scripts/unifdef.c

   1 /*
   2  * Copyright (c) 2002 - 2011 Tony Finch <dot@dotat.at>
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  */
  25
  26 /*
  27  * unifdef - remove ifdef'ed lines
  28  *
  29  * This code was derived from software contributed to Berkeley by Dave Yost.
  30  * It was rewritten to support ANSI C by Tony Finch. The original version
  31  * of unifdef carried the 4-clause BSD copyright licence. None of its code
  32  * remains in this version (though some of the names remain) so it now
  33  * carries a more liberal licence.
  34  *
  35  *  Wishlist:
  36  *      provide an option which will append the name of the
  37  *        appropriate symbol after #else's and #endif's
  38  *      provide an option which will check symbols after
  39  *        #else's and #endif's to see that they match their
  40  *        corresponding #ifdef or #ifndef
  41  *
  42  *   These require better buffer handling, which would also make
  43  *   it possible to handle all "dodgy" directives correctly.
  44  */
  45
  46 #include <sys/types.h>
  47 #include <sys/stat.h>
  48
  49 #include <ctype.h>
  50 #include <err.h>
  51 #include <errno.h>
  52 #include <stdarg.h>
  53 #include <stdbool.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <unistd.h>
  58
  59 const char copyright[] =
  60     "@(#) $Version: unifdef-2.5 $\n"
  61     "@(#) $Author: Tony Finch (dot@dotat.at) $\n"
  62     "@(#) $URL: http://dotat.at/prog/unifdef $\n"
  63 ;
  64
  65 /* types of input lines: */
  66 typedef enum {
  67         LT_TRUEI,               /* a true #if with ignore flag */
  68         LT_FALSEI,              /* a false #if with ignore flag */
  69         LT_IF,                  /* an unknown #if */
  70         LT_TRUE,                /* a true #if */
  71         LT_FALSE,               /* a false #if */
  72         LT_ELIF,                /* an unknown #elif */
  73         LT_ELTRUE,              /* a true #elif */
  74         LT_ELFALSE,             /* a false #elif */
  75         LT_ELSE,                /* #else */
  76         LT_ENDIF,               /* #endif */
  77         LT_DODGY,               /* flag: directive is not on one line */
  78         LT_DODGY_LAST = LT_DODGY + LT_ENDIF,
  79         LT_PLAIN,               /* ordinary line */
  80         LT_EOF,                 /* end of file */
  81         LT_ERROR,               /* unevaluable #if */
  82         LT_COUNT
  83 } Linetype;
  84
  85 static char const * const linetype_name[] = {
  86         "TRUEI", "FALSEI", "IF", "TRUE", "FALSE",
  87         "ELIF", "ELTRUE", "ELFALSE", "ELSE", "ENDIF",
  88         "DODGY TRUEI", "DODGY FALSEI",
  89         "DODGY IF", "DODGY TRUE", "DODGY FALSE",
  90         "DODGY ELIF", "DODGY ELTRUE", "DODGY ELFALSE",
  91         "DODGY ELSE", "DODGY ENDIF",
  92         "PLAIN", "EOF", "ERROR"
  93 };
  94
  95 /* state of #if processing */
  96 typedef enum {
  97         IS_OUTSIDE,
  98         IS_FALSE_PREFIX,        /* false #if followed by false #elifs */
  99         IS_TRUE_PREFIX,         /* first non-false #(el)if is true */
 100         IS_PASS_MIDDLE,         /* first non-false #(el)if is unknown */
 101         IS_FALSE_MIDDLE,        /* a false #elif after a pass state */
 102         IS_TRUE_MIDDLE,         /* a true #elif after a pass state */
 103         IS_PASS_ELSE,           /* an else after a pass state */
 104         IS_FALSE_ELSE,          /* an else after a true state */
 105         IS_TRUE_ELSE,           /* an else after only false states */
 106         IS_FALSE_TRAILER,       /* #elifs after a true are false */
 107         IS_COUNT
 108 } Ifstate;
 109
 110 static char const * const ifstate_name[] = {
 111         "OUTSIDE", "FALSE_PREFIX", "TRUE_PREFIX",
 112         "PASS_MIDDLE", "FALSE_MIDDLE", "TRUE_MIDDLE",
 113         "PASS_ELSE", "FALSE_ELSE", "TRUE_ELSE",
 114         "FALSE_TRAILER"
 115 };
 116
 117 /* state of comment parser */
 118 typedef enum {
 119         NO_COMMENT = false,     /* outside a comment */
 120         C_COMMENT,              /* in a comment like this one */
 121         CXX_COMMENT,            /* between // and end of line */
 122         STARTING_COMMENT,       /* just after slash-backslash-newline */
 123         FINISHING_COMMENT,      /* star-backslash-newline in a C comment */
 124         CHAR_LITERAL,           /* inside '' */
 125         STRING_LITERAL          /* inside "" */
 126 } Comment_state;
 127
 128 static char const * const comment_name[] = {
 129         "NO", "C", "CXX", "STARTING", "FINISHING", "CHAR", "STRING"
 130 };
 131
 132 /* state of preprocessor line parser */
 133 typedef enum {
 134         LS_START,               /* only space and comments on this line */
 135         LS_HASH,                /* only space, comments, and a hash */
 136         LS_DIRTY                /* this line can't be a preprocessor line */
 137 } Line_state;
 138
 139 static char const * const linestate_name[] = {
 140         "START", "HASH", "DIRTY"
 141 };
 142
 143 /*
 144  * Minimum translation limits from ISO/IEC 9899:1999 5.2.4.1
 145  */
 146 #define MAXDEPTH        64                      /* maximum #if nesting */
 147 #define MAXLINE         4096                    /* maximum length of line */
 148 #define MAXSYMS         4096                    /* maximum number of symbols */
 149
 150 /*
 151  * Sometimes when editing a keyword the replacement text is longer, so
 152  * we leave some space at the end of the tline buffer to accommodate this.
 153  */
 154 #define EDITSLOP        10
 155
 156 /*
 157  * For temporary filenames
 158  */
 159 #define TEMPLATE        "unifdef.XXXXXX"
 160
 161 /*
 162  * Globals.
 163  */
 164
 165 static bool             compblank;              /* -B: compress blank lines */
 166 static bool             lnblank;                /* -b: blank deleted lines */
 167 static bool             complement;             /* -c: do the complement */
 168 static bool             debugging;              /* -d: debugging reports */
 169 static bool             iocccok;                /* -e: fewer IOCCC errors */
 170 static bool             strictlogic;            /* -K: keep ambiguous #ifs */
 171 static bool             killconsts;             /* -k: eval constant #ifs */
 172 static bool             lnnum;                  /* -n: add #line directives */
 173 static bool             symlist;                /* -s: output symbol list */
 174 static bool             symdepth;               /* -S: output symbol depth */
 175 static bool             text;                   /* -t: this is a text file */
 176
 177 static const char      *symname[MAXSYMS];       /* symbol name */
 178 static const char      *value[MAXSYMS];         /* -Dsym=value */
 179 static bool             ignore[MAXSYMS];        /* -iDsym or -iUsym */
 180 static int              nsyms;                  /* number of symbols */
 181
 182 static FILE            *input;                  /* input file pointer */
 183 static const char      *filename;               /* input file name */
 184 static int              linenum;                /* current line number */
 185 static FILE            *output;                 /* output file pointer */
 186 static const char      *ofilename;              /* output file name */
 187 static bool             overwriting;            /* output overwrites input */
 188 static char             tempname[FILENAME_MAX]; /* used when overwriting */
 189
 190 static char             tline[MAXLINE+EDITSLOP];/* input buffer plus space */
 191 static char            *keyword;                /* used for editing #elif's */
 192
 193 static const char      *newline;                /* input file format */
 194 static const char       newline_unix[] = "\n";
 195 static const char       newline_crlf[] = "\r\n";
 196
 197 static Comment_state    incomment;              /* comment parser state */
 198 static Line_state       linestate;              /* #if line parser state */
 199 static Ifstate          ifstate[MAXDEPTH];      /* #if processor state */
 200 static bool             ignoring[MAXDEPTH];     /* ignore comments state */
 201 static int              stifline[MAXDEPTH];     /* start of current #if */
 202 static int              depth;                  /* current #if nesting */
 203 static int              delcount;               /* count of deleted lines */
 204 static unsigned         blankcount;             /* count of blank lines */
 205 static unsigned         blankmax;               /* maximum recent blankcount */
 206 static bool             constexpr;              /* constant #if expression */
 207 static bool             zerosyms = true;        /* to format symdepth output */
 208 static bool             firstsym;               /* ditto */
 209
 210 static int              exitstat;               /* program exit status */
 211
 212 static void             addsym(bool, bool, char *);
 213 static void             closeout(void);
 214 static void             debug(const char *, ...);
 215 static void             done(void);
 216 static void             error(const char *);
 217 static int              findsym(const char *);
 218 static void             flushline(bool);
 219 static Linetype         parseline(void);
 220 static Linetype         ifeval(const char **);
 221 static void             ignoreoff(void);
 222 static void             ignoreon(void);
 223 static void             keywordedit(const char *);
 224 static void             nest(void);
 225 static void             process(void);
 226 static const char      *skipargs(const char *);
 227 static const char      *skipcomment(const char *);
 228 static const char      *skipsym(const char *);
 229 static void             state(Ifstate);
 230 static int              strlcmp(const char *, const char *, size_t);
 231 static void             unnest(void);
 232 static void             usage(void);
 233 static void             version(void);
 234
 235 #define endsym(c) (!isalnum((unsigned char)c) && c != '_')
 236
 237 /*
 238  * The main program.
 239  */
 240 int
 241 main(int argc, char *argv[])
 242 {
 243         int opt;
 244
 245         while ((opt = getopt(argc, argv, "i:D:U:I:o:bBcdeKklnsStV")) != -1)
 246                 switch (opt) {
 247                 case 'i': /* treat stuff controlled by these symbols as text */
 248                         /*
 249                          * For strict backwards-compatibility the U or D
 250                          * should be immediately after the -i but it doesn't
 251                          * matter much if we relax that requirement.
 252                          */
 253                         opt = *optarg++;
 254                         if (opt == 'D')
 255                                 addsym(true, true, optarg);
 256                         else if (opt == 'U')
 257                                 addsym(true, false, optarg);
 258                         else
 259                                 usage();
 260                         break;
 261                 case 'D': /* define a symbol */
 262                         addsym(false, true, optarg);
 263                         break;
 264                 case 'U': /* undef a symbol */
 265                         addsym(false, false, optarg);
 266                         break;
 267                 case 'I': /* no-op for compatibility with cpp */
 268                         break;
 269                 case 'b': /* blank deleted lines instead of omitting them */
 270                 case 'l': /* backwards compatibility */
 271                         lnblank = true;
 272                         break;
 273                 case 'B': /* compress blank lines around removed section */
 274                         compblank = true;
 275                         break;
 276                 case 'c': /* treat -D as -U and vice versa */
 277                         complement = true;
 278                         break;
 279                 case 'd':
 280                         debugging = true;
 281                         break;
 282                 case 'e': /* fewer errors from dodgy lines */
 283                         iocccok = true;
 284                         break;
 285                 case 'K': /* keep ambiguous #ifs */
 286                         strictlogic = true;
 287                         break;
 288                 case 'k': /* process constant #ifs */
 289                         killconsts = true;
 290                         break;
 291                 case 'n': /* add #line directive after deleted lines */
 292                         lnnum = true;
 293                         break;
 294                 case 'o': /* output to a file */
 295                         ofilename = optarg;
 296                         break;
 297                 case 's': /* only output list of symbols that control #ifs */
 298                         symlist = true;
 299                         break;
 300                 case 'S': /* list symbols with their nesting depth */
 301                         symlist = symdepth = true;
 302                         break;
 303                 case 't': /* don't parse C comments */
 304                         text = true;
 305                         break;
 306                 case 'V': /* print version */
 307                         version();
 308                 default:
 309                         usage();
 310                 }
 311         argc -= optind;
 312         argv += optind;
 313         if (compblank && lnblank)
 314                 errx(2, "-B and -b are mutually exclusive");
 315         if (argc > 1) {
 316                 errx(2, "can only do one file");
 317         } else if (argc == 1 && strcmp(*argv, "-") != 0) {
 318                 filename = *argv;
 319                 input = fopen(filename, "rb");
 320                 if (input == NULL)
 321                         err(2, "can't open %s", filename);
 322         } else {
 323                 filename = "[stdin]";
 324                 input = stdin;
 325         }
 326         if (ofilename == NULL) {
 327                 ofilename = "[stdout]";
 328                 output = stdout;
 329         } else {
 330                 struct stat ist, ost;
 331                 if (stat(ofilename, &ost) == 0 &&
 332                     fstat(fileno(input), &ist) == 0)
 333                         overwriting = (ist.st_dev == ost.st_dev
 334                                     && ist.st_ino == ost.st_ino);
 335                 if (overwriting) {
 336                         const char *dirsep;
 337                         int ofd;
 338
 339                         dirsep = strrchr(ofilename, '/');
 340                         if (dirsep != NULL)
 341                                 snprintf(tempname, sizeof(tempname),
 342                                     "%.*s/" TEMPLATE,
 343                                     (int)(dirsep - ofilename), ofilename);
 344                         else
 345                                 snprintf(tempname, sizeof(tempname),
 346                                     TEMPLATE);
 347                         ofd = mkstemp(tempname);
 348                         if (ofd != -1)
 349                                 output = fdopen(ofd, "wb+");
 350                         if (output == NULL)
 351                                 err(2, "can't create temporary file");
 352                         fchmod(ofd, ist.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO));
 353                 } else {
 354                         output = fopen(ofilename, "wb");
 355                         if (output == NULL)
 356                                 err(2, "can't open %s", ofilename);
 357                 }
 358         }
 359         process();
 360         abort(); /* bug */
 361 }
 362
 363 static void
 364 version(void)
 365 {
 366         const char *c = copyright;
 367         for (;;) {
 368                 while (*++c != '$')
 369                         if (*c == '\0')
 370                                 exit(0);
 371                 while (*++c != '$')
 372                         putc(*c, stderr);
 373                 putc('\n', stderr);
 374         }
 375 }
 376
 377 static void
 378 usage(void)
 379 {
 380         fprintf(stderr, "usage: unifdef [-bBcdeKknsStV] [-Ipath]"
 381             " [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n");
 382         exit(2);
 383 }
 384
 385 /*
 386  * A state transition function alters the global #if processing state
 387  * in a particular way. The table below is indexed by the current
 388  * processing state and the type of the current line.
 389  *
 390  * Nesting is handled by keeping a stack of states; some transition
 391  * functions increase or decrease the depth. They also maintain the
 392  * ignore state on a stack. In some complicated cases they have to
 393  * alter the preprocessor directive, as follows.
 394  *
 395  * When we have processed a group that starts off with a known-false
 396  * #if/#elif sequence (which has therefore been deleted) followed by a
 397  * #elif that we don't understand and therefore must keep, we edit the
 398  * latter into a #if to keep the nesting correct. We use strncpy() to
 399  * overwrite the 4 byte token "elif" with "if  " without a '\0' byte.
 400  *
 401  * When we find a true #elif in a group, the following block will
 402  * always be kept and the rest of the sequence after the next #elif or
 403  * #else will be discarded. We edit the #elif into a #else and the
 404  * following directive to #endif since this has the desired behaviour.
 405  *
 406  * "Dodgy" directives are split across multiple lines, the most common
 407  * example being a multi-line comment hanging off the right of the
 408  * directive. We can handle them correctly only if there is no change
 409  * from printing to dropping (or vice versa) caused by that directive.
 410  * If the directive is the first of a group we have a choice between
 411  * failing with an error, or passing it through unchanged instead of
 412  * evaluating it. The latter is not the default to avoid questions from
 413  * users about unifdef unexpectedly leaving behind preprocessor directives.
 414  */
 415 typedef void state_fn(void);
 416
 417 /* report an error */
 418 static void Eelif (void) { error("Inappropriate #elif"); }
 419 static void Eelse (void) { error("Inappropriate #else"); }
 420 static void Eendif(void) { error("Inappropriate #endif"); }
 421 static void Eeof  (void) { error("Premature EOF"); }
 422 static void Eioccc(void) { error("Obfuscated preprocessor control line"); }
 423 /* plain line handling */
 424 static void print (void) { flushline(true); }
 425 static void drop  (void) { flushline(false); }
 426 /* output lacks group's start line */
 427 static void Strue (void) { drop();  ignoreoff(); state(IS_TRUE_PREFIX); }
 428 static void Sfalse(void) { drop();  ignoreoff(); state(IS_FALSE_PREFIX); }
 429 static void Selse (void) { drop();               state(IS_TRUE_ELSE); }
 430 /* print/pass this block */
 431 static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); }
 432 static void Pelse (void) { print();              state(IS_PASS_ELSE); }
 433 static void Pendif(void) { print(); unnest(); }
 434 /* discard this block */
 435 static void Dfalse(void) { drop();  ignoreoff(); state(IS_FALSE_TRAILER); }
 436 static void Delif (void) { drop();  ignoreoff(); state(IS_FALSE_MIDDLE); }
 437 static void Delse (void) { drop();               state(IS_FALSE_ELSE); }
 438 static void Dendif(void) { drop();  unnest(); }
 439 /* first line of group */
 440 static void Fdrop (void) { nest();  Dfalse(); }
 441 static void Fpass (void) { nest();  Pelif(); }
 442 static void Ftrue (void) { nest();  Strue(); }
 443 static void Ffalse(void) { nest();  Sfalse(); }
 444 /* variable pedantry for obfuscated lines */
 445 static void Oiffy (void) { if (!iocccok) Eioccc(); Fpass(); ignoreon(); }
 446 static void Oif   (void) { if (!iocccok) Eioccc(); Fpass(); }
 447 static void Oelif (void) { if (!iocccok) Eioccc(); Pelif(); }
 448 /* ignore comments in this block */
 449 static void Idrop (void) { Fdrop();  ignoreon(); }
 450 static void Itrue (void) { Ftrue();  ignoreon(); }
 451 static void Ifalse(void) { Ffalse(); ignoreon(); }
 452 /* modify this line */
 453 static void Mpass (void) { strncpy(keyword, "if  ", 4); Pelif(); }
 454 static void Mtrue (void) { keywordedit("else");  state(IS_TRUE_MIDDLE); }
 455 static void Melif (void) { keywordedit("endif"); state(IS_FALSE_TRAILER); }
 456 static void Melse (void) { keywordedit("endif"); state(IS_FALSE_ELSE); }
 457
 458 static state_fn * const trans_table[IS_COUNT][LT_COUNT] = {
 459 /* IS_OUTSIDE */
 460 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif,
 461   Oiffy, Oiffy, Fpass, Oif,   Oif,   Eelif, Eelif, Eelif, Eelse, Eendif,
 462   print, done,  abort },
 463 /* IS_FALSE_PREFIX */
 464 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif,
 465   Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc,
 466   drop,  Eeof,  abort },
 467 /* IS_TRUE_PREFIX */
 468 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif,
 469   Oiffy, Oiffy, Fpass, Oif,   Oif,   Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
 470   print, Eeof,  abort },
 471 /* IS_PASS_MIDDLE */
 472 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif,
 473   Oiffy, Oiffy, Fpass, Oif,   Oif,   Pelif, Oelif, Oelif, Pelse, Pendif,
 474   print, Eeof,  abort },
 475 /* IS_FALSE_MIDDLE */
 476 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif,
 477   Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
 478   drop,  Eeof,  abort },
 479 /* IS_TRUE_MIDDLE */
 480 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif,
 481   Oiffy, Oiffy, Fpass, Oif,   Oif,   Eioccc,Eioccc,Eioccc,Eioccc,Pendif,
 482   print, Eeof,  abort },
 483 /* IS_PASS_ELSE */
 484 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif,
 485   Oiffy, Oiffy, Fpass, Oif,   Oif,   Eelif, Eelif, Eelif, Eelse, Pendif,
 486   print, Eeof,  abort },
 487 /* IS_FALSE_ELSE */
 488 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif,
 489   Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc,
 490   drop,  Eeof,  abort },
 491 /* IS_TRUE_ELSE */
 492 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif,
 493   Oiffy, Oiffy, Fpass, Oif,   Oif,   Eelif, Eelif, Eelif, Eelse, Eioccc,
 494   print, Eeof,  abort },
 495 /* IS_FALSE_TRAILER */
 496 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif,
 497   Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc,
 498   drop,  Eeof,  abort }
 499 /*TRUEI  FALSEI IF     TRUE   FALSE  ELIF   ELTRUE ELFALSE ELSE  ENDIF
 500   TRUEI  FALSEI IF     TRUE   FALSE  ELIF   ELTRUE ELFALSE ELSE  ENDIF (DODGY)
 501   PLAIN  EOF    ERROR */
 502 };
 503
 504 /*
 505  * State machine utility functions
 506  */
 507 static void
 508 ignoreoff(void)
 509 {
 510         if (depth == 0)
 511                 abort(); /* bug */
 512         ignoring[depth] = ignoring[depth-1];
 513 }
 514 static void
 515 ignoreon(void)
 516 {
 517         ignoring[depth] = true;
 518 }
 519 static void
 520 keywordedit(const char *replacement)
 521 {
 522         snprintf(keyword, tline + sizeof(tline) - keyword,
 523             "%s%s", replacement, newline);
 524         print();
 525 }
 526 static void
 527 nest(void)
 528 {
 529         if (depth > MAXDEPTH-1)
 530                 abort(); /* bug */
 531         if (depth == MAXDEPTH-1)
 532                 error("Too many levels of nesting");
 533         depth += 1;
 534         stifline[depth] = linenum;
 535 }
 536 static void
 537 unnest(void)
 538 {
 539         if (depth == 0)
 540                 abort(); /* bug */
 541         depth -= 1;
 542 }
 543 static void
 544 state(Ifstate is)
 545 {
 546         ifstate[depth] = is;
 547 }
 548
 549 /*
 550  * Write a line to the output or not, according to command line options.
 551  */
 552 static void
 553 flushline(bool keep)
 554 {
 555         if (symlist)
 556                 return;
 557         if (keep ^ complement) {
 558                 bool blankline = tline[strspn(tline, " \t\r\n")] == '\0';
 559                 if (blankline && compblank && blankcount != blankmax) {
 560                         delcount += 1;
 561                         blankcount += 1;
 562                 } else {
 563                         if (lnnum && delcount > 0)
 564                                 printf("#line %d%s", linenum, newline);
 565                         fputs(tline, output);
 566                         delcount = 0;
 567                         blankmax = blankcount = blankline ? blankcount + 1 : 0;
 568                 }
 569         } else {
 570                 if (lnblank)
 571                         fputs(newline, output);
 572                 exitstat = 1;
 573                 delcount += 1;
 574                 blankcount = 0;
 575         }
 576         if (debugging)
 577                 fflush(output);
 578 }
 579
 580 /*
 581  * The driver for the state machine.
 582  */
 583 static void
 584 process(void)
 585 {
 586         /* When compressing blank lines, act as if the file
 587            is preceded by a large number of blank lines. */
 588         blankmax = blankcount = 1000;
 589         for (;;) {
 590                 Linetype lineval = parseline();
 591                 trans_table[ifstate[depth]][lineval]();
 592                 debug("process line %d %s -> %s depth %d",
 593                     linenum, linetype_name[lineval],
 594                     ifstate_name[ifstate[depth]], depth);
 595         }
 596 }
 597
 598 /*
 599  * Flush the output and handle errors.
 600  */
 601 static void
 602 closeout(void)
 603 {
 604         if (symdepth && !zerosyms)
 605                 printf("\n");
 606         if (fclose(output) == EOF) {
 607                 warn("couldn't write to %s", ofilename);
 608                 if (overwriting) {
 609                         unlink(tempname);
 610                         errx(2, "%s unchanged", filename);
 611                 } else {
 612                         exit(2);
 613                 }
 614         }
 615 }
 616
 617 /*
 618  * Clean up and exit.
 619  */
 620 static void
 621 done(void)
 622 {
 623         if (incomment)
 624                 error("EOF in comment");
 625         closeout();
 626         if (overwriting && rename(tempname, ofilename) == -1) {
 627                 warn("couldn't rename temporary file");
 628                 unlink(tempname);
 629                 errx(2, "%s unchanged", ofilename);
 630         }
 631         exit(exitstat);
 632 }
 633
 634 /*
 635  * Parse a line and determine its type. We keep the preprocessor line
 636  * parser state between calls in the global variable linestate, with
 637  * help from skipcomment().
 638  */
 639 static Linetype
 640 parseline(void)
 641 {
 642         const char *cp;
 643         int cursym;
 644         int kwlen;
 645         Linetype retval;
 646         Comment_state wascomment;
 647
 648         linenum++;
 649         if (fgets(tline, MAXLINE, input) == NULL)
 650                 return (LT_EOF);
 651         if (newline == NULL) {
 652                 if (strrchr(tline, '\n') == strrchr(tline, '\r') + 1)
 653                         newline = newline_crlf;
 654                 else
 655                         newline = newline_unix;
 656         }
 657         retval = LT_PLAIN;
 658         wascomment = incomment;
 659         cp = skipcomment(tline);
 660         if (linestate == LS_START) {
 661                 if (*cp == '#') {
 662                         linestate = LS_HASH;
 663                         firstsym = true;
 664                         cp = skipcomment(cp + 1);
 665                 } else if (*cp != '\0')
 666                         linestate = LS_DIRTY;
 667         }
 668         if (!incomment && linestate == LS_HASH) {
 669                 keyword = tline + (cp - tline);
 670                 cp = skipsym(cp);
 671                 kwlen = cp - keyword;
 672                 /* no way can we deal with a continuation inside a keyword */
 673                 if (strncmp(cp, "\\\r\n", 3) == 0 ||
 674                     strncmp(cp, "\\\n", 2) == 0)
 675                         Eioccc();
 676                 if (strlcmp("ifdef", keyword, kwlen) == 0 ||
 677                     strlcmp("ifndef", keyword, kwlen) == 0) {
 678                         cp = skipcomment(cp);
 679                         if ((cursym = findsym(cp)) < 0)
 680                                 retval = LT_IF;
 681                         else {
 682                                 retval = (keyword[2] == 'n')
 683                                     ? LT_FALSE : LT_TRUE;
 684                                 if (value[cursym] == NULL)
 685                                         retval = (retval == LT_TRUE)
 686                                             ? LT_FALSE : LT_TRUE;
 687                                 if (ignore[cursym])
 688                                         retval = (retval == LT_TRUE)
 689                                             ? LT_TRUEI : LT_FALSEI;
 690                         }
 691                         cp = skipsym(cp);
 692                 } else if (strlcmp("if", keyword, kwlen) == 0)
 693                         retval = ifeval(&cp);
 694                 else if (strlcmp("elif", keyword, kwlen) == 0)
 695                         retval = ifeval(&cp) - LT_IF + LT_ELIF;
 696                 else if (strlcmp("else", keyword, kwlen) == 0)
 697                         retval = LT_ELSE;
 698                 else if (strlcmp("endif", keyword, kwlen) == 0)
 699                         retval = LT_ENDIF;
 700                 else {
 701                         linestate = LS_DIRTY;
 702                         retval = LT_PLAIN;
 703                 }
 704                 cp = skipcomment(cp);
 705                 if (*cp != '\0') {
 706                         linestate = LS_DIRTY;
 707                         if (retval == LT_TRUE || retval == LT_FALSE ||
 708                             retval == LT_TRUEI || retval == LT_FALSEI)
 709                                 retval = LT_IF;
 710                         if (retval == LT_ELTRUE || retval == LT_ELFALSE)
 711                                 retval = LT_ELIF;
 712                 }
 713                 if (retval != LT_PLAIN && (wascomment || incomment)) {
 714                         retval += LT_DODGY;
 715                         if (incomment)
 716                                 linestate = LS_DIRTY;
 717                 }
 718                 /* skipcomment normally changes the state, except
 719                    if the last line of the file lacks a newline, or
 720                    if there is too much whitespace in a directive */
 721                 if (linestate == LS_HASH) {
 722                         size_t len = cp - tline;
 723                         if (fgets(tline + len, MAXLINE - len, input) == NULL) {
 724                                 /* append the missing newline */
 725                                 strcpy(tline + len, newline);
 726                                 cp += strlen(newline);
 727                                 linestate = LS_START;
 728                         } else {
 729                                 linestate = LS_DIRTY;
 730                         }
 731                 }
 732         }
 733         if (linestate == LS_DIRTY) {
 734                 while (*cp != '\0')
 735                         cp = skipcomment(cp + 1);
 736         }
 737         debug("parser line %d state %s comment %s line", linenum,
 738             comment_name[incomment], linestate_name[linestate]);
 739         return (retval);
 740 }
 741
 742 /*
 743  * These are the binary operators that are supported by the expression
 744  * evaluator.
 745  */
 746 static Linetype op_strict(int *p, int v, Linetype at, Linetype bt) {
 747         if(at == LT_IF || bt == LT_IF) return (LT_IF);
 748         return (*p = v, v ? LT_TRUE : LT_FALSE);
 749 }
 750 static Linetype op_lt(int *p, Linetype at, int a, Linetype bt, int b) {
 751         return op_strict(p, a < b, at, bt);
 752 }
 753 static Linetype op_gt(int *p, Linetype at, int a, Linetype bt, int b) {
 754         return op_strict(p, a > b, at, bt);
 755 }
 756 static Linetype op_le(int *p, Linetype at, int a, Linetype bt, int b) {
 757         return op_strict(p, a <= b, at, bt);
 758 }
 759 static Linetype op_ge(int *p, Linetype at, int a, Linetype bt, int b) {
 760         return op_strict(p, a >= b, at, bt);
 761 }
 762 static Linetype op_eq(int *p, Linetype at, int a, Linetype bt, int b) {
 763         return op_strict(p, a == b, at, bt);
 764 }
 765 static Linetype op_ne(int *p, Linetype at, int a, Linetype bt, int b) {
 766         return op_strict(p, a != b, at, bt);
 767 }
 768 static Linetype op_or(int *p, Linetype at, int a, Linetype bt, int b) {
 769         if (!strictlogic && (at == LT_TRUE || bt == LT_TRUE))
 770                 return (*p = 1, LT_TRUE);
 771         return op_strict(p, a || b, at, bt);
 772 }
 773 static Linetype op_and(int *p, Linetype at, int a, Linetype bt, int b) {
 774         if (!strictlogic && (at == LT_FALSE || bt == LT_FALSE))
 775                 return (*p = 0, LT_FALSE);
 776         return op_strict(p, a && b, at, bt);
 777 }
 778
 779 /*
 780  * An evaluation function takes three arguments, as follows: (1) a pointer to
 781  * an element of the precedence table which lists the operators at the current
 782  * level of precedence; (2) a pointer to an integer which will receive the
 783  * value of the expression; and (3) a pointer to a char* that points to the
 784  * expression to be evaluated and that is updated to the end of the expression
 785  * when evaluation is complete. The function returns LT_FALSE if the value of
 786  * the expression is zero, LT_TRUE if it is non-zero, LT_IF if the expression
 787  * depends on an unknown symbol, or LT_ERROR if there is a parse failure.
 788  */
 789 struct ops;
 790
 791 typedef Linetype eval_fn(const struct ops *, int *, const char **);
 792
 793 static eval_fn eval_table, eval_unary;
 794
 795 /*
 796  * The precedence table. Expressions involving binary operators are evaluated
 797  * in a table-driven way by eval_table. When it evaluates a subexpression it
 798  * calls the inner function with its first argument pointing to the next
 799  * element of the table. Innermost expressions have special non-table-driven
 800  * handling.
 801  */
 802 static const struct ops {
 803         eval_fn *inner;
 804         struct op {
 805                 const char *str;
 806                 Linetype (*fn)(int *, Linetype, int, Linetype, int);
 807         } op[5];
 808 } eval_ops[] = {
 809         { eval_table, { { "||", op_or } } },
 810         { eval_table, { { "&&", op_and } } },
 811         { eval_table, { { "==", op_eq },
 812                         { "!=", op_ne } } },
 813         { eval_unary, { { "<=", op_le },
 814                         { ">=", op_ge },
 815                         { "<", op_lt },
 816                         { ">", op_gt } } }
 817 };
 818
 819 /*
 820  * Function for evaluating the innermost parts of expressions,
 821  * viz. !expr (expr) number defined(symbol) symbol
 822  * We reset the constexpr flag in the last two cases.
 823  */
 824 static Linetype
 825 eval_unary(const struct ops *ops, int *valp, const char **cpp)
 826 {
 827         const char *cp;
 828         char *ep;
 829         int sym;
 830         bool defparen;
 831         Linetype lt;
 832
 833         cp = skipcomment(*cpp);
 834         if (*cp == '!') {
 835                 debug("eval%d !", ops - eval_ops);
 836                 cp++;
 837                 lt = eval_unary(ops, valp, &cp);
 838                 if (lt == LT_ERROR)
 839                         return (LT_ERROR);
 840                 if (lt != LT_IF) {
 841                         *valp = !*valp;
 842                         lt = *valp ? LT_TRUE : LT_FALSE;
 843                 }
 844         } else if (*cp == '(') {
 845                 cp++;
 846                 debug("eval%d (", ops - eval_ops);
 847                 lt = eval_table(eval_ops, valp, &cp);
 848                 if (lt == LT_ERROR)
 849                         return (LT_ERROR);
 850                 cp = skipcomment(cp);
 851                 if (*cp++ != ')')
 852                         return (LT_ERROR);
 853         } else if (isdigit((unsigned char)*cp)) {
 854                 debug("eval%d number", ops - eval_ops);
 855                 *valp = strtol(cp, &ep, 0);
 856                 if (ep == cp)
 857                         return (LT_ERROR);
 858                 lt = *valp ? LT_TRUE : LT_FALSE;
 859                 cp = skipsym(cp);
 860         } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) {
 861                 cp = skipcomment(cp+7);
 862                 debug("eval%d defined", ops - eval_ops);
 863                 if (*cp == '(') {
 864                         cp = skipcomment(cp+1);
 865                         defparen = true;
 866                 } else {
 867                         defparen = false;
 868                 }
 869                 sym = findsym(cp);
 870                 if (sym < 0) {
 871                         lt = LT_IF;
 872                 } else {
 873                         *valp = (value[sym] != NULL);
 874                         lt = *valp ? LT_TRUE : LT_FALSE;
 875                 }
 876                 cp = skipsym(cp);
 877                 cp = skipcomment(cp);
 878                 if (defparen && *cp++ != ')')
 879                         return (LT_ERROR);
 880                 constexpr = false;
 881         } else if (!endsym(*cp)) {
 882                 debug("eval%d symbol", ops - eval_ops);
 883                 sym = findsym(cp);
 884                 cp = skipsym(cp);
 885                 if (sym < 0) {
 886                         lt = LT_IF;
 887                         cp = skipargs(cp);
 888                 } else if (value[sym] == NULL) {
 889                         *valp = 0;
 890                         lt = LT_FALSE;
 891                 } else {
 892                         *valp = strtol(value[sym], &ep, 0);
 893                         if (*ep != '\0' || ep == value[sym])
 894                                 return (LT_ERROR);
 895                         lt = *valp ? LT_TRUE : LT_FALSE;
 896                         cp = skipargs(cp);
 897                 }
 898                 constexpr = false;
 899         } else {
 900                 debug("eval%d bad expr", ops - eval_ops);
 901                 return (LT_ERROR);
 902         }
 903
 904         *cpp = cp;
 905         debug("eval%d = %d", ops - eval_ops, *valp);
 906         return (lt);
 907 }
 908
 909 /*
 910  * Table-driven evaluation of binary operators.
 911  */
 912 static Linetype
 913 eval_table(const struct ops *ops, int *valp, const char **cpp)
 914 {
 915         const struct op *op;
 916         const char *cp;
 917         int val;
 918         Linetype lt, rt;
 919
 920         debug("eval%d", ops - eval_ops);
 921         cp = *cpp;
 922         lt = ops->inner(ops+1, valp, &cp);
 923         if (lt == LT_ERROR)
 924                 return (LT_ERROR);
 925         for (;;) {
 926                 cp = skipcomment(cp);
 927                 for (op = ops->op; op->str != NULL; op++)
 928                         if (strncmp(cp, op->str, strlen(op->str)) == 0)
 929                                 break;
 930                 if (op->str == NULL)
 931                         break;
 932                 cp += strlen(op->str);
 933                 debug("eval%d %s", ops - eval_ops, op->str);
 934                 rt = ops->inner(ops+1, &val, &cp);
 935                 if (rt == LT_ERROR)
 936                         return (LT_ERROR);
 937                 lt = op->fn(valp, lt, *valp, rt, val);
 938         }
 939
 940         *cpp = cp;
 941         debug("eval%d = %d", ops - eval_ops, *valp);
 942         debug("eval%d lt = %s", ops - eval_ops, linetype_name[lt]);
 943         return (lt);
 944 }
 945
 946 /*
 947  * Evaluate the expression on a #if or #elif line. If we can work out
 948  * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we
 949  * return just a generic LT_IF.
 950  */
 951 static Linetype
 952 ifeval(const char **cpp)
 953 {
 954         int ret;
 955         int val = 0;
 956
 957         debug("eval %s", *cpp);
 958         constexpr = killconsts ? false : true;
 959         ret = eval_table(eval_ops, &val, cpp);
 960         debug("eval = %d", val);
 961         return (constexpr ? LT_IF : ret == LT_ERROR ? LT_IF : ret);
 962 }
 963
 964 /*
 965  * Skip over comments, strings, and character literals and stop at the
 966  * next character position that is not whitespace. Between calls we keep
 967  * the comment state in the global variable incomment, and we also adjust
 968  * the global variable linestate when we see a newline.
 969  * XXX: doesn't cope with the buffer splitting inside a state transition.
 970  */
 971 static const char *
 972 skipcomment(const char *cp)
 973 {
 974         if (text || ignoring[depth]) {
 975                 for (; isspace((unsigned char)*cp); cp++)
 976                         if (*cp == '\n')
 977                                 linestate = LS_START;
 978                 return (cp);
 979         }
 980         while (*cp != '\0')
 981                 /* don't reset to LS_START after a line continuation */
 982                 if (strncmp(cp, "\\\r\n", 3) == 0)
 983                         cp += 3;
 984                 else if (strncmp(cp, "\\\n", 2) == 0)
 985                         cp += 2;
 986                 else switch (incomment) {
 987                 case NO_COMMENT:
 988                         if (strncmp(cp, "/\\\r\n", 4) == 0) {
 989                                 incomment = STARTING_COMMENT;
 990                                 cp += 4;
 991                         } else if (strncmp(cp, "/\\\n", 3) == 0) {
 992                                 incomment = STARTING_COMMENT;
 993                                 cp += 3;
 994                         } else if (strncmp(cp, "/*", 2) == 0) {
 995                                 incomment = C_COMMENT;
 996                                 cp += 2;
 997                         } else if (strncmp(cp, "//", 2) == 0) {
 998                                 incomment = CXX_COMMENT;
 999                                 cp += 2;
1000                         } else if (strncmp(cp, "\'", 1) == 0) {
1001                                 incomment = CHAR_LITERAL;
1002                                 linestate = LS_DIRTY;
1003                                 cp += 1;
1004                         } else if (strncmp(cp, "\"", 1) == 0) {
1005                                 incomment = STRING_LITERAL;
1006                                 linestate = LS_DIRTY;
1007                                 cp += 1;
1008                         } else if (strncmp(cp, "\n", 1) == 0) {
1009                                 linestate = LS_START;
1010                                 cp += 1;
1011                         } else if (strchr(" \r\t", *cp) != NULL) {
1012                                 cp += 1;
1013                         } else
1014                                 return (cp);
1015                         continue;
1016                 case CXX_COMMENT:
1017                         if (strncmp(cp, "\n", 1) == 0) {
1018                                 incomment = NO_COMMENT;
1019                                 linestate = LS_START;
1020                         }
1021                         cp += 1;
1022                         continue;
1023                 case CHAR_LITERAL:
1024                 case STRING_LITERAL:
1025                         if ((incomment == CHAR_LITERAL && cp[0] == '\'') ||
1026                             (incomment == STRING_LITERAL && cp[0] == '\"')) {
1027                                 incomment = NO_COMMENT;
1028                                 cp += 1;
1029                         } else if (cp[0] == '\\') {
1030                                 if (cp[1] == '\0')
1031                                         cp += 1;
1032                                 else
1033                                         cp += 2;
1034                         } else if (strncmp(cp, "\n", 1) == 0) {
1035                                 if (incomment == CHAR_LITERAL)
1036                                         error("unterminated char literal");
1037                                 else
1038                                         error("unterminated string literal");
1039                         } else
1040                                 cp += 1;
1041                         continue;
1042                 case C_COMMENT:
1043                         if (strncmp(cp, "*\\\r\n", 4) == 0) {
1044                                 incomment = FINISHING_COMMENT;
1045                                 cp += 4;
1046                         } else if (strncmp(cp, "*\\\n", 3) == 0) {
1047                                 incomment = FINISHING_COMMENT;
1048                                 cp += 3;
1049                         } else if (strncmp(cp, "*/", 2) == 0) {
1050                                 incomment = NO_COMMENT;
1051                                 cp += 2;
1052                         } else
1053                                 cp += 1;
1054                         continue;
1055                 case STARTING_COMMENT:
1056                         if (*cp == '*') {
1057                                 incomment = C_COMMENT;
1058                                 cp += 1;
1059                         } else if (*cp == '/') {
1060                                 incomment = CXX_COMMENT;
1061                                 cp += 1;
1062                         } else {
1063                                 incomment = NO_COMMENT;
1064                                 linestate = LS_DIRTY;
1065                         }
1066                         continue;
1067                 case FINISHING_COMMENT:
1068                         if (*cp == '/') {
1069                                 incomment = NO_COMMENT;
1070                                 cp += 1;
1071                         } else
1072                                 incomment = C_COMMENT;
1073                         continue;
1074                 default:
1075                         abort(); /* bug */
1076                 }
1077         return (cp);
1078 }
1079
1080 /*
1081  * Skip macro arguments.
1082  */
1083 static const char *
1084 skipargs(const char *cp)
1085 {
1086         const char *ocp = cp;
1087         int level = 0;
1088         cp = skipcomment(cp);
1089         if (*cp != '(')
1090                 return (cp);
1091         do {
1092                 if (*cp == '(')
1093                         level++;
1094                 if (*cp == ')')
1095                         level--;
1096                 cp = skipcomment(cp+1);
1097         } while (level != 0 && *cp != '\0');
1098         if (level == 0)
1099                 return (cp);
1100         else
1101         /* Rewind and re-detect the syntax error later. */
1102                 return (ocp);
1103 }
1104
1105 /*
1106  * Skip over an identifier.
1107  */
1108 static const char *
1109 skipsym(const char *cp)
1110 {
1111         while (!endsym(*cp))
1112                 ++cp;
1113         return (cp);
1114 }
1115
1116 /*
1117  * Look for the symbol in the symbol table. If it is found, we return
1118  * the symbol table index, else we return -1.
1119  */
1120 static int
1121 findsym(const char *str)
1122 {
1123         const char *cp;
1124         int symind;
1125
1126         cp = skipsym(str);
1127         if (cp == str)
1128                 return (-1);
1129         if (symlist) {
1130                 if (symdepth && firstsym)
1131                         printf("%s%3d", zerosyms ? "" : "\n", depth);
1132                 firstsym = zerosyms = false;
1133                 printf("%s%.*s%s",
1134                     symdepth ? " " : "",
1135                     (int)(cp-str), str,
1136                     symdepth ? "" : "\n");
1137                 /* we don't care about the value of the symbol */
1138                 return (0);
1139         }
1140         for (symind = 0; symind < nsyms; ++symind) {
1141                 if (strlcmp(symname[symind], str, cp-str) == 0) {
1142                         debug("findsym %s %s", symname[symind],
1143                             value[symind] ? value[symind] : "");
1144                         return (symind);
1145                 }
1146         }
1147         return (-1);
1148 }
1149
1150 /*
1151  * Add a symbol to the symbol table.
1152  */
1153 static void
1154 addsym(bool ignorethis, bool definethis, char *sym)
1155 {
1156         int symind;
1157         char *val;
1158
1159         symind = findsym(sym);
1160         if (symind < 0) {
1161                 if (nsyms >= MAXSYMS)
1162                         errx(2, "too many symbols");
1163                 symind = nsyms++;
1164         }
1165         symname[symind] = sym;
1166         ignore[symind] = ignorethis;
1167         val = sym + (skipsym(sym) - sym);
1168         if (definethis) {
1169                 if (*val == '=') {
1170                         value[symind] = val+1;
1171                         *val = '\0';
1172                 } else if (*val == '\0')
1173                         value[symind] = "1";
1174                 else
1175                         usage();
1176         } else {
1177                 if (*val != '\0')
1178                         usage();
1179                 value[symind] = NULL;
1180         }
1181         debug("addsym %s=%s", symname[symind],
1182             value[symind] ? value[symind] : "undef");
1183 }
1184
1185 /*
1186  * Compare s with n characters of t.
1187  * The same as strncmp() except that it checks that s[n] == '\0'.
1188  */
1189 static int
1190 strlcmp(const char *s, const char *t, size_t n)
1191 {
1192         while (n-- && *t != '\0')
1193                 if (*s != *t)
1194                         return ((unsigned char)*s - (unsigned char)*t);
1195                 else
1196                         ++s, ++t;
1197         return ((unsigned char)*s);
1198 }
1199
1200 /*
1201  * Diagnostics.
1202  */
1203 static void
1204 debug(const char *msg, ...)
1205 {
1206         va_list ap;
1207
1208         if (debugging) {
1209                 va_start(ap, msg);
1210                 vwarnx(msg, ap);
1211                 va_end(ap);
1212         }
1213 }
1214
1215 static void
1216 error(const char *msg)
1217 {
1218         if (depth == 0)
1219                 warnx("%s: %d: %s", filename, linenum, msg);
1220         else
1221                 warnx("%s: %d: %s (#if line %d depth %d)",
1222                     filename, linenum, msg, stifline[depth], depth);
1223         closeout();
1224         errx(2, "output may be truncated");
1225 }