mdw@git.distorted.org.uk Git - bascat/blob - bascat.c

   1 /* -*-c-*-
   2  *
   3  * $Id: bascat.c,v 1.5 1999/11/25 01:08:57 mdw Exp $
   4  *
   5  * Display BBC BASIC programs more or less anywhere
   6  *
   7  * (c) 1996, 1997 Matthew Wilcox and Mark Wooding
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Bascat.
  13  *
  14  * Bascat is free software; you can redistribute it and/or modify it
  15  * under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Bascat is distributed in the hope that it will be useful, but
  20  * WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with Bascat; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: bascat.c,v $
  32  * Revision 1.5  1999/11/25 01:08:57  mdw
  33  * Fix decoding of line numbers.
  34  *
  35  * Revision 1.4  1999/10/28 10:42:23  mdw
  36  * More minor twiddling.
  37  *
  38  * Revision 1.3  1999/10/28 10:18:17  mdw
  39  * Minor name changes for new coding standards.
  40  *
  41  * Revision 1.2  1998/06/26 11:29:28  mdw
  42  * Added support for line-numbers.
  43  *
  44  * Revision 1.1  1998/03/16 15:21:37  mdw
  45  * Files placed under CVS control.
  46  *
  47  * Revision 1.1  1997/07/23 01:19:33  mdw
  48  * Initial revision
  49  *
  50  */
  51
  52 /*----- Header files ------------------------------------------------------*/
  53
  54 /* --- ANSI library headers --- */
  55
  56 #include <ctype.h>
  57 #include <errno.h>
  58 #include <signal.h>
  59 #include <stdio.h>
  60 #include <stdlib.h>
  61 #include <string.h>
  62
  63 /* --- Operating system specific headers --- */
  64
  65 #ifdef HAVE_LIBTERMCAP
  66 #  include <termcap.h>
  67 #endif
  68 #include <unistd.h>
  69
  70 /* --- Private headers --- */
  71
  72 #include "mdwopt.h"
  73
  74 /*----- Version information -----------------------------------------------*/
  75
  76 #ifndef NDEBUG
  77 #  define D(x) x
  78 #else
  79 #  define D(x)
  80 #endif
  81
  82 /*----- Tokenisation tables -----------------------------------------------*
  83  *
  84  * These tables are from the BBC BASIC guide.  Additional verification
  85  * carried out on an A440 with RISC OS 3.1
  86  */
  87
  88 static const char *tok_base[] = {
  89   "OTHERWISE",
  90   "AND", "DIV", "EOR", "MOD", "OR", "ERROR", "LINE", "OFF",
  91   "STEP", "SPC", "TAB(", "ELSE", "THEN", "*", "OPENIN", "PTR",
  92   "PAGE", "TIME", "LOMEM", "HIMEM", "ABS", "ACS", "ADVAL", "ASC",
  93   "ASN", "ATN", "BGET", "COS", "COUNT", "DEG", "ERL", "ERR",
  94   "EVAL", "EXP", "EXT", "FALSE", "FN", "GET", "INKEY", "INSTR(",
  95   "INT", "LEN", "LN", "LOG", "NOT", "OPENUP", "OPENOUT", "PI",
  96   "POINT(", "POS", "RAD", "RND", "SGN", "SIN", "SQR", "TAN",
  97   "TO", "TRUE", "USR", "VAL", "VPOS", "CHR$", "GET$", "INKEY$",
  98   "LEFT$(", "MID$(", "RIGHT$(", "STR$", "STRING$(", "EOF", "*", "*",
  99   "*", "WHEN", "OF", "ENDCASE", "ELSE", "ENDIF", "ENDWHILE", "PTR",
 100   "PAGE", "TIME", "LOMEM", "HIMEM", "SOUND", "BPUT", "CALL", "CHAIN",
 101   "CLEAR", "CLOSE", "CLG", "CLS", "DATA", "DEF", "DIM", "DRAW",
 102   "END", "ENDPROC", "ENVELOPE", "FOR", "GOSUB", "GOTO", "GCOL", "IF",
 103   "INPUT", "LET", "LOCAL", "MODE", "MOVE", "NEXT", "ON", "VDU",
 104   "PLOT", "PRINT", "PROC", "READ", "REM", "REPEAT", "REPORT", "RESTORE",
 105   "RETURN", "RUN", "STOP", "COLOUR", "TRACE", "UNTIL", "WIDTH", "OSCLI"
 106 };
 107
 108 static const char *tok_c6[] = {
 109   "SUM", "BEAT"
 110 };
 111
 112 static const char *tok_c7[] = {
 113   "APPEND", "AUTO",
 114   "CRUNCH", "DELETE", "EDIT", "HELP", "LIST", "LOAD", "LVAR", "NEW",
 115   "OLD", "RENUMBER", "SAVE", "TEXTLOAD", "TEXTSAVE", "TWIN", "TWINO",
 116     "INSTALL"
 117 };
 118
 119 static const char *tok_c8[] = {
 120   "CASE", "CIRCLE",
 121   "FILL", "ORIGIN", "POINT", "RECTANGLE", "SWAP", "WHILE", "WAIT", "MOUSE",
 122   "QUIT", "SYS", "INSTALL", "LIBRARY", "TINT", "ELLIPSE", "BEATS", "TEMPO",
 123   "VOICES", "VOICE", "STEREO", "OVERLAY"
 124 };
 125
 126 #define ITEMS(array) (sizeof(array) / sizeof((array)[0]))
 127
 128 /*----- Static variables --------------------------------------------------*/
 129
 130 enum {
 131   s_keyword,                            /* Expecting a keyword next */
 132   s_normal,                             /* Normal state, reading input */
 133   s_comment,                            /* In a command (or literal *cmd) */
 134   s_quote,                              /* Inside a quoted string */
 135   s_c6, s_c7, s_c8,                     /* Various shift states */
 136   s_linex, s_liney, s_linez,            /* Line number states */
 137   s_dummy
 138 };
 139
 140 static int state = s_normal;            /* Current detokenisation state */
 141 static unsigned int lineno;             /* Line number */
 142
 143 enum {
 144   f_highlight = 1,                      /* Highlight keywords and things */
 145   f_linenumbers = 2,                    /* Display linenumbers on left */
 146   f_tty = 4,                            /* We're writing to TTY (or pager) */
 147   f_less = 8,                           /* We're piping through `less' */
 148   f_dummy
 149 };
 150
 151 static int flags;                       /* Various options flags */
 152
 153 #ifdef HAVE_LIBTERMCAP
 154 static char termcap[2048];              /* Terminal capabilities buffer */
 155 #endif
 156
 157 static char *pager = 0;                 /* Pointer to pager to use */
 158
 159 /*----- Main code ---------------------------------------------------------*/
 160
 161 /* --- @die@ --- *
 162  *
 163  * Arguments:   @char *p@ = pointer to a string
 164  *
 165  * Returns:     1
 166  *
 167  * Use:         Reports an error to the user and falls over flat on its face.
 168  */
 169
 170 static int die(const char *p)
 171 {
 172   fprintf(stderr, "%s: %s\n", optprog, p);
 173   return (1);
 174 }
 175
 176 /* --- @keyword@ --- *
 177  *
 178  * Arguments:   @char *s@ = pointer to keyword string
 179  *              @FILE *fp@ = stream to write onto
 180  *
 181  * Returns:     --
 182  *
 183  * Use:         Displays a keyword in a nice way.  There's some nasty hacking
 184  *              here to make GNU's `less' work properly.  `more' appears to
 185  *              cope with highlighting codes OK, so that's fine.  `less'
 186  *              prefers it if we attempt to `overstrike' the bolded
 187  *              characters.  What fun...
 188  */
 189
 190 static void keyword(const char *s, FILE *fp)
 191 {
 192 #ifdef HAVE_LIBTERMCAP
 193   if ((~flags & (f_less | f_highlight)) == 0) {
 194     while (*s) {
 195       putc(*s, fp);
 196       putc('\b', fp);
 197       putc(*s, fp);
 198       s++;
 199     }
 200   } else {
 201     static char buff[24];
 202     static char *hs, *he, *p = buff;
 203
 204     if (!hs) {
 205       if (flags & f_highlight) {
 206         hs = tgetstr("md", &p);
 207         he = tgetstr("me", &p);
 208       } else
 209         hs = he = "";
 210     }
 211     fputs(hs, fp);
 212     fputs(s, fp);
 213     fputs(he, fp);
 214   }
 215 #else
 216   fputs(s, fp);
 217 #endif
 218 }
 219
 220 /* --- @mbtok@ --- *
 221  *
 222  * Arguments:   @int byte@ = the current byte
 223  *              @const char *t[]@ = pointer to token table
 224  *              @int n@ = number of items in token table
 225  *              @FILE *fp@ = stream to write onto
 226  *
 227  * Returns:     0 if everything's OK
 228  *
 229  * Use:         Decodes multibyte tokens.
 230  */
 231
 232 static int mbtok(int byte, const char *t[], int n, FILE *fp)
 233 {
 234   byte -= 0x8E;
 235   if (byte >= n)
 236     return (die("Bad program: invalid multibyte token"));
 237   keyword(t[byte], fp);
 238   state = s_normal;
 239   return (0);
 240 }
 241
 242 /* --- @decode@ --- *
 243  *
 244  * Arguments:   @int byte@ = byte to decode
 245  *              @FILE *fp@ = stream to write onto
 246  *
 247  * Returns:     0 if everything's going OK
 248  *
 249  * Use:         Decodes a byte, changing states as necessary.
 250  */
 251
 252 static int decode(int byte, FILE *fp)
 253 {
 254   switch (state) {
 255
 256     /* --- Tokenised states --- */
 257
 258     case s_keyword:
 259       if (byte == '*')
 260         state = s_comment;
 261       else
 262         state = s_normal;
 263       /* Fall through here */
 264
 265     case s_normal:
 266       if (byte >= 0x7F) {
 267         switch (byte) {
 268           case 0xC6:
 269             state = s_c6;
 270             break;
 271           case 0xC7:
 272             state = s_c7;
 273             break;
 274           case 0xC8:
 275             state = s_c8;
 276             break;
 277           case 0x8D:
 278             state = s_linex;
 279             break;
 280           case 0x8B:                    /* ELSE */
 281           case 0x8C:                    /* THEN */
 282           case 0xF5:                    /* REPEAT (a funny one) */
 283             state = s_keyword;
 284             goto keyword;
 285             break;
 286           case 0xDC:                    /* DATA */
 287           case 0xF4:                    /* REM */
 288             state = s_comment;
 289             /* Fall through here */
 290           default:
 291           keyword:
 292             keyword(tok_base[byte - 0x7F], fp);
 293             break;
 294         }
 295       } else {
 296         if (byte == '"')
 297           state = s_quote;
 298         fputc(byte, fp);
 299       }
 300       break;
 301
 302     /* --- Non-tokenised states --- */
 303
 304     case s_quote:
 305       if (byte == '"')
 306         state = s_normal;
 307       /* Fall through here */
 308
 309     case s_comment:
 310       fputc(byte, fp);
 311       break;
 312
 313     /* --- Double-byte token states --- */
 314
 315     case s_c6:
 316       return (mbtok(byte, tok_c6, ITEMS(tok_c6), fp));
 317       break;
 318
 319     case s_c7:
 320       return (mbtok(byte, tok_c7, ITEMS(tok_c7), fp));
 321       break;
 322
 323     case s_c8:
 324       return (mbtok(byte, tok_c8, ITEMS(tok_c8), fp));
 325       break;
 326
 327     /* --- Encoded line number states --- */
 328
 329     case s_linex:
 330       byte ^= 0x54;
 331       lineno = (((byte & 0x30) << 2) |
 332                 ((byte & 0x0c) << 12) |
 333                 ((byte & 0x03)  << 16));
 334       state++;
 335       break;
 336
 337     case s_liney:
 338       lineno |= byte & 0x3f;
 339       state++;
 340       break;
 341
 342     case s_linez:
 343       lineno |= (byte & 0x3f) << 8;
 344       fprintf(fp, "%u", lineno);
 345       state = s_normal;
 346       break;
 347
 348   }
 349   return (0);
 350 }
 351
 352 /* --- @line@ --- *
 353  *
 354  * Arguments:   @FILE *in@ = input stream to read
 355  *              @FILE *out@ = output stream to write
 356  *
 357  * Returns:     Zero if there's another line after this one.
 358  *
 359  * Use:         Decodes a BASIC line into stuff to be written.
 360  */
 361
 362 static int line(FILE *in, FILE *out)
 363 {
 364   /* --- Read the line number --- */
 365
 366   {
 367     int a, b;
 368
 369     a = getc(in);
 370     D( fprintf(stderr, "ln_0 == %i\n", a); )
 371       if (a == EOF)
 372       goto eof;
 373     if (a == 0xFF)
 374       return (1);
 375
 376     b = getc(in);
 377     D( fprintf(stderr, "ln_1 == %i\n", b); )
 378       if (b == EOF)
 379       goto eof;
 380
 381     if (flags & f_linenumbers)
 382       fprintf(out, "%5i", (a << 8) + b);
 383   }
 384
 385   {
 386     int len;
 387     int byte;
 388
 389     len = getc(in);
 390     D( fprintf(stderr, "linelen == %i\n", len); )
 391       if (len == EOF)
 392       goto eof;
 393     len -= 4;
 394
 395     state = s_keyword;
 396     while (len) {
 397       byte = getc(in);
 398       D( fprintf(stderr, "state == %i, byte == %i\n",
 399                  state, byte); )
 400         if (byte == EOF)
 401         goto eof;
 402       decode(byte, out);
 403       len--;
 404     }
 405     putc('\n', out);
 406
 407     byte = getc(in);
 408     D( fprintf(stderr, "eol == %i\n", byte); )
 409       if (byte == EOF)
 410       goto eof;
 411     else if (byte != 0x0D)
 412       return (die("Bad program: expected end-of-line delimiter"));
 413   }
 414
 415   return (0);
 416
 417 eof:
 418   return (die("Bad program: unexpected end-of-file"));
 419 }
 420
 421 /* --- @file@ --- *
 422  *
 423  * Arguments:   @FILE *in@ = the input stream
 424  *              @FILE *out@ = the output stream
 425  *
 426  * Returns:     --
 427  *
 428  * Use:         Decodes an entire file.
 429  */
 430
 431 static void file(FILE *in, FILE *out)
 432 {
 433   int byte;
 434
 435   /* --- Check for the inital newline char --- */
 436
 437   byte = getc(in);
 438   if (byte != 0x0D)
 439     die("Bad program: doesn't start with a newline");
 440
 441   /* --- Now read the lines in one by one --- */
 442
 443   while (!line(in, out)) ;
 444
 445   /* --- Check that we're really at end-of-file --- */
 446
 447   byte = getc(in);
 448   if (byte != EOF)
 449     die("Found data after end of program");
 450 }
 451
 452 /* --- @sig_pipe@ --- *
 453  *
 454  * Arguments:   @int s@ = signal number
 455  *
 456  * Returns:     Doesn't
 457  *
 458  * Use:         Handles SIGPIPE signals, and gracefully kills the program.
 459  */
 460
 461 static void sig_pipe(int s)
 462 {
 463   (void) s;
 464   exit(0);                              /* Gracefully, oh yes */
 465 }
 466
 467 /* --- @options@ --- *
 468  *
 469  * Arguments:   @int c@ = number of arguments
 470  *              @char *v[]@ = pointer to arguments
 471  *              @char *s@ = pointer to short options
 472  *              @struct option *o@ = pointer to long options
 473  *
 474  * Returns:     --
 475  *
 476  * Use:         Parses lots of arguments.
 477  */
 478
 479 static void options(int c, char *v[], const char *s,
 480                         const struct option *o)
 481 {
 482   int i;
 483
 484   for (;;) {
 485     i = mdwopt(c, v, s, o, 0, 0, OPTF_NEGATION | OPTF_ENVVAR);
 486     if (i == -1)
 487       break;
 488
 489     switch (i) {
 490       case 'v':
 491       case 'h':
 492         printf("%s version " VERSION "\n", optprog);
 493         if (i == 'v')
 494           exit(0);
 495         printf("\n"
 496                "%s [-hv] [-n|+n] [-l|+l] [-p PAGER] [file...]\n"
 497                "\n"
 498                "Types BBC BASIC programs in a readable way.  Options "
 499                "currently supported are as\n"
 500                "follows:\n"
 501                "\n"
 502                "-h, --help:            Displays this evil help message\n"
 503                "-v, --version:         Displays the current version number\n"
 504                "-n, --line-numbers:    Displays line numbers for each line\n"
 505                "-l, --highlight:       Attempts to highlight keywords\n"
 506                "-p, --pager=PAGER:     Sets pager to use (default $PAGER)\n"
 507                "\n"
 508                "Prefix long options with `no-' to cancel them.  Use `+' to "
 509                "cancel short options.\n"
 510                "Options can also be placed in the `BASCAT' environment "
 511                "variable, if you don't\n"
 512                "like the standard settings.\n",
 513                optprog);
 514         exit(0);
 515         break;
 516       case 'n':
 517         flags |= f_linenumbers;
 518         break;
 519       case 'n' | OPTF_NEGATED:
 520         flags &= ~f_linenumbers;
 521         break;
 522       case 'l':
 523         flags |= f_highlight;
 524         break;
 525       case 'l' | OPTF_NEGATED:
 526         flags &= ~f_highlight;
 527         break;
 528       case 'p':
 529         pager = optarg;
 530         break;
 531     }
 532   }
 533 }
 534
 535 /* --- @main@ --- *
 536  *
 537  * Arguments:   @int argc@ = number of arguments
 538  *              @char *argc[]@ = pointer to what the arguments are
 539  *
 540  * Returns:     0 if it all worked
 541  *
 542  * Use:         Displays BASIC programs.
 543  */
 544
 545 int main(int argc, char *argv[])
 546 {
 547   static struct option opts[] = {
 548     { "help",           0,              0,      'h' },
 549     { "version",        0,              0,      'v' },
 550     { "line-numbers",   OPTF_NEGATE,    0,      'n' },
 551     { "highlight",      OPTF_NEGATE,    0,      'l' },
 552     { "pager",          OPTF_ARGREQ,    0,      'p' },
 553     { 0,                0,              0,      0 }
 554   };
 555   static char *shortopts = "hvn+l+p:";
 556
 557   /* --- Parse the command line options --- */
 558
 559   options(argc, argv, shortopts, opts);
 560
 561   /* --- Now do the job --- */
 562
 563   if (optind == argc && isatty(0)) {
 564     fprintf(stderr,
 565             "%s: No filenames given, and standard input is a tty\n"
 566             "To force reading from stdin, use `%s -'.  For help, type "
 567             "`%s --help'.\n",
 568             optprog, optprog, optprog);
 569     exit(0);
 570   }
 571
 572 #ifdef HAVE_LIBTERMCAP
 573   if (flags & f_highlight)
 574     tgetent(termcap, getenv("TERM"));
 575 #endif
 576
 577   {
 578     FILE *in;
 579     FILE *out;
 580
 581     /* --- If output is to a terminal, try paging --- *
 582      *
 583      * All programs which spew text should do this ;-)
 584      */
 585
 586     if (isatty(1)) {
 587       if (!pager)
 588         pager = getenv("PAGER");
 589       if (!pager)
 590         pager = PAGER;                  /* Worth a try */
 591       if (strstr(pager, "less"))
 592         flags |= f_less;                /* HACK!!! */
 593       out = popen(pager, "w");
 594       if (!out)
 595         out = stdout;
 596       else {
 597         flags |= f_tty;
 598         signal(SIGPIPE, sig_pipe);
 599       }
 600     } else
 601       out = stdout;
 602
 603     /* --- Now go through all the files --- */
 604
 605     if (optind == argc)
 606       file(stdin, out);
 607     else
 608       while (optind < argc) {
 609         if (strcmp(argv[optind], "-") == 0)
 610           file(stdin, out);
 611         else {
 612           in = fopen(argv[optind], "rb");
 613           if (!in) {
 614             fprintf(stderr,
 615                     "%s: Couldn't open input file: %s\n",
 616                     optprog, strerror(errno));
 617           } else {
 618             file(in, out);
 619             fclose(in);
 620           }
 621         }
 622         optind++;
 623       }
 624     if (flags & f_tty)
 625       pclose(out);
 626   }
 627
 628   return (0);
 629 }
 630
 631 /*----- That's all, folks -------------------------------------------------*/