3.c

/*
Name: Teagan Haddawy
Date: Tuesday Jan 6, 2026
Title: Lab 1 - Part 5
Description: Compares the time of the library functions vs system calls in order to copy
*/

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>

#define BUFFER_SIZE 2048

void func_copy(const char* src_file, const char* dst_file) //runs the same as 1.c
{
    FILE *src = fopen(src_file, "rb");
    if (src == NULL)
    {
        return;
    }

    FILE *dst = fopen(dst_file, "wb");
    if (dst == NULL)
    {
        return;
    }
    char *buf = malloc(BUFFER_SIZE);
    size_t bytes_read;

    while ((bytes_read = fread(buf, 1, BUFFER_SIZE, src)) > 0)
    {
        fwrite(buf, 1, bytes_read, dst);
    }
    free(buf);
    fclose(src);
    fclose(dst);
}

void syscall_copy(const char* src_file, const char* dst_file) //runs the same as 2.c
{
    int src_fd = open(src_file, O_RDONLY);
    if (src_fd < 0)
    {
        return;
    }
    int dst_fd = open(dst_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
    if (dst_fd < 0)
    {
        return;
    }
    char *buf = malloc(BUFFER_SIZE);
    ssize_t bytes_read;
    while ((bytes_read = read(src_fd, buf, BUFFER_SIZE)) > 0)
    {
        write(dst_fd, buf, bytes_read);
    }
    free(buf);
    close(src_fd);
    close(dst_fd);
}

int main(int argc, char *argv[])
{
    if (argc != 3) //checks for 3 arguments needed
    {
        fprintf(stderr, "Usage: %s <src_filename> <dst_filename>", argv[0]);
        exit(1);
    }
    clock_t start, end; //creates a clock start and end
    double func_time, syscall_time;
    start = clock(); //starts the clock
    func_copy(argv[1], argv[2]); //completes a copy using function calls
    end = clock(); //end the clock when its finished
    func_time = (double)(end - start) / CLOCKS_PER_SEC; //calculate time for first method
    start = clock(); //start clock for system call method
    syscall_copy(argv[1], argv[2]); // completes the copy using system calls
    end = clock(); //ends clock for system call method
    syscall_time = (double)(end - start) / CLOCKS_PER_SEC; //calculate time
    printf("Function time: %f\n", func_time);
    printf("System Call time: %f\n", syscall_time);
    return 0;
}