ucar.unidata.io.BeLeDataInputStream Maven / Gradle / Ivy
/*
* Copyright (c) 1998-2018 University Corporation for Atmospheric Research/Unidata
* See LICENSE for license information.
*/
package ucar.unidata.io;
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
* @deprecated not part of public API.
*/
@Deprecated
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) {
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
*/
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 n little-endian doubles from a random access file.
*
*
* 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 n little-endian longs from a random access file.
*
*
* 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;
}
}
}