2 * CDE - Common Desktop Environment
4 * Copyright (c) 1993-2012, The Open Group. All rights reserved.
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24 * $XConsortium: ifparser.c /main/10 1996/09/28 16:15:18 rws $
26 * Copyright 1992 Network Computing Devices, Inc.
28 * Permission to use, copy, modify, and distribute this software and its
29 * documentation for any purpose and without fee is hereby granted, provided
30 * that the above copyright notice appear in all copies and that both that
31 * copyright notice and this permission notice appear in supporting
32 * documentation, and that the name of Network Computing Devices may not be
33 * used in advertising or publicity pertaining to distribution of the software
34 * without specific, written prior permission. Network Computing Devices makes
35 * no representations about the suitability of this software for any purpose.
36 * It is provided ``as is'' without express or implied warranty.
38 * NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
39 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
40 * IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL,
41 * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
42 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
43 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
44 * PERFORMANCE OF THIS SOFTWARE.
47 * Network Computing Devices, Inc.
49 * Simple if statement processor
51 * This module can be used to evaluate string representations of C language
52 * if constructs. It accepts the following grammar:
55 * | VALUE BINOP EXPRESSION
57 * VALUE := '(' EXPRESSION ')'
60 * | 'defined' '(' variable ')'
61 * | 'defined' variable
62 * | # variable '(' variable-list ')'
66 * BINOP := '*' | '/' | '%'
69 * | '<' | '>' | '<=' | '>='
74 * The normal C order of precidence is supported.
77 * External Entry Points:
79 * ParseIfExpression parse a string for #if
85 /****************************************************************************
86 Internal Macros and Utilities for Parser
87 ****************************************************************************/
89 #define DO(val) if (!(val)) return NULL
90 #define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
91 #define SKIPSPACE(ccc) while (isspace(*ccc)) ccc++
92 #define isvarfirstletter(ccc) (isalpha(ccc) || (ccc) == '_')
96 parse_variable (g, cp, varp)
103 if (!isvarfirstletter (*cp))
104 return CALLFUNC(g, handle_error) (g, cp, "variable name");
108 for (cp++; isalnum(*cp) || *cp == '_'; cp++) ;
114 parse_number (g, cp, valp)
122 return CALLFUNC(g, handle_error) (g, cp, "number");
124 *valp = strtol(cp, &cp, 0);
125 /* skip trailing qualifiers */
126 while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++;
130 for (cp++; isdigit(*cp); cp++) ;
136 parse_character (g, cp, valp)
146 case 'n': val = '\n'; break;
147 case 't': val = '\t'; break;
148 case 'v': val = '\v'; break;
149 case 'b': val = '\b'; break;
150 case 'r': val = '\r'; break;
151 case 'f': val = '\f'; break;
152 case 'a': val = '\a'; break;
153 case '\\': val = '\\'; break;
154 case '?': val = '\?'; break;
155 case '\'': val = '\''; break;
156 case '\"': val = '\"'; break;
157 case 'x': val = (char) strtol (cp + 2, NULL, 16); break;
158 default: val = (char) strtol (cp + 1, NULL, 8); break;
162 while (*cp != '\'') cp++;
168 parse_value (g, cp, valp)
183 DO (cp = ParseIfExpression (g, cp + 1, valp));
186 return CALLFUNC(g, handle_error) (g, cp, ")");
188 return cp + 1; /* skip the right paren */
191 DO (cp = parse_value (g, cp + 1, valp));
196 DO (cp = parse_value (g, cp + 1, valp));
201 DO (cp = parse_variable (g, cp + 1, &var));
204 return CALLFUNC(g, handle_error) (g, cp, "(");
206 DO (cp = parse_variable (g, cp + 1, &var));
208 } while (*cp && *cp != ')');
210 return CALLFUNC(g, handle_error) (g, cp, ")");
215 DO (cp = parse_character (g, cp + 1, valp));
217 return CALLFUNC(g, handle_error) (g, cp, "'");
221 if (strncmp (cp, "defined", 7) == 0 && !isalnum(cp[7])) {
231 DO (cp = parse_variable (g, cp, &var));
234 if (paren && *cp != ')')
235 return CALLFUNC(g, handle_error) (g, cp, ")");
236 *valp = (*(g->funcs.eval_defined)) (g, var, len);
237 return cp + paren; /* skip the right paren */
243 DO (cp = parse_number (g, cp, valp));
244 } else if (!isvarfirstletter(*cp))
245 return CALLFUNC(g, handle_error) (g, cp, "variable or number");
247 DO (cp = parse_variable (g, cp, &var));
248 *valp = (*(g->funcs.eval_variable)) (g, var, cp - var);
257 parse_product (g, cp, valp)
264 DO (cp = parse_value (g, cp, valp));
269 DO (cp = parse_product (g, cp + 1, &rightval));
270 *valp = (*valp * rightval);
274 DO (cp = parse_product (g, cp + 1, &rightval));
275 *valp = (*valp / rightval);
279 DO (cp = parse_product (g, cp + 1, &rightval));
280 *valp = (*valp % rightval);
288 parse_sum (g, cp, valp)
295 DO (cp = parse_product (g, cp, valp));
300 DO (cp = parse_sum (g, cp + 1, &rightval));
301 *valp = (*valp + rightval);
305 DO (cp = parse_sum (g, cp + 1, &rightval));
306 *valp = (*valp - rightval);
314 parse_shift (g, cp, valp)
321 DO (cp = parse_sum (g, cp, valp));
327 DO (cp = parse_shift (g, cp + 2, &rightval));
328 *valp = (*valp << rightval);
334 DO (cp = parse_shift (g, cp + 2, &rightval));
335 *valp = (*valp >> rightval);
344 parse_inequality (g, cp, valp)
351 DO (cp = parse_shift (g, cp, valp));
357 DO (cp = parse_inequality (g, cp + 2, &rightval));
358 *valp = (*valp <= rightval);
360 DO (cp = parse_inequality (g, cp + 1, &rightval));
361 *valp = (*valp < rightval);
367 DO (cp = parse_inequality (g, cp + 2, &rightval));
368 *valp = (*valp >= rightval);
370 DO (cp = parse_inequality (g, cp + 1, &rightval));
371 *valp = (*valp > rightval);
380 parse_equality (g, cp, valp)
387 DO (cp = parse_inequality (g, cp, valp));
394 DO (cp = parse_equality (g, cp + 1, &rightval));
395 *valp = (*valp == rightval);
401 DO (cp = parse_equality (g, cp + 2, &rightval));
402 *valp = (*valp != rightval);
410 parse_band (g, cp, valp)
417 DO (cp = parse_equality (g, cp, valp));
423 DO (cp = parse_band (g, cp + 1, &rightval));
424 *valp = (*valp & rightval);
433 parse_bor (g, cp, valp)
440 DO (cp = parse_band (g, cp, valp));
446 DO (cp = parse_bor (g, cp + 1, &rightval));
447 *valp = (*valp | rightval);
456 parse_land (g, cp, valp)
463 DO (cp = parse_bor (g, cp, valp));
469 return CALLFUNC(g, handle_error) (g, cp, "&&");
470 DO (cp = parse_land (g, cp + 2, &rightval));
471 *valp = (*valp && rightval);
479 parse_lor (g, cp, valp)
486 DO (cp = parse_land (g, cp, valp));
492 return CALLFUNC(g, handle_error) (g, cp, "||");
493 DO (cp = parse_lor (g, cp + 2, &rightval));
494 *valp = (*valp || rightval);
501 /****************************************************************************
502 External Entry Points
503 ****************************************************************************/
506 ParseIfExpression (g, cp, valp)
511 return parse_lor (g, cp, valp);