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197 lines
7.5 KiB
197 lines
7.5 KiB
// kelondroNaturalOrder.java
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// -----------------------
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// part of The Kelondro Database
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// (C) by Michael Peter Christen; mc@anomic.de
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// first published on http://www.anomic.de
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// Frankfurt, Germany, 2005
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// created 29.12.2005
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//
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// $LastChangedDate: 2005-09-22 22:01:26 +0200 (Thu, 22 Sep 2005) $
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// $LastChangedRevision: 774 $
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// $LastChangedBy: orbiter $
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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//
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// Using this software in any meaning (reading, learning, copying, compiling,
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// running) means that you agree that the Author(s) is (are) not responsible
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// for cost, loss of data or any harm that may be caused directly or indirectly
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// by usage of this softare or this documentation. The usage of this software
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// is on your own risk. The installation and usage (starting/running) of this
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// software may allow other people or application to access your computer and
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// any attached devices and is highly dependent on the configuration of the
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// software which must be done by the user of the software; the author(s) is
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// (are) also not responsible for proper configuration and usage of the
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// software, even if provoked by documentation provided together with
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// the software.
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//
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// Any changes to this file according to the GPL as documented in the file
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// gpl.txt aside this file in the shipment you received can be done to the
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// lines that follows this copyright notice here, but changes must not be
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// done inside the copyright notive above. A re-distribution must contain
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// the intact and unchanged copyright notice.
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// Contributions and changes to the program code must be marked as such.
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package de.anomic.kelondro;
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import java.util.Comparator;
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public final class kelondroNaturalOrder extends kelondroAbstractOrder implements kelondroOrder, Comparator<Object>, Cloneable {
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public static final kelondroOrder naturalOrder = new kelondroNaturalOrder(true);
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public kelondroNaturalOrder(boolean ascending) {
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this.asc = ascending;
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this.zero = null;
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}
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public boolean wellformed(byte[] a) {
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return true;
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}
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public boolean wellformed(byte[] a, int astart, int alength) {
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return true;
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}
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public final Object clone() {
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kelondroNaturalOrder o = new kelondroNaturalOrder(this.asc);
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o.rotate(this.zero);
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return o;
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}
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public final static kelondroOrder bySignature(String signature) {
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if (signature.equals("nd")) return new kelondroNaturalOrder(false);
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if (signature.equals("nu")) return new kelondroNaturalOrder(true);
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return null;
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}
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public final String signature() {
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if (!asc) return "nd";
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if ( asc) return "nu";
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return null;
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}
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private final static long cardinalI(byte[] key) {
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// returns a cardinal number in the range of 0 .. Long.MAX_VALUE
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long c = 0;
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int p = 0;
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while ((p < 8) && (p < key.length)) c = (c << 8) | ((long) key[p++] & 0xFF);
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while (p++ < 8) c = (c << 8);
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c = c >>> 1;
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return c;
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}
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public final long cardinal(byte[] key) {
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if (this.zero == null) return cardinalI(key);
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long zeroCardinal = cardinalI(this.zero);
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long keyCardinal = cardinalI(key);
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if (keyCardinal > zeroCardinal) return keyCardinal - zeroCardinal;
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return Long.MAX_VALUE - keyCardinal + zeroCardinal;
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}
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public final static byte[] encodeLong(long c, int length) {
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byte[] b = new byte[length];
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while (length > 0) {
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b[--length] = (byte) (c & 0xFF);
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c >>= 8;
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}
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return b;
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}
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public final static void encodeLong(long c, byte[] b, int offset, int length) {
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assert offset + length <= b.length;
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while (length > 0) {
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b[--length + offset] = (byte) (c & 0xFF);
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c >>= 8;
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}
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}
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public final static long decodeLong(byte[] s) {
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if (s == null) return 0;
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long c = 0;
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int p = 0;
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while (p < s.length) c = (c << 8) | ((long) s[p++] & 0xFF);
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return c;
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}
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public final static long decodeLong(byte[] s, int offset, int length) {
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if (s == null) return 0;
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long c = 0;
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final int m = Math.min(s.length, offset + length);
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while (offset < m) c = (c << 8) | ((long) s[offset++] & 0xFF);
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return c;
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}
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private static final int sig(int x) {
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return (x > 0) ? 1 : (x < 0) ? -1 : 0;
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}
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// Compares its two arguments for order.
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// Returns -1, 0, or 1 as the first argument
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// is less than, equal to, or greater than the second.
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// two arrays are also equal if one array is a subset of the other's array
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// with filled-up char(0)-values
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public final int compare(byte[] a, byte[] b) {
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return (asc) ? compare0(a, 0, a.length, b, 0, b.length) : compare0(b, 0, b.length, a, 0, a.length);
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}
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public final int compare(byte[] a, int aoffset, int alength, byte[] b, int boffset, int blength) {
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return (asc) ? compare0(a, aoffset, alength, b, boffset, blength) : compare0(b, boffset, blength, a, aoffset, alength);
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}
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public final int compare0(byte[] a, int aoffset, int alength, byte[] b, int boffset, int blength) {
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if (zero == null) return compares(a, aoffset, alength, b, boffset, blength);
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// we have an artificial start point. check all combinations
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final int az = compares(a, aoffset, alength, zero, 0, zero.length); // -1 if a < z; 0 if a == z; 1 if a > z
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final int bz = compares(b, boffset, blength, zero, 0, zero.length); // -1 if b < z; 0 if b == z; 1 if b > z
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if (az == bz) return compares(a, aoffset, alength, b, boffset, blength);
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return sig(az - bz);
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}
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public static final boolean equal(byte[] a, byte[] b) {
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if ((a == null) && (b == null)) return true;
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if ((a == null) || (b == null)) return false;
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return compares(a, 0, a.length, b, 0, b.length) == 0;
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}
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public static final int compares(byte[] a, int aoffset, int alength, byte[] b, int boffset, int blength) {
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int i = 0;
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final int al = Math.min(alength, a.length - aoffset);
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final int bl = Math.min(blength, b.length - boffset);
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int aa, bb;
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while ((i < al) && (i < bl)) {
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aa = 0xff & (int) a[i + aoffset];
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bb = 0xff & (int) b[i + boffset];
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if (aa > bb) return 1;
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if (aa < bb) return -1;
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// else the bytes are equal and it may go on yet undecided
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i++;
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}
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// compare length
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if (al > bl) return 1;
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if (al < bl) return -1;
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// they are equal
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return 0;
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}
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public static void main(String[] args) {
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byte[] t = new byte[12];
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for (int i = 0; i < 12; i++) t[i] = (byte) 255;
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t[0] = (byte) 127;
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kelondroOrder o = new kelondroNaturalOrder(true);
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System.out.println(o.partition(t, 16));
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}
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}
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