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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(¤t_time_range, now); | |
96 | } else { | |
97 | write_line(conf, ¤t_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, ¤t_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 | } |