a string hashing function found in Warcraft III

wc3hash.c

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <inttypes.h>

typedef uint8_t u8;
typedef uint32_t u32;
typedef uint64_t u64;

const u64 table[16] = {
    // magic numbers for each possible value of a nybble.
    0x486E26EEDCAA16B3, 0xE1918EEF202DAFDB,
    0x341C7DC71C365303, 0x40EF2D3765FD5E49,
    0xD6057177904ECE93, 0x1C38024F98FD323B,
    0xE3061AE7A39B0FA1, 0x9797F25FE4444563,
    0xCD2EC20C8DC1B898, 0x31759633799A306D,
    0x8C2063852E6E9627, 0x79237D9973922C66,
    0x8728628D28628824, 0x8F1F7E9625887795,
    0x296E3281389C0D60, 0x6F4893CA61636542
};

u64 wc3hash(const char *key, size_t len, u64 hash, bool isPath) {
    // technically there doesn't seem to be a
    // length argument in the original function,
    // I'm just adding it so you can hash strings with '\0' in them.

    if (key == NULL)
        return 0;

    if (hash == 0)
        hash = 0x7FED7FED7FED7FED;

    u64 state = 0xEEEEEEEEEEEEEEEE;

    for (size_t i = 0; i < len; i++) {
        u8 v;
        if (isPath) {
            char c = key[i];
            if (c >= 'a' && c <= 'z')
                c -= 'a' - 'A'; // uppercase
            if (c == '/')
                c = '\\'; // DOS-style paths

            v = (u8)c;
        } else {
            v = (u8)key[i];
        }

        hash += state;
        hash ^= table[v >> 4] + table[v & 0xF];
        state += state << 5;
        state += hash + v + 3;
    }

    if (hash == 0)
        return 1;

    return hash;
}

u64 wc3hashC(const char *key) {
    // simple interface that only takes a null-terminated string.
    return wc3hash(key, strlen(key), 0, true);
}

int main(int argc, char **argv) {
    if (argc == 1) {
        const char str[] = "IseeDeadPeople";
        u64 hash = wc3hashC(str);
        fprintf(stderr, "%" PRIX64 " should equal 701EA16D47F385FC\n", hash);
        return hash != 0x701EA16D47F385FC;
    }

    for (int i = 1; i < argc; i++) {
        u64 hash = wc3hashC(argv[i]);
        u32 hash32 = (hash >> 32) ^ hash;
        printf("%" PRIX64 "\t%08X\n", hash, hash32);
    }
    return 0;
}