1 files changed, 336 insertions, 0 deletions
diff --git a/src/preproc/html/pushback.cpp b/src/preproc/html/pushback.cpp
new file mode 100644
index 0000000..100ac0b
--- /dev/null
+++ b/src/preproc/html/pushback.cpp
@@ -0,0 +1,336 @@
+/* Copyright (C) 2000-2020 Free Software Foundation, Inc.
+     Written by Gaius Mulley (gaius@glam.ac.uk).
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "lib.h"
+
+#include <signal.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <errno.h>
+#include "errarg.h"
+#include "error.h"
+#include "stringclass.h"
+#include "posix.h"
+#include "nonposix.h"
+
+#include <errno.h>
+#include <sys/types.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include "pushback.h"
+#include "pre-html.h"
+
+#if !defined(TRUE)
+#   define TRUE  (1==1)
+#endif
+
+#if !defined(FALSE)
+#   define FALSE (1==0)
+#endif
+
+#   define ERROR(X)   (void)(fprintf(stderr, "%s:%d error %s\n", __FILE__, __LINE__, X) && \
+                            (fflush(stderr)) && localexit(1))
+
+
+#define MAXPUSHBACKSTACK 4096                  /* maximum number of character that can be pushed back */
+
+
+/*
+ *  constructor for pushBackBuffer
+ */
+
+pushBackBuffer::pushBackBuffer (char *filename)
+{
+  charStack = (char *)malloc(MAXPUSHBACKSTACK);
+  if (charStack == 0) {
+    sys_fatal("malloc");
+  }
+  stackPtr = 0;   /* index to push back stack        */
+  verbose  = 0;
+  eofFound = FALSE;
+  lineNo   = 1;
+  if (strcmp(filename, "") != 0) {
+    stdIn = dup(0);
+    if (stdIn < 0) {
+      sys_fatal("dup stdin");
+    }
+    close(0);
+    if (open(filename, O_RDONLY) != 0) {
+      sys_fatal("when trying to open file");
+    } else {
+      fileName = filename;
+    }
+  }
+}
+
+pushBackBuffer::~pushBackBuffer ()
+{
+  if (charStack != 0) {
+    free(charStack);
+  }
+  close(0);
+  /* restore stdin in file descriptor 0 */
+  if (dup(stdIn) < 0) {
+    sys_fatal("restore stdin");
+  }
+  close(stdIn);
+}
+
+/*
+ *  localexit - wraps exit with a return code to aid the ERROR macro.
+ */
+
+int localexit (int i)
+{
+  exit(i);
+  return( 1 );
+}
+
+/*
+ *  getPB - returns a character, possibly a pushed back character.
+ */
+
+char pushBackBuffer::getPB (void)
+{
+  if (stackPtr>0) {
+    stackPtr--;
+    return( charStack[stackPtr] );
+  } else {
+    char ch;
+
+    if (read(0, &ch, 1) == 1) {
+      if (verbose) {
+	printf("%c", ch);
+      }
+      if (ch == '\n') {
+	lineNo++;
+      }
+      return( ch );
+    } else {
+      eofFound = TRUE;
+      return( eof );
+    }
+  }
+}
+
+/*
+ *  putPB - pushes a character onto the push back stack.
+ *          The same character is returned.
+ */
+
+char pushBackBuffer::putPB (char ch)
+{
+  if (stackPtr<MAXPUSHBACKSTACK) {
+    charStack[stackPtr] = ch ;
+    stackPtr++;
+  } else {
+    ERROR("max push back stack exceeded, increase MAXPUSHBACKSTACK constant");
+  }
+  return( ch );
+}
+
+/*
+ *  isWhite - returns TRUE if a white character is found. This character is NOT consumed.
+ */
+
+static int isWhite (char ch)
+{
+  return( (ch==' ') || (ch == '\t') || (ch == '\n') );
+}
+
+/*
+ *  skipToNewline - skips characters until a newline is seen.
+ */
+
+void pushBackBuffer::skipToNewline (void)
+{
+  while ((putPB(getPB()) != '\n') && (! eofFound)) {
+    getPB();
+  }
+}
+
+/*
+ *  skipUntilToken - skips until a token is seen
+ */
+
+void pushBackBuffer::skipUntilToken (void)
+{
+  char ch;
+
+  while ((isWhite(putPB(getPB())) || (putPB(getPB()) == '#')) && (! eofFound)) {
+    ch = getPB();
+    if (ch == '#') {
+      skipToNewline();
+    }
+  }
+}
+
+/*
+ *  isString - returns TRUE if the string, s, matches the pushed back string.
+ *             if TRUE is returned then this string is consumed, otherwise it is
+ *             left alone.
+ */
+
+int pushBackBuffer::isString (const char *s)
+{
+  int length=strlen(s);
+  int i=0;
+
+  while ((i<length) && (putPB(getPB())==s[i])) {
+    if (getPB() != s[i]) {
+      ERROR("assert failed");
+    }
+    i++;
+  }
+  if (i==length) {
+    return( TRUE );
+  } else {
+    i--;
+    while (i>=0) {
+      if (putPB(s[i]) != s[i]) {
+	ERROR("assert failed");
+      }
+      i--;
+    }
+  }
+  return( FALSE );
+}
+
+/*
+ *  isDigit - returns TRUE if the character, ch, is a digit.
+ */
+
+static int isDigit (char ch)
+{
+  return( ((ch>='0') && (ch<='9')) );
+}
+
+/*
+ *  isHexDigit - returns TRUE if the character, ch, is a hex digit.
+ */
+
+#if 0
+static int isHexDigit (char ch)
+{
+  return( (isDigit(ch)) || ((ch>='a') && (ch<='f')) );
+}
+#endif
+
+/*
+ *  readInt - returns an integer from the input stream.
+ */
+
+int pushBackBuffer::readInt (void)
+{
+  int  c =0;
+  int  i =0;
+  int  s =1;
+  char ch=getPB();
+
+  while (isWhite(ch)) {
+    ch=getPB();
+  }
+  // now read integer
+
+  if (ch == '-') {
+    s = -1;
+    ch = getPB();
+  }
+  while (isDigit(ch)) {
+    i *= 10;
+    if ((ch>='0') && (ch<='9')) {
+      i += (int)(ch-'0');
+    }
+    ch = getPB();
+    c++;
+  }
+  if (ch != putPB(ch)) {
+    ERROR("assert failed");
+  }
+  return( i*s );
+}
+
+/*
+ *  convertToFloat - converts integers, a and b into a.b
+ */
+
+static double convertToFloat (int a, int b)
+{
+  int c=10;
+  double f;
+
+  while (b>c) {
+    c *= 10;
+  }
+  f = ((double)a) + (((double)b)/((double)c));
+  return( f );
+}
+
+/*
+ *  readNumber - returns a float representing the word just read.
+ */
+
+double pushBackBuffer::readNumber (void)
+{
+  int i;
+  char ch;
+
+  i = readInt();
+  if ((ch = getPB()) == '.') {
+    return convertToFloat(i, readInt());
+  }
+  putPB(ch);
+  return (double)i;
+}
+
+/*
+ *  readString - reads a string terminated by white space
+ *               and returns a malloced area of memory containing
+ *               a copy of the characters.
+ */
+
+char *pushBackBuffer::readString (void)
+{
+  char  buffer[MAXPUSHBACKSTACK];
+  char *str = 0;
+  int   i=0;
+  char ch=getPB();
+
+  while (isWhite(ch)) {
+    ch=getPB();
+  }
+  while ((i < MAXPUSHBACKSTACK) && (! isWhite(ch)) && (! eofFound)) {
+    buffer[i] = ch;
+    i++;
+    ch = getPB();
+  }
+  if (i < MAXPUSHBACKSTACK) {
+    buffer[i] = (char)0;
+    str = (char *)malloc(strlen(buffer)+1);
+    strcpy(str, buffer);
+  }
+  return( str );
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72: