Bachelors_Thesis_Code/helper_code/fagprojekt_code/hash_table.cpp

#include "hash_table.hpp"
#include "hashed_string.hpp"

#include <stdint.h>
#include <string.h>

Hash_table::Hash_table(Hash_function * hash_function) : hash_function(hash_function) {
    m = hash_function->get_m();

    words = new Hashed_string[m];
}

Hash_table::~Hash_table() {
    delete hash_function;
    delete[] words;
}

size_t Hash_table::get_distict_words() {
    return distinct_words;
}

void Hash_table::hash(My_string * word) {
    uint64_t hash = hash_function->hash(word);
    distinct_words += words[hash].append(new Hashed_string(word));
}

void Hash_table::hash(Hashed_string * hs) {
    uint64_t hash = hash_function->hash( &(hs->string) );
    distinct_words += words[hash].append(hs);
}

void Hash_table::rehash(Hash_function * hash_function) {
    delete this->hash_function;
    this->hash_function = hash_function;

    size_t old_m = m;
    m = this->hash_function->get_m();

    Hashed_string * old_words = this->words;

    words = new Hashed_string[m];

    distinct_words = 0; // reset, because we are hashing all the words once more

    for (size_t i = 0; i < old_m; i++) {
        Hashed_string * hs = &(old_words[i]);
        // skip the initializer Hashed_string
        while (hs->next != NULL) {
            hs = hs->next;
            hash(new Hashed_string(hs));
        }
    }

    // delete the old stuff
    delete[] old_words;
}