/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements.  See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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.apache.regexp;import java.io.InputStream;import java.io.IOException;/** * Encapsulates java.io.InputStream as CharacterIterator. * * @author <a href="mailto:ales.novak@netbeans.com">Ales Novak</a> * @version CVS $Id: StreamCharacterIterator.java 518156 2007-03-14 14:31:26Z vgritsenko $ */public final class StreamCharacterIterator implements CharacterIterator{    /** Underlying is */    private final InputStream is;    /** Buffer of read chars */    private final StringBuffer buff;    /** read end? */    private boolean closed;    /** @param is an InputStream, which is parsed */    public StreamCharacterIterator(InputStream is)    {        this.is = is;        this.buff = new StringBuffer(512);        this.closed = false;    }    /** @return a substring */    public String substring(int beginIndex, int endIndex)    {        try        {            ensure(endIndex);            return buff.toString().substring(beginIndex, endIndex);        }        catch (IOException e)        {            throw new StringIndexOutOfBoundsException(e.getMessage());        }    }    /** @return a substring */    public String substring(int beginIndex)    {        try        {            readAll();            return buff.toString().substring(beginIndex);        }        catch (IOException e)        {            throw new StringIndexOutOfBoundsException(e.getMessage());        }    }    /** @return a character at the specified position. */    public char charAt(int pos)    {        try        {            ensure(pos);            return buff.charAt(pos);        }        catch (IOException e)        {            throw new StringIndexOutOfBoundsException(e.getMessage());        }    }    /** @return <tt>true</tt> iff if the specified index is after the end of the character stream */    public boolean isEnd(int pos)    {        if (buff.length() > pos)        {            return false;        }        else        {            try            {                ensure(pos);                return (buff.length() <= pos);            }            catch (IOException e)            {                throw new StringIndexOutOfBoundsException(e.getMessage());            }        }    }    /** Reads n characters from the stream and appends them to the buffer */    private int read(int n) throws IOException    {        if (closed)        {            return 0;        }        int c;        int i = n;        while (--i >= 0)        {            c = is.read();            if (c < 0) // EOF            {                closed = true;                break;            }            buff.append((char) c);        }        return n - i;    }    /** Reads rest of the stream. */    private void readAll() throws IOException    {        while(! closed)        {            read(1000);        }    }    /** Reads chars up to the idx */    private void ensure(int idx) throws IOException    {        if (closed)        {            return;        }        if (idx < buff.length())        {            return;        }        read(idx + 1 - buff.length());    }}