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authorRich Felker <dalias@aerifal.cx>2018-02-06 12:31:06 -0500
committerRich Felker <dalias@aerifal.cx>2018-02-06 12:31:06 -0500
commitc7f0da4134d4e7f2efd295e7fb738c65c469fbd1 (patch)
treef28bc3fc1b716d9919a5c48c2fa379b6ea1bd500
parent596207aa38b0db33f222c9924a1310fee3de88b5 (diff)
downloadmusl-c7f0da4134d4e7f2efd295e7fb738c65c469fbd1.tar.gz
adjust strftime + modifier to match apparent intent of POSIX
it's unclear from the specification whether the word "consumes" in "consumes more than four bytes to represent a year" refers just to significant places or includes leading zeros due to field width padding. however the examples in the rationale indicate that the latter was the intent. in particular, the year 270 is shown being formatted by %+5Y as +0270 rather than 00270. previously '+' prefixing was implemented just by comparing the year against 10000. instead, count the number of significant digits and padding bytes to be added, and use the total to determine whether to apply the '+' prefix. based on testing by Dennis W├Âlfing.
-rw-r--r--src/time/strftime.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/src/time/strftime.c b/src/time/strftime.c
index 16b3bb21..708875ee 100644
--- a/src/time/strftime.c
+++ b/src/time/strftime.c
@@ -251,15 +251,21 @@ size_t __strftime_l(char *restrict s, size_t n, const char *restrict f, const st
t = __strftime_fmt_1(&buf, &k, *f, tm, loc, pad);
if (!t) break;
if (width) {
+ /* Trim off any sign and leading zeros, then
+ * count remaining digits to determine behavior
+ * for the + flag. */
if (*t=='+' || *t=='-') t++, k--;
for (; *t=='0' && t[1]-'0'<10U; t++, k--);
- width--;
- if (plus && tm->tm_year >= 10000-1900)
- s[l++] = '+';
- else if (tm->tm_year < -1900)
+ if (width < k) width = k;
+ size_t d;
+ for (d=0; t[d]-'0'<10U; d++);
+ if (tm->tm_year < -1900) {
s[l++] = '-';
- else
- width++;
+ width--;
+ } else if (plus && d+(width-k) >= (*p=='C'?3:5)) {
+ s[l++] = '+';
+ width--;
+ }
for (; width > k && l < n; width--)
s[l++] = '0';
}