org.xBaseJ.indexes.Node Maven / Gradle / Ivy
/**
* eobjects.org MetaModel
* Copyright (C) 2010 eobjects.org
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.xBaseJ.indexes;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import org.xBaseJ.DBF;
import org.xBaseJ.DbaseUtils;
import org.xBaseJ.xBaseJException;
/**
* This class is courtesy of the xBaseJ project: http://xbasej.sourceforge.net/
*
* Copyright 1997-2007 - American Coders, LTD - Raleigh NC USA
*
*
* American Coders, Ltd
* P. O. Box 97462
* Raleigh, NC 27615 USA
* 1-919-846-2014
* http://www.americancoders.com
*
*
* @author Joe McVerry, American Coders Ltd.
*/
public class Node extends Object implements Cloneable {
public RandomAccessFile nfile;
public int pos = 0;
public int keys_in_a_Node = 0;
public int keys_in_this_Node = 0;
public int key_expression_size = 0;
public int record_number = 0;
public char keyType = 'C';
public byte key_buffer[];
public int lower_level[];
public int key_record_number[];
public NodeKey key_expression[];
public Node prev = null;
public Node next = null;
public boolean branch = false;
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
return null;
}
}
public Node(RandomAccessFile file, int keys_in, int key_size, char keyType,
int rn, boolean iBranch) {
nfile = file;
keys_in_a_Node = keys_in;
key_expression_size = key_size;
keys_in_this_Node = 0;
this.keyType = keyType;
record_number = rn;
branch = iBranch;
key_buffer = new byte[key_size];
key_expression = new NodeKey[keys_in + 2];
key_record_number = new int[keys_in + 2];
lower_level = new int[keys_in + 2];
for (int i = 0; i < keys_in; i++) {
key_record_number[i] = 0;
lower_level[i] = 0;
}
prev = null;
next = null;
}
public void set_pos(int ipos) {
pos = ipos;
}
public void set_key_expression_size(int l) {
key_expression_size = l;
}
public int pos_up() {
return ++pos;
}
public void set_record_number(int r) throws xBaseJException {
if (r == 0)
throw new xBaseJException("Invalid record number in set");
record_number = r;
}
public int get_record_number() {
return record_number;
}
public int pos_down() {
return --pos;
}
public int get_pos() {
return pos;
}
public void set_key_record_number(int r) {
key_record_number[pos] = r;
}
public int get_key_record_number() {
return key_record_number[pos];
}
public void set_lower_level(int level) {
lower_level[pos] = level;
}
public int get_lower_level() {
return lower_level[pos];
}
public void set_keys_in_this_Node(int c) {
keys_in_this_Node = c;
}
public int get_keys_in_this_Node() {
return keys_in_this_Node;
}
public void set_key_value(NodeKey key) {
key_expression[pos] = key;
}
public void set_key_value(String key) {
key_expression[pos] = new NodeKey(key);
}
public void set_key_value(double key) {
key_expression[pos] = new NodeKey(new Double(key));
}
public NodeKey get_key_value() {
return key_expression[pos];
}
public void read() throws IOException {
int i, j, k;
long longrecn = record_number;
nfile.seek(longrecn * 512);
keys_in_this_Node = DbaseUtils.x86(nfile.readInt());
for (i = 0; i < keys_in_a_Node; i++) {
lower_level[i] = DbaseUtils.x86(nfile.readInt());
key_record_number[i] = DbaseUtils.x86(nfile.readInt());
if (keyType == 'N') {
key_expression[i] = new NodeKey(new Double(Double
.longBitsToDouble(nfile.readLong())));
} else {
nfile.readFully(key_buffer, 0, key_expression_size);
for (k = 0; k < key_expression_size && key_buffer[k] != 0; k++)
;
try {
key_expression[i] = new NodeKey(new String(key_buffer, 0,
k, DBF.encodedType));
} catch (UnsupportedEncodingException UEE) {
key_expression[i] = new NodeKey(
new String(key_buffer, 0, k));
}
}
j = key_expression_size % 4;
if (j > 0)
j = 4 - j;
for (k = 0; k < j; k++)
nfile.readByte();
} // for i
if (lower_level[0] > 0)
branch = true;
else
branch = false;
lower_level[i] = DbaseUtils.x86(nfile.readInt());
}
public void write() throws IOException, xBaseJException {
int i, j, k, ll = 512;
if (record_number == 0)
throw new xBaseJException("Invalid record number in write");
long longrecn = record_number;
nfile.seek(longrecn * 512);
nfile.writeInt(DbaseUtils.x86(keys_in_this_Node));
ll -= 4; // sizeof(int)
for (i = 0; i < keys_in_this_Node && i < keys_in_a_Node
&& key_expression[i] != null; i++) {
if (key_expression[i] == null)
throw new xBaseJException("Missing node key expression at " + i);
if ((lower_level[0] == 0) && (key_record_number[i] == 0))
throw new xBaseJException(
"Logic mismatch, both pointers are zero");
nfile.writeInt(DbaseUtils.x86(lower_level[i]));
ll -= 4;
nfile.writeInt(DbaseUtils.x86(key_record_number[i]));
ll -= 4;
if (key_expression[i].getType() == 'N') {
double d = key_expression[i].toDouble();
nfile.writeLong(Double.doubleToLongBits(d));
}
if (key_expression[i].getType() == 'C') {
int x;
byte bytebuffer[];
try {
bytebuffer = key_expression[i].toString().getBytes(
DBF.encodedType);
} catch (UnsupportedEncodingException UEE) {
bytebuffer = key_expression[i].toString().getBytes();
}
for (x = 0; x < bytebuffer.length; x++)
key_buffer[x] = bytebuffer[x];
for (; x < key_expression_size; x++)
key_buffer[x] = 0;
nfile.write(key_buffer, 0, key_expression_size);
}
ll -= key_expression_size; // sizeof(2 ints) and full key length to
// its 4 byte alignment
j = key_expression_size % 4;
if (j > 0)
j = 4 - j; // 4 byte alignment
key_buffer[0] = 0;
for (k = 0; k < j; k++) {
nfile.write(key_buffer[0]);
ll--;
}
} // for i
if ((branch == true) && (lower_level[i] == 0))
throw new xBaseJException(
"Logic mismatch, lower level pointer is zero");
nfile.writeInt(DbaseUtils.x86(lower_level[i]));
ll -= 4; // sizeof(int)
if (ll > 0) {
// a Node is 512 bytes long;
byte temp[] = new byte[ll];
nfile.write(temp, 0, ll);
}
}
public void set_next(Node nxt) {
next = nxt;
}
public void set_prev(Node prv) {
prev = prv;
}
public Node get_next() {
return next;
}
public Node get_prev() {
return prev;
}
public void set_prev_page(int t) throws xBaseJException {
throw new xBaseJException("method not available");
}
public boolean isBranch() {
return branch;
}
}
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