one regex per day, optional leading zeroes for numeric month and dayHEADcalendar

1 files changed, 27 insertions, 17 deletions

diff --git a/calendar.c b/calendar.c
index 8011cb7..1cb953a 100644
--- a/calendar.c
+++ b/calendar.c
@@ -26,9 +26,22 @@
 #include <locale.h>
 #include <regex.h>
 #include <stdio.h>
+#include <string.h>
 #include <time.h>
 #include <unistd.h>
 
+static void optional_zero(size_t n, char buf[static n], char spec, struct tm *tm)
+{
+	char fmt[] = { '%', spec, '\0' };
+	strftime(buf, n, fmt, tm);
+	if (buf[0] != '0') {
+		return;
+	}
+
+	spec = buf[1];
+	snprintf(buf, n, "0?%c", spec);
+}
+
 int main(int argc, char *argv[])
 {
 	setlocale(LC_ALL, "");
@@ -51,13 +64,13 @@ int main(int argc, char *argv[])
 	regex_t re[12] = { { 0 } };
 	time_t now = time(NULL);
 	struct tm *tm = localtime(&now);
-	size_t nregs = 6;	/* 3 for today, 3 for tomorrow */
+	size_t nregs = 2;	/* 1 for today, 1 for tomorrow */
 	switch (tm->tm_wday) {
 	case 5: /* Friday, extend another day */
-		nregs += 3;
+		nregs += 1;
 		/* FALLTHRU */
 	case 6: /* Saturday, extend one day */
-		nregs += 3;
+		nregs += 1;
 		/* FALLTHRU */
 	default:
 		break;
@@ -65,22 +78,19 @@ int main(int argc, char *argv[])
 
 	const long SECONDS_PER_DAY = 60 * 60 * 24;
 	const int REFLAGS = REG_ICASE | REG_NOSUB | REG_EXTENDED;
-	for (size_t i = 0; i < nregs; i += 3) {
-		char buf[64];
-		strftime(buf, sizeof(buf), "%b.? *%e", tm);
-		if (regcomp(re + i, buf, REFLAGS) != 0) {
-			perror(buf);
-			return 1;
-		}
+	for (size_t i = 0; i < nregs; i += 1) {
+		char dom[4];
+		optional_zero(sizeof(dom), dom, 'd', tm);
 
-		strftime(buf, sizeof(buf), "%B *%e", tm);
-		if (regcomp(re + i + 1, buf, REFLAGS) != 0) {
-			perror(buf);
-			return 1;
-		}
+		char mon[4];
+		optional_zero(sizeof(mon), mon, 'm', tm);
 
-		strftime(buf, sizeof(buf), "%m/%d", tm);
-		if (regcomp(re + i + 2, buf, REFLAGS) != 0) {
+		char buf[64];
+		strftime(buf, sizeof(buf), "((%b.?|%B) +|", tm);
+		strcat(buf, mon);
+		strcat(buf, "/)");
+		strcat(buf, dom);
+		if (regcomp(re + i, buf, REFLAGS) != 0) {
 			perror(buf);
 			return 1;
 		}