#include 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) { int i, j; UINT16 h; for (i = 0; i < 32; i++) { 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 %d=0x%hhx\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() { int i; buildhashtable(); printf("static UINT16 HuffIndexLOM[32] = {\n"); for (i = 0; i < 32; i++) { if (i == 31) printf("0x%hx };\n", HashTable[i]); else printf("0x%hx, ", HashTable[i]); } for (i = 0; i < 32; i++) if (i != getvalue(HuffCodeLOM[i])) printf("Fail :( at %d : 0x%04x got %d\n", i, HuffCodeLOM[i], getvalue(HuffCodeLOM[i])); return 0; }