1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
#include <stdio.h>
typedef unsigned short UINT16;
typedef unsigned char BYTE;
static UINT16 HuffCodeLOM[] = { 0x0001, 0x0000, 0x0002, 0x0009, 0x0006, 0x0005, 0x000d, 0x000b,
0x0003, 0x001b, 0x0007, 0x0017, 0x0037, 0x000f, 0x004f, 0x006f,
0x002f, 0x00ef, 0x001f, 0x005f, 0x015f, 0x009f, 0x00df, 0x01df,
0x003f, 0x013f, 0x00bf, 0x01bf, 0x007f, 0x017f, 0x00ff, 0x01ff };
UINT16 HashTable[32] = { [0 ... 31] = 0xffff };
BYTE tab[4] = { 0, 4, 10, 19 };
UINT16 hash(UINT16 key)
{
return ((key & 0x1f) ^ (key >> 5) ^ (key >> 9));
}
BYTE minihash(UINT16 key)
{
BYTE h;
h = (key >> 4) & 0xf;
return ((h ^ (h >> 2) ^ (h >> 3)) & 0x3);
}
void buildhashtable(void)
{
for (int i = 0; i < 32; i++)
{
UINT16 h = hash(HuffCodeLOM[i]);
if (HashTable[h] != 0xffff)
{
HashTable[h] ^= (HuffCodeLOM[i] & 0xfe0) ^ 0xfe0;
HashTable[tab[minihash(HuffCodeLOM[i])]] = i;
}
else
{
HashTable[h] = i;
HashTable[h] ^= 0xfe0;
}
printf("at %d %" PRIu16 "=0x%" PRIx16 "\n", i, h, HashTable[h]);
}
}
BYTE getvalue(UINT16 huff)
{
UINT16 h = HashTable[hash(huff)];
if ((h ^ huff) >> 5)
{
return h & 0x1f;
}
else
return HashTable[tab[minihash(huff)]];
}
main()
{
buildhashtable();
printf("static UINT16 HuffIndexLOM[32] = {\n");
for (int i = 0; i < 32; i++)
{
if (i == 31)
printf("0x%" PRIx16 " };\n", HashTable[i]);
else
printf("0x%" PRIx16 ", ", HashTable[i]);
}
for (int i = 0; i < 32; i++)
if (i != getvalue(HuffCodeLOM[i]))
printf("Fail :( at %d : 0x%04" PRIx16 " got %" PRIu8 "\n", i, HuffCodeLOM[i],
getvalue(HuffCodeLOM[i]));
return 0;
}
|
