LibVNCServer/LibVNCClient
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zlib.c
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1 /*
2  * Copyright (C) 2000 Tridia Corporation. All Rights Reserved.
3  * Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved.
4  *
5  * This is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This software is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this software; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
18  * USA.
19  */
20 
21 #ifdef LIBVNCSERVER_HAVE_LIBZ
22 
23 /*
24  * zlib.c - handle zlib encoding.
25  *
26  * This file shouldn't be compiled directly. It is included multiple times by
27  * rfbproto.c, each time with a different definition of the macro BPP. For
28  * each value of BPP, this file defines a function which handles an zlib
29  * encoded rectangle with BPP bits per pixel.
30  */
31 
32 #define HandleZlibBPP CONCAT2E(HandleZlib,BPP)
33 #define CARDBPP CONCAT3E(uint,BPP,_t)
34 
35 static rfbBool
36 HandleZlibBPP (rfbClient* client, int rx, int ry, int rw, int rh)
37 {
38  rfbZlibHeader hdr;
39  int remaining;
40  int inflateResult;
41  int toRead;
42 
43  /* First make sure we have a large enough raw buffer to hold the
44  * decompressed data. In practice, with a fixed BPP, fixed frame
45  * buffer size and the first update containing the entire frame
46  * buffer, this buffer allocation should only happen once, on the
47  * first update.
48  */
49  if ( client->raw_buffer_size < (( rw * rh ) * ( BPP / 8 ))) {
50 
51  if ( client->raw_buffer != NULL ) {
52 
53  free( client->raw_buffer );
54 
55  }
56 
57  client->raw_buffer_size = (( rw * rh ) * ( BPP / 8 ));
58  client->raw_buffer = (char*) malloc( client->raw_buffer_size );
59 
60  }
61 
62  if (!ReadFromRFBServer(client, (char *)&hdr, sz_rfbZlibHeader))
63  return FALSE;
64 
65  remaining = rfbClientSwap32IfLE(hdr.nBytes);
66 
67  /* Need to initialize the decompressor state. */
68  client->decompStream.next_in = ( Bytef * )client->buffer;
69  client->decompStream.avail_in = 0;
70  client->decompStream.next_out = ( Bytef * )client->raw_buffer;
71  client->decompStream.avail_out = client->raw_buffer_size;
72  client->decompStream.data_type = Z_BINARY;
73 
74  /* Initialize the decompression stream structures on the first invocation. */
75  if ( client->decompStreamInited == FALSE ) {
76 
77  inflateResult = inflateInit( &client->decompStream );
78 
79  if ( inflateResult != Z_OK ) {
81  "inflateInit returned error: %d, msg: %s\n",
82  inflateResult,
83  client->decompStream.msg);
84  return FALSE;
85  }
86 
87  client->decompStreamInited = TRUE;
88 
89  }
90 
91  inflateResult = Z_OK;
92 
93  /* Process buffer full of data until no more to process, or
94  * some type of inflater error, or Z_STREAM_END.
95  */
96  while (( remaining > 0 ) &&
97  ( inflateResult == Z_OK )) {
98 
99  if ( remaining > RFB_BUFFER_SIZE ) {
100  toRead = RFB_BUFFER_SIZE;
101  }
102  else {
103  toRead = remaining;
104  }
105 
106  /* Fill the buffer, obtaining data from the server. */
107  if (!ReadFromRFBServer(client, client->buffer,toRead))
108  return FALSE;
109 
110  client->decompStream.next_in = ( Bytef * )client->buffer;
111  client->decompStream.avail_in = toRead;
112 
113  /* Need to uncompress buffer full. */
114  inflateResult = inflate( &client->decompStream, Z_SYNC_FLUSH );
115 
116  /* We never supply a dictionary for compression. */
117  if ( inflateResult == Z_NEED_DICT ) {
118  rfbClientLog("zlib inflate needs a dictionary!\n");
119  return FALSE;
120  }
121  if ( inflateResult < 0 ) {
122  rfbClientLog(
123  "zlib inflate returned error: %d, msg: %s\n",
124  inflateResult,
125  client->decompStream.msg);
126  return FALSE;
127  }
128 
129  /* Result buffer allocated to be at least large enough. We should
130  * never run out of space!
131  */
132  if (( client->decompStream.avail_in > 0 ) &&
133  ( client->decompStream.avail_out <= 0 )) {
134  rfbClientLog("zlib inflate ran out of space!\n");
135  return FALSE;
136  }
137 
138  remaining -= toRead;
139 
140  } /* while ( remaining > 0 ) */
141 
142  if ( inflateResult == Z_OK ) {
143 
144  /* Put the uncompressed contents of the update on the screen. */
145  CopyRectangle(client, (uint8_t *)client->raw_buffer, rx, ry, rw, rh);
146  }
147  else {
148 
149  rfbClientLog(
150  "zlib inflate returned error: %d, msg: %s\n",
151  inflateResult,
152  client->decompStream.msg);
153  return FALSE;
154 
155  }
156 
157  return TRUE;
158 }
159 
160 #undef CARDBPP
161 
162 #endif