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/*
* Anarres C Preprocessor
* Copyright (c) 2007-2008, Shevek
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package org.anarres.cpp;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import javax.annotation.Nonnull;
import static org.anarres.cpp.Token.*;
/* This source should always be active, since we don't expand macros
* in any inactive context. */
/* pp */ class MacroTokenSource extends Source {
private final Macro macro;
private final Iterator<Token> tokens; /* Pointer into the macro. */
private final List<Argument> args; /* { unexpanded, expanded } */
private Iterator<Token> arg; /* "current expansion" */
/* pp */ MacroTokenSource(Macro m, List<Argument> args) {
this.macro = m;
this.tokens = m.getTokens().iterator();
this.args = args;
this.arg = null;
}
@Override
/* pp */ boolean isExpanding(Macro m) {
/* When we are expanding an arg, 'this' macro is not
* being expanded, and thus we may re-expand it. */
if (/* XXX this.arg == null && */this.macro == m)
return true;
return super.isExpanding(m);
}
/* XXX Called from Preprocessor [ugly]. */
/* pp */ static void escape(@Nonnull StringBuilder buf, @Nonnull CharSequence cs) {
if (buf == null)
throw new NullPointerException("Buffer was null.");
if (cs == null)
throw new NullPointerException("CharSequence was null.");
for (int i = 0; i < cs.length(); i++) {
char c = cs.charAt(i);
switch (c) {
case '\\':
buf.append("\\\\");
break;
case '"':
buf.append("\\\"");
break;
case '\n':
buf.append("\\n");
break;
case '\r':
buf.append("\\r");
break;
default:
buf.append(c);
}
}
}
private void concat(StringBuilder buf, Argument arg) {
Iterator<Token> it = arg.iterator();
while (it.hasNext()) {
Token tok = it.next();
buf.append(tok.getText());
}
}
private Token stringify(Token pos, Argument arg) {
StringBuilder buf = new StringBuilder();
concat(buf, arg);
// System.out.println("Concat: " + arg + " -> " + buf);
StringBuilder str = new StringBuilder("\"");
escape(str, buf);
str.append("\"");
// System.out.println("Escape: " + buf + " -> " + str);
return new Token(STRING,
pos.getLine(), pos.getColumn(),
str.toString(), buf.toString());
}
/* At this point, we have consumed the first M_PASTE.
* @see Macro#addPaste(Token) */
private void paste(Token ptok)
throws IOException,
LexerException {
StringBuilder buf = new StringBuilder();
Token err = null;
/* We know here that arg is null or expired,
* since we cannot paste an expanded arg. */
int count = 2;
for (int i = 0; i < count; i++) {
if (!tokens.hasNext()) {
/* XXX This one really should throw. */
error(ptok.getLine(), ptok.getColumn(),
"Paste at end of expansion");
buf.append(' ').append(ptok.getText());
break;
}
Token tok = tokens.next();
// System.out.println("Paste " + tok);
switch (tok.getType()) {
case M_PASTE:
/* One extra to paste, plus one because the
* paste token didn't count. */
count += 2;
ptok = tok;
break;
case M_ARG:
int idx = ((Integer) tok.getValue()).intValue();
concat(buf, args.get(idx));
break;
/* XXX Test this. */
case CCOMMENT:
case CPPCOMMENT:
break;
default:
buf.append(tok.getText());
break;
}
}
/* Push and re-lex. */
/*
StringBuilder src = new StringBuilder();
escape(src, buf);
StringLexerSource sl = new StringLexerSource(src.toString());
*/
StringLexerSource sl = new StringLexerSource(buf.toString());
/* XXX Check that concatenation produces a valid token. */
arg = new SourceIterator(sl);
}
public Token token()
throws IOException,
LexerException {
for (;;) {
/* Deal with lexed tokens first. */
if (arg != null) {
if (arg.hasNext()) {
Token tok = arg.next();
/* XXX PASTE -> INVALID. */
assert tok.getType() != M_PASTE :
"Unexpected paste token";
return tok;
}
arg = null;
}
if (!tokens.hasNext())
return new Token(EOF, -1, -1, ""); /* End of macro. */
Token tok = tokens.next();
int idx;
switch (tok.getType()) {
case M_STRING:
/* Use the nonexpanded arg. */
idx = ((Integer) tok.getValue()).intValue();
return stringify(tok, args.get(idx));
case M_ARG:
/* Expand the arg. */
idx = ((Integer) tok.getValue()).intValue();
// System.out.println("Pushing arg " + args.get(idx));
arg = args.get(idx).expansion();
break;
case M_PASTE:
paste(tok);
break;
default:
return tok;
}
} /* for */
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
buf.append("expansion of ").append(macro.getName());
Source parent = getParent();
if (parent != null)
buf.append(" in ").append(String.valueOf(parent));
return buf.toString();
}
}
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