1 /******************************************************************************
2
3 gif_hash.h - magfic constants and declarations for GIF LZW
4
5 ******************************************************************************/
6
7 #ifndef _GIF_HASH_H_
8 #define _GIF_HASH_H_
9
10 #include <unistd.h>
11 #include <stdint.h>
12
13 #define HT_SIZE 8192 /* 12bits = 4096 or twice as big! */
14 #define HT_KEY_MASK 0x1FFF /* 13bits keys */
15 #define HT_KEY_NUM_BITS 13 /* 13bits keys */
16 #define HT_MAX_KEY 8191 /* 13bits - 1, maximal code possible */
17 #define HT_MAX_CODE 4095 /* Biggest code possible in 12 bits. */
18
19 /* The 32 bits of the long are divided into two parts for the key & code: */
20 /* 1. The code is 12 bits as our compression algorithm is limited to 12bits */
21 /* 2. The key is 12 bits Prefix code + 8 bit new char or 20 bits. */
22 /* The key is the upper 20 bits. The code is the lower 12. */
23 #define HT_GET_KEY(l) (l >> 12)
24 #define HT_GET_CODE(l) (l & 0x0FFF)
25 #define HT_PUT_KEY(l) (l << 12)
26 #define HT_PUT_CODE(l) (l & 0x0FFF)
27
28 typedef struct GifHashTableType {
29 uint32_t HTable[HT_SIZE];
30 } GifHashTableType;
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1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /******************************************************************************
26
27 gif_hash.h - magfic constants and declarations for GIF LZW
28
29 ******************************************************************************/
30
31 #ifndef _GIF_HASH_H_
32 #define _GIF_HASH_H_
33
34 #include <stdint.h>
35
36 #define HT_SIZE 8192 /* 12bits = 4096 or twice as big! */
37 #define HT_KEY_MASK 0x1FFF /* 13bits keys */
38 #define HT_KEY_NUM_BITS 13 /* 13bits keys */
39 #define HT_MAX_KEY 8191 /* 13bits - 1, maximal code possible */
40 #define HT_MAX_CODE 4095 /* Biggest code possible in 12 bits. */
41
42 /* The 32 bits of the long are divided into two parts for the key & code: */
43 /* 1. The code is 12 bits as our compression algorithm is limited to 12bits */
44 /* 2. The key is 12 bits Prefix code + 8 bit new char or 20 bits. */
45 /* The key is the upper 20 bits. The code is the lower 12. */
46 #define HT_GET_KEY(l) (l >> 12)
47 #define HT_GET_CODE(l) (l & 0x0FFF)
48 #define HT_PUT_KEY(l) (l << 12)
49 #define HT_PUT_CODE(l) (l & 0x0FFF)
50
51 typedef struct GifHashTableType {
52 uint32_t HTable[HT_SIZE];
53 } GifHashTableType;
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