From ff65df1228d77143a806a37f75f10c06ad17df79 Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom@tomsmeding.com>
Date: Thu, 8 Jun 2023 10:18:11 +0200
Subject: Allow printing timestamps with -s

---
 .gitignore |  1 +
 main.cpp   | 38 +++++++++++++++++++++++++++++++++-----
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/.gitignore b/.gitignore
index 38a0404..6b106b0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 /obj
 datetags
+.ccls-cache/
diff --git a/main.cpp b/main.cpp
index 51262e9..047b556 100644
--- a/main.cpp
+++ b/main.cpp
@@ -3,17 +3,45 @@
 #include <sys/time.h>
 
 
-int main() {
+static void print_usage(const char *argv0) {
+	std::cerr
+		<< "Usage: " << argv0 << " [OPTIONS]\n"
+		<< "  -h    Show this help\n"
+		<< "  -t    Print tags in local time format\n"
+		<< "  -s    Print tags in timestamp format\n"
+		<< std::flush;
+}
+
+int main(int argc, char **argv) {
+	bool print_local_time = true;
+	for (int i = 1; i < argc; i++) {
+		if (argv[i][0] != '-') {
+			std::cerr << "Unrecognised argument: '" << argv[i] << "'" << std::endl;
+			print_usage(argv[0]);
+			return 1;
+		}
+		for (int j = 1; argv[i][j]; j++) {
+			switch (argv[i][j]) {
+				case 'h': print_usage(argv[0]); return 0;
+				case 't': print_local_time = true; break;
+				case 's': print_local_time = false; break;
+			}
+		}
+	}
+
 	std::string line;
 	while (std::getline(std::cin, line)) {
 		struct timeval tv;
 		gettimeofday(&tv, nullptr);
 
-		const struct tm *tm = localtime(&tv.tv_sec);
-
 		char buffer[128];
-		const ssize_t nw =
-			strftime(buffer, sizeof buffer - 7, "%Y-%m-%d %H:%M:%S.", tm);
+		ssize_t nw = 0;
+		if (print_local_time) {
+			const struct tm *tm = localtime(&tv.tv_sec);
+			nw = strftime(buffer, sizeof buffer - 7, "%Y-%m-%d %H:%M:%S.", tm);
+		} else {
+			nw = snprintf(buffer, sizeof buffer - 7, "%ld.", tv.tv_sec);
+		}
 
 		int multiplier = 100000;
 		for (int i = 0; i < 6; i++) {
-- 
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