字符串的哈希處理

unsigned int SDBMHash(const char* str)
{
unsigned int hash = 0;
while(*str)
{
hashValue = static_cast<unsigned int>(*str++) + (hash<<6)+(hash<<16)-hash
}


return (hash & 0x7FFFFFFF)
}


unsigned int APHash(const char* str)
{
unsigned int hash = 0;
for(int i=0;*str;++i)
{
if((i&1)==0)
{
hash ^= ((hash<<7)^(static_cast<unsigned int>(*str++))^(hash>>3));
}
else
{
hash ^= (~((hash<<11)^(static_cast<unsigned int>(*str++)^(hash>>5)));
}
}
return (hash & 0x7FFFFFFF)
}


unsigned int RSHash(const char* str)
{
unsigned int a = 63689;
unsigned int b = 378551;
unsigned int hash = 0;
while(*str)
{
hash = hash*a+(*str++);
a *= b;
}
return (hash & 0x7FFFFFFF);
}


//三重檢測確保字符串
unsigned int hash(const char* str,hashTable* table)
{
unsigned int hashId = SDBMHash(str);
table[hashId].checkHash1 = APHash(str);
table[hashId].checkHash2 = RSHash(str);
}