begin refactoring strftime to make adding field widths easier

src/time/strftime.c

@@ -44,25 +44,18 @@ static int week_num(const struct tm *tm)
 	return val;
 }
 
-size_t __strftime_l(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm, locale_t loc)
+size_t __strftime_l(char *restrict, size_t, const char *restrict, const struct tm *restrict, locale_t);
+
+int __strftime_fmt_1(char *s, size_t n, int f, const struct tm *tm, locale_t loc)
 {
 	nl_item item;
 	int val;
 	const char *fmt;
 	size_t l;
-	for (l=0; *f && l<n; f++) {
-		if (*f != '%') {
-literal:
-			s[l++] = *f;
-			continue;
-		}
-do_fmt:
-		switch (*++f) {
-		case '%':
-			goto literal;
-		case 'E':
-		case 'O':
-			goto do_fmt;
+
+	if (n<2) return 0;
+
+	switch (f) {
 	case 'a':
 		item = ABDAY_1 + tm->tm_wday;
 		goto nl_strcat;
@@ -103,7 +96,7 @@ do_fmt:
 		val = tm->tm_year + 1900;
 		if (tm->tm_yday < 3 && week_num(tm) != 1) val--;
 		else if (tm->tm_yday > 360 && week_num(tm) == 1) val++;
-			if (*f=='g') {
+		if (f=='g') {
 			fmt = "%02d";
 			val %= 100;
 		}
@@ -131,8 +124,9 @@ do_fmt:
 		fmt = "%02d";
 		goto number;
 	case 'n':
-			s[l++] = '\n';
-			continue;
+		s[0] = '\n';
+		s[1] = 0;
+		return 1;
 	case 'p':
 		item = tm->tm_hour >= 12 ? PM_STR : AM_STR;
 		goto nl_strcat;
@@ -147,8 +141,9 @@ do_fmt:
 		fmt = "%02d";
 		goto number;
 	case 't':
-			s[l++] = '\t';
-			continue;
+		s[0] = '\t';
+		s[1] = 0;
+		return 1;
 	case 'T':
 		fmt = "%H:%M:%S";
 		goto recu_strftime;
@@ -188,24 +183,39 @@ do_fmt:
 		goto number;
 	case 'z':
 		val = -tm->__tm_gmtoff;
-			l += snprintf(s+l, n-l, "%+.2d%.2d", val/3600, abs(val%3600)/60);
-			continue;
+		return snprintf(s, n, "%+.2d%.2d", val/3600, abs(val%3600)/60);
 	case 'Z':
-			l += snprintf(s+l, n-l, "%s", tm->__tm_zone);
-			continue;
+		return snprintf(s, n, "%s", tm->__tm_zone);
+	case '%':
+		s[0] = '%';
+		s[1] = 0;
+		return 1;
 	default:
 		return 0;
 	}
 number:
-		l += snprintf(s+l, n-l, fmt, val);
-		continue;
+	return snprintf(s, n, fmt, val);
 nl_strcat:
-		l += snprintf(s+l, n-l, "%s", __nl_langinfo_l(item, loc));
-		continue;
+	return snprintf(s, n, "%s", __nl_langinfo_l(item, loc));
 nl_strftime:
 	fmt = __nl_langinfo_l(item, loc);
 recu_strftime:
-		l += __strftime_l(s+l, n-l, fmt, tm, loc);
+	return __strftime_l(s, n, fmt, tm, loc);
+}
+
+size_t __strftime_l(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm, locale_t loc)
+{
+	size_t l, k;
+	for (l=0; *f && l<n; f++) {
+		if (*f != '%') {
+			s[l++] = *f;
+			continue;
+		}
+		f++;
+		if (*f == 'E' || *f == 'O') f++;
+		k = __strftime_fmt_1(s+l, n-l, *f, tm, loc);
+		if (!k) return 0;
+		l += k;
 	}
 	if (l >= n) return 0;
 	s[l] = 0;