Java tutorial
/* * $Id: PRTokeniser.java 3947 2009-06-02 17:51:05Z trumpetinc $ * * 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.IOException; /** * * @author Paulo Soares (psoares@consiste.pt) */ 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; public static final boolean delims[] = { true, true, false, false, false, false, false, false, false, false, true, true, false, true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, false, false, false, false, true, false, false, true, true, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, true, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false }; static final String EMPTY = ""; protected RandomAccessFileOrArray file; protected int type; protected String stringValue; protected int reference; protected int generation; protected boolean hexString; public PRTokeniser(String filename) throws IOException { file = new RandomAccessFileOrArray(filename); } public PRTokeniser(byte pdfIn[]) { file = new RandomAccessFileOrArray(pdfIn); } public PRTokeniser(RandomAccessFileOrArray file) { this.file = file; } 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 RandomAccessFileOrArray getFile() { return 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 static final boolean isDelimiterWhitespace(int ch) { return delims[ch + 1]; } public int getTokenType() { return type; } public String getStringValue() { return stringValue; } public int getReference() { return reference; } public int getGeneration() { return generation; } public void backOnePosition(int ch) { if (ch != -1) file.pushBack((byte) ch); } public void throwError(String error) throws IOException { throw new IOException(error + " at file pointer " + file.getFilePointer()); } public char checkPdfHeader() throws IOException { file.setStartOffset(0); String str = readString(1024); int idx = str.indexOf("%PDF-"); if (idx < 0) throw new IOException("PDF header signature not found."); file.setStartOffset(idx); return str.charAt(idx + 7); } public void checkFdfHeader() throws IOException { file.setStartOffset(0); String str = readString(1024); int idx = str.indexOf("%FDF-1.2"); if (idx < 0) throw new IOException("FDF header signature not found."); file.setStartOffset(idx); } 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.parseInt(n1); generation = Integer.parseInt(n2); return; } } } // if we hit here, the file is either corrupt (stream ended unexpectedly), // or the last token ended exactly at the end of a stream. This last // case can occur inside an Object Stream. } public boolean nextToken() throws IOException { int ch = 0; do { ch = file.read(); } while (ch != -1 && isWhitespace(ch)); if (ch == -1) return false; // Note: We have to initialize stringValue here, after we've looked for the end of the stream, // to ensure that we don't lose the value of a token that might end exactly at the end // of the stream StringBuffer outBuf = null; stringValue = EMPTY; switch (ch) { case '[': type = TK_START_ARRAY; break; case ']': type = TK_END_ARRAY; break; case '/': { outBuf = new StringBuffer(); type = TK_NAME; while (true) { ch = file.read(); if (delims[ch + 1]) break; if (ch == '#') { ch = (getHex(file.read()) << 4) + getHex(file.read()); } outBuf.append((char) ch); } backOnePosition(ch); break; } case '>': ch = file.read(); if (ch != '>') throwError("'>' not expected"); type = TK_END_DIC; break; case '<': { int v1 = file.read(); if (v1 == '<') { type = TK_START_DIC; break; } outBuf = new StringBuffer(); type = TK_STRING; hexString = true; int v2 = 0; while (true) { while (isWhitespace(v1)) v1 = file.read(); if (v1 == '>') break; v1 = getHex(v1); if (v1 < 0) break; v2 = file.read(); while (isWhitespace(v2)) v2 = file.read(); if (v2 == '>') { ch = v1 << 4; outBuf.append((char) ch); break; } v2 = getHex(v2); if (v2 < 0) break; ch = (v1 << 4) + v2; outBuf.append((char) ch); v1 = file.read(); } if (v1 < 0 || v2 < 0) throwError("Error reading string"); break; } case '%': type = TK_COMMENT; do { ch = file.read(); } while (ch != -1 && ch != '\r' && ch != '\n'); break; case '(': { outBuf = new StringBuffer(); type = TK_STRING; hexString = false; int nesting = 0; while (true) { ch = file.read(); if (ch == -1) break; if (ch == '(') { ++nesting; } else if (ch == ')') { --nesting; } else if (ch == '\\') { boolean lineBreak = false; ch = file.read(); switch (ch) { case 'n': ch = '\n'; break; case 'r': ch = '\r'; break; case 't': ch = '\t'; break; case 'b': ch = '\b'; break; case 'f': ch = '\f'; break; case '(': case ')': case '\\': break; case '\r': lineBreak = true; ch = file.read(); if (ch != '\n') backOnePosition(ch); break; case '\n': lineBreak = true; break; default: { if (ch < '0' || ch > '7') { break; } int octal = ch - '0'; ch = file.read(); if (ch < '0' || ch > '7') { backOnePosition(ch); ch = octal; break; } octal = (octal << 3) + ch - '0'; ch = file.read(); if (ch < '0' || ch > '7') { backOnePosition(ch); ch = octal; break; } octal = (octal << 3) + ch - '0'; ch = octal & 0xff; break; } } if (lineBreak) continue; if (ch < 0) break; } else if (ch == '\r') { ch = file.read(); if (ch < 0) break; if (ch != '\n') { backOnePosition(ch); ch = '\n'; } } if (nesting == -1) break; outBuf.append((char) ch); } if (ch == -1) throwError("Error reading string"); break; } default: { outBuf = new StringBuffer(); if (ch == '-' || ch == '+' || ch == '.' || (ch >= '0' && ch <= '9')) { type = TK_NUMBER; do { outBuf.append((char) ch); ch = file.read(); } while (ch != -1 && ((ch >= '0' && ch <= '9') || ch == '.')); } else { type = TK_OTHER; do { outBuf.append((char) ch); ch = file.read(); } while (!delims[ch + 1]); } backOnePosition(ch); break; } } if (outBuf != null) stringValue = outBuf.toString(); return true; } public int intValue() { return Integer.parseInt(stringValue); } public boolean readLineSegment(byte input[]) throws IOException { int c = -1; boolean eol = false; int ptr = 0; int len = input.length; // ssteward, pdftk-1.10, 040922: // skip initial whitespace; added this because PdfReader.rebuildXref() // assumes that line provided by readLineSegment does not have init. whitespace; if (ptr < len) { while (isWhitespace((c = read()))) ; } while (!eol && ptr < len) { switch (c) { case -1: case '\n': eol = true; break; case '\r': eol = true; int cur = getFilePointer(); if ((read()) != '\n') { seek(cur); } break; default: input[ptr++] = (byte) c; break; } // break loop? do it before we read() again if (eol || len <= ptr) { break; } else { c = read(); } } if (ptr >= len) { eol = false; while (!eol) { switch (c = read()) { case -1: case '\n': eol = true; break; case '\r': eol = true; int cur = getFilePointer(); if ((read()) != '\n') { seek(cur); } break; } } } if ((c == -1) && (ptr == 0)) { return false; } if (ptr + 2 <= len) { input[ptr++] = (byte) ' '; input[ptr] = (byte) 'X'; } return true; } public static int[] checkObjectStart(byte line[]) { try { PRTokeniser tk = new PRTokeniser(line); int num = 0; int gen = 0; if (!tk.nextToken() || tk.getTokenType() != TK_NUMBER) return null; num = tk.intValue(); if (!tk.nextToken() || tk.getTokenType() != TK_NUMBER) return null; gen = tk.intValue(); if (!tk.nextToken()) return null; if (!tk.getStringValue().equals("obj")) return null; return new int[] { num, gen }; } catch (Exception ioe) { // empty on purpose } return null; } public boolean isHexString() { return this.hexString; } }