Files
annotate/annotate.c
2025-08-07 21:11:55 -07:00

65 lines
1.2 KiB
C
Executable File

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#define BUF_SIZE 1024
void print_now(void) {
time_t now;
time(&now);
struct tm *time_parts = localtime(&now);
if (!time_parts) {
perror("Error getting time");
exit(3);
}
printf("[%d-%02d-%02d %02d:%02d:%02d] ",
time_parts->tm_year + 1900,
time_parts->tm_mon + 1,
time_parts->tm_mday,
time_parts->tm_hour,
time_parts->tm_min,
time_parts->tm_sec);
}
/**
* Program that reads from STDIN and writes to STDOUT with each line annotated
* with the current date and time
*/
int main(void) {
char buffer[BUF_SIZE];
// when true, print the time on the next iteration
// allows us to avoid printing after the last newline
bool output_time = true;
ssize_t count_read;
while ((count_read = read(STDIN_FILENO, buffer, BUF_SIZE))) {
for (ssize_t i=0; i < count_read; i++) {
if (output_time && !feof(stdin)) {
print_now();
output_time = false;
}
fputc(buffer[i], stdout);
if (buffer[i] == '\n') {
output_time = true;
}
}
}
if (count_read < 0) {
perror("Error reading from stdin");
exit(1);
}
fflush(stdout);
return 0;
}