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   char *time_format;
  31 } conf_t;
  32
  33 typedef struct {
  34   time_t start, end;
  35 } time_range_t;
  36
  37 const time_t NULL_TIME = (time_t)-1;
  38
  39 static time_range_t make_time_range(time_t t) { return (time_range_t){t, t}; }
  40
  41 static void extend_time_range(time_range_t *r, time_t t) { r->end = t; }
  42
  43 static char *read_line() {
  44   char *line = NULL;
  45   int scanf_ret = scanf("%m[^\n]", &line);
  46   if (scanf_ret == EOF && ferror(stdin))
  47     die_err("Error reading");
  48   int newline = getchar();
  49   if (newline != EOF && newline != (int)'\n')
  50     die("Expected newline");
  51   if (scanf_ret == 0 && newline == (int)'\n')
  52     return strdup("\n");
  53   return line;
  54 }
  55
  56 static void format_time(conf_t *conf, char *buf, size_t size, time_t *t) {
  57   struct tm *tm = localtime(t);
  58   if (tm == NULL)
  59     die_err("Couldn't unpack time");
  60   if (strftime(buf, size, conf->time_format, tm) == 0)
  61     die_err("Couldn't format time");
  62 }
  63
  64 static void write_line(conf_t *conf, time_range_t *range, char *line) {
  65   if (line == NULL)
  66     return;
  67   if (conf->time_format) {
  68     const size_t MAX_TIMESTAMP_LENGTH = 1024;
  69     char a[MAX_TIMESTAMP_LENGTH];
  70     char b[MAX_TIMESTAMP_LENGTH];
  71     format_time(conf, a, MAX_TIMESTAMP_LENGTH, &range->start);
  72     format_time(conf, b, MAX_TIMESTAMP_LENGTH, &range->end);
  73     if (printf("%s %s %s\n", a, b, line) < 0)
  74       die("Couldn't write");
  75   } else {
  76     if (printf("%ld %ld %s\n", range->start, range->end, line) < 0)
  77       die("Couldn't write");
  78   }
  79   if (fflush(stdout) == EOF)
  80     die_err("Couldn't flush");
  81 }
  82
  83 static int same(char *a, char *b) { return a && b && strcmp(a, b) == 0; }
  84
  85 static void uniqt(conf_t *conf) {
  86   char *current_line = NULL;
  87   time_range_t current_time_range = make_time_range(NULL_TIME);
  88   for (;;) {
  89     char *new_line = read_line();
  90     if (new_line == NULL)
  91       break;
  92     time_t now = time(NULL);
  93     if (same(current_line, new_line)) {
  94       free(new_line);
  95       extend_time_range(&current_time_range, now);
  96     } else {
  97       write_line(conf, &current_time_range, current_line);
  98       free(current_line);
  99       current_line = new_line;
 100       current_time_range = make_time_range(now);
 101     }
 102   }
 103   write_line(conf, &current_time_range, current_line);
 104   free(current_line);
 105 }
 106
 107 void usage() { die("usage: uniqt [-f time_format]"); }
 108
 109 conf_t parse_command_line(int argc, char *argv[]) {
 110   conf_t conf;
 111   conf.time_format = NULL;
 112
 113   for (int i = 1; i < argc; i++) {
 114     if (strcmp(argv[i], "-f") == 0) {
 115       if (i + 1 >= argc)
 116         die("-f requires an argument");
 117       i++;
 118       conf.time_format = argv[i];
 119     } else
 120       usage();
 121   }
 122
 123   return conf;
 124 }
 125
 126 int main(int argc, char *argv[]) {
 127   conf_t conf = parse_command_line(argc, argv);
 128   uniqt(&conf);
 129   return 0;
 130 }