Quadcap Embeddable Database

com/quadcap/sql/types/CompareValues.java

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package com.quadcap.sql.types;

/* Copyright 1997 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;

import com.quadcap.sql.index.Comparator;

import com.quadcap.sql.io.ObjectInputStream;
import com.quadcap.sql.io.ObjectOutputStream;

import com.quadcap.util.Debug;
import com.quadcap.util.Util;

/**
 * Generic multi-field comparator implementation
 *
 * @author Stan Bailes
 */
public class CompareValues extends Comparator {
    int                         directions;
    int                         cnt;
    
    public CompareValues() {}

    public CompareValues(int count) {
        this.cnt = count;
        this.directions = ~((~0) << count);
    }
    
    public void addField(boolean asc) {
        directions <<= 1;
        if (asc) directions |= 1;
        cnt++;
    }

    //#ifdef NOTDEF
//-    public int compare2(byte[] a, int aoff, int alen,
//-                     byte[] b, int boff, int blen) {
//-     try {
//-         int alim = aoff + alen;
//-         int blim = boff + blen;
//-         for (int i = 0; i < cnt; i++) {
//-             int as = a[aoff++] & 0xff;
//-             if ((as & 0x80) == 0) {
//-                 as <<= 8;
//-                 as |= a[aoff++] & 0xff;
//-             } else {
//-                 as &= 0x7f;
//-             }
//-             int bs = b[boff++] & 0xff;
//-             if ((bs & 0x80) == 0) {
//-                 bs <<= 8;
//-                 bs |= b[boff++] & 0xff;
//-             } else {
//-                 bs &= 0x7f;
//-             }
//-             for (int j = 0; j < as && j < bs; j++) {
//-                 int av = a[aoff++] & 0xff;
//-                 int bv = b[boff++] & 0xff;
//-                 if (av == bv) continue;
//-                 boolean asc = ((directions >> (cnt - i - 1)) & 1) != 0;
//-                 return ((av < bv) ^ asc) ? -1 : 1;
//-             }
//-         }
//-         return 0;
//-     } catch (Exception e) {
//-         throw new RuntimeException(e.toString());
//-     }
//-    }
    //#endif


    public int compare(byte[] a, int aoff, int alen,
                       byte[] b, int boff, int blen) {
        try {
            ByteArrayInputStream ai = new ByteArrayInputStream(a, aoff, alen);
            ObjectInputStream aoi = new ObjectInputStream(ai);
            ByteArrayInputStream bi = new ByteArrayInputStream(b, boff, blen);
            ObjectInputStream boi = new ObjectInputStream(bi);
            for (int i = 0; i < cnt; i++) {
                Value va = (Value)aoi.readObject();
                Value vb = (Value)boi.readObject();
                Value cmp = Value.binop(Op.COMPARE, va, vb);
                //Debug.println("[" + i + "]: " + cmp + " <= (" + va + ") vs (" + vb + ")");
                ValueInteger vi = (ValueInteger)cmp;
                int ret = vi.intValue();
                if (ret != 0) {
                    boolean asc = ((directions >> (cnt - i - 1)) & 1) != 0;
                    ret = asc ? ret : 0 - ret;
                    return ret;
                }
            }
            return 0;
        } catch (Exception e) {
            //#ifdef DEBUG
            Debug.print(e);
            Debug.println("a = " + Util.hexBytes(a, aoff, alen));
            Debug.println("b = " + Util.hexBytes(b, boff, blen));
            //#endif
            throw new RuntimeException(e.toString());
        }
    }
}