src/preproc/html/pushback.cpp

   1 // -*- C++ -*-
   2 /* Copyright (C) 2000, 2001, 2003, 2004, 2005 Free Software Foundation, Inc.
   3      Written by Gaius Mulley (gaius@glam.ac.uk).
   4
   5 This file is part of groff.
   6
   7 groff is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License along
  18 with groff; see the file COPYING.  If not, write to the Free Software
  19 Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
  20
  21 #include "lib.h"
  22
  23 #include <signal.h>
  24 #include <ctype.h>
  25 #include <assert.h>
  26 #include <stdlib.h>
  27 #include <errno.h>
  28 #include "errarg.h"
  29 #include "error.h"
  30 #include "stringclass.h"
  31 #include "posix.h"
  32 #include "nonposix.h"
  33
  34 #include <errno.h>
  35 #include <sys/types.h>
  36 #ifdef HAVE_UNISTD_H
  37 #include <unistd.h>
  38 #endif
  39
  40 #include "pushback.h"
  41 #include "pre-html.h"
  42
  43 #if !defined(TRUE)
  44 #   define TRUE  (1==1)
  45 #endif
  46
  47 #if !defined(FALSE)
  48 #   define FALSE (1==0)
  49 #endif
  50
  51 #   define ERROR(X)   (void)(fprintf(stderr, "%s:%d error %s\n", __FILE__, __LINE__, X) && \
  52                             (fflush(stderr)) && localexit(1))
  53
  54
  55 #define MAXPUSHBACKSTACK 4096                  /* maximum number of character that can be pushed back */
  56
  57
  58 /*
  59  *  constructor for pushBackBuffer
  60  */
  61
  62 pushBackBuffer::pushBackBuffer (char *filename)
  63 {
  64   charStack = (char *)malloc(MAXPUSHBACKSTACK);
  65   if (charStack == 0) {
  66     sys_fatal("malloc");
  67   }
  68   stackPtr = 0;   /* index to push back stack        */
  69   debug    = 0;
  70   verbose  = 0;
  71   eofFound = FALSE;
  72   lineNo   = 1;
  73   if (strcmp(filename, "") != 0) {
  74     stdIn = dup(0);
  75     close(0);
  76     if (open(filename, O_RDONLY) != 0) {
  77       sys_fatal("when trying to open file");
  78     } else {
  79       fileName = filename;
  80     }
  81   }
  82 }
  83
  84 pushBackBuffer::~pushBackBuffer ()
  85 {
  86   if (charStack != 0) {
  87     free(charStack);
  88   }
  89   close(0);
  90   /* restore stdin in file descriptor 0 */
  91   dup(stdIn);
  92   close(stdIn);
  93 }
  94
  95 /*
  96  *  localexit - wraps exit with a return code to aid the ERROR macro.
  97  */
  98
  99 int localexit (int i)
 100 {
 101   exit(i);
 102   return( 1 );
 103 }
 104
 105 /*
 106  *  getPB - returns a character, possibly a pushed back character.
 107  */
 108
 109 char pushBackBuffer::getPB (void)
 110 {
 111   if (stackPtr>0) {
 112     stackPtr--;
 113     return( charStack[stackPtr] );
 114   } else {
 115     char ch;
 116
 117     if (read(0, &ch, 1) == 1) {
 118       if (verbose) {
 119         printf("%c", ch);
 120       }
 121       if (ch == '\n') {
 122         lineNo++;
 123       }
 124       return( ch );
 125     } else {
 126       eofFound = TRUE;
 127       return( eof );
 128     }
 129   }
 130 }
 131
 132 /*
 133  *  putPB - pushes a character onto the push back stack.
 134  *          The same character is returned.
 135  */
 136
 137 char pushBackBuffer::putPB (char ch)
 138 {
 139   if (stackPtr<MAXPUSHBACKSTACK) {
 140     charStack[stackPtr] = ch ;
 141     stackPtr++;
 142   } else {
 143     ERROR("max push back stack exceeded, increase MAXPUSHBACKSTACK constant");
 144   }
 145   return( ch );
 146 }
 147
 148 /*
 149  *  isWhite - returns TRUE if a white character is found. This character is NOT consumed.
 150  */
 151
 152 static int isWhite (char ch)
 153 {
 154   return( (ch==' ') || (ch == '\t') || (ch == '\n') );
 155 }
 156
 157 /*
 158  *  skipToNewline - skips characters until a newline is seen.
 159  */
 160
 161 void pushBackBuffer::skipToNewline (void)
 162 {
 163   while ((putPB(getPB()) != '\n') && (! eofFound)) {
 164     getPB();
 165   }
 166 }
 167
 168 /*
 169  *  skipUntilToken - skips until a token is seen
 170  */
 171
 172 void pushBackBuffer::skipUntilToken (void)
 173 {
 174   char ch;
 175
 176   while ((isWhite(putPB(getPB())) || (putPB(getPB()) == '#')) && (! eofFound)) {
 177     ch = getPB();
 178     if (ch == '#') {
 179       skipToNewline();
 180     }
 181   }
 182 }
 183
 184 /*
 185  *  isString - returns TRUE if the string, s, matches the pushed back string.
 186  *             if TRUE is returned then this string is consumed, otherwise it is
 187  *             left alone.
 188  */
 189
 190 int pushBackBuffer::isString (const char *s)
 191 {
 192   int length=strlen(s);
 193   int i=0;
 194
 195   while ((i<length) && (putPB(getPB())==s[i])) {
 196     if (getPB() != s[i]) {
 197       ERROR("assert failed");
 198     }
 199     i++;
 200   }
 201   if (i==length) {
 202     return( TRUE );
 203   } else {
 204     i--;
 205     while (i>=0) {
 206       if (putPB(s[i]) != s[i]) {
 207         ERROR("assert failed");
 208       }
 209       i--;
 210     }
 211   }
 212   return( FALSE );
 213 }
 214
 215 /*
 216  *  isDigit - returns TRUE if the character, ch, is a digit.
 217  */
 218
 219 static int isDigit (char ch)
 220 {
 221   return( ((ch>='0') && (ch<='9')) );
 222 }
 223
 224 /*
 225  *  isHexDigit - returns TRUE if the character, ch, is a hex digit.
 226  */
 227
 228 #if 0
 229 static int isHexDigit (char ch)
 230 {
 231   return( (isDigit(ch)) || ((ch>='a') && (ch<='f')) );
 232 }
 233 #endif
 234
 235 /*
 236  *  readInt - returns an integer from the input stream.
 237  */
 238
 239 int pushBackBuffer::readInt (void)
 240 {
 241   int  c =0;
 242   int  i =0;
 243   int  s =1;
 244   char ch=getPB();
 245
 246   while (isWhite(ch)) {
 247     ch=getPB();
 248   }
 249   // now read integer
 250
 251   if (ch == '-') {
 252     s = -1;
 253     ch = getPB();
 254   }
 255   while (isDigit(ch)) {
 256     i *= 10;
 257     if ((ch>='0') && (ch<='9')) {
 258       i += (int)(ch-'0');
 259     }
 260     ch = getPB();
 261     c++;
 262   }
 263   if (ch != putPB(ch)) {
 264     ERROR("assert failed");
 265   }
 266   return( i*s );
 267 }
 268
 269 /*
 270  *  convertToFloat - converts integers, a and b into a.b
 271  */
 272
 273 static double convertToFloat (int a, int b)
 274 {
 275   int c=10;
 276   double f;
 277
 278   while (b>c) {
 279     c *= 10;
 280   }
 281   f = ((double)a) + (((double)b)/((double)c));
 282   return( f );
 283 }
 284
 285 /*
 286  *  readNumber - returns a float representing the word just read.
 287  */
 288
 289 double pushBackBuffer::readNumber (void)
 290 {
 291   int i;
 292   char ch;
 293
 294   i = readInt();
 295   if ((ch = getPB()) == '.') {
 296     return convertToFloat(i, readInt());
 297   }
 298   putPB(ch);
 299   return (double)i;
 300 }
 301
 302 /*
 303  *  readString - reads a string terminated by white space
 304  *               and returns a malloced area of memory containing
 305  *               a copy of the characters.
 306  */
 307
 308 char *pushBackBuffer::readString (void)
 309 {
 310   char  buffer[MAXPUSHBACKSTACK];
 311   char *str = 0;
 312   int   i=0;
 313   char ch=getPB();
 314
 315   while (isWhite(ch)) {
 316     ch=getPB();
 317   }
 318   while ((i < MAXPUSHBACKSTACK) && (! isWhite(ch)) && (! eofFound)) {
 319     buffer[i] = ch;
 320     i++;
 321     ch = getPB();
 322   }
 323   if (i < MAXPUSHBACKSTACK) {
 324     buffer[i] = (char)0;
 325     str = (char *)malloc(strlen(buffer)+1);
 326     strcpy(str, buffer);
 327   }
 328   return( str );
 329 }