prtokeniser.java

一个java操作pdf文件的开发包,很好用的.

/*
 * $Id: PRTokeniser.java,v 1.16 2002/11/19 08:33:35 blowagie Exp $
 * $Name:  $
 *
 * Copyright 2001, 2002 by 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 java.io.*;
/**
 *
 * @author  Paulo Soares ([e-mail])
 */
public class PRTokeniser {
    
    public static final int TK_NUMBER = 1;
    public static final int TK_STRING = 2;
    public static final int TK_NAME = 3;
    public static final int TK_COMMENT = 4;
    public static final int TK_START_ARRAY = 5;
    public static final int TK_END_ARRAY = 6;
    public static final int TK_START_DIC = 7;
    public static final int TK_END_DIC = 8;
    public static final int TK_REF = 9;
    public static final int TK_OTHER = 10;
    
    static final String EMPTY = "";

    
    protected RandomAccessFileOrArray file;
    protected int type;
    protected String stringValue;
    protected int reference;
    protected int generation;
    
    private static final int LINE_SEGMENT_SIZE = 256;

    public PRTokeniser(String filename) throws IOException {
        file = new RandomAccessFileOrArray(filename);
    }

    public PRTokeniser(byte pdfIn[]) {
        file = new RandomAccessFileOrArray(pdfIn);
    }
    
    public void seek(int pos) throws IOException {
        file.seek(pos);
    }
    
    public int getFilePointer() throws IOException {
        return file.getFilePointer();
    }

    public void close() throws IOException {
        file.close();
    }
    
    public int length() throws IOException {
        return file.length();
    }

    public int read() throws IOException {
        return file.read();
    }
    
    public RandomAccessFileOrArray getSafeFile() {
        return new RandomAccessFileOrArray(file);
    }
    
    public String readString(int size) throws IOException {
        StringBuffer buf = new StringBuffer();
        int ch;
        while ((size--) > 0) {
            ch = file.read();
            if (ch == -1)
                break;
            buf.append((char)ch);
        }
        return buf.toString();
    }

    public static final boolean isWhitespace(int ch) {
        return (ch == 0 || ch == 9 || ch == 10 || ch == 12 || ch == 13 || ch == 32);
    }
    
    public static final boolean isDelimiter(int ch) {
        return (ch == '(' || ch == ')' || ch == '<' || ch == '>' || ch == '[' || ch == ']' || ch == '/' || ch == '%');
    }

    public int getTokenType() {
        return type;
    }
    
    public String getStringValue() {
        return stringValue;
    }
    
    public int getReference() {
        return reference;
    }
    
    public int getGeneration() {
        return generation;
    }
    
    public void backOnePosition() throws IOException {
        file.seek(file.getFilePointer() - 1);
    }
    
    public void throwError(String error) throws IOException {
        throw new IOException(error + " at file pointer " + file.getFilePointer());
    }
    
    public void checkPdfHeader() throws IOException {
        String str = readString(7);
        if (!str.equals("%PDF-1."))
            throw new IOException("PDF header signature not found.");
    }
    
    public void checkFdfHeader() throws IOException {
        String str = readString(8);
        if (!str.equals("%FDF-1.2"))
            throw new IOException("FDF header signature not found.");
    }

    public int getStartxref() throws IOException {
        int size = Math.min(1024, file.length());
        int pos = file.length() - size;
        file.seek(pos);
        String str = readString(1024);
        int idx = str.lastIndexOf("startxref");
        if (idx < 0)
            throw new IOException("PDF startxref not found.");
        return pos + idx;
    }

    public static int getHex(int v) {
        if (v >= '0' && v <= '9')
            return v - '0';
        if (v >= 'A' && v <= 'F')
            return v - 'A' + 10;
        if (v >= 'a' && v <= 'f')
            return v - 'a' + 10;
        return -1;
    }
    
    public void nextValidToken() throws IOException {
        int level = 0;
        String n1 = null;
        String n2 = null;
        int ptr = 0;
        while (nextToken()) {
            if (type == TK_COMMENT)
                continue;
            switch (level) {
                case 0:
                {
                    if (type != TK_NUMBER)
                        return;
                    ptr = file.getFilePointer();
                    n1 = stringValue;
                    ++level;
                    break;
                }
                case 1:
                {
                    if (type != TK_NUMBER) {
                        file.seek(ptr);
                        type = TK_NUMBER;
                        stringValue = n1;
                        return;
                    }
                    n2 = stringValue;
                    ++level;
                    break;
                }
                default:
                {
                    if (type != TK_OTHER || !stringValue.equals("R")) {
                        file.seek(ptr);
                        type = TK_NUMBER;
                        stringValue = n1;
                        return;
                    }
                    type = TK_REF;
                    reference = Integer.valueOf(n1).intValue();
                    generation = Integer.valueOf(n2).intValue();
                    return;
                }
            }
        }
        throwError("Unexpected end of file");
    }
    
    public boolean nextToken() throws IOException {
        StringBuffer outBuf = null;
        stringValue = EMPTY;
        int ch = 0;
        do {
            ch = file.read();
        } while (ch != -1 && isWhitespace(ch));
        if (ch == -1)
            return false;
        switch (ch) {
            case '[':
                type = TK_START_ARRAY;
                break;
            case ']':
                type = TK_END_ARRAY;
                break;
            case '/':
            {
                outBuf = new StringBuffer();
                type = TK_NAME;
                while (true) {