/*
* Copyright 1998-2009 University Corporation for Atmospheric Research/Unidata
*
* Portions of this software were developed by the Unidata Program at the
* University Corporation for Atmospheric Research.
*
* Access and use of this software shall impose the following obligations
* and understandings on the user. The user is granted the right, without
* any fee or cost, to use, copy, modify, alter, enhance and distribute
* this software, and any derivative works thereof, and its supporting
* documentation for any purpose whatsoever, provided that this entire
* notice appears in all copies of the software, derivative works and
* supporting documentation. Further, UCAR requests that the user credit
* UCAR/Unidata in any publications that result from the use of this
* software or in any product that includes this software. The names UCAR
* and/or Unidata, however, may not be used in any advertising or publicity
* to endorse or promote any products or commercial entity unless specific
* written permission is obtained from UCAR/Unidata. The user also
* understands that UCAR/Unidata is not obligated to provide the user with
* any support, consulting, training or assistance of any kind with regard
* to the use, operation and performance of this software nor to provide
* the user with any updates, revisions, new versions or "bug fixes."
*
* THIS SOFTWARE IS PROVIDED BY UCAR/UNIDATA "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL,
* INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE ACCESS, USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package ucar.nc2.ui.gis.shapefile;
import java.io.IOException;
import java.io.InputStream;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.BufferedInputStream;
import java.net.URL;
/**
* Big-endian little-endian data input stream, from which numbers in
* both big- and little-endian representations can be read. This is
* needed for ESRI shapefiles, for example, since they contain both
* big- and little-endian representations.
*
* @author Russ Rew
*/
public class BeLeDataInputStream extends DataInputStream {
private byte w[] = new byte[8]; // work array for buffering bytes
private static final int kLongs = 128; // arbitrary, probably big enough
private long[] longWorkSpace = new long[kLongs];
private byte[] byteWorkSpace = new byte[8 * kLongs];
/**
* Construct a bigEndian-littleEndian input stream from an input stream.
*
* @param inputStream from which to read
*/
public BeLeDataInputStream(InputStream inputStream) throws IOException {
super(inputStream);
}
/**
* Construct a bigEndian-littleEndian input stream from a file.
*
* @param filename of file
*/
public BeLeDataInputStream(String filename) throws IOException {
this(new BufferedInputStream(new FileInputStream(filename)));
}
/**
* Construct a bigEndian-littleEndian input stream from a URL.
*
* @param url of remote data
* @throws IOException if there was a problem reading the file.
*/
public BeLeDataInputStream(URL url) throws IOException {
this(new BufferedInputStream(new DataInputStream(url.openStream())));
}
/**
* read an int in little endian format
*
* @return int created from next 4 bytes in stream, in littleEndian order
*/
public int readLEInt()
throws IOException {
readFully(w, 0, 4);
return (w[3] & 0xff) << 24 |
(w[2] & 0xff) << 16 |
(w[1] & 0xff) << 8 |
(w[0] & 0xff);
}
/**
* read a double in little endian format
*
* @return double from next 8 bytes in stream, littleEndian order
*/
public double readLEDouble() throws IOException {
return Double.longBitsToDouble(readLELong());
}
/**
* Reads <code>n</code> little-endian doubles from a random access file.
* <p/>
* <p> This method is provided for speed when accessing a number
* of consecutive values of the same type.
*
* @param d the buffer into which the doubles are read
* @param n number of little-endian doubles to read
*/
public final void readLEDoubles(double[] d, int n) throws IOException {
int nLeft = n;
int dCount = 0;
int nToRead = kLongs;
while (nLeft > 0) {
if (nToRead > nLeft)
nToRead = nLeft;
readLELongs(longWorkSpace, nToRead);
for (int i = 0; i < nToRead; i++) {
d[dCount++] = Double.longBitsToDouble(longWorkSpace[i]);
}
nLeft -= nToRead;
}
}
/**
* read a long in little endian format
*
* @return long from next 8 bytes in stream, littleEndian order
*/
public long readLELong() throws IOException {
readFully(w, 0, 8);
return
(long) (w[7] & 0xff) << 56 |
(long) (w[6] & 0xff) << 48 |
(long) (w[5] & 0xff) << 40 |
(long) (w[4] & 0xff) << 32 |
(long) (w[3] & 0xff) << 24 |
(long) (w[2] & 0xff) << 16 |
(long) (w[1] & 0xff) << 8 |
(long) (w[0] & 0xff);
}
/**
* Reads <code>n</code> little-endian longs from a random access file.
* <p/>
* <p> This method is provided for speed when accessing a number
* of consecutive values of the same type.
*
* @param lbuf the buffer into which the longs are read
* @param n the number of little-endian longs to read
*/
public final void readLELongs(long lbuf[], int n) throws IOException {
int nLeft = n;
int lCount = 0;
int nToRead = kLongs;
while (nLeft > 0) {
if (nToRead > nLeft)
nToRead = nLeft;
readFully(byteWorkSpace, 0, 8 * nToRead);
int j = 0;
for (int i = 0; i < nToRead; i++) {
lbuf[lCount++] =
(long) (byteWorkSpace[j] & 0xff) |
(long) (byteWorkSpace[j + 1] & 0xff) << 8 |
(long) (byteWorkSpace[j + 2] & 0xff) << 16 |
(long) (byteWorkSpace[j + 3] & 0xff) << 24 |
(long) (byteWorkSpace[j + 4] & 0xff) << 32 |
(long) (byteWorkSpace[j + 5] & 0xff) << 40 |
(long) (byteWorkSpace[j + 6] & 0xff) << 48 |
(long) (byteWorkSpace[j + 7] & 0xff) << 56;
j += 8;
}
nLeft -= nToRead;
}
}
}