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
36void*
37ppcontext(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}
66