74 lines
2.0 KiB
C
74 lines
2.0 KiB
C
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#include<stdio.h>
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typedef unsigned short uint16;
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typedef unsigned char uint8;
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static uint16 HuffCodeLOM[] = {
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0x0001, 0x0000, 0x0002, 0x0009, 0x0006, 0x0005, 0x000d, 0x000b, 0x0003, 0x001b, 0x0007, 0x0017, 0x0037,
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0x000f, 0x004f, 0x006f, 0x002f, 0x00ef, 0x001f, 0x005f, 0x015f, 0x009f, 0x00df, 0x01df, 0x003f, 0x013f, 0x00bf,
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0x01bf, 0x007f, 0x017f, 0x00ff, 0x01ff };
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uint16 HashTable[32] = { [0 ... 31] = 0xffff };
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uint8 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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uint8 minihash(uint16 key)
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{
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uint8 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 %d=0x%hhx\n",i,h,HashTable[h]);
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}
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}
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uint8 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%hx };\n",HashTable[i]);
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else
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printf("0x%hx, ",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%04x got %d\n",i,HuffCodeLOM[i],getvalue(HuffCodeLOM[i]));
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return 0;
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}
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