[PATCH v3] strftime,strptime: have %q represent the quarter of year

["Pádraig Brady" <P@draigBrady.com>]

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On 04/11/16 11:33, Rafal Luzynski wrote:
> Hi,
> 
> Shouldn't strptime() family also support the same?

I was debating that, but you're right,
strptime() should support that for consistency.

Updated patch is attached, which also adjusts
to Paul Eggert's optimization.

thanks,
Pádraig

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From ad0ed0247612bf7d85afe1af0c8a61e804db274c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Thu, 3 Nov 2016 19:36:59 +0000
Subject: [PATCH] strftime,strptime: have %q represent the quarter of year

This is already supported by gnulib, and for example
simplifies quarter determination at the shell, which
currently needs to use "$(( ($(date +%-m)-1)/3+1 ))".

* manual/time.texi: Document %q for str[fp]time.
* time/strftime_l.c: Implement %q.
* time/strptime_l.c: Likewise.
* time/tst-strftime.c: Add a test case.
* time/tst-strptime3.c: Likewise.
* NEWS: Mention the new feature.
---
 NEWS                 |  3 +++
 manual/time.texi     | 12 ++++++++++++
 time/strftime_l.c    |  7 +++++++
 time/strptime_l.c    | 18 ++++++++++++++++++
 time/tst-strftime.c  | 25 +++++++++++++++++++++++++
 time/tst-strptime3.c | 20 ++++++++++++++++++++
 6 files changed, 85 insertions(+)

diff --git a/NEWS b/NEWS
index 65184b1..e08f9ed 100644
--- a/NEWS
+++ b/NEWS
@@ -119,6 +119,9 @@ Version 2.25
   variable for a particular architecture in the GCC source file
   'gcc/config.gcc'.
 
+* strftime and strptime now support the %q directive to represent
+  the quarter of the year, with January starting the first quarter.
+
 Security related changes:
 
   On ARM EABI (32-bit), generating a backtrace for execution contexts which
diff --git a/manual/time.texi b/manual/time.texi
index 6a899b7..5ba0558 100644
--- a/manual/time.texi
+++ b/manual/time.texi
@@ -1510,6 +1510,12 @@ most locales @samp{AM}/@samp{PM} format is not supported, in such cases
 
 This format is a GNU extension.
 
+@item %q
+Quarter of the year (@samp{1}@dots{}@samp{4}),
+with January starting the first quarter.
+
+This format is a GNU extension.
+
 @item %r
 The complete calendar time using the AM/PM format of the current locale.
 
@@ -1926,6 +1932,12 @@ all and therefore the conversion fails.
 
 @code{%P} is a GNU extension following a GNU extension to @code{strftime}.
 
+@item %q
+Quarter of the year (@samp{1}@dots{}@samp{4}),
+with January starting the first quarter.
+
+This format is a GNU extension.
+
 @item %r
 The complete time using the AM/PM format of the current locale.
 
diff --git a/time/strftime_l.c b/time/strftime_l.c
index 1205035..09d9373 100644
--- a/time/strftime_l.c
+++ b/time/strftime_l.c
@@ -1085,6 +1085,13 @@ __strftime_internal (CHAR_T *s, size_t maxsize, const CHAR_T *format,
 	  goto underlying_strftime;
 #endif
 
+	case L_('q'):           /* Quarter of year.  GNU extension.  */
+	  if (modifier == L_('E'))
+	    goto bad_format;
+
+	  DO_NUMBER (1, ((tp->tm_mon * 11) >> 5) + 1);
+	  break;
+
 	case L_('R'):
 	  subfmt = L_("%H:%M");
 	  goto subformat;
diff --git a/time/strptime_l.c b/time/strptime_l.c
index 3a56947..f957e40 100644
--- a/time/strptime_l.c
+++ b/time/strptime_l.c
@@ -593,6 +593,15 @@ __strptime_internal (const char *rp, const char *fmt, struct tm *tmp,
 	  else
 	    s.is_pm = 0;
 	  break;
+	case 'q':
+	  /* Match quarter of year.  GNU extension.  */
+	  get_number (1, 4, 1);
+	  tm->tm_mon = (val - 1) * 3;
+	  tm->tm_mday = 1;
+	  s.have_mon = 1;
+	  s.have_mday = 1;
+	  s.want_xday = 1;
+	  break;
 	case 'r':
 #ifdef _NL_CURRENT
 	  if (s.decided != raw)
@@ -1050,6 +1059,15 @@ __strptime_internal (const char *rp, const char *fmt, struct tm *tmp,
 	      get_alt_number (0, 59, 2);
 	      tm->tm_min = val;
 	      break;
+	    case 'q':
+	      /* Match quarter using alternate numeric symbols.  */
+	      get_alt_number (1, 4, 1);
+	      tm->tm_mon = (val - 1) * 3;
+	      tm->tm_mday = 1;
+	      s.have_mon = 1;
+	      s.have_mday = 1;
+	      s.want_xday = 1;
+	      break;
 	    case 'S':
 	      /* Match seconds using alternate numeric symbols.  */
 	      get_alt_number (0, 61, 2);
diff --git a/time/tst-strftime.c b/time/tst-strftime.c
index af3ff72..62ee6c0 100644
--- a/time/tst-strftime.c
+++ b/time/tst-strftime.c
@@ -154,6 +154,31 @@ do_test (void)
 	}
     }
 
+  /* Check %q.  */
+  for (size_t mon = 1; mon <= 12; mon++)
+    {
+      char out[2];
+      char exp[2] = {0,};
+      struct tm qtm = { .tm_mon = mon - 1 };
+      char fmt[3] = {'%','q','\0'};
+
+      size_t r = strftime (out, sizeof (out), fmt, &qtm);
+      if (r == 0)
+        {
+          puts ("strftime(\"%q\") failed");
+          result = 1;
+          break;
+        }
+
+      exp[0] = mon < 4 ? '1' : mon < 7 ? '2' : mon < 10 ? '3' : '4';
+      if (strcmp (out, exp) != 0)
+        {
+          printf ("strftime %%q: expected \"%s\", got \"%s\"\n", exp, out);
+          result = 1;
+          break;
+        }
+    }
+
   return result + do_bz18985 ();
 }
 
diff --git a/time/tst-strptime3.c b/time/tst-strptime3.c
index d53f51e..b08f6f4 100644
--- a/time/tst-strptime3.c
+++ b/time/tst-strptime3.c
@@ -48,6 +48,26 @@ do_test (void)
       result = 1;
     }
 
+  memset (&tm, 0xaa, sizeof (tm));
+  for (size_t q = 1; q <= 4; q++)
+    {
+      char in[2] = {0,};
+      in[0] = q + '0';
+      int exp_mon = q == 1 ? 0 : q == 2 ? 3 : q == 3 ? 6 : 9;
+      char fmt[3] = {'%','q','\0'};
+
+      if (strptime (in, fmt, &tm) == NULL)
+        {
+          puts ("strptime failed");
+          result = 1;
+        }
+      if (tm.tm_mon != exp_mon || tm.tm_mday != 1)
+        {
+          puts ("unexpected tm content");
+          result = 1;
+        }
+    }
+
   return result;
 }
 
-- 
2.5.5