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R3600/modules/miscutil/lib/solrutils/org/invenio_software/solr/InvenioBitSet.java
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InvenioBitSet.java
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// Author: Jan Iwaszkiewicz
package org.invenio_software.solr;
import java.io.*;
import java.util.BitSet;
import java.util.Arrays;
public class InvenioBitSet extends BitSet {
private static final long serialVersionUID = 1L;
public InvenioBitSet() {
super();
}
public InvenioBitSet(int nbits) {
super(nbits);
}
// TODO: remove the trailing 8 bytes (added by intbitset format) and test
public InvenioBitSet(byte[] bytes) {
this(bytes == null? 0 : bytes.length * 8);
for (int i = 0; i < size(); i++) {
if (isBitOn(i, bytes))
set(i);
}
}
// convert to a byte array to be used as intbitset in Invenio
public byte[] toByteArray() {
if (size() == 0)
return new byte[0];
// Find highest bit
int hiBit = -1;
for (int i = 0; i < size(); i++) {
if (get(i))
hiBit = i;
}
// was: int n = (hiBit + 8) / 8;
// +128 (64 for trailing zeros used in intbitset and 64 to avoid trancating)
int n = ((hiBit + 128) / 64) * 8;
byte[] bytes = new byte[n];
if (n == 0)
return bytes;
Arrays.fill(bytes, (byte)0);
for (int i=0; i<n*8; i++) {
if (get(i))
setBit(i, bytes);
}
return bytes;
}
protected static int BIT_MASK[] =
// {0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01};
{0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};
protected static boolean isBitOn(int bit, byte[] bytes) {
int size = bytes == null ? 0 : bytes.length*8;
if (bit >= size)
return false;
return (bytes[bit/8] & BIT_MASK[bit%8]) != 0;
}
protected static void setBit(int bit, byte[] bytes) {
int size = bytes == null ? 0 : bytes.length*8;
if (bit >= size)
throw new ArrayIndexOutOfBoundsException("Byte array too small");
bytes[bit/8] |= BIT_MASK[bit%8];
}
}
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