Java tutorial
/* This file is part of the iText (R) project. Copyright (c) 1998-2019 iText Group NV Authors: Bruno Lowagie, Paulo Soares, et al. This program is free software; you can redistribute it and/or modify it under the terms of the GNU Affero General Public License version 3 as published by the Free Software Foundation with the addition of the following permission added to Section 15 as permitted in Section 7(a): FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS This program 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 Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program; if not, see http://www.gnu.org/licenses or write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA, 02110-1301 USA, or download the license from the following URL: http://itextpdf.com/terms-of-use/ The interactive user interfaces in modified source and object code versions of this program must display Appropriate Legal Notices, as required under Section 5 of the GNU Affero General Public License. In accordance with Section 7(b) of the GNU Affero General Public License, a covered work must retain the producer line in every PDF that is created or manipulated using iText. You can be released from the requirements of the license by purchasing a commercial license. Buying such a license is mandatory as soon as you develop commercial activities involving the iText software without disclosing the source code of your own applications. These activities include: offering paid services to customers as an ASP, serving PDFs on the fly in a web application, shipping iText with a closed source product. For more information, please contact iText Software Corp. at this address: sales@itextpdf.com */ package com.itextpdf.kernel.pdf; import com.itextpdf.io.font.PdfEncodings; import com.itextpdf.io.source.ByteBuffer; import com.itextpdf.io.source.PdfTokenizer; import com.itextpdf.io.util.StreamUtil; import java.nio.charset.StandardCharsets; /** * A {@code PdfString}-class is the PDF-equivalent of a * JAVA-{@code String}-object. * <p> * A string is a sequence of characters delimited by parenthesis. * If a string is too long to be conveniently placed on a single line, it may * be split across multiple lines by using the backslash character (\) at the * end of a line to indicate that the string continues on the following line. * Within a string, the backslash character is used as an escape to specify * unbalanced parenthesis, non-printing ASCII characters, and the backslash * character itself. Use of the \<i>ddd</i> escape sequence is the preferred * way to represent characters outside the printable ASCII character set.<br> * This object is described in the 'Portable Document Format Reference Manual * version 1.7' section 3.2.3 (page 53-56). * @see PdfObject */ public class PdfString extends PdfPrimitiveObject { private static final long serialVersionUID = 390789504287887010L; protected String value; protected String encoding; protected boolean hexWriting = false; private int decryptInfoNum; private int decryptInfoGen; // if it's not null: content shall contain encrypted data; value shall be null private PdfEncryption decryption; public PdfString(String value, String encoding) { super(); assert value != null; this.value = value; this.encoding = encoding; } public PdfString(String value) { this(value, null); } public PdfString(byte[] content) { super(); if (content != null && content.length > 0) { StringBuilder str = new StringBuilder(content.length); for (byte b : content) { str.append((char) (b & 0xff)); } this.value = str.toString(); } else { this.value = ""; } } /** * Only PdfReader can use this method! */ protected PdfString(byte[] content, boolean hexWriting) { super(content); this.hexWriting = hexWriting; } private PdfString() { super(); } @Override public byte getType() { return STRING; } public boolean isHexWriting() { return hexWriting; } public PdfString setHexWriting(boolean hexWriting) { if (value == null) { generateValue(); } content = null; this.hexWriting = hexWriting; return this; } public String getValue() { if (value == null) generateValue(); return value; } /** * Gets the encoding of this string. */ public String getEncoding() { return encoding; } /** * Returns the Unicode {@code String} value of this * {@code PdfString}-object. */ public String toUnicodeString() { if (encoding != null && encoding.length() != 0) { return getValue(); } if (content == null) { generateContent(); } byte[] b = decodeContent(); if (b.length >= 2 && b[0] == (byte) 0xFE && b[1] == (byte) 0xFF) { return PdfEncodings.convertToString(b, PdfEncodings.UNICODE_BIG); } else if (b.length >= 3 && b[0] == (byte) 0xEF && b[1] == (byte) 0xBB && b[2] == (byte) 0xBF) { return PdfEncodings.convertToString(b, PdfEncodings.UTF8); } else { return PdfEncodings.convertToString(b, PdfEncodings.PDF_DOC_ENCODING); } } /** * Gets bytes of String-value considering encoding. * * @return byte array */ // Analog of com.itextpdf.text.pdf.PdfString.getBytes() method in iText5. public byte[] getValueBytes() { if (value == null) generateValue(); if (encoding != null && PdfEncodings.UNICODE_BIG.equals(encoding) && PdfEncodings.isPdfDocEncoding(value)) return PdfEncodings.convertToBytes(value, PdfEncodings.PDF_DOC_ENCODING); else return PdfEncodings.convertToBytes(value, encoding); } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; PdfString that = (PdfString) o; String v1 = getValue(); String v2 = that.getValue(); if (v1 != null && v1.equals(v2)) { String e1 = getEncoding(); String e2 = that.getEncoding(); if ((e1 == null && e2 == null) || (e1 != null && e1.equals(e2))) { return true; } } return false; } @Override public String toString() { if (value == null) { return new String(decodeContent(), StandardCharsets.ISO_8859_1); } else { return getValue(); } } @Override public int hashCode() { String v = getValue(); String e = getEncoding(); int result = v != null ? v.hashCode() : 0; return 31 * result + (e != null ? e.hashCode() : 0); } /** * Marks this string object as not encrypted in the encrypted document. * <p> * If it's marked so, it will be considered as already in plaintext and decryption will not be performed for it. * In order to have effect, this method shall be called before {@link #getValue()} and {@link #getValueBytes()} methods. * <p> * NOTE: this method is only needed in a very specific cases of encrypted documents. E.g. digital signature dictionary * /Contents entry shall not be encrypted. Also this method isn't meaningful in non-encrypted documents. */ public void markAsUnencryptedObject() { setState(PdfObject.UNENCRYPTED); } void setDecryption(int decryptInfoNum, int decryptInfoGen, PdfEncryption decryption) { this.decryptInfoNum = decryptInfoNum; this.decryptInfoGen = decryptInfoGen; this.decryption = decryption; } protected void generateValue() { assert content != null : "No byte[] content to generate value"; value = PdfEncodings.convertToString(decodeContent(), null); if (decryption != null) { decryption = null; content = null; } } @Override protected void generateContent() { content = encodeBytes(getValueBytes()); } /** * Encrypt content of {@code value} and set as content. {@code generateContent()} won't be called. * * @param encrypt @see PdfEncryption * @return true if value was encrypted, otherwise false. */ protected boolean encrypt(PdfEncryption encrypt) { if (checkState(PdfObject.UNENCRYPTED)) { return false; } if (encrypt != decryption) { if (decryption != null) { generateValue(); } if (encrypt != null && !encrypt.isEmbeddedFilesOnly()) { byte[] b = encrypt.encryptByteArray(getValueBytes()); content = encodeBytes(b); return true; } } return false; } protected byte[] decodeContent() { byte[] decodedBytes = PdfTokenizer.decodeStringContent(content, hexWriting); if (decryption != null && !checkState(PdfObject.UNENCRYPTED)) { decryption.setHashKeyForNextObject(decryptInfoNum, decryptInfoGen); decodedBytes = decryption.decryptByteArray(decodedBytes); } return decodedBytes; } /** * Escape special symbols or convert to hexadecimal string. * This method don't change either {@code value} or {@code content} ot the {@code PdfString}. * * @param bytes byte array to manipulate with. * @return Hexadecimal string or string with escaped symbols in byte array view. */ protected byte[] encodeBytes(byte[] bytes) { if (hexWriting) { ByteBuffer buf = new ByteBuffer(bytes.length * 2); for (byte b : bytes) { buf.appendHex(b); } return buf.getInternalBuffer(); } else { ByteBuffer buf = StreamUtil.createBufferedEscapedString(bytes); return buf.toByteArray(1, buf.size() - 2); } } @Override protected PdfObject newInstance() { return new PdfString(); } @Override protected void copyContent(PdfObject from, PdfDocument document) { super.copyContent(from, document); PdfString string = (PdfString) from; value = string.value; hexWriting = string.hexWriting; decryption = string.decryption; decryptInfoNum = string.decryptInfoNum; decryptInfoGen = string.decryptInfoGen; encoding = string.encoding; } }