/*
* Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.apple.internal.jobjc.generator.utils;
import java.io.StringWriter;
/**
* Stream-like class backed by a string. Useful for parsers.
*/
public class StringStream{
private String data;
private int pos;
public StringStream(String s){
QA.nonNull(s);
this.data = s;
this.pos = 0;
}
/**
* Number of characters left.
*/
public int left(){ return data.length() - pos; }
/**
* Are there any characters left?
*/
public boolean atEOF(){ return left() <= 0; }
/**
* Read next character.
*/
public char read(){ return data.charAt(pos++); }
/**
* Read n characters and return string.
*/
public String readN(int n){
String s = data.substring(pos, pos + n);
pos += n;
return s;
}
/**
* Read until the next char is c, and return the string.
*/
public String readUntil(char c){
int ix = data.indexOf(c, pos);
if(ix == -1) throw new RuntimeException("readUntil did not find character '" + c + "'");
return readN(data.indexOf(c, pos) - pos);
}
/**
* Read until the next char is one in s, and return the string.
*/
public String readUntilEither(String s) {
int ix = Integer.MAX_VALUE;
for(char c : s.toCharArray()){
int ixx = data.indexOf(c, pos);
if(ixx >= 0 && ixx < ix)
ix = ixx;
}
if(ix == -1) throw new RuntimeException("readUntilEither did not find any character in '" + s + "'");
return readN(ix - pos);
}
public String readWhile(String s) {
StringWriter sw = new StringWriter();
while(s.indexOf(peek()) != -1)
sw.append(read());
return sw.toString();
}
public String readWhileDigits() {
return readWhile("0123456789");
}
/**
* @return the nth char from the current position.
*/
public char peekAt(int n){ return data.charAt(pos + n); }
/**
* @return the next n chars.
*/
public String peekN(int n){ return data.substring(pos, pos + n); }
/**
* @return the next char.
*/
public char peek(){ return peekAt(0); }
/**
* Skip n chars ahead.
*/
public void seekN(int n){ pos += n; }
/**
* Skip 1 char ahead.
*/
public void seek(){ seekN(1); }
/**
* If the next character is c, seek over it. Otherwise throw RuntimeException.
*/
public void eat(char c) {
if(peek() != c) throw new RuntimeException("Parser expected '" + c + "' but got '" + peek() + "'.");
seek();
}
/**
* If the next characters are the same as those in s, seek over them. Otherwise throw RuntimeException.
*/
public void eat(String s) {
String pn = peekN(s.length());
if(!pn.equals(s)) throw new RuntimeException("Parser expected '" + s + "' but got '" + pn + "'.");
seekN(s.length());
}
@Override
public String toString(){
return data;
}
/**
* @return the remaining characters as a String.
*/
public String remainingToString() {
return data.substring(pos);
}
}