#include "../port.h"

/*
** A simple and fast generic string hasher based on Peter K. Pearson's
** article in CACM 33-6, pp. 677.
*/

static unsigned char T[] = {
    1, 87, 49, 12, 176, 178, 102, 166, 121, 193, 6, 84, 249, 230, 44, 163,
    14, 197, 213, 181, 161, 85, 218, 80, 64, 239, 24, 226, 236, 142, 38, 200,
    110, 177, 104, 103, 141, 253, 255, 50, 77, 101, 81, 18, 45, 96, 31, 222,
    25, 107, 190, 70, 86, 237, 240, 34, 72, 242, 20, 214, 244, 227, 149, 235,
    97, 234, 57, 22, 60, 250, 82, 175, 208, 5, 127, 199, 111, 62, 135, 248,
    174, 169, 211, 58, 66, 154, 106, 195, 245, 171, 17, 187, 182, 179, 0, 243,
    132, 56, 148, 75, 128, 133, 158, 100, 130, 126, 91, 13, 153, 246, 216, 219,
    119, 68, 223, 78, 83, 88, 201, 99, 122, 11, 92, 32, 136, 114, 52, 10,
    138, 30, 48, 183, 156, 35, 61, 26, 143, 74, 251, 94, 129, 162, 63, 152,
    170, 7, 115, 167, 241, 206, 3, 150, 55, 59, 151, 220, 90, 53, 23, 131, 
    125, 173, 15, 238, 79, 95, 89, 16, 105, 137, 225, 224, 217, 160, 37, 123,
    118, 73, 2, 157, 46, 116, 9, 145, 134, 228, 207, 212, 202, 215, 69, 229,
    27, 188, 67, 124, 168, 252, 42, 4, 29, 108, 21, 247, 19, 205, 39, 203,
    233, 40, 186, 147, 198, 192, 155, 33, 164, 191, 98, 204, 165, 180, 117, 76,
    140, 36, 210, 172, 41, 54, 159, 8, 185, 232, 113, 196, 231, 47, 146, 120,
    51, 65, 28, 144, 254, 221, 93, 189, 194, 139, 112, 43, 71, 109, 184, 209,
};

/* alignment hint */
union quadchar { struct { unsigned char c0, c1, c2, c3; } c; int32 i; };

int hashblock(char *s, mp_int len, int max) {
    int hi, lo;
    register union quadchar *p = (union quadchar *)s;
    register int i = max;

    if (len < i) {
	i = len;
    }
    hi = lo = 0;
    do {
	lo = T[lo ^ p->c.c0];
	hi = T[hi ^ p->c.c1];
	lo = T[lo ^ p->c.c2];
	lo = T[lo ^ p->c.c3];
	p++;
    } while ((i -= 4) > 0);
    return (hi << 8) + lo;
}

int hashstr(char *s, mp_int len, int max) {
    int hi, lo;
    register unsigned char *p = (void *)s;
    register int i = max;

    if (len < i) {
	i = len;
    }
    hi = lo = 0;
    while ((i -= 4) >= 0) {
	lo ^= *p;
	lo = T[lo];
	hi ^= p[1];
	hi = T[hi];
	lo ^= p[2];
	lo = T[lo];
	lo ^= p[3];
	lo = T[lo];
	p+=4;
    }
    switch (i) {
      case -1:
	lo = T[lo ^ *p++];
      case -2:
	hi = T[hi ^ *p++];
      case -3:
	lo = T[lo ^ *p];
    }
    return (hi << 8) + lo;
}