randomaccessfileorarray.java

处理PDF

/*
 * $Id: RandomAccessFileOrArray.java 3488 2008-06-02 14:19:26Z blowagie $
 *
 * Copyright 2001, 2002 Paulo Soares
 *
 * The contents of this file are subject to the Mozilla Public License Version 1.1
 * (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the License.
 *
 * The Original Code is 'iText, a free JAVA-PDF library'.
 *
 * The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
 * the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
 * All Rights Reserved.
 * Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
 * are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
 *
 * Contributor(s): all the names of the contributors are added in the source code
 * where applicable.
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
 * provisions of LGPL are applicable instead of those above.  If you wish to
 * allow use of your version of this file only under the terms of the LGPL
 * License and not to allow others to use your version of this file under
 * the MPL, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the LGPL.
 * If you do not delete the provisions above, a recipient may use your version
 * of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the MPL as stated above or under the terms of the GNU
 * Library General Public License as published by the Free Software Foundation;
 * either version 2 of the License, or any later version.
 *
 * This library 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 Library general Public License for more
 * details.
 *
 * If you didn't download this code from the following link, you should check if
 * you aren't using an obsolete version:
 * http://www.lowagie.com/iText/
 */

package com.lowagie.text.pdf;

import com.lowagie.text.Document;
import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.URL;
import java.nio.channels.FileChannel;
/** An implementation of a RandomAccessFile for input only
 * that accepts a file or a byte array as data source.
 *
 * @author Paulo Soares ([e-mail])
 */
public class RandomAccessFileOrArray implements DataInput {
    
    MappedRandomAccessFile rf;
    RandomAccessFile trf;
    boolean plainRandomAccess;
    String filename;
    byte arrayIn[];
    int arrayInPtr;
    byte back;
    boolean isBack = false;
    
    /** Holds value of property startOffset. */
    private int startOffset = 0;

    public RandomAccessFileOrArray(String filename) throws IOException {
    	this(filename, false, Document.plainRandomAccess);
    }
    
    public RandomAccessFileOrArray(String filename, boolean forceRead, boolean plainRandomAccess) throws IOException {
        this.plainRandomAccess = plainRandomAccess;
        File file = new File(filename);
        if (!file.canRead()) {
            if (filename.startsWith("file:/") || filename.startsWith("http://") || filename.startsWith("https://") || filename.startsWith("jar:")) {
                InputStream is = new URL(filename).openStream();
                try {
                    this.arrayIn = InputStreamToArray(is);
                    return;
                }
                finally {
                    try {is.close();}catch(IOException ioe){}
                }
            }
            else {
                InputStream is = BaseFont.getResourceStream(filename);
                if (is == null)
                    throw new IOException(filename + " not found as file or resource.");
                try {
                    this.arrayIn = InputStreamToArray(is);
                    return;
                }
                finally {
                    try {is.close();}catch(IOException ioe){}
                }
            }
        }
        else if (forceRead) {
            InputStream s = null;
            try {
                s = new FileInputStream(file);
                this.arrayIn = InputStreamToArray(s);
            }
            finally {
                try {if (s != null) {s.close();}}catch(Exception e){}
            }
        	return;
        }
        this.filename = filename;
        if (plainRandomAccess)
            trf = new RandomAccessFile(filename, "r");
        else
            rf = new MappedRandomAccessFile(filename, "r");
    }

    public RandomAccessFileOrArray(URL url) throws IOException {
        InputStream is = url.openStream();
        try {
            this.arrayIn = InputStreamToArray(is);
        }
        finally {
            try {is.close();}catch(IOException ioe){}
        }
    }

    public RandomAccessFileOrArray(InputStream is) throws IOException {
        this.arrayIn = InputStreamToArray(is);
    }
    
    public static byte[] InputStreamToArray(InputStream is) throws IOException {
        byte b[] = new byte[8192];
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        while (true) {
            int read = is.read(b);
            if (read < 1)
                break;
            out.write(b, 0, read);
        }
        out.close();
        return out.toByteArray();
    }

    public RandomAccessFileOrArray(byte arrayIn[]) {
        this.arrayIn = arrayIn;
    }
    
    public RandomAccessFileOrArray(RandomAccessFileOrArray file) {
        filename = file.filename;
        arrayIn = file.arrayIn;
        startOffset = file.startOffset;
        plainRandomAccess = file.plainRandomAccess;
    }
    
    public void pushBack(byte b) {
        back = b;
        isBack = true;
    }
    
    public int read() throws IOException {
        if(isBack) {
            isBack = false;
            return back & 0xff;
        }
        if (arrayIn == null)
            return plainRandomAccess ? trf.read() : rf.read();
        else {
            if (arrayInPtr >= arrayIn.length)
                return -1;
            return arrayIn[arrayInPtr++] & 0xff;
        }
    }
    
    public int read(byte[] b, int off, int len) throws IOException {
        if (len == 0)
            return 0;
        int n = 0;
        if (isBack) {
            isBack = false;
            if (len == 1) {
                b[off] = back;
                return 1;
            }
            else {
                n = 1;
                b[off++] = back;
                --len;
            }
        }
        if (arrayIn == null) {
            return (plainRandomAccess ? trf.read(b, off, len) : rf.read(b, off, len)) + n;
        }
        else {
            if (arrayInPtr >= arrayIn.length)
                return -1;
            if (arrayInPtr + len > arrayIn.length)
                len = arrayIn.length - arrayInPtr;
            System.arraycopy(arrayIn, arrayInPtr, b, off, len);
            arrayInPtr += len;
            return len + n;
        }
    }
    
    public int read(byte b[]) throws IOException {
        return read(b, 0, b.length);
    }
    
    public void readFully(byte b[]) throws IOException {
        readFully(b, 0, b.length);
    }
    
    public void readFully(byte b[], int off, int len) throws IOException {
        int n = 0;
        do {
            int count = read(b, off + n, len - n);
            if (count < 0)
                throw new EOFException();
            n += count;
        } while (n < len);
    }
    
    public long skip(long n) throws IOException {
        return skipBytes((int)n);
    }
    
    public int skipBytes(int n) throws IOException {
        if (n <= 0) {
            return 0;
        }
        int adj = 0;
        if (isBack) {
            isBack = false;
            if (n == 1) {
                return 1;
            }
            else {
                --n;
                adj = 1;
            }
        }
        int pos;
        int len;
        int newpos;
        
        pos = getFilePointer();
        len = length();
        newpos = pos + n;
        if (newpos > len) {
            newpos = len;
        }
        seek(newpos);
        
        /* return the actual number of bytes skipped */
        return newpos - pos + adj;
    }
    
    public void reOpen() throws IOException {
        if (filename != null && rf == null && trf == null) {
            if (plainRandomAccess)
                trf = new RandomAccessFile(filename, "r");
            else
                rf = new MappedRandomAccessFile(filename, "r");
        }
        seek(0);
    }
    
    protected void insureOpen() throws IOException {
        if (filename != null && rf == null && trf == null) {
            reOpen();
        }
    }
    
    public boolean isOpen() {
        return (filename == null || rf != null || trf != null);
    }
    
    public void close() throws IOException {
        isBack = false;
        if (rf != null) {
            rf.close();
            rf = null;
            // it's very expensive to open a memory mapped file and for the usage pattern of this class
            // in iText it's faster the next re-openings to be done as a plain random access
            // file
            plainRandomAccess = true;
        }
        else if (trf != null) {
            trf.close();
            trf = null;
        }
    }
    
    public int length() throws IOException {
        if (arrayIn == null) {
            insureOpen();
            return (int)(plainRandomAccess ? trf.length() : rf.length()) - startOffset;
        }
        else
            return arrayIn.length - startOffset;
    }
    
    public void seek(int pos) throws IOException {
        pos += startOffset;
        isBack = false;
        if (arrayIn == null) {
            insureOpen();
            if (plainRandomAccess)
                trf.seek(pos);
            else