82 lines
1.7 KiB
C
82 lines
1.7 KiB
C
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#include <stdio.h>
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typedef unsigned short UINT16;
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typedef unsigned char BYTE;
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static UINT16 HuffCodeLOM[] = { 0x0001, 0x0000, 0x0002, 0x0009, 0x0006, 0x0005, 0x000d, 0x000b,
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0x0003, 0x001b, 0x0007, 0x0017, 0x0037, 0x000f, 0x004f, 0x006f,
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0x002f, 0x00ef, 0x001f, 0x005f, 0x015f, 0x009f, 0x00df, 0x01df,
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0x003f, 0x013f, 0x00bf, 0x01bf, 0x007f, 0x017f, 0x00ff, 0x01ff };
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UINT16 HashTable[32] = { [0 ... 31] = 0xffff };
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BYTE tab[4] = { 0, 4, 10, 19 };
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UINT16 hash(UINT16 key)
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{
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return ((key & 0x1f) ^ (key >> 5) ^ (key >> 9));
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}
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BYTE minihash(UINT16 key)
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{
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BYTE h;
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h = (key >> 4) & 0xf;
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return ((h ^ (h >> 2) ^ (h >> 3)) & 0x3);
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}
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void buildhashtable(void)
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{
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int i, j;
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UINT16 h;
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for (i = 0; i < 32; i++)
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{
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h = hash(HuffCodeLOM[i]);
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if (HashTable[h] != 0xffff)
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{
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HashTable[h] ^= (HuffCodeLOM[i] & 0xfe0) ^ 0xfe0;
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HashTable[tab[minihash(HuffCodeLOM[i])]] = i;
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}
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else
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{
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HashTable[h] = i;
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HashTable[h] ^= 0xfe0;
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}
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printf("at %d %" PRIu16 "=0x%" PRIx16 "\n", i, h, HashTable[h]);
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}
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}
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BYTE getvalue(UINT16 huff)
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{
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UINT16 h = HashTable[hash(huff)];
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if ((h ^ huff) >> 5)
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{
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return h & 0x1f;
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}
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else
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return HashTable[tab[minihash(huff)]];
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}
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main()
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{
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int i;
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buildhashtable();
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printf("static UINT16 HuffIndexLOM[32] = {\n");
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for (i = 0; i < 32; i++)
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{
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if (i == 31)
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printf("0x%" PRIx16 " };\n", HashTable[i]);
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else
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printf("0x%" PRIx16 ", ", HashTable[i]);
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}
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for (i = 0; i < 32; i++)
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if (i != getvalue(HuffCodeLOM[i]))
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printf("Fail :( at %d : 0x%04" PRIx16 " got %" PRIu8 "\n", i, HuffCodeLOM[i],
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getvalue(HuffCodeLOM[i]));
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return 0;
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}
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