src/preproc/html/pushback.cpp

   1 // -*- C++ -*-
   2 /* Copyright (C) 2000, 2001, 2003, 2004 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   int old;
  87
  88   if (charStack != 0) {
  89     free(charStack);
  90   }
  91   close(0);
  92   /* restore stdin in file descriptor 0 */
  93   old = dup(stdIn);
  94   close(stdIn);
  95 }
  96
  97 /*
  98  *  localexit - wraps exit with a return code to aid the ERROR macro.
  99  */
 100
 101 int localexit (int i)
 102 {
 103   exit(i);
 104   return( 1 );
 105 }
 106
 107 /*
 108  *  getPB - returns a character, possibly a pushed back character.
 109  */
 110
 111 char pushBackBuffer::getPB (void)
 112 {
 113   if (stackPtr>0) {
 114     stackPtr--;
 115     return( charStack[stackPtr] );
 116   } else {
 117     char ch;
 118
 119     if (read(0, &ch, 1) == 1) {
 120       if (verbose) {
 121         printf("%c", ch);
 122       }
 123       if (ch == '\n') {
 124         lineNo++;
 125       }
 126       return( ch );
 127     } else {
 128       eofFound = TRUE;
 129       return( eof );
 130     }
 131   }
 132 }
 133
 134 /*
 135  *  putPB - pushes a character onto the push back stack.
 136  *          The same character is returned.
 137  */
 138
 139 char pushBackBuffer::putPB (char ch)
 140 {
 141   if (stackPtr<MAXPUSHBACKSTACK) {
 142     charStack[stackPtr] = ch ;
 143     stackPtr++;
 144   } else {
 145     ERROR("max push back stack exceeded, increase MAXPUSHBACKSTACK constant");
 146   }
 147   return( ch );
 148 }
 149
 150 /*
 151  *  isWhite - returns TRUE if a white character is found. This character is NOT consumed.
 152  */
 153
 154 static int isWhite (char ch)
 155 {
 156   return( (ch==' ') || (ch == '\t') || (ch == '\n') );
 157 }
 158
 159 /*
 160  *  skipToNewline - skips characters until a newline is seen.
 161  */
 162
 163 void pushBackBuffer::skipToNewline (void)
 164 {
 165   char ch;
 166
 167   while ((putPB(getPB()) != '\n') && (! eofFound)) {
 168     ch = getPB();
 169   }
 170 }
 171
 172 /*
 173  *  skipUntilToken - skips until a token is seen
 174  */
 175
 176 void pushBackBuffer::skipUntilToken (void)
 177 {
 178   char ch;
 179
 180   while ((isWhite(putPB(getPB())) || (putPB(getPB()) == '#')) && (! eofFound)) {
 181     ch = getPB();
 182     if (ch == '#') {
 183       skipToNewline();
 184     }
 185   }
 186 }
 187
 188 /*
 189  *  isString - returns TRUE if the string, s, matches the pushed back string.
 190  *             if TRUE is returned then this string is consumed, otherwise it is
 191  *             left alone.
 192  */
 193
 194 int pushBackBuffer::isString (const char *s)
 195 {
 196   int length=strlen(s);
 197   int i=0;
 198
 199   while ((i<length) && (putPB(getPB())==s[i])) {
 200     if (getPB() != s[i]) {
 201       ERROR("assert failed");
 202     }
 203     i++;
 204   }
 205   if (i==length) {
 206     return( TRUE );
 207   } else {
 208     i--;
 209     while (i>=0) {
 210       if (putPB(s[i]) != s[i]) {
 211         ERROR("assert failed");
 212       }
 213       i--;
 214     }
 215   }
 216   return( FALSE );
 217 }
 218
 219 /*
 220  *  isDigit - returns TRUE if the character, ch, is a digit.
 221  */
 222
 223 static int isDigit (char ch)
 224 {
 225   return( ((ch>='0') && (ch<='9')) );
 226 }
 227
 228 /*
 229  *  isHexDigit - returns TRUE if the character, ch, is a hex digit.
 230  */
 231
 232 #if 0
 233 static int isHexDigit (char ch)
 234 {
 235   return( (isDigit(ch)) || ((ch>='a') && (ch<='f')) );
 236 }
 237 #endif
 238
 239 /*
 240  *  readInt - returns an integer from the input stream.
 241  */
 242
 243 int pushBackBuffer::readInt (void)
 244 {
 245   int  c =0;
 246   int  i =0;
 247   int  s =1;
 248   char ch=getPB();
 249
 250   while (isWhite(ch)) {
 251     ch=getPB();
 252   }
 253   // now read integer
 254
 255   if (ch == '-') {
 256     s = -1;
 257     ch = getPB();
 258   }
 259   while (isDigit(ch)) {
 260     i *= 10;
 261     if ((ch>='0') && (ch<='9')) {
 262       i += (int)(ch-'0');
 263     }
 264     ch = getPB();
 265     c++;
 266   }
 267   if (ch != putPB(ch)) {
 268     ERROR("assert failed");
 269   }
 270   return( i*s );
 271 }
 272
 273 /*
 274  *  convertToFloat - converts integers, a and b into a.b
 275  */
 276
 277 static double convertToFloat (int a, int b)
 278 {
 279   int c=10;
 280   double f;
 281
 282   while (b>c) {
 283     c *= 10;
 284   }
 285   f = ((double)a) + (((double)b)/((double)c));
 286   return( f );
 287 }
 288
 289 /*
 290  *  readNumber - returns a float representing the word just read.
 291  */
 292
 293 double pushBackBuffer::readNumber (void)
 294 {
 295   int i;
 296   char ch;
 297
 298   i = readInt();
 299   if ((ch = getPB()) == '.') {
 300     return convertToFloat(i, readInt());
 301   }
 302   putPB(ch);
 303   return (double)i;
 304 }
 305
 306 /*
 307  *  readString - reads a string terminated by white space
 308  *               and returns a malloced area of memory containing
 309  *               a copy of the characters.
 310  */
 311
 312 char *pushBackBuffer::readString (void)
 313 {
 314   char  buffer[MAXPUSHBACKSTACK];
 315   char *str = 0;
 316   int   i=0;
 317   char ch=getPB();
 318
 319   while (isWhite(ch)) {
 320     ch=getPB();
 321   }
 322   while ((i < MAXPUSHBACKSTACK) && (! isWhite(ch)) && (! eofFound)) {
 323     buffer[i] = ch;
 324     i++;
 325     ch = getPB();
 326   }
 327   if (i < MAXPUSHBACKSTACK) {
 328     buffer[i] = (char)0;
 329     str = (char *)malloc(strlen(buffer)+1);
 330     strcpy(str, buffer);
 331   }
 332   return( str );
 333 }