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/* |
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* $XConsortium: ifparser.c,v 1.7 94/01/18 21:30:50 rws Exp $ |
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* Copyright (c) 1998-2003 Carnegie Mellon University. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* 3. The name "Carnegie Mellon University" must not be used to |
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* endorse or promote products derived from this software without |
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* prior written permission. For permission or any other legal |
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* details, please contact |
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* Office of Technology Transfer |
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* Carnegie Mellon University |
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* 5000 Forbes Avenue |
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* Pittsburgh, PA 15213-3890 |
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* (412) 268-4387, fax: (412) 268-7395 |
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* tech-transfer@andrew.cmu.edu |
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* |
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* 4. Redistributions of any form whatsoever must retain the following |
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* acknowledgment: |
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* "This product includes software developed by Computing Services |
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* at Carnegie Mellon University (http://www.cmu.edu/computing/)." |
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* |
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* CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO |
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* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY |
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* AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE |
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* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN |
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* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING |
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* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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* |
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* |
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* Copyright 1992 Network Computing Devices, Inc. |
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* |
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* Permission to use, copy, modify, and distribute this software and its |
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* documentation for any purpose and without fee is hereby granted, provided |
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* that the above copyright notice appear in all copies and that both that |
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* copyright notice and this permission notice appear in supporting |
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* documentation, and that the name of Network Computing Devices may not be |
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* used in advertising or publicity pertaining to distribution of the software |
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* without specific, written prior permission. Network Computing Devices makes |
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* no representations about the suitability of this software for any purpose. |
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* It is provided ``as is'' without express or implied warranty. |
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* |
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* NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS |
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* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, |
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* IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL, |
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* INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM |
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE |
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* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR |
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* PERFORMANCE OF THIS SOFTWARE. |
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* |
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* Author: Jim Fulton |
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* Network Computing Devices, Inc. |
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* |
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* Simple if statement processor |
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* |
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* This module can be used to evaluate string representations of C language |
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* if constructs. It accepts the following grammar: |
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* |
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* EXPRESSION := VALUE |
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* | VALUE BINOP EXPRESSION |
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* |
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* VALUE := '(' EXPRESSION ')' |
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* | '!' VALUE |
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* | '-' VALUE |
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* | 'defined' '(' variable ')' |
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* | 'defined' variable |
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* | # variable '(' variable-list ')' |
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* | variable |
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* | number |
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* |
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* BINOP := '*' | '/' | '%' |
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* | '+' | '-' |
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* | '<<' | '>>' |
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* | '<' | '>' | '<=' | '>=' |
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* | '==' | '!=' |
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* | '&' | '|' |
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* | '&&' | '||' |
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* |
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* The normal C order of precidence is supported. |
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* |
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* |
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* External Entry Points: |
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* |
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* ParseIfExpression parse a string for #if |
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*/ |
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|
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#include "ifparser.h" |
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#include <ctype.h> |
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|
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/**************************************************************************** |
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Internal Macros and Utilities for Parser |
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****************************************************************************/ |
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|
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#define DO(val) if (!(val)) return NULL |
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#define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff)) |
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#define SKIPSPACE(ccc) while (isspace(*ccc)) ccc++ |
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#define isvarfirstletter(ccc) (isalpha(ccc) || (ccc) == '_') |
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|
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|
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static const char * |
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parse_variable (g, cp, varp) |
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IfParser *g; |
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const char *cp; |
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const char **varp; |
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{ |
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SKIPSPACE (cp); |
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|
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if (!isvarfirstletter (*cp)) |
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return CALLFUNC(g, handle_error) (g, cp, "variable name"); |
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|
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*varp = cp; |
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/* EMPTY */ |
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for (cp++; isalnum(*cp) || *cp == '_'; cp++) ; |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_number (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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SKIPSPACE (cp); |
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|
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if (!isdigit(*cp)) |
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return CALLFUNC(g, handle_error) (g, cp, "number"); |
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|
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#ifdef WIN32 |
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*valp = strtol(cp, &cp, 0); |
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#else |
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*valp = atoi (cp); |
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/* EMPTY */ |
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for (cp++; isdigit(*cp); cp++) ; |
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#endif |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_value (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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const char *var; |
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|
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*valp = 0; |
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|
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SKIPSPACE (cp); |
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if (!*cp) |
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return cp; |
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|
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switch (*cp) { |
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case '(': |
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DO (cp = ParseIfExpression (g, cp + 1, valp)); |
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SKIPSPACE (cp); |
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if (*cp != ')') |
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return CALLFUNC(g, handle_error) (g, cp, ")"); |
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|
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return cp + 1; /* skip the right paren */ |
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|
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case '!': |
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DO (cp = parse_value (g, cp + 1, valp)); |
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*valp = !(*valp); |
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return cp; |
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|
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case '-': |
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DO (cp = parse_value (g, cp + 1, valp)); |
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*valp = -(*valp); |
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return cp; |
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|
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case '#': |
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DO (cp = parse_variable (g, cp + 1, &var)); |
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SKIPSPACE (cp); |
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if (*cp != '(') |
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return CALLFUNC(g, handle_error) (g, cp, "("); |
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do { |
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DO (cp = parse_variable (g, cp + 1, &var)); |
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SKIPSPACE (cp); |
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} while (*cp && *cp != ')'); |
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if (*cp != ')') |
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return CALLFUNC(g, handle_error) (g, cp, ")"); |
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*valp = 1; /* XXX */ |
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return cp + 1; |
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|
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case 'd': |
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if (strncmp (cp, "defined", 7) == 0 && !isalnum(cp[7])) { |
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int paren = 0; |
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cp += 7; |
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SKIPSPACE (cp); |
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if (*cp == '(') { |
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paren = 1; |
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cp++; |
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} |
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DO (cp = parse_variable (g, cp, &var)); |
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SKIPSPACE (cp); |
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if (paren && *cp != ')') |
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return CALLFUNC(g, handle_error) (g, cp, ")"); |
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*valp = (*(g->funcs.eval_defined)) (g, var, cp - var); |
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return cp + paren; /* skip the right paren */ |
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} |
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/* fall out */ |
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} |
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|
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if (isdigit(*cp)) { |
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DO (cp = parse_number (g, cp, valp)); |
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} else if (!isvarfirstletter(*cp)) |
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return CALLFUNC(g, handle_error) (g, cp, "variable or number"); |
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else { |
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DO (cp = parse_variable (g, cp, &var)); |
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*valp = (*(g->funcs.eval_variable)) (g, var, cp - var); |
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} |
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|
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return cp; |
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} |
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|
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|
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|
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static const char * |
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parse_product (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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int rightval; |
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|
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DO (cp = parse_value (g, cp, valp)); |
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SKIPSPACE (cp); |
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|
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switch (*cp) { |
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case '*': |
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DO (cp = parse_product (g, cp + 1, &rightval)); |
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*valp = (*valp * rightval); |
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break; |
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|
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case '/': |
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DO (cp = parse_product (g, cp + 1, &rightval)); |
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*valp = (*valp / rightval); |
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break; |
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|
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case '%': |
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DO (cp = parse_product (g, cp + 1, &rightval)); |
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*valp = (*valp % rightval); |
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break; |
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} |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_sum (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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int rightval; |
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|
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DO (cp = parse_product (g, cp, valp)); |
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SKIPSPACE (cp); |
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|
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switch (*cp) { |
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case '+': |
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DO (cp = parse_sum (g, cp + 1, &rightval)); |
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*valp = (*valp + rightval); |
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break; |
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|
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case '-': |
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DO (cp = parse_sum (g, cp + 1, &rightval)); |
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*valp = (*valp - rightval); |
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break; |
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} |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_shift (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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int rightval; |
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|
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DO (cp = parse_sum (g, cp, valp)); |
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SKIPSPACE (cp); |
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|
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switch (*cp) { |
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case '<': |
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if (cp[1] == '<') { |
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DO (cp = parse_shift (g, cp + 2, &rightval)); |
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*valp = (*valp << rightval); |
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} |
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break; |
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|
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case '>': |
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if (cp[1] == '>') { |
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DO (cp = parse_shift (g, cp + 2, &rightval)); |
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*valp = (*valp >> rightval); |
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} |
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break; |
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} |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_inequality (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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int rightval; |
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|
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DO (cp = parse_shift (g, cp, valp)); |
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SKIPSPACE (cp); |
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|
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switch (*cp) { |
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case '<': |
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if (cp[1] == '=') { |
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DO (cp = parse_inequality (g, cp + 2, &rightval)); |
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*valp = (*valp <= rightval); |
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} else { |
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DO (cp = parse_inequality (g, cp + 1, &rightval)); |
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*valp = (*valp < rightval); |
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} |
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break; |
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|
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case '>': |
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if (cp[1] == '=') { |
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DO (cp = parse_inequality (g, cp + 2, &rightval)); |
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*valp = (*valp >= rightval); |
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} else { |
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DO (cp = parse_inequality (g, cp + 1, &rightval)); |
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*valp = (*valp > rightval); |
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} |
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break; |
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} |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_equality (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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int rightval; |
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|
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DO (cp = parse_inequality (g, cp, valp)); |
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SKIPSPACE (cp); |
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|
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switch (*cp) { |
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case '=': |
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if (cp[1] == '=') |
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cp++; |
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DO (cp = parse_equality (g, cp + 1, &rightval)); |
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*valp = (*valp == rightval); |
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break; |
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|
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case '!': |
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if (cp[1] != '=') |
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break; |
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DO (cp = parse_equality (g, cp + 2, &rightval)); |
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*valp = (*valp != rightval); |
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break; |
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} |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_band (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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int rightval; |
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|
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DO (cp = parse_equality (g, cp, valp)); |
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SKIPSPACE (cp); |
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|
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switch (*cp) { |
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case '&': |
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if (cp[1] != '&') { |
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DO (cp = parse_band (g, cp + 1, &rightval)); |
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*valp = (*valp & rightval); |
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} |
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break; |
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} |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_bor (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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int rightval; |
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|
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DO (cp = parse_band (g, cp, valp)); |
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SKIPSPACE (cp); |
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|
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switch (*cp) { |
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case '|': |
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if (cp[1] != '|') { |
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DO (cp = parse_bor (g, cp + 1, &rightval)); |
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*valp = (*valp | rightval); |
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} |
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break; |
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} |
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return cp; |
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} |
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|
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|
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static const char * |
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parse_land (g, cp, valp) |
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IfParser *g; |
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const char *cp; |
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int *valp; |
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{ |
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int rightval; |
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|
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DO (cp = parse_bor (g, cp, valp)); |
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SKIPSPACE (cp); |
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|
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switch (*cp) { |
| 442 |
case '&': |
| 443 |
if (cp[1] != '&') |
| 444 |
return CALLFUNC(g, handle_error) (g, cp, "&&"); |
| 445 |
DO (cp = parse_land (g, cp + 2, &rightval)); |
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*valp = (*valp && rightval); |
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break; |
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} |
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return cp; |
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} |
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|
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|
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static const char * |
| 454 |
parse_lor (g, cp, valp) |
| 455 |
IfParser *g; |
| 456 |
const char *cp; |
| 457 |
int *valp; |
| 458 |
{ |
| 459 |
int rightval; |
| 460 |
|
| 461 |
DO (cp = parse_land (g, cp, valp)); |
| 462 |
SKIPSPACE (cp); |
| 463 |
|
| 464 |
switch (*cp) { |
| 465 |
case '|': |
| 466 |
if (cp[1] != '|') |
| 467 |
return CALLFUNC(g, handle_error) (g, cp, "||"); |
| 468 |
DO (cp = parse_lor (g, cp + 2, &rightval)); |
| 469 |
*valp = (*valp || rightval); |
| 470 |
break; |
| 471 |
} |
| 472 |
return cp; |
| 473 |
} |
| 474 |
|
| 475 |
|
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/**************************************************************************** |
| 477 |
External Entry Points |
| 478 |
****************************************************************************/ |
| 479 |
|
| 480 |
const char * |
| 481 |
ParseIfExpression (g, cp, valp) |
| 482 |
IfParser *g; |
| 483 |
const char *cp; |
| 484 |
int *valp; |
| 485 |
{ |
| 486 |
return parse_lor (g, cp, valp); |
| 487 |
} |
| 488 |
|
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|
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