time: in strptime(), make %z accept [+-]HH:MM tz [BZ #17887]

In ISO 8601, +03:30 is a valid time zone. Currently, strptime() only
parses it as a 2-digit time zone an believes this is +03:00. This change
makes it accept a single colon.

ChangeLog

@@ -1,3 +1,9 @@
+2015-09-18  Vincent Bernat  <vincent@bernat.im>
+
+	[BZ #17887]
+	* time/strptime_l.c (__strptime_internal): Make %z accept
+	[+-]HH:MM time zones.
+
 2015-09-18  Vincent Bernat  <vincent@bernat.im>
 
 	[BZ #17886]

NEWS

@@ -11,11 +11,11 @@ Version 2.23
 
   2542, 2543, 2558, 2898, 4404, 6803, 14341, 14912, 15384, 15786, 15918,
   16141, 16296, 16415, 16517, 16519, 16520, 16521, 16734, 16973, 16985,
-  17118, 17243, 17244, 17787, 17886, 17905, 18084, 18086, 18240, 18265,
-  18370, 18421, 18480, 18525, 18595, 18610, 18618, 18647, 18661, 18674,
-  18675, 18681, 18757, 18778, 18781, 18787, 18789, 18790, 18795, 18796,
-  18820, 18823, 18824, 18857, 18863, 18870, 18872, 18873, 18875, 18887,
-  18921, 18951, 18952, 18961, 18966, 18967, 18970, 18977.
+  17118, 17243, 17244, 17787, 17886, 17887, 17905, 18084, 18086, 18240,
+  18265, 18370, 18421, 18480, 18525, 18595, 18610, 18618, 18647, 18661,
+  18674, 18675, 18681, 18757, 18778, 18781, 18787, 18789, 18790, 18795,
+  18796, 18820, 18823, 18824, 18857, 18863, 18870, 18872, 18873, 18875,
+  18887, 18921, 18951, 18952, 18961, 18966, 18967, 18970, 18977.
 
 * The obsolete header <regexp.h> has been removed.  Programs that require
   this header must be updated to use <regex.h> instead.

time/strptime_l.c

@@ -749,9 +749,11 @@ __strptime_internal (rp, fmt, tmp, statep LOCALE_PARAM)
 	    rp++;
 	  break;
 	case 'z':
-	  /* We recognize three formats: if two digits are given, these
-	     specify hours.  If fours digits are used, minutes are
-	     also specified.  'Z' is equivalent to +0000.  */
+	  /* We recognize four formats:
+	     1. Two digits specify hours.
+	     2. Four digits specify hours and minutes.
+	     3. Two digits, ':', and two digits specify hours and minutes.
+	     4. 'Z' is equivalent to +0000.  */
 	  {
 	    val = 0;
 	    while (ISSPACE (*rp))
@@ -770,6 +772,8 @@ __strptime_internal (rp, fmt, tmp, statep LOCALE_PARAM)
 	      {
 		val = val * 10 + *rp++ - '0';
 		++n;
+		if (*rp == ':' && n == 2 && isdigit (*(rp + 1)))
+		  ++rp;
 	      }
 	    if (n == 2)
 	      val *= 100;

time/tst-strptime2.c

@@ -35,7 +35,8 @@ static bool verbose;
    following fields:
      Sign field consisting of a '+' or '-' sign,
      Hours field in two decimal digits, and
-     optional Minutes field in two decimal digits.
+     optional Minutes field in two decimal digits. Optionally,
+     a ':' is used to seperate hours and minutes.
 
    This function may write test strings with minutes values outside
    the valid range 00-59.  These are invalid strings and useful for
@@ -56,7 +57,7 @@ static bool verbose;
    range of 00 to 59.  */
 
 static long int
-mkbuf (char *buf, bool neg, unsigned int hhmm, size_t ndigits)
+mkbuf (char *buf, bool neg, bool colon, unsigned int hhmm, size_t ndigits)
 {
   const int mm_max = 59;
   char sign = neg ? '-' : '+';
@@ -66,7 +67,10 @@ mkbuf (char *buf, bool neg, unsigned int hhmm, size_t ndigits)
   long int expect = LONG_MAX;
 
   i = sprintf (buf, "%s %c", dummy_string, sign);
-  snprintf (buf + i, ndigits + 1, "%04u", hhmm);
+  if (colon)
+    snprintf (buf + i, ndigits + 2, "%02u:%02u", hh, mm);
+  else
+    snprintf (buf + i, ndigits + 1, "%04u", hhmm);
 
   if (mm <= mm_max && (ndigits == 2 || ndigits == 4))
     {
@@ -177,11 +181,22 @@ do_test (void)
       {
 	/* Test both positive and negative signs.  */
 
-	expect = mkbuf (buf, false, hhmm, ndigits);
+	expect = mkbuf (buf, false, false, hhmm, ndigits);
 	result |= compare (buf, expect, nresult);
 
-	expect = mkbuf (buf, true, hhmm, ndigits);
+	expect = mkbuf (buf, true, false, hhmm, ndigits);
 	result |= compare (buf, expect, nresult);
+
+	/* Test with colon as well.  */
+
+	if (ndigits >= 3)
+	  {
+	    expect = mkbuf (buf, false, true, hhmm, ndigits);
+	    result |= compare (buf, expect, nresult);
+
+	    expect = mkbuf (buf, true, true, hhmm, ndigits);
+	    result |= compare (buf, expect, nresult);
+	  }
       }
 
   if (result > 0 || verbose)