LibVNCServer/LibVNCClient
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zrlepalettehelper.c
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1 /*
2  * Copyright (C) 2002 RealVNC Ltd. All Rights Reserved.
3  * Copyright (C) 2003 Sun Microsystems, Inc.
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 #include "zrlepalettehelper.h"
22 #include <assert.h>
23 #include <string.h>
24 
25 #define ZRLE_HASH(pix) (((pix) ^ ((pix) >> 17)) & 4095)
26 
28 {
29  memset(helper->palette, 0, sizeof(helper->palette));
30  memset(helper->index, 255, sizeof(helper->index));
31  memset(helper->key, 0, sizeof(helper->key));
32  helper->size = 0;
33 }
34 
36 {
37  if (helper->size < ZRLE_PALETTE_MAX_SIZE) {
38  int i = ZRLE_HASH(pix);
39 
40  while (helper->index[i] != 255 && helper->key[i] != pix)
41  i++;
42  if (helper->index[i] != 255) return;
43 
44  helper->index[i] = helper->size;
45  helper->key[i] = pix;
46  helper->palette[helper->size] = pix;
47  }
48  helper->size++;
49 }
50 
52 {
53  int i = ZRLE_HASH(pix);
54 
55  assert(helper->size <= ZRLE_PALETTE_MAX_SIZE);
56 
57  while (helper->index[i] != 255 && helper->key[i] != pix)
58  i++;
59  if (helper->index[i] != 255) return helper->index[i];
60 
61  return -1;
62 }