git.scottworley.com Git - uniqt/blob - uniqt.c

   1 #define _POSIX_C_SOURCE 200809L
   2
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <time.h>
   7
   8 void die(const char *message) {
   9   fputs(message, stderr);
  10   fputc('\n', stderr);
  11   exit(1);
  12 }
  13
  14 void die_err(const char *message) {
  15   perror(message);
  16   exit(1);
  17 }
  18
  19 char *encode_time(time_t t) {
  20   struct tm tm;
  21   localtime_r(&t, &tm);
  22   const size_t size = 20;
  23   char *out = (char *)malloc(size);
  24   if (strftime(out, size, "%Y %m %d %H %M %S", &tm) != size - 1)
  25     die("Couldn't format time");
  26   return out;
  27 }
  28
  29 typedef struct {
  30   time_t start, end;
  31 } time_range_t;
  32
  33 const time_t NULL_TIME = (time_t)-1;
  34
  35 static time_range_t make_time_range(time_t t) { return (time_range_t){t, t}; }
  36
  37 static void extend_time_range(time_range_t *r, time_t t) { r->end = t; }
  38
  39 static char *read_line() {
  40   char *line = NULL;
  41   int scanf_ret = scanf("%m[^\n]", &line);
  42   if (scanf_ret == EOF && ferror(stdin))
  43     die_err("Error reading");
  44   int newline = getchar();
  45   if (newline != EOF && newline != (int)'\n')
  46     die("Expected newline");
  47   if (scanf_ret == 0 && newline == (int)'\n')
  48     return strdup("\n");
  49   return line;
  50 }
  51
  52 static void write_line(time_range_t *range, char *line) {
  53   if (line == NULL)
  54     return;
  55   if (printf("%ld %ld %s\n", range->start, range->end, line) < 0)
  56     die("Couldn't write");
  57   if (fflush(stdout) == EOF)
  58     die_err("Couldn't flush");
  59 }
  60
  61 static int same(char *a, char *b) { return a && b && strcmp(a, b) == 0; }
  62
  63 static void uniqt() {
  64   char *current_line = NULL;
  65   time_range_t current_time_range = make_time_range(NULL_TIME);
  66   for (;;) {
  67     char *new_line = read_line();
  68     if (new_line == NULL)
  69       break;
  70     time_t now = time(NULL);
  71     if (same(current_line, new_line)) {
  72       free(new_line);
  73       extend_time_range(&current_time_range, now);
  74     } else {
  75       write_line(&current_time_range, current_line);
  76       free(current_line);
  77       current_line = new_line;
  78       current_time_range = make_time_range(now);
  79     }
  80   }
  81   write_line(&current_time_range, current_line);
  82   free(current_line);
  83 }
  84
  85 int main() {
  86   uniqt();
  87   return 0;
  88 }