typedef unsigned long int u4; /* unsigned 4-byte type */
typedef unsigned char u1; /* unsigned 1-byte type */
/* The mixing step */
#define mix(a,b,c) \
{ \
a=a-b; a=a-c; a=a^(c>>13); \
b=b-c; b=b-a; b=b^(a<<8>>13); \
a=a-b; a=a-c; a=a^(c>>12); \
b=b-c; b=b-a; b=b^(a<<16>>5); \
a=a-b; a=a-c; a=a^(c>>3); \
b=b-c; b=b-a; b=b^(a<<10>>15); \
}
/* The whole new hash function */
u4 hash( k, length, initval)
register u1 *k; /* the key */
u4 length; /* the length of the key in bytes */
u4 initval; /* the previous hash, or an arbitrary value */
{
register u4 a,b,c; /* the internal state */
u4 len; /* how many key bytes still need mixing */
/* Set up the internal state */
len = length;
a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
c = initval; /* variable initialization of internal state */
/*---------------------------------------- handle most of the key */
while (len >= 12)
{
a=a+(k[0]+((u4)k[1]<<8)+((u4)k[2]<<16) +((u4)k[3]<<24));
b=b+(k[4]+((u4)k[5]<<8)+((u4)k[6]<<16) +((u4)k[7]<<24));
c=c+(k[8]+((u4)k[9]<<8)+((u4)k[10]<<16)+((u4)k[11]<<24));
mix(a,b,c);
k = k+12; len = len-12;
}
/*------------------------------------- handle the last 11 bytes */
c = c+length;
switch(len) /* all the case statements fall through */
{
case 11: c=c+((u4)k[10]<<24);
case 10: c=c+((u4)k[9]<<16);
case 9 : c=c+((u4)k[8]<<8);
/* the first byte of c is reserved for the length */
case 8 : b=b+((u4)k[7]<<24);
case 7 : b=b+((u4)k[6]<<16);
case 6 : b=b+((u4)k[5]<<8);
case 5 : b=b+k[4];
case 4 : a=a+((u4)k[3]<<24);
case 3 : a=a+((u4)k[2]<<16);
case 2 : a=a+((u4)k[1]<<8);
case 1 : a=a+k[0];
/* case 0: nothing left to add */
}
mix(a,b,c);
/*-------------------------------------------- report the result */
return c;
}
Though I really should be getting back to work on my code...
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