001 //$HeadURL: svn+ssh://rbezema@svn.wald.intevation.org/deegree/base/branches/2.2_testing/src/org/deegree/io/shpapi/FileHeader.java $
002
003 /*---------------- FILE HEADER ------------------------------------------
004
005 This file is part of deegree.
006 Copyright (C) 2001-2008 by:
007 EXSE, Department of Geography, University of Bonn
008 http://www.giub.uni-bonn.de/deegree/
009 lat/lon GmbH
010 http://www.lat-lon.de
011
012 This library is free software; you can redistribute it and/or
013 modify it under the terms of the GNU Lesser General Public
014 License as published by the Free Software Foundation; either
015 version 2.1 of the License, or (at your option) any later version.
016
017 This library is distributed in the hope that it will be useful,
018 but WITHOUT ANY WARRANTY; without even the implied warranty of
019 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
020 Lesser General Public License for more details.
021
022 You should have received a copy of the GNU Lesser General Public
023 License along with this library; if not, write to the Free Software
024 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
025
026 Contact:
027
028 Andreas Poth
029 lat/lon GmbH
030 Aennchenstr. 19
031 53115 Bonn
032 Germany
033 E-Mail: poth@lat-lon.de
034
035 Prof. Dr. Klaus Greve
036 Department of Geography
037 University of Bonn
038 Meckenheimer Allee 166
039 53115 Bonn
040 Germany
041 E-Mail: greve@giub.uni-bonn.de
042
043
044 ---------------------------------------------------------------------------*/
045
046 package org.deegree.io.shpapi;
047
048
049 import java.io.IOException;
050 import java.io.RandomAccessFile;
051
052 import org.deegree.model.spatialschema.ByteUtils;
053
054 /**
055 * Class representing an ESRI Index File Header.
056 * <p>
057 * Uses class ByteUtils ShapeUtils modified
058 * from the original package com.bbn.openmap.layer.shape
059 * <br>
060 * Copyright (C) 1998 BBN Corporation 10 Moulton St. Cambridge, MA 02138
061 * <br>
062 *
063 * @version 16.08.2000
064 * @author Andreas Poth
065 *
066 */
067
068
069 public class FileHeader {
070
071 /*
072 * The buffer that holds the 100 byte header.
073 */
074 private byte[] header;
075
076 /*
077 * Holds the length of the file, in bytes.
078 */
079 private long fileLength;
080
081 /*
082 * Holds the version of the file, as an int.
083 */
084 private int fileVersion;
085
086 /*
087 * Holds the shape type of the file.
088 */
089 private int fileShapeType;
090
091 /*
092 * Holds the bounds of the file (four pairs of doubles).
093 */
094 private SHPEnvelope fileMBR;
095
096 /*
097 * local copy of the index-file randomaccess variable;
098 */
099 private RandomAccessFile rafShp = null;
100
101
102 /**
103 * Construct a IndexFileHeader from a file name.
104 */
105 public FileHeader(RandomAccessFile rafShp_) throws IOException {
106
107 rafShp = rafShp_;
108
109 initHeader(false);
110 }
111
112 /**
113 * Construct a IndexFileHeader from a file name.
114 */
115 public FileHeader(RandomAccessFile rafShp_, boolean newHeader) throws IOException {
116
117 rafShp = rafShp_;
118
119 initHeader(newHeader);
120 }
121
122
123 /**
124 * method: getFileMBR();<BR>
125 * Returns the bounding box of this shape file. The bounding box<BR>
126 * is the smallest rectangle that encloses all the shapes in the<BR>
127 * file.<BR>
128 */
129
130 public SHPEnvelope getFileMBR() {
131
132 return fileMBR;
133
134 }
135
136 /**
137 * method: getFileLength()<BR>
138 * returns the length of the shape file in bytes<BR>
139 */
140 public long getFileLength() {
141
142 return fileLength;
143
144 }
145
146 /**
147 * method: getFileVersion()<BR>
148 * returns the version of the shape file<BR>
149 */
150 public int getFileVersion() {
151
152 return fileVersion;
153
154 }
155
156 /**
157 * method: getFileShapeType()<BR>
158 * returns the code for the shape type of the file<BR>
159 */
160 public int getFileShapeType() {
161 return fileShapeType;
162 }
163
164 /**
165 * Reads the header of a Shape file. If the file<BR>
166 * is empty, a blank header is written and then read. If the<BR>
167 * file is not empty, the header is read.<BR>
168 * After this function runs, the file pointer is set to byte 100,<BR>
169 * the first byte of the first record in the file.<BR>
170 */
171
172 private void initHeader(boolean newHeader) throws IOException {
173
174 if (newHeader) writeHeader();
175 /*
176 if (rafShp.read() == -1) {
177 //File is empty, write a new one (what else???)
178 writeHeader();
179 }
180 */
181 readHeader();
182 }
183
184 /**
185 * method: writeHeader()<BR>
186 * Writes a blank header into the shape file.<BR>
187 */
188 public void writeHeader() throws IOException {
189
190 header = new byte[ShapeConst.SHAPE_FILE_HEADER_LENGTH];
191
192 ByteUtils.writeBEInt(header, 0, ShapeConst.SHAPE_FILE_CODE);
193 ByteUtils.writeBEInt(header, 24, 50);
194
195 // empty shape file size in 16 bit words
196 ByteUtils.writeLEInt(header, 28, ShapeConst.SHAPE_FILE_VERSION);
197 ByteUtils.writeLEInt(header, 32, ShapeConst.SHAPE_TYPE_NULL);
198 ByteUtils.writeLEDouble(header, 36, 0.0);
199 ByteUtils.writeLEDouble(header, 44, 0.0);
200 ByteUtils.writeLEDouble(header, 52, 0.0);
201 ByteUtils.writeLEDouble(header, 60, 0.0);
202
203 rafShp.seek(0);
204 rafShp.write(header, 0, ShapeConst.SHAPE_FILE_HEADER_LENGTH);
205
206 }
207
208 /**
209 * method: writeHeader(int filelength, byte shptype,SHPEnvelope mbr)<BR>
210 * Writes a header into the shape file.<BR>
211 */
212 public void writeHeader(int filelength, int shptype, SHPEnvelope mbr) throws IOException {
213
214 header = new byte[ShapeConst.SHAPE_FILE_HEADER_LENGTH];
215
216 ByteUtils.writeBEInt(header, 0, ShapeConst.SHAPE_FILE_CODE);
217 ByteUtils.writeBEInt(header, 24, filelength / 2);
218 ByteUtils.writeLEInt(header, 28, ShapeConst.SHAPE_FILE_VERSION);
219 ByteUtils.writeLEInt(header, 32, shptype);
220 ShapeUtils.writeBox(header, 36, mbr);
221
222 rafShp.seek(0);
223 rafShp.write(header, 0, ShapeConst.SHAPE_FILE_HEADER_LENGTH);
224 }
225
226 /**
227 * Reads and parses the header of the file. Values from the header<BR>
228 * are stored in the fields of this class.<BR>
229 */
230 private void readHeader() throws IOException {
231
232 header = new byte[ShapeConst.SHAPE_FILE_HEADER_LENGTH];
233
234 /*
235 * Make sure we're at the beginning of the file
236 */
237 rafShp.seek(0);
238
239 rafShp.read(header, 0, ShapeConst.SHAPE_FILE_HEADER_LENGTH);
240
241 int fileCode = ByteUtils.readBEInt(header, 0);
242
243 if (fileCode != ShapeConst.SHAPE_FILE_CODE) {
244
245 throw new IOException("Invalid file code, " + "probably not a shape file");
246
247 }
248
249 fileVersion = ByteUtils.readLEInt(header, 28);
250
251 if (fileVersion != ShapeConst.SHAPE_FILE_VERSION) {
252
253 throw new IOException("Unable to read shape files with version " +
254 fileVersion);
255
256 }
257
258 fileLength = ByteUtils.readBEInt(header, 24);
259
260 /*
261 * convert from 16-bit words to 8-bit bytes
262 */
263 fileLength *= 2;
264
265 fileShapeType = ByteUtils.readLEInt(header, 32);
266
267 /*
268 * read ESRIBoundingBox and convert to SHPEnvelope
269 */
270 fileMBR = new SHPEnvelope(ShapeUtils.readBox(header, 36));
271
272 }
273
274 }