// kelondroNaturalOrder.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: 2005-09-22 22:01:26 +0200 (Thu, 22 Sep 2005) $
// $LastChangedRevision: 774 $
// $LastChangedBy: orbiter $
//
// 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 de.anomic.kelondro;
import java.util.Comparator;
public final class kelondroNaturalOrder extends kelondroAbstractOrder<byte[]> implements kelondroByteOrder, Comparator<byte[]>, Cloneable {
public static final kelondroByteOrder naturalOrder = new kelondroNaturalOrder(true);
public static final Comparator<String> naturalComparator = new kelondroByteOrder.StringOrder(naturalOrder);
public kelondroNaturalOrder(final boolean ascending) {
this.asc = ascending;
this.zero = null;
}
public boolean wellformed(final byte[] a) {
return true;
}
public boolean wellformed(final byte[] a, final int astart, final int alength) {
return true;
}
public final kelondroOrder<byte[]> clone() {
final kelondroNaturalOrder o = new kelondroNaturalOrder(this.asc);
o.rotate(this.zero);
return o;
}
public static kelondroByteOrder orderBySignature(final String signature) {
kelondroByteOrder oo = null;
if (oo == null) oo = kelondroNaturalOrder.bySignature(signature);
if (oo == null) oo = kelondroBase64Order.bySignature(signature);
if (oo == null) oo = new kelondroNaturalOrder(true);
return oo;
}
public final static kelondroByteOrder bySignature(final String signature) {
if (signature.equals("nd")) return new kelondroNaturalOrder(false);
if (signature.equals("nu")) return new kelondroNaturalOrder(true);
return null;
}
public final String signature() {
if (!asc) return "nd";
if ( asc) return "nu";
return null;
}
private final static long cardinalI(final byte[] key) {
// returns a cardinal number in the range of 0 .. Long.MAX_VALUE
long c = 0;
int p = 0;
while ((p < 8) && (p < key.length)) c = (c << 8) | ((long) key[p++] & 0xFF);
while (p++ < 8) c = (c << 8);
c = c >>> 1;
return c;
}
public final long cardinal(final byte[] key) {
if (this.zero == null) return cardinalI(key);
final long zeroCardinal = cardinalI(this.zero);
final long keyCardinal = cardinalI(key);
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) {
return (asc) ? compare0(a, 0, a.length, b, 0, b.length) : compare0(b, 0, b.length, a, 0, a.length);
}
public final int compare(final byte[] a, final int aoffset, final int alength, final byte[] b, final int boffset, final int blength) {
return (asc) ? compare0(a, aoffset, alength, b, boffset, blength) : compare0(b, boffset, blength, a, aoffset, alength);
}
public final int compare0(final byte[] a, final int aoffset, final int alength, final byte[] b, final int boffset, final int blength) {
if (zero == null) return compares(a, aoffset, alength, b, boffset, blength);
// we have an artificial start point. check all combinations
final int az = compares(a, aoffset, alength, zero, 0, zero.length); // -1 if a < z; 0 if a == z; 1 if a > z
final int bz = compares(b, boffset, blength, zero, 0, zero.length); // -1 if b < z; 0 if b == z; 1 if b > z
if (az == bz) return compares(a, aoffset, alength, b, boffset, blength);
return sig(az - bz);
}
public static final boolean equal(final byte[] a, final byte[] b) {
if ((a == null) && (b == null)) return true;
if ((a == null) || (b == null)) return false;
return compares(a, 0, a.length, b, 0, b.length) == 0;
}
public static final int compares(final byte[] a, final int aoffset, final int alength, final byte[] b, final int boffset, final int blength) {
int i = 0;
final int al = Math.min(alength, a.length - aoffset);
final int bl = Math.min(blength, b.length - boffset);
int aa, bb;
while ((i < al) && (i < bl)) {
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++;
}
// compare length
if (al > bl) return 1;
if (al < bl) return -1;
// they are equal
return 0;
}
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 kelondroOrder<byte[]> o = new kelondroNaturalOrder(true);
System.out.println(o.partition(t, 16));
}
}