// NaturalOrder.java
// -----------------------
// part of The Kelondro Database
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://www.anomic.de
// Frankfurt, Germany, 2005
// created 29.12.2005
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package net.yacy.kelondro.order;
import java.util.Comparator;
import java.util.Iterator;
import net.yacy.cora.ranking.AbstractOrder;
import net.yacy.cora.ranking.Order;
import net.yacy.kelondro.index.HandleSet;
public final class NaturalOrder extends AbstractOrder<byte[]> implements ByteOrder, Comparator<byte[]>, Cloneable {
public static final ByteOrder naturalOrder = new NaturalOrder(true);
public static final Comparator<String> naturalComparator = new StringOrder(naturalOrder);
public NaturalOrder(final boolean ascending) {
this.asc = ascending;
this.zero = null;
}
public HandleSet getHandleSet(final int keylength, final int space) {
return new HandleSet(keylength, this, space);
}
public boolean wellformed(final byte[] a) {
return true;
}
public boolean wellformed(final byte[] a, final int astart, final int alength) {
return true;
}
public final Order<byte[]> clone() {
final NaturalOrder o = new NaturalOrder(this.asc);
o.rotate(this.zero);
return o;
}
public static ByteOrder orderBySignature(final String signature) {
ByteOrder oo = null;
if (oo == null) oo = NaturalOrder.bySignature(signature);
if (oo == null) oo = Base64Order.bySignature(signature);
if (oo == null) oo = new NaturalOrder(true);
return oo;
}
public final static ByteOrder bySignature(final String signature) {
if (signature.equals("nd")) return new NaturalOrder(false);
if (signature.equals("nu")) return new NaturalOrder(true);
return null;
}
public final String signature() {
if (!this.asc) return "nd";
if ( this.asc) return "nu";
return null;
}
private final static long cardinalI(final byte[] key, int off, final int len) {
// returns a cardinal number in the range of 0 .. Long.MAX_VALUE
long c = 0;
final int lim = off + Math.min(8, len);
final int lim8 = off + 8;
while (off < lim) c = (c << 8) | ((long) key[off++] & 0xFF);
while (off++ < lim8) c = (c << 8);
c = c >>> 1;
return c;
}
public final long cardinal(final byte[] key) {
if (this.zero == null) return cardinalI(key, 0, key.length);
final long zeroCardinal = cardinalI(this.zero, 0, this.zero.length);
final long keyCardinal = cardinalI(key, 0, key.length);
if (keyCardinal > zeroCardinal) return keyCardinal - zeroCardinal;
return Long.MAX_VALUE - keyCardinal + zeroCardinal;
}
public long cardinal(final byte[] key, final int off, final int len) {
if (this.zero == null) return cardinalI(key, off, len);
final long zeroCardinal = cardinalI(this.zero, 0, this.zero.length);
final long keyCardinal = cardinalI(key, off, len);
if (keyCardinal > zeroCardinal) return keyCardinal - zeroCardinal;
return Long.MAX_VALUE - keyCardinal + zeroCardinal;
}
public final static byte[] encodeLong(long c, int length) {
final byte[] b = new byte[length];
while (length > 0) {
b[--length] = (byte) (c & 0xFF);
c >>= 8;
}
return b;
}
public final static void encodeLong(long c, final byte[] b, final int offset, int length) {
assert offset + length <= b.length;
while (length > 0) {
b[--length + offset] = (byte) (c & 0xFF);
c >>= 8;
}
}
public final static long decodeLong(final byte[] s) {
if (s == null) return 0;
long c = 0;
int p = 0;
while (p < s.length) c = (c << 8) | ((long) s[p++] & 0xFF);
return c;
}
public final static long decodeLong(final byte[] s, int offset, final int length) {
if (s == null) return 0;
long c = 0;
final int m = Math.min(s.length, offset + length);
while (offset < m) c = (c << 8) | ((long) s[offset++] & 0xFF);
return c;
}
private static final int sig(final int x) {
return (x > 0) ? 1 : (x < 0) ? -1 : 0;
}
// Compares its two arguments for order.
// Returns -1, 0, or 1 as the first argument
// is less than, equal to, or greater than the second.
// two arrays are also equal if one array is a subset of the other's array
// with filled-up char(0)-values
public final int compare(final byte[] a, final byte[] b) {
if (a.length == b.length) {
return (this.asc) ? compare0(a, b, a.length) : compare0(b, 0, a, 0, a.length);
}
final int length = Math.min(a.length, b.length);
if (this.asc) {
final int c = compare0(a, b, length);
if (c != 0) return c;
return (a.length > b.length) ? 1 : -1;
}
final int c = compare0(b, a, length);
if (c != 0) return c;
return (a.length > b.length) ? -1 : 1;
}
public final int compare(final byte[] a, final byte[] b, final int length) {
return (this.asc) ? compare0(a, b, length) : compare0(b, a, length);
}
public final int compare(final byte[] a, final int aoffset, final byte[] b, final int boffset, final int length) {
return (this.asc) ? compare0(a, aoffset, b, boffset, length) : compare0(b, boffset, a, aoffset, length);
}
private final int compare0(final byte[] a, final byte[] b, final int length) {
if (this.zero == null) return compares(a, b, length);
// we have an artificial start point. check all combinations
assert length == this.zero.length;
final int az = compares(a, this.zero, length); // -1 if a < z; 0 if a == z; 1 if a > z
final int bz = compares(b, this.zero, length); // -1 if b < z; 0 if b == z; 1 if b > z
if (az == bz) return compares(a, b, length);
return sig(az - bz);
}
private final int compare0(final byte[] a, final int aoffset, final byte[] b, final int boffset, final int length) {
if (this.zero == null) return compares(a, aoffset, b, boffset, length);
// we have an artificial start point. check all combinations
assert length == this.zero.length;
final int az = compares(a, aoffset, this.zero, 0, length); // -1 if a < z; 0 if a == z; 1 if a > z
final int bz = compares(b, boffset, this.zero, 0, length); // -1 if b < z; 0 if b == z; 1 if b > z
if (az == bz) return compares(a, aoffset, b, boffset, length);
return sig(az - bz);
}
public final boolean equal(final byte[] a, final byte[] b) {
if ((a == null) && (b == null)) return true;
if ((a == null) || (b == null)) return false;
if (a.length != b.length) return false;
int astart = 0;
int bstart = 0;
int length = a.length;
while (length-- != 0) {
if (a[astart++] != b[bstart++]) return false;
}
return true;
}
public final boolean equal(final byte[] a, int astart, final byte[] b, int bstart, int length) {
if ((a == null) && (b == null)) return true;
if ((a == null) || (b == null)) return false;
while (length-- != 0) {
if (a[astart++] != b[bstart++]) return false;
}
return true;
}
private static final int compares(final byte[] a, final byte[] b, final int length) {
int i = 0;
int aa, bb;
while (i < length) {
aa = 0xff & a[i];
bb = 0xff & b[i];
if (aa > bb) return 1;
if (aa < bb) return -1;
// else the bytes are equal and it may go on yet undecided
i++;
}
// they are equal
return 0;
}
private static final int compares(final byte[] a, final int aoffset, final byte[] b, final int boffset, final int length) {
int i = 0;
int aa, bb;
while (i < length) {
aa = 0xff & a[i + aoffset];
bb = 0xff & b[i + boffset];
if (aa > bb) return 1;
if (aa < bb) return -1;
// else the bytes are equal and it may go on yet undecided
i++;
}
// they are equal
return 0;
}
public static final String arrayList(final byte[] b, final int start, int length) {
if (b == null) return "NULL";
if (b.length == 0) return "[]";
length = Math.min(length, b.length - start);
final StringBuilder sb = new StringBuilder(b.length * 4);
sb.append('[').append(Integer.toString(b[start])).append(',');
for (int i = 1; i < length; i++) sb.append(' ').append(Integer.toString(b[start + i])).append(',');
sb.append(']');
return sb.toString();
}
public static final String table(final byte[] b, final int linewidth) {
if (b == null) return "NULL";
if (b.length == 0) return "[]";
final StringBuilder sb = new StringBuilder(b.length * 4);
for (int i = 0; i < b.length; i++) {
if (i % linewidth == 0)
sb.append('\n').append("# ").append(Integer.toHexString(i)).append(": ");
else
sb.append(',');
sb.append(' ').append(Integer.toString(0xff & b[i]));
if (i >= 65535) break;
}
sb.append('\n');
return sb.toString();
}
public static Iterator<Long> LongIterator(final Iterator<byte[]> b256Iterator) {
return new LongIter(b256Iterator);
}
public static class LongIter implements Iterator<Long> {
private final Iterator<byte[]> b256Iterator;
public LongIter(final Iterator<byte[]> b256Iterator) {
this.b256Iterator = b256Iterator;
}
public boolean hasNext() {
return this.b256Iterator.hasNext();
}
public Long next() {
final byte[] b = this.b256Iterator.next();
assert (b != null);
if (b == null) return null;
return Long.valueOf(decodeLong(b));
}
public void remove() {
this.b256Iterator.remove();
}
}
public static void main(final String[] args) {
final byte[] t = new byte[12];
for (int i = 0; i < 12; i++) t[i] = (byte) 255;
t[0] = (byte) 127;
final Order<byte[]> o = new NaturalOrder(true);
System.out.println(o.partition(t, 16));
}
}