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/*
* Anarres C Preprocessor
* Copyright (C) 2007 Shevek
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.anarres.cpp;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.PushbackReader;
import java.io.Reader;
import java.io.StringReader;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import static org.anarres.cpp.Token.*;
/**
* An input to the Preprocessor.
*
* Inputs may come from Files, Strings or other sources. The
* preprocessor maintains a stack of Sources. Operations such as
* file inclusion or token pasting will push a new source onto
* the Preprocessor stack. Sources pop from the stack when they
* are exhausted; this may be transparent or explicit.
*
* BUG: Error messages are not handled properly.
*/
public abstract class Source implements Iterable<Token> {
private Source parent;
private boolean autopop;
private PreprocessorListener listener;
/* LineNumberReader */
/*
// We can't do this, since we would lose the LexerException
private class Itr implements Iterator {
private Token next = null;
private void advance() {
try {
if (next != null)
next = token();
}
catch (IOException e) {
throw new UnsupportedOperationException(
"Failed to advance token iterator: " +
e.getMessage()
);
}
}
public boolean hasNext() {
return next.getType() != EOF;
}
public Token next() {
advance();
Token t = next;
next = null;
return t;
}
public void remove() {
throw new UnsupportedOperationException(
"Cannot remove tokens from a Source."
);
}
}
*/
public Source() {
this.parent = null;
this.autopop = false;
}
/* pp */ void setParent(Source parent, boolean autopop) {
this.parent = parent;
this.autopop = autopop;
}
/* pp */ final Source getParent() {
return parent;
}
// @OverrideMustInvoke
/* pp */ void init(Preprocessor pp) {
setListener(pp.getListener());
}
/* Actually just used for testing. */
public void setListener(PreprocessorListener pl) {
this.listener = pl;
}
/**
* Returns the File currently being lexed.
*
* If this Source is not a {@link FileLexerSource}, then
* it will ask the parent Source, and so forth recursively.
* If no Source on the stack is a FileLexerSource, returns null.
*/
/* pp */ File getFile() {
Source parent = getParent();
while (parent != null) {
File file = parent.getFile();
if (file != null)
return file;
parent = parent.getParent();
}
return null;
}
/* pp */ String getName() {
Source parent = getParent();
while (parent != null) {
String name = parent.getName();
if (name != null)
return name;
parent = parent.getParent();
}
return null;
}
public int getLine() {
Source parent = getParent();
if (parent == null)
return 0;
return parent.getLine();
}
public int getColumn() {
Source parent = getParent();
if (parent == null)
return 0;
return parent.getColumn();
}
/* pp */ boolean isExpanding(Macro m) {
Source parent = getParent();
if (parent != null)
return parent.isExpanding(m);
return false;
}
/**
* Returns true if this Source should be transparently popped
* from the input stack.
*
* Examples of such sources are macro expansions.
*/
/* pp */ boolean isAutopop() {
return autopop;
}
/* pp */ boolean isNumbered() {
return false;
}
/**
* Returns the next Token parsed from this input stream.
*
* @see Token
*/
public abstract Token token()
throws IOException,
LexerException;
public Iterator<Token> iterator() {
return new SourceIterator(this);
}
/**
* Skips tokens until the end of line.
*
* @param white true if only whitespace is permitted on the
* remainder of the line.
* @return the NL token.
*/
public Token skipline(boolean white)
throws IOException,
LexerException {
for (;;) {
Token tok = token();
switch (tok.getType()) {
case EOF:
/* There ought to be a newline before EOF.
* At least, in any skipline context. */
/* XXX Are we sure about this? */
warning(tok.getLine(), tok.getColumn(),
"No newline before end of file");
return tok;
case NL:
/* This may contain one or more newlines. */
return tok;
case COMMENT:
case WHITESPACE:
break;
default:
/* XXX Check white, if required. */
if (white)
warning(tok.getLine(), tok.getColumn(),
"Unexpected nonwhite token");
break;
}
}
}
protected void error(int line, int column, String msg)
throws LexerException {
if (listener != null)
listener.handleError(this, line, column, msg);
else
throw new LexerException("Error at " + line + ":" + column + ": " + msg);
}
protected void warning(int line, int column, String msg)
throws LexerException {
if (listener != null)
listener.handleWarning(this, line, column, msg);
else
throw new LexerException("Warning at " + line + ":" + column + ": " + msg);
}
}
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