lib/posixtm.y

   1 /* Parse dates for touch.
   2    Copyright (C) 1989, 1990, 1991 Free Software Foundation Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by Jim Kingdon and David MacKenzie. */
  19 %{
  20
  21 #ifdef HAVE_CONFIG_H
  22 #include <config.h>
  23 #endif
  24
  25 /* The following block of alloca-related preprocessor directives is here
  26    solely to allow compilation by non GNU-C compilers of the C parser
  27    produced from this file by old versions of bison.  Newer versions of
  28    bison include a block similar to this one in bison.simple.  */
  29
  30 #ifdef __GNUC__
  31 #define alloca __builtin_alloca
  32 #else
  33 #ifdef HAVE_ALLOCA_H
  34 #include <alloca.h>
  35 #else
  36 #ifdef _AIX
  37  #pragma alloca
  38 #else
  39 void *alloca ();
  40 #endif
  41 #endif
  42 #endif
  43
  44 #include <stdio.h>
  45 #include <sys/types.h>
  46
  47 #ifdef TM_IN_SYS_TIME
  48 #include <sys/time.h>
  49 #else
  50 #include <time.h>
  51 #endif
  52
  53 /* Some old versions of bison generate parsers that use bcopy.
  54    That loses on systems that don't provide the function, so we have
  55    to redefine it here.  */
  56 #if !defined (HAVE_BCOPY) && defined (HAVE_MEMCPY) && !defined (bcopy)
  57 #define bcopy(from, to, len) memcpy ((to), (from), (len))
  58 #endif
  59
  60 #define YYDEBUG 1
  61
  62 /* Lexical analyzer's current scan position in the input string. */
  63 static char *curpos;
  64
  65 /* The return value. */
  66 static struct tm t;
  67
  68 time_t mktime ();
  69
  70 /* Remap normal yacc parser interface names (yyparse, yylex, yyerror, etc),
  71    as well as gratuitiously global symbol names, so we can have multiple
  72    yacc generated parsers in the same program.  Note that these are only
  73    the variables produced by yacc.  If other parser generators (bison,
  74    byacc, etc) produce additional global names that conflict at link time,
  75    then those parser generators need to be fixed instead of adding those
  76    names to this list. */
  77
  78 #define yymaxdepth pt_maxdepth
  79 #define yyparse pt_parse
  80 #define yylex   pt_lex
  81 #define yyerror pt_error
  82 #define yylval  pt_lval
  83 #define yychar  pt_char
  84 #define yydebug pt_debug
  85 #define yypact  pt_pact
  86 #define yyr1    pt_r1
  87 #define yyr2    pt_r2
  88 #define yydef   pt_def
  89 #define yychk   pt_chk
  90 #define yypgo   pt_pgo
  91 #define yyact   pt_act
  92 #define yyexca  pt_exca
  93 #define yyerrflag pt_errflag
  94 #define yynerrs pt_nerrs
  95 #define yyps    pt_ps
  96 #define yypv    pt_pv
  97 #define yys     pt_s
  98 #define yy_yys  pt_yys
  99 #define yystate pt_state
 100 #define yytmp   pt_tmp
 101 #define yyv     pt_v
 102 #define yy_yyv  pt_yyv
 103 #define yyval   pt_val
 104 #define yylloc  pt_lloc
 105 #define yyreds  pt_reds          /* With YYDEBUG defined */
 106 #define yytoks  pt_toks          /* With YYDEBUG defined */
 107 #define yylhs   pt_yylhs
 108 #define yylen   pt_yylen
 109 #define yydefred pt_yydefred
 110 #define yydgoto pt_yydgoto
 111 #define yysindex pt_yysindex
 112 #define yyrindex pt_yyrindex
 113 #define yygindex pt_yygindex
 114 #define yytable  pt_yytable
 115 #define yycheck  pt_yycheck
 116
 117 static int yylex ();
 118 static int yyerror ();
 119
 120 %}
 121
 122 %token DIGIT
 123
 124 %%
 125 date :
 126        digitpair /* month */
 127        digitpair /* day */
 128        digitpair /* hours */
 129        digitpair /* minutes */
 130        year
 131        seconds {
 132                  if ($1 >= 1 && $1 <= 12)
 133                    t.tm_mon = $1 - 1;
 134                  else {
 135                    YYABORT;
 136                  }
 137                  if ($2 >= 1 && $2 <= 31)
 138                    t.tm_mday = $2;
 139                  else {
 140                    YYABORT;
 141                  }
 142                  if ($3 >= 0 && $3 <= 23)
 143                    t.tm_hour = $3;
 144                  else {
 145                    YYABORT;
 146                  }
 147                  if ($4 >= 0 && $4 <= 59)
 148                    t.tm_min = $4;
 149                  else {
 150                    YYABORT;
 151                  }
 152                }
 153
 154 year : digitpair {
 155                    t.tm_year = $1;
 156                    /* Deduce the century based on the year.
 157                       See POSIX.2 section 4.63.3.  */
 158                    if ($1 <= 68)
 159                      t.tm_year += 100;
 160                  }
 161     | digitpair digitpair {
 162                             t.tm_year = $1 * 100 + $2;
 163                             if (t.tm_year < 1900) {
 164                               YYABORT;
 165                             } else
 166                               t.tm_year -= 1900;
 167                           }
 168     | /* empty */ {
 169                     time_t now;
 170                     struct tm *tmp;
 171
 172                     /* Use current year.  */
 173                     time (&now);
 174                     tmp = localtime (&now);
 175                     t.tm_year = tmp->tm_year;
 176                   }
 177     ;
 178
 179 seconds : /* empty */ {
 180                         t.tm_sec = 0;
 181                       }
 182         | '.' digitpair {
 183                           if ($2 >= 0 && $2 <= 61)
 184                             t.tm_sec = $2;
 185                           else {
 186                             YYABORT;
 187                           }
 188                         }
 189         ;
 190
 191 digitpair : DIGIT DIGIT {
 192                           $$ = $1 * 10 + $2;
 193                         }
 194           ;
 195 %%
 196 static int
 197 yylex ()
 198 {
 199   char ch = *curpos++;
 200
 201   if (ch >= '0' && ch <= '9')
 202     {
 203       yylval = ch - '0';
 204       return DIGIT;
 205     }
 206   else if (ch == '.' || ch == 0)
 207     return ch;
 208   else
 209     return '?';                 /* Cause an error.  */
 210 }
 211
 212 static int
 213 yyerror ()
 214 {
 215   return 0;
 216 }
 217
 218 /* Parse a POSIX-style date and return it, or (time_t)-1 for an error.  */
 219
 220 time_t
 221 posixtime (s)
 222      char *s;
 223 {
 224   curpos = s;
 225   /* Let mktime decide whether it is daylight savings time.  */
 226   t.tm_isdst = -1;
 227   if (yyparse ())
 228     return (time_t)-1;
 229   else
 230     return mktime (&t);
 231 }
 232
 233 /* Parse a POSIX-style date and return it, or NULL for an error.  */
 234
 235 struct tm *
 236 posixtm (s)
 237      char *s;
 238 {
 239   if (posixtime (s) == -1)
 240     return NULL;
 241   return &t;
 242 }