/*
 * reader.c
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

int main(int argc, char *argv[])
{
    char *file_data;
    struct stat sb;
    int fd;
    char buf[1];

    /* open the file */
    if((fd = open("test-file", O_RDONLY)) < 0) {
        perror("open");
        exit(1);
    }

    /* get file metadata, most especially its size */
    if(fstat(fd, &sb) < 0) {
        perror("fstat");
        exit(2);
    }

    /* set up the mapping */
    file_data = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);

    /* pause */
    write(1, "hit enter to output file contents\n", 34);
    read(0, buf, 1);

    /* write the data to stdout */
    write(1, file_data, sb.st_size);

    /* pause */
    write(1, "hit enter to output file contents again\n", 40);
    read(0, buf, 1);

    /* write the data to stdout */
    write(1, file_data, sb.st_size);

    /* clean up after ourselves */
    munmap(file_data, sb.st_size);
    close(fd);
}