San Mehat | a430b2b | 2014-09-23 08:30:51 -0700 | [diff] [blame] | 1 | /* |
| 2 | * zlib.c |
| 3 | * |
| 4 | * Routines to implement zlib based encoding (deflate). |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * Copyright (C) 2000 Tridia Corporation. All Rights Reserved. |
| 9 | * Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved. |
| 10 | * |
| 11 | * This is free software; you can redistribute it and/or modify |
| 12 | * it under the terms of the GNU General Public License as published by |
| 13 | * the Free Software Foundation; either version 2 of the License, or |
| 14 | * (at your option) any later version. |
| 15 | * |
| 16 | * This software is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | * GNU General Public License for more details. |
| 20 | * |
| 21 | * You should have received a copy of the GNU General Public License |
| 22 | * along with this software; if not, write to the Free Software |
| 23 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
| 24 | * USA. |
| 25 | * |
| 26 | * For the latest source code, please check: |
| 27 | * |
| 28 | * http://www.developVNC.org/ |
| 29 | * |
| 30 | * or send email to feedback@developvnc.org. |
| 31 | */ |
| 32 | |
| 33 | #include <rfb/rfb.h> |
| 34 | |
| 35 | /* |
| 36 | * zlibBeforeBuf contains pixel data in the client's format. |
| 37 | * zlibAfterBuf contains the zlib (deflated) encoding version. |
| 38 | * If the zlib compressed/encoded version is |
| 39 | * larger than the raw data or if it exceeds zlibAfterBufSize then |
| 40 | * raw encoding is used instead. |
| 41 | */ |
| 42 | |
| 43 | /* |
| 44 | * Out of lazyiness, we use thread local storage for zlib as we did for |
| 45 | * tight. N.B. ZRLE does it the traditional way with per-client storage |
| 46 | * (and so at least ZRLE will work threaded on older systems.) |
| 47 | */ |
| 48 | #if LIBVNCSERVER_HAVE_LIBPTHREAD && LIBVNCSERVER_HAVE_TLS && !defined(TLS) && defined(__linux__) |
| 49 | #define TLS __thread |
| 50 | #endif |
| 51 | #ifndef TLS |
| 52 | #define TLS |
| 53 | #endif |
| 54 | |
| 55 | static TLS int zlibBeforeBufSize = 0; |
| 56 | static TLS char *zlibBeforeBuf = NULL; |
| 57 | |
| 58 | static TLS int zlibAfterBufSize = 0; |
| 59 | static TLS char *zlibAfterBuf = NULL; |
| 60 | static TLS int zlibAfterBufLen = 0; |
| 61 | |
| 62 | void rfbZlibCleanup(rfbScreenInfoPtr screen) |
| 63 | { |
| 64 | if (zlibBeforeBufSize) { |
| 65 | free(zlibBeforeBuf); |
| 66 | zlibBeforeBufSize=0; |
| 67 | } |
| 68 | if (zlibAfterBufSize) { |
| 69 | zlibAfterBufSize=0; |
| 70 | free(zlibAfterBuf); |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | |
| 75 | /* |
| 76 | * rfbSendOneRectEncodingZlib - send a given rectangle using one Zlib |
| 77 | * rectangle encoding. |
| 78 | */ |
| 79 | |
| 80 | static rfbBool |
| 81 | rfbSendOneRectEncodingZlib(rfbClientPtr cl, |
| 82 | int x, |
| 83 | int y, |
| 84 | int w, |
| 85 | int h) |
| 86 | { |
| 87 | rfbFramebufferUpdateRectHeader rect; |
| 88 | rfbZlibHeader hdr; |
| 89 | int deflateResult; |
| 90 | int previousOut; |
| 91 | int i; |
| 92 | char *fbptr = (cl->scaledScreen->frameBuffer + (cl->scaledScreen->paddedWidthInBytes * y) |
| 93 | + (x * (cl->scaledScreen->bitsPerPixel / 8))); |
| 94 | |
| 95 | int maxRawSize; |
| 96 | int maxCompSize; |
| 97 | |
| 98 | maxRawSize = (cl->scaledScreen->width * cl->scaledScreen->height |
| 99 | * (cl->format.bitsPerPixel / 8)); |
| 100 | |
| 101 | if (zlibBeforeBufSize < maxRawSize) { |
| 102 | zlibBeforeBufSize = maxRawSize; |
| 103 | if (zlibBeforeBuf == NULL) |
| 104 | zlibBeforeBuf = (char *)malloc(zlibBeforeBufSize); |
| 105 | else |
| 106 | zlibBeforeBuf = (char *)realloc(zlibBeforeBuf, zlibBeforeBufSize); |
| 107 | } |
| 108 | |
| 109 | /* zlib compression is not useful for very small data sets. |
| 110 | * So, we just send these raw without any compression. |
| 111 | */ |
| 112 | if (( w * h * (cl->scaledScreen->bitsPerPixel / 8)) < |
| 113 | VNC_ENCODE_ZLIB_MIN_COMP_SIZE ) { |
| 114 | |
| 115 | int result; |
| 116 | |
| 117 | /* The translation function (used also by the in raw encoding) |
| 118 | * requires 4/2/1 byte alignment in the output buffer (which is |
| 119 | * updateBuf for the raw encoding) based on the bitsPerPixel of |
| 120 | * the viewer/client. This prevents SIGBUS errors on some |
| 121 | * architectures like SPARC, PARISC... |
| 122 | */ |
| 123 | if (( cl->format.bitsPerPixel > 8 ) && |
| 124 | ( cl->ublen % ( cl->format.bitsPerPixel / 8 )) != 0 ) { |
| 125 | if (!rfbSendUpdateBuf(cl)) |
| 126 | return FALSE; |
| 127 | } |
| 128 | |
| 129 | result = rfbSendRectEncodingRaw(cl, x, y, w, h); |
| 130 | |
| 131 | return result; |
| 132 | |
| 133 | } |
| 134 | |
| 135 | /* |
| 136 | * zlib requires output buffer to be slightly larger than the input |
| 137 | * buffer, in the worst case. |
| 138 | */ |
| 139 | maxCompSize = maxRawSize + (( maxRawSize + 99 ) / 100 ) + 12; |
| 140 | |
| 141 | if (zlibAfterBufSize < maxCompSize) { |
| 142 | zlibAfterBufSize = maxCompSize; |
| 143 | if (zlibAfterBuf == NULL) |
| 144 | zlibAfterBuf = (char *)malloc(zlibAfterBufSize); |
| 145 | else |
| 146 | zlibAfterBuf = (char *)realloc(zlibAfterBuf, zlibAfterBufSize); |
| 147 | } |
| 148 | |
| 149 | |
| 150 | /* |
| 151 | * Convert pixel data to client format. |
| 152 | */ |
| 153 | (*cl->translateFn)(cl->translateLookupTable, &cl->screen->serverFormat, |
| 154 | &cl->format, fbptr, zlibBeforeBuf, |
| 155 | cl->scaledScreen->paddedWidthInBytes, w, h); |
| 156 | |
| 157 | cl->compStream.next_in = ( Bytef * )zlibBeforeBuf; |
| 158 | cl->compStream.avail_in = w * h * (cl->format.bitsPerPixel / 8); |
| 159 | cl->compStream.next_out = ( Bytef * )zlibAfterBuf; |
| 160 | cl->compStream.avail_out = maxCompSize; |
| 161 | cl->compStream.data_type = Z_BINARY; |
| 162 | |
| 163 | /* Initialize the deflation state. */ |
| 164 | if ( cl->compStreamInited == FALSE ) { |
| 165 | |
| 166 | cl->compStream.total_in = 0; |
| 167 | cl->compStream.total_out = 0; |
| 168 | cl->compStream.zalloc = Z_NULL; |
| 169 | cl->compStream.zfree = Z_NULL; |
| 170 | cl->compStream.opaque = Z_NULL; |
| 171 | |
| 172 | deflateInit2( &(cl->compStream), |
| 173 | cl->zlibCompressLevel, |
| 174 | Z_DEFLATED, |
| 175 | MAX_WBITS, |
| 176 | MAX_MEM_LEVEL, |
| 177 | Z_DEFAULT_STRATEGY ); |
| 178 | /* deflateInit( &(cl->compStream), Z_BEST_COMPRESSION ); */ |
| 179 | /* deflateInit( &(cl->compStream), Z_BEST_SPEED ); */ |
| 180 | cl->compStreamInited = TRUE; |
| 181 | |
| 182 | } |
| 183 | |
| 184 | previousOut = cl->compStream.total_out; |
| 185 | |
| 186 | /* Perform the compression here. */ |
| 187 | deflateResult = deflate( &(cl->compStream), Z_SYNC_FLUSH ); |
| 188 | |
| 189 | /* Find the total size of the resulting compressed data. */ |
| 190 | zlibAfterBufLen = cl->compStream.total_out - previousOut; |
| 191 | |
| 192 | if ( deflateResult != Z_OK ) { |
| 193 | rfbErr("zlib deflation error: %s\n", cl->compStream.msg); |
| 194 | return FALSE; |
| 195 | } |
| 196 | |
| 197 | /* Note that it is not possible to switch zlib parameters based on |
| 198 | * the results of the compression pass. The reason is |
| 199 | * that we rely on the compressor and decompressor states being |
| 200 | * in sync. Compressing and then discarding the results would |
| 201 | * cause lose of synchronization. |
| 202 | */ |
| 203 | |
| 204 | /* Update statics */ |
| 205 | rfbStatRecordEncodingSent(cl, rfbEncodingZlib, sz_rfbFramebufferUpdateRectHeader + sz_rfbZlibHeader + zlibAfterBufLen, |
| 206 | + w * (cl->format.bitsPerPixel / 8) * h); |
| 207 | |
| 208 | if (cl->ublen + sz_rfbFramebufferUpdateRectHeader + sz_rfbZlibHeader |
| 209 | > UPDATE_BUF_SIZE) |
| 210 | { |
| 211 | if (!rfbSendUpdateBuf(cl)) |
| 212 | return FALSE; |
| 213 | } |
| 214 | |
| 215 | rect.r.x = Swap16IfLE(x); |
| 216 | rect.r.y = Swap16IfLE(y); |
| 217 | rect.r.w = Swap16IfLE(w); |
| 218 | rect.r.h = Swap16IfLE(h); |
| 219 | rect.encoding = Swap32IfLE(rfbEncodingZlib); |
| 220 | |
| 221 | memcpy(&cl->updateBuf[cl->ublen], (char *)&rect, |
| 222 | sz_rfbFramebufferUpdateRectHeader); |
| 223 | cl->ublen += sz_rfbFramebufferUpdateRectHeader; |
| 224 | |
| 225 | hdr.nBytes = Swap32IfLE(zlibAfterBufLen); |
| 226 | |
| 227 | memcpy(&cl->updateBuf[cl->ublen], (char *)&hdr, sz_rfbZlibHeader); |
| 228 | cl->ublen += sz_rfbZlibHeader; |
| 229 | |
| 230 | for (i = 0; i < zlibAfterBufLen;) { |
| 231 | |
| 232 | int bytesToCopy = UPDATE_BUF_SIZE - cl->ublen; |
| 233 | |
| 234 | if (i + bytesToCopy > zlibAfterBufLen) { |
| 235 | bytesToCopy = zlibAfterBufLen - i; |
| 236 | } |
| 237 | |
| 238 | memcpy(&cl->updateBuf[cl->ublen], &zlibAfterBuf[i], bytesToCopy); |
| 239 | |
| 240 | cl->ublen += bytesToCopy; |
| 241 | i += bytesToCopy; |
| 242 | |
| 243 | if (cl->ublen == UPDATE_BUF_SIZE) { |
| 244 | if (!rfbSendUpdateBuf(cl)) |
| 245 | return FALSE; |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | return TRUE; |
| 250 | |
| 251 | } |
| 252 | |
| 253 | |
| 254 | /* |
| 255 | * rfbSendRectEncodingZlib - send a given rectangle using one or more |
| 256 | * Zlib encoding rectangles. |
| 257 | */ |
| 258 | |
| 259 | rfbBool |
| 260 | rfbSendRectEncodingZlib(rfbClientPtr cl, |
| 261 | int x, |
| 262 | int y, |
| 263 | int w, |
| 264 | int h) |
| 265 | { |
| 266 | int maxLines; |
| 267 | int linesRemaining; |
| 268 | rfbRectangle partialRect; |
| 269 | |
| 270 | partialRect.x = x; |
| 271 | partialRect.y = y; |
| 272 | partialRect.w = w; |
| 273 | partialRect.h = h; |
| 274 | |
| 275 | /* Determine maximum pixel/scan lines allowed per rectangle. */ |
| 276 | maxLines = ( ZLIB_MAX_SIZE(w) / w ); |
| 277 | |
| 278 | /* Initialize number of scan lines left to do. */ |
| 279 | linesRemaining = h; |
| 280 | |
| 281 | /* Loop until all work is done. */ |
| 282 | while ( linesRemaining > 0 ) { |
| 283 | |
| 284 | int linesToComp; |
| 285 | |
| 286 | if ( maxLines < linesRemaining ) |
| 287 | linesToComp = maxLines; |
| 288 | else |
| 289 | linesToComp = linesRemaining; |
| 290 | |
| 291 | partialRect.h = linesToComp; |
| 292 | |
| 293 | /* Encode (compress) and send the next rectangle. */ |
| 294 | if ( ! rfbSendOneRectEncodingZlib( cl, |
| 295 | partialRect.x, |
| 296 | partialRect.y, |
| 297 | partialRect.w, |
| 298 | partialRect.h )) { |
| 299 | |
| 300 | return FALSE; |
| 301 | } |
| 302 | |
| 303 | /* Technically, flushing the buffer here is not extrememly |
| 304 | * efficient. However, this improves the overall throughput |
| 305 | * of the system over very slow networks. By flushing |
| 306 | * the buffer with every maximum size zlib rectangle, we |
| 307 | * improve the pipelining usage of the server CPU, network, |
| 308 | * and viewer CPU components. Insuring that these components |
| 309 | * are working in parallel actually improves the performance |
| 310 | * seen by the user. |
| 311 | * Since, zlib is most useful for slow networks, this flush |
| 312 | * is appropriate for the desired behavior of the zlib encoding. |
| 313 | */ |
| 314 | if (( cl->ublen > 0 ) && |
| 315 | ( linesToComp == maxLines )) { |
| 316 | if (!rfbSendUpdateBuf(cl)) { |
| 317 | |
| 318 | return FALSE; |
| 319 | } |
| 320 | } |
| 321 | |
| 322 | /* Update remaining and incremental rectangle location. */ |
| 323 | linesRemaining -= linesToComp; |
| 324 | partialRect.y += linesToComp; |
| 325 | |
| 326 | } |
| 327 | |
| 328 | return TRUE; |
| 329 | |
| 330 | } |
| 331 | |