wc.c

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <string.h>


#define MAX_FILES_COUNT 1000
#define MAX_LINE_LENGTH 10000

#define OUT 0
#define IN 1

struct file_info {
    char* file_name;
    FILE* file_ptr;
};


int total_lines, total_words, total_chars;
pthread_mutex_t mutex;


void* compute_word_count(void* args) {

    struct file_info* file = (struct file_info*) args;
    int lines, words, chars;

    char* file_name = file -> file_name;
    FILE* file_ptr = file -> file_ptr;

    lines = words = chars = 0;

    char buffer[MAX_LINE_LENGTH];

    while(fgets(buffer, sizeof(buffer), file_ptr) != NULL) {
        lines++;
        int i = 0;
        int state = OUT;
        while(buffer[i] != '\0') {
            chars++;
            if(buffer[i] == ' ' || buffer[i] == '\t' || buffer[i] == '\n')
                state = OUT;
            else if(state == OUT) {
                words++;
                state = IN;
            }
            i++;
        }
    }
    printf("%2d %4d %8d %16s\n", lines, words, chars, file_name);
    pthread_mutex_lock(&mutex);
    total_lines += lines;
    total_words += words;
    total_chars += chars;
    pthread_mutex_unlock(&mutex);
}


void get_word_count(struct file_info files[], int count) {
    pthread_t tid[MAX_FILES_COUNT];
    pthread_mutex_init(&mutex, NULL);
    for(int i = 0; i < count; i++) {
        pthread_create(&tid[i], NULL, &compute_word_count, &files[i]);
    }
    for(int i = 0; i < count; i++) {
        pthread_join(tid[i], NULL);
    }
    pthread_mutex_destroy(&mutex);

    printf("%2d %4d %8d %16s\n", total_lines, total_words, total_chars, "total");
}


int main(int argc, char* argv[])
{
    FILE* file_ptr[MAX_FILES_COUNT];
    struct file_info files[MAX_FILES_COUNT];
    int valid_files = 0;
    if(argc - 1 > MAX_FILES_COUNT) {
        fprintf(stderr, "File count limit exceeded. Remove %d files.", argc - 1 - MAX_FILES_COUNT);
    }
    for(int i = 0; i < argc - 1; i++) {
        file_ptr[valid_files] = fopen(argv[i + 1], "r");
        if(file_ptr[valid_files] == NULL)
            fprintf(stderr, "File %s not found\n", argv[i + 1]);
        else {
            files[valid_files].file_ptr = file_ptr[valid_files];
            files[valid_files].file_name = argv[i + 1];
            valid_files++;
        }
    }

    get_word_count(files, valid_files);

    for(int i = 0; i < valid_files; i++) {
        fclose(file_ptr[i]);
    }

    return 0;
}