soltools/mkdepend/ifparser.c

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * $XConsortium: ifparser.c,v 1.8 95/06/03 00:01:41 gildea Exp $
   4  *
   5  * Copyright 1992 Network Computing Devices, Inc.
   6  *
   7  * Permission to use, copy, modify, and distribute this software and its
   8  * documentation for any purpose and without fee is hereby granted, provided
   9  * that the above copyright notice appear in all copies and that both that
  10  * copyright notice and this permission notice appear in supporting
  11  * documentation, and that the name of Network Computing Devices may not be
  12  * used in advertising or publicity pertaining to distribution of the software
  13  * without specific, written prior permission.  Network Computing Devices makes
  14  * no representations about the suitability of this software for any purpose.
  15  * It is provided ``as is'' without express or implied warranty.
  16  *
  17  * NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
  18  * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
  19  * IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL,
  20  * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  21  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  22  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  23  * PERFORMANCE OF THIS SOFTWARE.
  24  *
  25  * Author:  Jim Fulton
  26  *          Network Computing Devices, Inc.
  27  *
  28  * Simple if statement processor
  29  *
  30  * This module can be used to evaluate string representations of C language
  31  * if constructs.  It accepts the following grammar:
  32  *
  33  *     EXPRESSION   :=  VALUE
  34  *           |  VALUE  BINOP    EXPRESSION
  35  *
  36  *     VALUE        :=  '('  EXPRESSION  ')'
  37  *           |  '!'  VALUE
  38  *           |  '-'  VALUE
  39  *           |  'defined'  '('  variable  ')'
  40  *           |  'defined'  variable
  41  *           |  # variable '(' variable-list ')'
  42  *           |  variable
  43  *           |  number
  44  *
  45  *     BINOP        :=  '*' |  '/'  |  '%'
  46  *           |  '+' |  '-'
  47  *           |  '<<'    |  '>>'
  48  *           |  '<' |  '>'  |  '<='  |  '>='
  49  *           |  '=='    |  '!='
  50  *           |  '&' |  '|'
  51  *           |  '&&'    |  '||'
  52  *
  53  * The normal C order of precedence is supported.
  54  *
  55  *
  56  * External Entry Points:
  57  *
  58  *     ParseIfExpression        parse a string for #if
  59  */
  60
  61 #include "ifparser.h"
  62 #include <ctype.h>
  63 #include <stdlib.h>
  64 #include <string.h>
  65
  66 /****************************************************************************
  67            Internal Macros and Utilities for Parser
  68  ****************************************************************************/
  69
  70 #define DO(val) if (!(val)) return NULL
  71 #define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
  72 #define SKIPSPACE(ccc) while (isspace((unsigned char)*ccc)) ccc++
  73 #define isvarfirstletter(ccc) (isalpha((unsigned char)(ccc)) || (ccc) == '_')
  74
  75
  76 static const char *
  77 parse_variable (IfParser *g, const char *cp, const char **varp)
  78 {
  79     SKIPSPACE (cp);
  80
  81     if (!isvarfirstletter (*cp))
  82         return CALLFUNC(g, handle_error) (g, cp, "variable name");
  83
  84     *varp = cp;
  85     /* EMPTY */
  86     for (cp++; isalnum((unsigned char)*cp) || *cp == '_'; cp++) ;
  87     return cp;
  88 }
  89
  90
  91 static const char *
  92 parse_number (IfParser *g, const char *cp, int *valp)
  93 {
  94     SKIPSPACE (cp);
  95
  96     if (!isdigit((unsigned char)*cp))
  97         return CALLFUNC(g, handle_error) (g, cp, "number");
  98
  99 #ifdef _WIN32
 100     {
 101         char *cp2;
 102         *valp = strtol(cp, &cp2, 0);
 103     }
 104 #else
 105     *valp = atoi (cp);
 106     /* EMPTY */
 107     for (cp++; isdigit((unsigned char)*cp); cp++) ;
 108 #endif
 109     return cp;
 110 }
 111
 112
 113 static const char *
 114 parse_value (IfParser *g, const char *cp, int *valp)
 115 {
 116     const char *var;
 117
 118     *valp = 0;
 119
 120     SKIPSPACE (cp);
 121     if (!*cp)
 122         return cp;
 123
 124     switch (*cp) {
 125       case '(':
 126         DO (cp = ParseIfExpression (g, cp + 1, valp));
 127         SKIPSPACE (cp);
 128         if (*cp != ')')
 129             return CALLFUNC(g, handle_error) (g, cp, ")");
 130
 131         return cp + 1;          /* skip the right paren */
 132
 133       case '!':
 134         DO (cp = parse_value (g, cp + 1, valp));
 135         *valp = !(*valp);
 136         return cp;
 137
 138       case '-':
 139         DO (cp = parse_value (g, cp + 1, valp));
 140         *valp = -(*valp);
 141         return cp;
 142
 143       case '#':
 144         DO (cp = parse_variable (g, cp + 1, &var));
 145         SKIPSPACE (cp);
 146         if (*cp != '(')
 147             return CALLFUNC(g, handle_error) (g, cp, "(");
 148         do {
 149             DO (cp = parse_variable (g, cp + 1, &var));
 150             SKIPSPACE (cp);
 151         } while (*cp && *cp != ')');
 152         if (*cp != ')')
 153             return CALLFUNC(g, handle_error) (g, cp, ")");
 154         *valp = 1; /* XXX */
 155         return cp + 1;
 156
 157       case 'd':
 158         if (strncmp (cp, "defined", 7) == 0 && !isalnum((unsigned char)cp[7])) {
 159             int paren = 0;
 160             size_t len;
 161
 162             cp += 7;
 163             SKIPSPACE (cp);
 164             if (*cp == '(') {
 165               paren = 1;
 166               cp++;
 167             }
 168             DO (cp = parse_variable (g, cp, &var));
 169             len = (size_t)(cp - var);
 170             SKIPSPACE (cp);
 171             if (paren && *cp != ')')
 172                 return CALLFUNC(g, handle_error) (g, cp, ")");
 173             *valp = (*(g->funcs.eval_defined)) (g, var, len);
 174             return cp + paren;      /* skip the right paren */
 175         }
 176     /* fall out */
 177     }
 178
 179     if (isdigit((unsigned char)*cp)) {
 180       DO (cp = parse_number (g, cp, valp));
 181     } else if (!isvarfirstletter(*cp))
 182       return CALLFUNC(g, handle_error) (g, cp, "variable or number");
 183     else {
 184       DO (cp = parse_variable (g, cp, &var));
 185       *valp = (*(g->funcs.eval_variable)) (g, var, (size_t)(cp - var));
 186     }
 187
 188     return cp;
 189 }
 190
 191
 192
 193 static const char *
 194 parse_product (IfParser *g, const char *cp, int *valp)
 195 {
 196     int rightval;
 197
 198     DO (cp = parse_value (g, cp, valp));
 199     SKIPSPACE (cp);
 200
 201     switch (*cp) {
 202       case '*':
 203         DO (cp = parse_product (g, cp + 1, &rightval));
 204         *valp = (*valp * rightval);
 205         break;
 206
 207       case '/':
 208         DO (cp = parse_product (g, cp + 1, &rightval));
 209
 210         /* Do nothing in the divide-by-zero case. */
 211         if (rightval) {
 212             *valp = (*valp / rightval);
 213         }
 214         break;
 215
 216       case '%':
 217         DO (cp = parse_product (g, cp + 1, &rightval));
 218         *valp = (*valp % rightval);
 219         break;
 220     }
 221     return cp;
 222 }
 223
 224
 225 static const char *
 226 parse_sum (IfParser *g, const char *cp, int *valp)
 227 {
 228     int rightval;
 229
 230     DO (cp = parse_product (g, cp, valp));
 231     SKIPSPACE (cp);
 232
 233     switch (*cp) {
 234       case '+':
 235         DO (cp = parse_sum (g, cp + 1, &rightval));
 236         *valp = (*valp + rightval);
 237         break;
 238
 239       case '-':
 240         DO (cp = parse_sum (g, cp + 1, &rightval));
 241         *valp = (*valp - rightval);
 242         break;
 243     }
 244     return cp;
 245 }
 246
 247
 248 static const char *
 249 parse_shift (IfParser *g, const char *cp, int *valp)
 250 {
 251     int rightval;
 252
 253     DO (cp = parse_sum (g, cp, valp));
 254     SKIPSPACE (cp);
 255
 256     switch (*cp) {
 257       case '<':
 258         if (cp[1] == '<') {
 259             DO (cp = parse_shift (g, cp + 2, &rightval));
 260             *valp = (*valp << rightval);
 261         }
 262         break;
 263
 264       case '>':
 265         if (cp[1] == '>') {
 266             DO (cp = parse_shift (g, cp + 2, &rightval));
 267             *valp = (*valp >> rightval);
 268         }
 269         break;
 270     }
 271     return cp;
 272 }
 273
 274
 275 static const char *
 276 parse_inequality (IfParser *g, const char *cp, int *valp)
 277 {
 278     int rightval;
 279
 280     DO (cp = parse_shift (g, cp, valp));
 281     SKIPSPACE (cp);
 282
 283     switch (*cp) {
 284       case '<':
 285         if (cp[1] == '=') {
 286             DO (cp = parse_inequality (g, cp + 2, &rightval));
 287             *valp = (*valp <= rightval);
 288         } else {
 289             DO (cp = parse_inequality (g, cp + 1, &rightval));
 290             *valp = (*valp < rightval);
 291         }
 292         break;
 293
 294       case '>':
 295         if (cp[1] == '=') {
 296             DO (cp = parse_inequality (g, cp + 2, &rightval));
 297             *valp = (*valp >= rightval);
 298         } else {
 299             DO (cp = parse_inequality (g, cp + 1, &rightval));
 300             *valp = (*valp > rightval);
 301         }
 302         break;
 303     }
 304     return cp;
 305 }
 306
 307
 308 static const char *
 309 parse_equality (IfParser *g, const char *cp, int *valp)
 310 {
 311     int rightval;
 312
 313     DO (cp = parse_inequality (g, cp, valp));
 314     SKIPSPACE (cp);
 315
 316     switch (*cp) {
 317       case '=':
 318         if (cp[1] == '=')
 319             cp++;
 320         DO (cp = parse_equality (g, cp + 1, &rightval));
 321         *valp = (*valp == rightval);
 322         break;
 323
 324       case '!':
 325         if (cp[1] != '=')
 326             break;
 327         DO (cp = parse_equality (g, cp + 2, &rightval));
 328         *valp = (*valp != rightval);
 329         break;
 330     }
 331     return cp;
 332 }
 333
 334
 335 static const char *
 336 parse_band (IfParser *g, const char *cp, int *valp)
 337 {
 338     int rightval;
 339
 340     DO (cp = parse_equality (g, cp, valp));
 341     SKIPSPACE (cp);
 342
 343     switch (*cp) {
 344       case '&':
 345         if (cp[1] != '&') {
 346             DO (cp = parse_band (g, cp + 1, &rightval));
 347             *valp = (*valp & rightval);
 348         }
 349         break;
 350     }
 351     return cp;
 352 }
 353
 354
 355 static const char *
 356 parse_bor (IfParser *g, const char *cp, int *valp)
 357 {
 358     int rightval;
 359
 360     DO (cp = parse_band (g, cp, valp));
 361     SKIPSPACE (cp);
 362
 363     switch (*cp) {
 364       case '|':
 365         if (cp[1] != '|') {
 366             DO (cp = parse_bor (g, cp + 1, &rightval));
 367             *valp = (*valp | rightval);
 368         }
 369         break;
 370     }
 371     return cp;
 372 }
 373
 374
 375 static const char *
 376 parse_land (IfParser *g, const char *cp, int *valp)
 377 {
 378     int rightval;
 379
 380     DO (cp = parse_bor (g, cp, valp));
 381     SKIPSPACE (cp);
 382
 383     switch (*cp) {
 384       case '&':
 385         if (cp[1] != '&')
 386             return CALLFUNC(g, handle_error) (g, cp, "&&");
 387         DO (cp = parse_land (g, cp + 2, &rightval));
 388         *valp = (*valp && rightval);
 389         break;
 390     }
 391     return cp;
 392 }
 393
 394
 395 static const char *
 396 parse_lor (IfParser *g, const char *cp, int *valp)
 397 {
 398     int rightval;
 399
 400     DO (cp = parse_land (g, cp, valp));
 401     SKIPSPACE (cp);
 402
 403     switch (*cp) {
 404       case '|':
 405         if (cp[1] != '|')
 406             return CALLFUNC(g, handle_error) (g, cp, "||");
 407         DO (cp = parse_lor (g, cp + 2, &rightval));
 408         *valp = (*valp || rightval);
 409         break;
 410     }
 411     return cp;
 412 }
 413
 414
 415 /****************************************************************************
 416                  External Entry Points
 417  ****************************************************************************/
 418
 419 const char *
 420 ParseIfExpression (IfParser *g, const char *cp, int *valp)
 421 {
 422     return parse_lor (g, cp, valp);
 423 }
 424
 425
 426 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */