initial commit

.gitignore

@@ -0,0 +1,10 @@
+# binary files
+annotate
+
+# object files
+*.o
+
+# temp stuff
+*.swp
+*.swo
+.DS_STORE

Makefile

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+CFLAGS=--std=c99 -O2 -Wall -Wextra -pedantic
+
+annotate: annotate.o
+
+clean:
+	rm -f annotate *.o
+
+.PHONY: clean

annotate.c

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+#include <stdio.h>
+#include <stdbool.h>
+#include <time.h>
+#include <unistd.h>
+
+#define BUF_SIZE 1024
+#define PRINT_BUF_SIZE 1280
+
+void print_now() {
+  time_t now;
+  time(&now);
+
+  struct tm *time_parts = localtime(&now);
+
+  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() {
+  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;
+      }
+
+      if (buffer[i] == '\n') {
+        printf("\n");
+        fflush(stdout);
+        output_time = true;
+      } else {
+        fputc(buffer[i], stdout);
+      }
+    }
+  }
+
+  if (count_read < 0) {
+    perror("Error reading from stdin");
+    return 1;
+  }
+
+  fflush(stdout);
+
+  return 0;
+}