##b
#define __RFB_CONCAT2E(a,b) __RFB_CONCAT2(a,b)
#endif
#ifdef CPIXEL
#define PIXEL_T __RFB_CONCAT2E(zrle_U,BPP)
#define zrleOutStreamWRITE_PIXEL __RFB_CONCAT2E(zrleOutStreamWriteOpaque,CPIXEL)
#define ZRLE_ENCODE __RFB_CONCAT2E(zrleEncode,CPIXEL)
#define ZRLE_ENCODE_TILE __RFB_CONCAT2E(zrleEncodeTile,CPIXEL)
#define BPPOUT 24
#else
#define PIXEL_T __RFB_CONCAT2E(zrle_U,BPP)
#define zrleOutStreamWRITE_PIXEL __RFB_CONCAT2E(zrleOutStreamWriteOpaque,BPP)
#define ZRLE_ENCODE __RFB_CONCAT2E(zrleEncode,BPP)
#define ZRLE_ENCODE_TILE __RFB_CONCAT2E(zrleEncodeTile,BPP)
#define BPPOUT BPP
#endif
#ifndef ZRLE_ONCE
#define ZRLE_ONCE
static const int bitsPerPackedPixel[] = {
0, 1, 2, 2, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4
};
static zrlePaletteHelper paletteHelper;
#endif /* ZRLE_ONCE */
void ZRLE_ENCODE_TILE (PIXEL_T* data, int w, int h, zrleOutStream* os);
void ZRLE_ENCODE (int x, int y, int w, int h,
zrleOutStream* os, void* buf
EXTRA_ARGS
)
{
int ty;
for (ty = y; ty < y+h; ty += rfbZRLETileHeight) {
int tx, th = rfbZRLETileHeight;
if (th > y+h-ty) th = y+h-ty;
for (tx = x; tx < x+w; tx += rfbZRLETileWidth) {
int tw = rfbZRLETileWidth;
if (tw > x+w-tx) tw = x+w-tx;
GET_IMAGE_INTO_BUF(tx,ty,tw,th,buf);
ZRLE_ENCODE_TILE((PIXEL_T*)buf, tw, th, os);
}
}
zrleOutStreamFlush(os);
}
void ZRLE_ENCODE_TILE (PIXEL_T* data, int w, int h, zrleOutStream* os)
{
/* First find the palette and the number of runs */
zrlePaletteHelper *ph;
int runs = 0;
int singlePixels = 0;
rfbBool useRle;
rfbBool usePalette;
int estimatedBytes;
int plainRleBytes;
int i;
PIXEL_T* ptr = data;
PIXEL_T* end = ptr + h * w;
*end = ~*(end-1); /* one past the end is different so the while loop ends */
ph = &paletteHelper;
zrlePaletteHelperInit(ph);
while (ptr < end) {
PIXEL_T pix = *ptr;
if (*++ptr != pix) {
singlePixels++;
} else {
while (*++ptr == pix) ;
runs++;
}
zrlePaletteHelperInsert(ph, pix);
}
/* Solid tile is a special case */
if (ph->size == 1) {
zrleOutStreamWriteU8(os, 1);
zrleOutStreamWRITE_PIXEL(os, ph->palette[0]);
return;
}
// Try to work out whether to use RLE and/or a palette. We do this by
// estimating the number of bytes which will be generated and picking the
// method which results in the fewest bytes. Of course this may not result
// in the fewest bytes after compression...
useRle = FALSE;
usePalette = FALSE;
estimatedBytes = w * h * (BPPOUT/8); // start assuming raw
plainRleBytes = ((BPPOUT/8)+1) * (runs + singlePixels);
if (plainRleBytes < estimatedBytes) {
useRle = TRUE;
estimatedBytes = plainRleBytes;
}
if (ph->size < 128) {
int paletteRleBytes = (BPPOUT/8) * ph->size + 2 * runs + singlePixels;
if (paletteRleBytes < estimatedBytes) {
useRle = TRUE;
usePalette = TRUE;
estimatedBytes = paletteRleBytes;
}
if (ph->size < 17) {
int packedBytes = ((BPPOUT/8) * ph->size +
w * h * bitsPerPackedPixel[ph->size-1] / 8);
if (packedBytes < estimatedBytes) {
useRle = FALSE;
usePalette = TRUE;
estimatedBytes = packedBytes;
}
}
}
if (!usePalette) ph->size = 0;
zrleOutStreamWriteU8(os, (useRle ? 128 : 0) | ph->size);
for (i = 0; i < ph->size; i++) {
zrleOutStreamWRITE_PIXEL(os, ph->palette[i]);
}
if (useRle) {
PIXEL_T* ptr = data;
PIXEL_T* end = ptr + w * h;
PIXEL_T* runStart;
PIXEL_T pix;
while (ptr < end) {
int len;
runStart = ptr;
pix = *ptr++;
while (*ptr == pix && ptr < end)
ptr++;
len = ptr - runStart;
if (len <= 2 && usePalette) {
int index = zrlePaletteHelperLookup(ph, pix);
if (len == 2)
zrleOutStreamWriteU8(os, index);
zrleOutStreamWriteU8(os, index);
continue;
}
if (usePalette) {
int index = zrlePaletteHelperLookup(ph, pix);
zrleOutStreamWriteU8(os, index | 128);
} else {
zrleOutStreamWRITE_PIXEL(os, pix);
}
len -= 1;
while (len >= 255) {
zrleOutStreamWriteU8(os, 255);
len -= 255;
}
zrleOutStreamWriteU8(os, len);
}
} else {
// no RLE
if (usePalette) {
int bppp;
PIXEL_T* ptr = data;
// packed pixels
assert (ph->size < 17);
bppp = bitsPerPackedPixel[ph->size-1];
for (i = 0; i < h; i++) {
zrle_U8 nbits = 0;
zrle_U8 byte = 0;
PIXEL_T* eol = ptr + w;
while (ptr < eol) {
PIXEL_T pix = *ptr++;
zrle_U8 index = zrlePaletteHelperLookup(ph, pix);
byte = (byte << bppp) | index;
nbits += bppp;
if (nbits >= 8) {
zrleOutStreamWriteU8(os, byte);
nbits = 0;
}
}
if (nbits > 0) {
byte <<= 8 - nbits;
zrleOutStreamWriteU8(os, byte);
}
}
} else {
// raw
#ifdef CPIXEL
PIXEL_T *ptr;
for (ptr = data; ptr < data+w*h; ptr++) {
zrleOutStreamWRITE_PIXEL(os, *ptr);
}
#else
zrleOutStreamWriteBytes(os, (zrle_U8 *)data, w*h*(BPP/8));
#endif
}
}
}
#undef PIXEL_T
#undef zrleOutStreamWRITE_PIXEL
#undef ZRLE_ENCODE
#undef ZRLE_ENCODE_TILE
#undef BPPOUT