readlex.c

/* gcc -g -o readlex readlex.c -Isrc */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "index.h"

int
main(void)
{
    int i;
    FILE *fp;
    struct lexicon_entry lex_entry;

    if (!(fp = fopen("lexicon", "r"))) {
        perror("fopen");
        return EXIT_FAILURE;
    }


    for (i = 0; i < 5; ++i) {
        memset(&lex_entry, 0x0, sizeof(struct lexicon_entry));

        /*
         * Read in the first three members of the lexicon_entry struct.
         *
         * 4 + 4 + 2 bytes
         */
        fread(&lex_entry, sizeof(lex_entry.doc_freq) + sizeof(lex_entry.offset)
                + sizeof(lex_entry.len), 1, fp);

        /* allocate memory for the `term` member */
        lex_entry.term = (char *)calloc(1, lex_entry.len + 1);
        fread(lex_entry.term, lex_entry.len, 1, fp);

        /*
         * using `calloc` above means we already have a `\0` char terminating our
         * string, the following is not necessary, but let's do it anyway.
         */
        lex_entry.term[lex_entry.len] = '\0';

        printf("lex_entry.doc_freq: %d\n", lex_entry.doc_freq);
        printf("lex_entry.offset: %d\n", lex_entry.offset);
        printf("lex_entry.len: %d\n", lex_entry.len);
        printf("lex_entry.term: %s\n", lex_entry.term);

        free(lex_entry.term);
    }

    return 0;
}