usr/src/lib/libpp/common/ppcontext.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1986-2009 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                                                                      *
  19 ***********************************************************************/
  20 #pragma prototyped
  21 /*
  22  * Glenn Fowler
  23  * AT&T Research
  24  *
  25  * preprocessor context switch
  26  *
  27  *      args            op                              return
  28  *      (0,0)           free current context            0
  29  *      (0,1)           save current context            current
  30  *      (p,0)           free context p                  0
  31  *      (p,1)           make p current context          previous
  32  */
  33
  34 #include "pplib.h"
  35
  36 void*
  37 ppcontext(void* context, int flags)
  38 {
  39         struct ppcontext*       np = (struct ppcontext*)context;
  40         struct ppcontext*       op;
  41
  42         if (flags & 01)
  43         {
  44                 if (!(op = pp.context)) op = pp.context = newof(0, struct ppcontext, 1, 0);
  45                 memcpy(op, _PP_CONTEXT_BASE_, sizeof(struct ppcontext));
  46         }
  47         else
  48         {
  49                 if (!(op = np)) op = (struct ppcontext*)_PP_CONTEXT_BASE_;
  50                 if (op->filtab) hashfree(op->filtab);
  51                 if (op->prdtab) hashfree(op->prdtab);
  52                 if (op->symtab) hashfree(op->symtab);
  53                 if (op->date) free(op->date);
  54                 if (op->time) free(op->time);
  55                 if (np)
  56                 {
  57                         free(np);
  58                         np = 0;
  59                 }
  60                 memzero(op, sizeof(struct ppcontext));
  61                 op = 0;
  62         }
  63         if (np) memcpy(_PP_CONTEXT_BASE_, np, sizeof(struct ppcontext));
  64         return((void*)op);
  65 }