/* 使用前要先调用函数prepareCryptTable()初始化编码表。 */ DWORD cryptTable[0x500]; /* 编码表 */ void prepareCryptTable() { DWORD seed = 0x00100001, index1 = 0, index2 = 0, i; for( index1 = 0; index1<0x100; index1++ ) { for( index2 = index1, i = 0; i < 5; i++, index2 += 0x100 ) { DWORD temp1, temp2; seed = (seed * 125 + 3) % 0x2AAAAB; temp1 = (seed & 0xFFFF) << 0x10; seed = (seed * 125 + 3) % 0x2AAAAB; temp2 = (seed & 0xFFFF); cryptTable[index2] = ( temp1 | temp2 ); } } } DWORD HashString( const char *lpszName, DWORD dwHashType, int len ) { unsigned char *key = (unsigned char *)lpszName; DWORD seed1 = 0x7FED7FED; DWORD seed2 = 0xEEEEEEEE; int ch; for(;len > 0; len--) { ch = *key++; seed1 = cryptTable[(dwHashType << 8) + ch] ^ (seed1 + seed2); seed2 = ch + seed1 + seed2 + (seed2 << 5) + 3; } return seed1; }
#define get16bits(d) (*((const UINT16 *) (d))) DWORD SuperFastHash (const char * data, int len) { UINT32 hash = len, tmp; INT32 rem; if (len <= 0 || data == NULL) return 0; rem = len & 3; len >>= 2; /* Main loop */ for (;len > 0; len--) { hash += get16bits (data); tmp = (get16bits (data+2) << 11) ^ hash; hash = (hash << 16) ^ tmp; data += 2*sizeof (UINT16); hash += hash >> 11; } /* Handle end cases */ switch (rem) { case 3: hash += get16bits (data); hash ^= hash << 16; hash ^= data[sizeof (UINT16)] << 18; hash += hash >> 11; break; case 2: hash += get16bits (data); hash ^= hash << 11; hash += hash >> 17; break; case 1: hash += *data; hash ^= hash << 10; hash += hash >> 1; } /* Force "avalanching" of final 127 bits */ hash ^= hash << 3; hash += hash >> 5; hash ^= hash << 4; hash += hash >> 17; hash ^= hash << 25; hash += hash >> 6; return hash; }