rewrite from yacc-based version

diff --git a/lib/posixtm.c b/lib/posixtm.c
new file mode 100644 (file)
index 0000000..6993050
--- /dev/null
+++ b/lib/posixtm.c
@@ -0,0 +1,215 @@
+/* Parse dates for touch.
+   Copyright (C) 1989, 1990, 1991, 1998 Free Software Foundation Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* Yacc-based version written by Jim Kingdon and David MacKenzie.
+   Rewritten by Jim Meyering.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdio.h>
+#include <sys/types.h>
+
+#ifdef TM_IN_SYS_TIME
+# include <sys/time.h>
+#else
+# include <time.h>
+#endif
+
+/* The return value. */
+static struct tm t;
+
+time_t mktime ();
+
+/*
+  POSIX requires:
+
+  touch -t [[CC]YY]mmddhhmm[.ss] FILE...
+    8, 10, or 12 digits, followed by optional .ss
+    (PDS_LEADING_YEAR | PDS_CENTURY | PDS_SECONDS)
+
+  touch mmddhhmm[YY] FILE...
+    8 or 10 digits
+    (PDS_TRAILING_YEAR)
+
+  date mmddhhmm[[CC]YY]
+    8, 10, or 12 digits
+    (PDS_TRAILING_YEAR | PDS_CENTURY)
+
+*/
+
+/* FIXME: put these in posixtm.h */
+/* POSIX Date Syntax flags.  */
+#define PDS_LEADING_YEAR 1
+#define PDS_TRAILING_YEAR 2
+#define PDS_CENTURY 4
+#define PDS_SECONDS 8
+
+static int
+year (const int *digit_pair, size_t n, int allow_century)
+{
+  switch (n)
+    {
+    case 1:
+      t.tm_year = *digit_pair;
+      /* Deduce the century based on the year.
+        See POSIX.2 section 4.63.3.  */
+      if (digit_pair[0] <= 68)
+       t.tm_year += 100;
+      break;
+
+    case 2:
+      if (!allow_century)
+       return 1;
+      t.tm_year = digit_pair[0] * 100 + digit_pair[1];
+      if (t.tm_year < 1900)
+       return 1;
+      t.tm_year -= 1900;
+      break;
+
+    case 0:
+      {
+       time_t now;
+       struct tm *tmp;
+
+       /* Use current year.  */
+       time (&now);
+       tmp = localtime (&now);
+       t.tm_year = tmp->tm_year;
+      }
+      break;
+
+    default:
+      abort ();
+    }
+
+  return 0;
+}
+
+static int
+posix_time_parse (const char *s, unsigned int syntax_bits)
+{
+  const char *dot;
+  int pair[6];
+  int *p;
+  int i;
+
+  size_t s_len = strlen (s);
+  size_t len = (((syntax_bits & PDS_SECONDS) && (dot = strchr (s, '.')))
+               ? dot - s
+               : s_len);
+
+  if (len != 8 && len != 10 && len != 12)
+    return 1;
+
+  if (dot)
+    {
+      if (!(syntax_bits & PDS_SECONDS))
+       return 1;
+
+      if (s_len - len != 3)
+       return 1;
+    }
+
+  for (i = 0; i < len; i++)
+    if (!ISDIGIT (s[i]))
+      return 1;
+
+  len /= 2;
+  for (i = 0; i < len; i++)
+    pair[i] = 10 * (s[2*i] - '0') + s[2*i + 1] - '0';
+
+  p = pair;
+  if (syntax_bits & PDS_LEADING_YEAR)
+    {
+      if (year (p, len - 4, syntax_bits & PDS_CENTURY))
+       return 1;
+      p += len - 4;
+      len = 4;
+    }
+
+  /* Handle 8 digits worth of `MMDDhhmm'.  */
+  if (*p < 1 || *p > 12)
+    return 1;
+  t.tm_mon = *p - 1;
+
+  ++p; --len;
+  if (*p < 1 || *p > 31)
+    return 1;
+  t.tm_mday = *p;
+
+  ++p; --len;
+  if (*p < 0 || *p > 23)
+    return 1;
+  t.tm_hour = *p;
+
+  ++p; --len;
+  if (*p < 0 || *p > 59)
+    return 1;
+  t.tm_min = *p;
+
+  /* Handle any trailing year.  */
+  if (syntax_bits & PDS_TRAILING_YEAR)
+    {
+      if (year (p, len, syntax_bits & PDS_CENTURY))
+       return 1;
+    }
+
+  /* Handle seconds.  */
+  if (!dot)
+    {
+      t.tm_sec = 0;
+    }
+  else
+    {
+      int seconds;
+
+      ++dot;
+      if (!ISDIGIT (dot[0]) || !ISDIGIT (dot[1]))
+       return 1;
+      seconds = 10 * (dot[0] - '0') + dot[1] - '0';
+
+      if (seconds < 0 || seconds > 61)
+       return 1;
+      t.tm_sec = seconds;
+    }
+
+  return 0;
+}
+
+/* Parse a POSIX-style date and return it, or (time_t)-1 for an error.  */
+
+struct tm *
+posixtime (const char *s)
+{
+  t.tm_isdst = -1;
+  if (posix_time_parse (s))
+    return (time_t)-1;
+  else
+    return mktime (&t);
+}
+
+/* Parse a POSIX-style date and return it, or NULL for an error.  */
+
+struct tm *
+posixtm (const char *s)
+{
+  if (posixtime (s) == -1)
+    return NULL;
+  return &t;
+}