From ccbd1d7dc5189f4637468a8136f672e60ee0e531 Mon Sep 17 00:00:00 2001
From: Jim Meyering <jim@meyering.net>
Date: Sun, 1 Nov 1992 05:44:29 +0000
Subject: Initial revision

---
 lib/posixtm.y | 173 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 173 insertions(+)
 create mode 100644 lib/posixtm.y

(limited to 'lib/posixtm.y')

diff --git a/lib/posixtm.y b/lib/posixtm.y
new file mode 100644
index 000000000..bb5b40e75
--- /dev/null
+++ b/lib/posixtm.y
@@ -0,0 +1,173 @@
+/* Parse dates for touch.
+   Copyright (C) 1989, 1990, 1991 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* Written by Jim Kingdon and David MacKenzie. */
+%{
+#ifdef __GNUC__
+#define alloca __builtin_alloca
+#else
+#ifdef sparc
+#include <alloca.h>
+#else
+#ifdef _AIX
+ #pragma alloca
+#else
+char *alloca ();
+#endif
+#endif
+#endif
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <time.h>
+
+#define YYDEBUG 1
+
+/* Lexical analyzer's current scan position in the input string. */
+static char *curpos;
+
+/* The return value. */
+static struct tm t;
+
+time_t mktime ();
+
+#define yyparse posixtime_yyparse
+static int yylex ();
+static int yyerror ();
+%}
+
+%token DIGIT
+
+%%
+date :
+       digitpair /* month */
+       digitpair /* day */
+       digitpair /* hours */
+       digitpair /* minutes */
+       year
+       seconds {
+	         if ($1 >= 1 && $1 <= 12)
+		   t.tm_mon = $1 - 1;
+		 else {
+		   YYABORT;
+		 }
+		 if ($2 >= 1 && $2 <= 31)
+		   t.tm_mday = $2;
+		 else {
+		   YYABORT;
+		 }
+		 if ($3 >= 0 && $3 <= 23)
+		   t.tm_hour = $3;
+		 else {
+		   YYABORT;
+		 }
+		 if ($4 >= 0 && $4 <= 59)
+		   t.tm_min = $4;
+		 else {
+		   YYABORT;
+		 }
+	       }
+
+year : digitpair {
+                   t.tm_year = $1;
+		   /* Deduce the century based on the year.
+		      See POSIX.2 section 4.63.3.  */
+		   if ($1 <= 68)
+		     t.tm_year += 100;
+		 }
+    | digitpair digitpair {
+                            t.tm_year = $1 * 100 + $2;
+			    if (t.tm_year < 1900) {
+			      YYABORT;
+			    } else
+			      t.tm_year -= 1900;
+			  }
+    | /* empty */ {
+                    time_t now;
+		    struct tm *tmp;
+
+                    /* Use current year.  */
+                    time (&now);
+		    tmp = localtime (&now);
+		    t.tm_year = tmp->tm_year;
+		  }
+    ;
+
+seconds : /* empty */ {
+                        t.tm_sec = 0;
+		      }
+        | '.' digitpair {
+	                  if ($2 >= 0 && $2 <= 61)
+			    t.tm_sec = $2;
+			  else {
+			    YYABORT;
+			  }
+			}
+        ;
+
+digitpair : DIGIT DIGIT {
+                          $$ = $1 * 10 + $2;
+			}
+          ;
+%%
+static int
+yylex ()
+{
+  char ch = *curpos++;
+
+  if (ch >= '0' && ch <= '9')
+    {
+      yylval = ch - '0';
+      return DIGIT;
+    }
+  else if (ch == '.' || ch == 0)
+    return ch;
+  else
+    return '?';			/* Cause an error.  */
+}
+
+static int
+yyerror ()
+{
+  return 0;
+}
+
+/* Parse a POSIX-style date and return it, or (time_t)-1 for an error.  */
+
+time_t
+posixtime (s)
+     char *s;
+{
+  curpos = s;
+  /* Let mktime decide whether it is daylight savings time.  */
+  t.tm_isdst = -1;
+  if (yyparse ())
+    return (time_t)-1;
+  else
+    return mktime (&t);
+}
+
+/* Parse a POSIX-style date and return it, or NULL for an error.  */
+
+struct tm *
+posixtm (s)
+     char *s;
+{
+  if (posixtime (s) == -1)
+    return NULL;
+  return &t;
+}
-- 
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