CDN_DNS/trie/trie.c

#include "trie.h"

#define INPUT_FILE "../data/routing-data"
#define READ_MODE "r"
#define GET_BIT(key, bit) ( ( key.l[ bit / 64 ] & (1ul << (63 - bit % 64)) ) != 0 )


trie_node_t create_node() {
    trie_node_t ret = calloc(1, sizeof(struct trie_node)); /* sets null childs and invalid */
    return ret;
}

trie_holder_t create_holder() {
    trie_holder_t ret = malloc(sizeof(struct trie_holder));
    ret->_size = 0;
    ret->_root = create_node();
    return ret;
}

int trie_insert(trie_holder_t t, ipv6_t key, int val, int mask) {
    trie_node_t iter = t->_root;
    trie_node_t* next = &t->_root;
    int i = 0;

    for (;i <= 128 - mask; ++i) {
        if (!*(next = GET_BIT(key, i) ? &iter->_l : &iter->_r))
            *next = create_node();
        
        iter = *next;
    }
    
    if (iter->_rule_valid == VALID_RULE) {
        printf("WARNING: conflicting rule %x:%x:%x:%x:%x:%x:%x:%x", 
            key.s[0], key.s[1], key.s[2], key.s[3],
            key.s[4], key.s[5], key.s[6], key.s[7]);
        
        printf("/%d %d\n", mask, val);
        return 0;
    }

    iter->_rule_valid = VALID_RULE;
    iter->_rule = val;

    return 1;
}

int trie_search(trie_holder_t t, ipv6_t key) {
    return 0;
}


/*------------------------------------------------------------*/


int parse_line(ipv6_t* key, int* val, int* mask, FILE* f) { /*! assumes only good input */
    memset(key, 0, sizeof(ipv6_t));

    fscanf(f, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx", 
        &key->s[0], &key->s[1], &key->s[2], &key->s[3], &key->s[4],
        &key->s[5], &key->s[6], &key->s[7]);

    if (feof(f)) return 0; /* ends with newline */
    while (fgetc(f) != '/');
    
    fscanf(f, "%d %d", mask, val);
    return !feof(f);
}

int load_input(trie_holder_t t) {
    int val;
    int mask;
    ipv6_t key;

    FILE* f;
    int cnt = 0;
    
    if (!(f = fopen(INPUT_FILE, READ_MODE)))
        perror("cant open input file");
    
    while (parse_line(&key, &val, &mask, f)) {
        trie_insert(t, key, val, mask);
        ++cnt;
    }
    return cnt;
}

int main() {
    trie_holder_t t = create_holder();

    /*
    unsigned key[4] = {8927349, 9872346, 898097878, 928398629};
    int i;
       00000000100010000011100001110101 00000000100101101010001111011010 00110101100001111110001011010110 00110111010101100011110100100101
       00000000100010000011100001110101 00000000100101101010001111011010 00110101100001111110001011010110 00110111010101100011110100100101
    
    for (i = 0; i < 128; ++i) {
        printf("%d", GET_BIT(key, i));
    }
    printf("\n");
    return 0;
    */

    printf("Loaded %d rules\n", load_input(t) );
    return 0;
}