1 /*********************************************************************** 2 * * 3 * This software is part of the ast package * 4 * Copyright (c) 1986-2007 AT&T Knowledge Ventures * 5 * and is licensed under the * 6 * Common Public License, Version 1.0 * 7 * by AT&T Knowledge Ventures * 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 } 66