speller.c

/****************************************************************************
 * speller.c
 *
 * Computer Science 50
 * Problem Set 6
 *
 * Implements a spell-checker.
 ***************************************************************************/

#include <ctype.h>
#include <stdio.h>
#include <sys/resource.h>
#include <sys/time.h>

#include "dictionary.h"


// default dictionary
#define DICTIONARY "/home/cs50/pset6/dictionaries/large"

// prototype
double calculate(const struct rusage *b, const struct rusage *a);


int
main(int argc, char *argv[])
{
    // check for correct number of args
    if (argc != 2 && argc != 3)
    {
        printf("Usage: speller [dictionary] text\n");
        return 1;
    }

    // structs for timing data
    struct rusage before, after;

    // benchmarks
    double ti_load = 0.0, ti_check = 0.0, ti_size = 0.0, ti_unload = 0.0;

    // determine dictionary to use
    char *dictionary = (argc == 3) ? argv[1] : DICTIONARY;

    // load dictionary
    getrusage(RUSAGE_SELF, &before);
    bool loaded = load(dictionary);
    getrusage(RUSAGE_SELF, &after);

    // abort if dictionary not loaded
    if (!loaded)
    {
        printf("Could not load %s.\n", dictionary);
        return 2;
    }

    // calculate time to load dictionary
    ti_load = calculate(&before, &after);

    // try to open text
    char *text = (argc == 3) ? argv[2] : argv[1];
    FILE *fp = fopen(text, "r");
    if (fp == NULL)
    {
        printf("Could not open %s.\n", text);
        unload();
        return 3;
    }

    // prepare to report misspellings
    printf("\nMISSPELLED WORDS\n\n");

    // prepare to spell-check
    int index = 0, misspellings = 0, words = 0;
    char word[LENGTH+1];

    // spell-check each word in text
    for (int c = fgetc(fp); c != EOF; c = fgetc(fp))
    {
        // allow only alphabetical characters and apostrophes
        if (isalpha(c) || (c == '\'' && index > 0))
        {
            // append character to word
            word[index] = c;
            index++;

            // ignore alphabetical strings too long to be words
            if (index > LENGTH)
            {
                // consume remainder of alphabetical string
                while ((c = fgetc(fp)) != EOF && isalpha(c));

                // prepare for new word
                index = 0;
            }
        }

        // ignore words with numbers (like MS Word can)
        else if (isdigit(c))
        {
            // consume remainder of alphanumeric string
            while ((c = fgetc(fp)) != EOF && isalnum(c));

            // prepare for new word
            index = 0;
        }

        // we must have found a whole word
        else if (index > 0)
        {
            // terminate current word
            word[index] = '\0';

            // update counter
            words++;

            // check word's spelling
            getrusage(RUSAGE_SELF, &before);
            bool misspelled = !check(word);
            getrusage(RUSAGE_SELF, &after);

            // update benchmark
            ti_check += calculate(&before, &after);

            // print word if misspelled
            if (misspelled)
            {
                printf("%s\n", word);
                misspellings++;
            }

            // prepare for next word
            index = 0;
        }
    }

    // check whether there was an error
    if (ferror(fp))
    {
        fclose(fp);
        printf("Error reading %s.\n", text);
        unload();
        return 4;
    }

    // close text
    fclose(fp);

    // determine dictionary's size
    getrusage(RUSAGE_SELF, &before);
    unsigned int n = size();
    getrusage(RUSAGE_SELF, &after);

    // calculate time to determine dictionary's size
    ti_size = calculate(&before, &after);

    // unload dictionary
    getrusage(RUSAGE_SELF, &before);
    bool unloaded = unload();
    getrusage(RUSAGE_SELF, &after);

    // abort if dictionary not unloaded
    if (!unloaded)
    {
        printf("Could not unload %s.\n", dictionary);
        return 5;
    }

    // calculate time to unload dictionary
    ti_unload = calculate(&before, &after);

    // report benchmarks
    printf("\nWORDS MISSPELLED:     %d\n", misspellings);
    printf("WORDS IN DICTIONARY:  %d\n", n);
    printf("WORDS IN TEXT:        %d\n", words);
    printf("TIME IN load:         %.2f\n", ti_load);
    printf("TIME IN check:        %.2f\n", ti_check);
    printf("TIME IN size:         %.2f\n", ti_size);
    printf("TIME IN unload:       %.2f\n", ti_unload);
    printf("TIME IN TOTAL:        %.2f\n\n", 
     ti_load + ti_check + ti_size + ti_unload);

    // that's all folks
    return 0;
}


/*
 * Returns number of seconds between b and a.
 */

double
calculate(const struct rusage *b, const struct rusage *a)
{
    if (b == NULL || a == NULL)
        return 0;
    else
        return ((((a->ru_utime.tv_sec * 1000000 + a->ru_utime.tv_usec) -
                 (b->ru_utime.tv_sec * 1000000 + b->ru_utime.tv_usec)) +
                ((a->ru_stime.tv_sec * 1000000 + a->ru_stime.tv_usec) -
                 (b->ru_stime.tv_sec * 1000000 + b->ru_stime.tv_usec)))
                / 1000000.0);
}