more strftime refactoring

make __strftime_fmt_1 return a string (possibly in the caller-provided
temp buffer) rather than writing into the output buffer. this approach
makes more sense when padding to a minimum field width might be
required, and it's also closer to what wcsftime wants.

diff --git a/src/time/strftime.c b/src/time/strftime.c
index 87e87d5..d90b690 100644 (file)
--- a/src/time/strftime.c
+++ b/src/time/strftime.c
@@ -46,15 +46,13 @@ static int week_num(const struct tm *tm)
 
 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)
+const char *__strftime_fmt_1(char (*s)[100], int f, const struct tm *tm, locale_t loc)
 {
        nl_item item;
        int val;
        const char *fmt;
        size_t l;
 
-       if (n<2) return 0;
-
        switch (f) {
        case 'a':
                item = ABDAY_1 + tm->tm_wday;
@@ -124,9 +122,7 @@ int __strftime_fmt_1(char *s, size_t n, int f, const struct tm *tm, locale_t loc
                fmt = "%02d";
                goto number;
        case 'n':
-               s[0] = '\n';
-               s[1] = 0;
-               return 1;
+               return "\n";
        case 'p':
                item = tm->tm_hour >= 12 ? PM_STR : AM_STR;
                goto nl_strcat;
@@ -141,9 +137,7 @@ int __strftime_fmt_1(char *s, size_t n, int f, const struct tm *tm, locale_t loc
                fmt = "%02d";
                goto number;
        case 't':
-               s[0] = '\t';
-               s[1] = 0;
-               return 1;
+               return "\t";
        case 'T':
                fmt = "%H:%M:%S";
                goto recu_strftime;
@@ -183,43 +177,51 @@ int __strftime_fmt_1(char *s, size_t n, int f, const struct tm *tm, locale_t loc
                goto number;
        case 'z':
                val = -tm->__tm_gmtoff;
-               return snprintf(s, n, "%+.2d%.2d", val/3600, abs(val%3600)/60);
+               snprintf(*s, sizeof *s, "%+.2d%.2d", val/3600, abs(val%3600)/60);
+               return *s;
        case 'Z':
-               return snprintf(s, n, "%s", tm->__tm_zone);
+               return tm->__tm_zone;
        case '%':
-               s[0] = '%';
-               s[1] = 0;
-               return 1;
+               return "%";
        default:
                return 0;
        }
 number:
-       return snprintf(s, n, fmt, val);
+       snprintf(*s, sizeof *s, fmt, val);
+       return *s;
 nl_strcat:
-       return snprintf(s, n, "%s", __nl_langinfo_l(item, loc));
+       return __nl_langinfo_l(item, loc);
 nl_strftime:
        fmt = __nl_langinfo_l(item, loc);
 recu_strftime:
-       return __strftime_l(s, n, fmt, tm, loc);
+       l = __strftime_l(*s, sizeof *s, fmt, tm, loc);
+       if (!l) return 0;
+       return *s;
 }
 
 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++) {
+       char buf[100];
+       const char *t;
+       for (l=0; l+1<n; f++) {
+               if (!*f) {
+                       s[l] = 0;
+                       return l;
+               }
                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;
+               t = __strftime_fmt_1(&buf, *f, tm, loc);
+               if (!t || (k = strlen(t)) >= n-l)
+                       return 0;
+               memcpy(s+l, t, k);
                l += k;
        }
-       if (l >= n) return 0;
-       s[l] = 0;
-       return l;
+       return 0;
 }
 
 size_t strftime(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm)