src/shift.c

   1 /*
   2 ** Splint - annotation-assisted static program checker
   3 ** Copyright (C) 1994-2003 University of Virginia,
   4 **         Massachusetts Institute of Technology
   5 **
   6 ** This program is free software; you can redistribute it and/or modify it
   7 ** under the terms of the GNU General Public License as published by the
   8 ** Free Software Foundation; either version 2 of the License, or (at your
   9 ** option) any later version.
  10 **
  11 ** This program is distributed in the hope that it will be useful, but
  12 ** WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 ** General Public License for more details.
  15 **
  16 ** The GNU General Public License is available from http://www.gnu.org/ or
  17 ** the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  18 ** MA 02111-1307, USA.
  19 **
  20 ** For information on splint: info@splint.org
  21 ** To report a bug: splint-bug@splint.org
  22 ** For more information: http://www.splint.org
  23 */
  24
  25 /*
  26 ** shift.c
  27 **
  28 ** Larch shift sequence manager
  29 **
  30 **      Tokens are sent by the parser to this module.  Here they are saved
  31 **      for awhile in a stack, and delivered on demand during reduce actions.
  32 **      The coordination between what the parser sends here and what reduce
  33 **      consumes here must be maintained by the programmer.
  34 **
  35 */
  36
  37 # include "splintMacros.nf"
  38 # include "basic.h"
  39 # include "shift.h"
  40
  41 /*@constant static int SHIFTMAX=200;@*/
  42 # define SHIFTMAX 200
  43
  44 static o_ltoken Shifts[SHIFTMAX];
  45 static int shiftIndex;
  46
  47 static bool
  48 LSLGenIsEmptyShiftStack (void)
  49 {
  50   return (shiftIndex == 0);
  51 }
  52
  53 void LSLGenShift (ltoken tok)
  54 {
  55   if (shiftIndex < SHIFTMAX)
  56     {
  57       Shifts[shiftIndex] = ltoken_copy (tok);
  58       shiftIndex++;
  59     }
  60   else
  61     {
  62       llbuglit ("LSLGenShift: needs MoreMem ()");
  63     }
  64 }
  65
  66 extern void
  67 LSLGenShiftOnly (/*@only@*/ ltoken tok)
  68 {
  69   if (shiftIndex < SHIFTMAX)
  70     {
  71       Shifts[shiftIndex] = tok;
  72       shiftIndex++;
  73     }
  74   else
  75     {
  76       llbugexitlit ("LSLGenShift: needs MoreMem ()");
  77     }
  78 }
  79
  80 extern ltoken
  81 LSLGenTopPopShiftStack (void)
  82 {
  83   ltoken res;
  84
  85   if (LSLGenIsEmptyShiftStack ())
  86     {
  87       lclfatalbug ("LSLGenTopPopShiftStack: Empty stack");
  88     }
  89
  90   res = Shifts[--shiftIndex];
  91   Shifts[shiftIndex] = ltoken_undefined;
  92   /*@-retalias@*/ /*@-dependenttrans@*/
  93   return res;
  94   /*@=retalias@*/ /*@=dependenttrans@*/
  95 }
  96