datefmt

commit 4a6628c744ccce5e3bb8fa7e02419c0f59a40247
parent 531e2369b30db01593bd17840fe399802a757791
Author: William Casarin <jb55@jb55.com>
Date:   Thu, 20 Oct 2022 11:26:03 -0700

Add --timeago timestamp formatting

Enables relative timestamp formatting (2h, etc.)

Changelog-Added: Add --timeago: relative timestamp formatting
Signed-off-by: William Casarin <jb55@jb55.com>

Diffstat:
M
datefmt.c
 | 
50
+++++++++++++++++++++++++++++++++++++++++++++++---

1 file changed, 47 insertions(+), 3 deletions(-)
diff --git a/datefmt.c b/datefmt.c
@@ -22,6 +22,7 @@ struct parser {
 	int n_digits;
 	int dir;
 	int ms;
+	int timeago;
 	const char *format;
 	char digits[15];
 };
@@ -79,9 +80,48 @@ static int time_matches(struct parser *parser, int64_t ts)
 	return 1;
 }
 
-static enum state doaction(int c, enum state new_state, struct parser *parser)
+static void print_timeago(int64_t previous)
+{
+	time_t now = time(NULL);
+
+	int ms_per_minute = 60 * 1000;
+	int ms_per_hour = ms_per_minute * 60;
+	int ms_per_day = ms_per_hour * 24;
+	int ms_per_month = ms_per_day * 30;
+	int ms_per_year = ms_per_day * 365;
+
+	int elapsed = now - previous;
+
+	if (elapsed < ms_per_minute) {
+		printf("%ds", elapsed / 1000);
+	} else if (elapsed < ms_per_hour) {
+		printf("%dm", elapsed / ms_per_minute);
+	} else if (elapsed < ms_per_day) {
+		printf("%dh", elapsed / ms_per_hour);
+	} else if (elapsed < ms_per_month) {
+		printf("%dd", elapsed / ms_per_day);
+	} else if (elapsed < ms_per_year) {
+		printf("%dmth", elapsed / ms_per_month);
+	} else {
+		printf("%dyr", elapsed / ms_per_year);
+	}
+}
+
+static void print_time(const char *format, char *charbuf, int64_t ts, int timeago)
 {
 	static char timebuf[128];
+
+	if (timeago) {
+		print_timeago(ts);
+		printf("%s", charbuf);
+	} else {
+		strftime(timebuf, sizeof(timebuf), format, localtime((time_t*)&ts));
+		printf("%s%s", timebuf, charbuf);
+	}
+}
+
+static enum state doaction(int c, enum state new_state, struct parser *parser)
+{
 	char charbuf[2];
 	int64_t ts;
 
@@ -99,8 +139,7 @@ static enum state doaction(int c, enum state new_state, struct parser *parser)
 		ts = strtoll(parser->digits, NULL, 10);
 		/* found date */
 		if (time_matches(parser, ts)) {
-			strftime(timebuf, sizeof(timebuf), parser->format, localtime((time_t*)&ts));
-			printf("%s%s", timebuf, charbuf);
+			print_time(parser->format, charbuf, ts, parser->timeago);
 		} else {
 			print_rest(parser, charbuf, &new_state);
 		}
@@ -175,6 +214,7 @@ static void parser_init(struct parser *parser)
 	parser->before = -1;
 	parser->dir = 0;
 	parser->ms = 0;
+	parser->timeago = 0;
 	parser->n_digits = 0;
 	parser->format = fmt? fmt : "%F %R";
 }
@@ -188,6 +228,7 @@ static void usage() {
 	printf("  -p, --past               only format timestamps in the past \n");
 	printf("      --version	           display version information and exit \n");
 	printf("  -m, --ms	           interpret timestamps as milliseconds instead of seconds \n");
+	printf("  -t, --timeago	           custom format: show age of timestamp (1h, 2d, etc) \n");
 
 	printf("\n  FORMAT\n    a strftime format string, defaults to '%%F %%R'\n");
 
@@ -246,6 +287,9 @@ static void parse_arg(int *argc, char **argv, struct parser *parser)
 	} else if (!strcmp("--ms", argv[0]) || !strcmp("-m", argv[0])) {
 		parser->ms = 1;
 		shift_arg(argc, argv);
+	} else if (!strcmp("--timeago", argv[0]) || !strcmp("-t", argv[0])) {
+		parser->timeago = 1;
+		shift_arg(argc, argv);
 	} else {
 		parser->format = (const char*)argv[0];
 		shift_arg(argc, argv);