src/pre-html/pushback.cpp

   1 /*@
   2  * Copyright (c) 2014 - 2015 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   3  *
   4  * Copyright (C) 2000, 2001, 2003 - 2005 Free Software Foundation, Inc.
   5  *      Written by Gaius Mulley (gaius@glam.ac.uk).
   6  *
   7  * This 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  * This 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
  22 #include "config.h"
  23 #include "html-config.h"
  24
  25 #include <sys/types.h>
  26
  27 #include <assert.h>
  28 #include <ctype.h>
  29 #include <errno.h>
  30 #include <signal.h>
  31 #include <stdlib.h>
  32
  33 #include "errarg.h"
  34 #include "error.h"
  35 #include "lib.h"
  36 #include "nonposix.h"
  37 #include "posix.h"
  38 #include "stringclass.h"
  39
  40 #include "pushback.h"
  41 #include "pre-html.h"
  42
  43 #define ERROR(X) \
  44   (void)(fprintf(stderr, "%s:%d error %s\n", __FILE__, __LINE__, X) &&\
  45    (fflush(stderr)) && localexit(1))
  46
  47 pushBackBuffer::pushBackBuffer (char *filename)
  48 {
  49   charStack = (char *)malloc(MAXPUSHBACKSTACK);
  50   if (charStack == 0) {
  51     sys_fatal("malloc");
  52   }
  53   stackPtr = 0;   /* index to push back stack        */
  54   debug    = 0;
  55   verbose  = 0;
  56   eofFound = false;
  57   lineNo   = 1;
  58   if (strcmp(filename, "") != 0) {
  59     stdIn = dup(0);
  60     close(0);
  61     if (open(filename, O_RDONLY) != 0) {
  62       sys_fatal("when trying to open file");
  63     } else {
  64       fileName = filename;
  65     }
  66   }
  67 }
  68
  69 pushBackBuffer::~pushBackBuffer ()
  70 {
  71   if (charStack != 0) {
  72     free(charStack);
  73   }
  74   close(0);
  75   /* restore stdin in file descriptor 0 */
  76   dup(stdIn);
  77   close(stdIn);
  78 }
  79
  80 /*
  81  *  localexit - wraps exit with a return code to aid the ERROR macro.
  82  */
  83
  84 int localexit (int i)
  85 {
  86   exit(i);
  87   return( 1 );
  88 }
  89
  90 /*
  91  *  getPB - returns a character, possibly a pushed back character.
  92  */
  93
  94 char pushBackBuffer::getPB (void)
  95 {
  96   if (stackPtr>0) {
  97     stackPtr--;
  98     return( charStack[stackPtr] );
  99   } else {
 100     char ch;
 101
 102     if (read(0, &ch, 1) == 1) {
 103       if (verbose) {
 104         printf("%c", ch);
 105       }
 106       if (ch == '\n') {
 107         lineNo++;
 108       }
 109       return( ch );
 110     } else {
 111       eofFound = true;
 112       return( eof );
 113     }
 114   }
 115 }
 116
 117 /*
 118  *  putPB - pushes a character onto the push back stack.
 119  *          The same character is returned.
 120  */
 121
 122 char pushBackBuffer::putPB (char ch)
 123 {
 124   if (stackPtr<MAXPUSHBACKSTACK) {
 125     charStack[stackPtr] = ch ;
 126     stackPtr++;
 127   } else {
 128     ERROR("max push back stack exceeded, increase MAXPUSHBACKSTACK constant");
 129   }
 130   return( ch );
 131 }
 132
 133 /*
 134  *  isWhite - returns true if a white character is found. This character is NOT consumed.
 135  */
 136
 137 static int isWhite (char ch)
 138 {
 139   return( (ch==' ') || (ch == '\t') || (ch == '\n') );
 140 }
 141
 142 /*
 143  *  skipToNewline - skips characters until a newline is seen.
 144  */
 145
 146 void pushBackBuffer::skipToNewline (void)
 147 {
 148   while ((putPB(getPB()) != '\n') && (! eofFound)) {
 149     getPB();
 150   }
 151 }
 152
 153 /*
 154  *  skipUntilToken - skips until a token is seen
 155  */
 156
 157 void pushBackBuffer::skipUntilToken (void)
 158 {
 159   char ch;
 160
 161   while ((isWhite(putPB(getPB())) || (putPB(getPB()) == '#')) && (! eofFound)) {
 162     ch = getPB();
 163     if (ch == '#') {
 164       skipToNewline();
 165     }
 166   }
 167 }
 168
 169 /*
 170  *  isString - returns true if the string, s, matches the pushed back string.
 171  *             if true is returned then this string is consumed, otherwise it is
 172  *             left alone.
 173  */
 174
 175 int pushBackBuffer::isString (const char *s)
 176 {
 177   int length=strlen(s);
 178   int i=0;
 179
 180   while ((i<length) && (putPB(getPB())==s[i])) {
 181     if (getPB() != s[i]) {
 182       ERROR("assert failed");
 183     }
 184     i++;
 185   }
 186   if (i==length) {
 187     return true;
 188   } else {
 189     i--;
 190     while (i>=0) {
 191       if (putPB(s[i]) != s[i]) {
 192         ERROR("assert failed");
 193       }
 194       i--;
 195     }
 196   }
 197   return false;
 198 }
 199
 200 /*
 201  *  isDigit - returns true if the character, ch, is a digit.
 202  */
 203
 204 static int isDigit (char ch)
 205 {
 206   return( ((ch>='0') && (ch<='9')) );
 207 }
 208
 209 /*
 210  *  isHexDigit - returns true if the character, ch, is a hex digit.
 211  */
 212
 213 #if 0
 214 static int isHexDigit (char ch)
 215 {
 216   return( (isDigit(ch)) || ((ch>='a') && (ch<='f')) );
 217 }
 218 #endif
 219
 220 /*
 221  *  readInt - returns an integer from the input stream.
 222  */
 223
 224 int pushBackBuffer::readInt (void)
 225 {
 226   int  c =0;
 227   int  i =0;
 228   int  s =1;
 229   char ch=getPB();
 230
 231   while (isWhite(ch)) {
 232     ch=getPB();
 233   }
 234   // now read integer
 235
 236   if (ch == '-') {
 237     s = -1;
 238     ch = getPB();
 239   }
 240   while (isDigit(ch)) {
 241     i *= 10;
 242     if ((ch>='0') && (ch<='9')) {
 243       i += (int)(ch-'0');
 244     }
 245     ch = getPB();
 246     c++;
 247   }
 248   if (ch != putPB(ch)) {
 249     ERROR("assert failed");
 250   }
 251   return( i*s );
 252 }
 253
 254 /*
 255  *  convertToFloat - converts integers, a and b into a.b
 256  */
 257
 258 static double convertToFloat (int a, int b)
 259 {
 260   int c=10;
 261   double f;
 262
 263   while (b>c) {
 264     c *= 10;
 265   }
 266   f = ((double)a) + (((double)b)/((double)c));
 267   return( f );
 268 }
 269
 270 /*
 271  *  readNumber - returns a float representing the word just read.
 272  */
 273
 274 double pushBackBuffer::readNumber (void)
 275 {
 276   int i;
 277   char ch;
 278
 279   i = readInt();
 280   if ((ch = getPB()) == '.') {
 281     return convertToFloat(i, readInt());
 282   }
 283   putPB(ch);
 284   return (double)i;
 285 }
 286
 287 /*
 288  *  readString - reads a string terminated by white space
 289  *               and returns a malloced area of memory containing
 290  *               a copy of the characters.
 291  */
 292
 293 char *pushBackBuffer::readString (void)
 294 {
 295   char  buffer[MAXPUSHBACKSTACK];
 296   char *str = 0;
 297   int   i=0;
 298   char ch=getPB();
 299
 300   while (isWhite(ch)) {
 301     ch=getPB();
 302   }
 303   while ((i < MAXPUSHBACKSTACK) && (! isWhite(ch)) && (! eofFound)) {
 304     buffer[i] = ch;
 305     i++;
 306     ch = getPB();
 307   }
 308   if (i < MAXPUSHBACKSTACK) {
 309     buffer[i] = (char)0;
 310     str = (char *)malloc(strlen(buffer)+1);
 311     strcpy(str, buffer);
 312   }
 313   return( str );
 314 }
 315
 316 // s-it2-mode