各种字符串hash

unsigned int SDBMHash(char *str){
 	unsigned int hash = 0; 
 	while (*str) { 
 	// equivalent to:
 	 	hash = 65599*hash + (*str++);
 	 	 hash = (*str++) + (hash << 6) + (hash << 16) - hash; 
 	  } 
    return (hash & 0x7FFFFFFF);
    } 
// RS Hash Function
unsigned int RSHash(char *str){
	 unsigned int b = 378551; 
	 	unsigned int a = 63689;
	   unsigned int hash = 0;
	    while (*str) { 
	    hash = hash * a + (*str++); a *= b;
	   } 
    return (hash & 0x7FFFFFFF);
} 
// JS Hash Function
unsigned int JSHash(char *str){
  unsigned int hash = 1315423911; 
   while (*str) { 
   	hash ^= ((hash << 5) + (*str++) + (hash >> 2)); 
   } 
  return (hash & 0x7FFFFFFF);
} 
// P. J. Weinberger Hash Function
unsigned int PJWHash(char *str){
 	unsigned int BitsInUnignedInt = (unsigned int)(sizeof(unsigned int) * 8); 
 		unsigned int ThreeQuarters = (unsigned int)((BitsInUnignedInt * 3) / 4); 
 		  unsigned int OneEighth = (unsigned int)(BitsInUnignedInt / 8); 
 		unsigned int HighBits = (unsigned int)(0xFFFFFFFF) << (BitsInUnignedInt - OneEighth); 
 	unsigned int hash = 0; 
 		unsigned int test = 0; 
 	  while (*str) {
 	   hash = (hash << OneEighth) + (*str++); 
 	   if ((test = hash & HighBits) != 0 {
 	    hash = ((hash ^ (test >> ThreeQuarters)) & (~HighBits)); 
 	    } 
 	  }
     return (hash & 0x7FFFFFFF);
   }
 // ELF Hash Function
unsigned int ELFHash(char *str){
 	 unsigned int hash = 0;
 		  unsigned int x = 0;
 	   while (*str) {
 	  	  hash = (hash << 4) + (*str++);
 	   		  if ((x = hash & 0xF0000000L) != 0) {
 	    		 	 hash ^= (x >> 24);
 	       			hash &= ~x;
 	        	  }
 	      } 
 	return (hash & 0x7FFFFFFF);
 }
 // BKDR Hash Function
unsigned int BKDRHash(char *str){
	unsigned int seed = 131; 
	// 31 131 1313 13131 131313 etc.. 
	unsigned int hash = 0; 
	while (*str) {
		 hash = hash * seed + (*str++);
	 } 
    return (hash & 0x7FFFFFFF);
} 
// DJB Hash Function
unsigned int DJBHash(char *str){ 
		unsigned int hash = 5381; 
		  while (*str) { 
		  	 hash += (hash << 5) + (*str++);
		  } 
	return (hash & 0x7FFFFFFF);
} 
// AP Hash Function
unsigned int APHash(char *str){
	 unsigned int hash = 0; 
		 int i; 
	  for (i=0; *str; i++) {
	   		if ((i & 1) == 0) { 
	   			hash ^= ((hash << 7) ^ (*str++) ^ (hash >> 3)); 
	   		} 	   	
	   		else {
	   			 hash ^= (~((hash << 11) ^ (*str++) ^ (hash >> 5))); 
	   		     } 
	  }
      return (hash & 0x7FFFFFFF);
}