// BDecoder.java
// -----------------------
// part of YaCy
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://www.anomic.de
// Frankfurt, Germany, 2010
// Created 03.01.2010
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// this is an BDecoder implementation according to http://wiki.theory.org/BitTorrentSpecification
//
// 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.util;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import net.yacy.cora.document.encoding.ASCII;
import net.yacy.cora.document.encoding.UTF8;
public class BDecoder {
private final static byte[] _e = "e".getBytes();
private final static byte[] _i = "i".getBytes();
private final static byte[] _d = "d".getBytes();
private final static byte[] _l = "l".getBytes();
private final static byte[] _p = ":".getBytes();
private final byte[] b;
private int pos;
public BDecoder(byte[] b) {
this.b = b;
this.pos = 0;
}
public static enum BType {
string, integer, list, dictionary;
}
public static interface BObject {
public BType getType();
public byte[] getString();
public long getInteger();
public List<BObject> getList();
public Map<String, BObject> getMap();
@Override
public String toString();
public void toStream(OutputStream os) throws IOException;
}
private static abstract class BDfltObject implements BObject {
@Override
public long getInteger() {
throw new UnsupportedOperationException();
}
@Override
public List<BObject> getList() {
throw new UnsupportedOperationException();
}
@Override
public Map<String, BObject> getMap() {
throw new UnsupportedOperationException();
}
@Override
public byte[] getString() {
throw new UnsupportedOperationException();
}
@Override
public BType getType() {
throw new UnsupportedOperationException();
}
@Override
public String toString() {
throw new UnsupportedOperationException();
}
}
public static class BStringObject extends BDfltObject implements BObject {
private byte[] b;
public BStringObject(byte[] b) {
this.b = b;
}
@Override
public BType getType() {
return BType.string;
}
@Override
public byte[] getString() {
return this.b;
}
@Override
public String toString() {
return UTF8.String(this.b);
}
@Override
public void toStream(OutputStream os) throws IOException {
os.write(ASCII.getBytes(Integer.toString(this.b.length)));
os.write(_p);
os.write(this.b);
}
private static void toStream(OutputStream os, byte[] b) throws IOException {
os.write(ASCII.getBytes(Integer.toString(b.length)));
os.write(_p);
os.write(b);
}
private static void toStream(OutputStream os, String s) throws IOException {
final byte[] b = UTF8.getBytes(s);
os.write(ASCII.getBytes(Integer.toString(b.length)));
os.write(_p);
os.write(b);
}
}
public static class BListObject extends BDfltObject implements BObject {
private List<BObject> l;
public BListObject(List<BObject> l) {
this.l = l;
}
@Override
public BType getType() {
return BType.list;
}
@Override
public List<BObject> getList() {
return this.l;
}
@Override
public String toString() {
StringBuilder s = new StringBuilder(l.size() * 40 + 1);
s.append("[");
for (final BObject o: l) s.append(o.toString()).append(",");
s.setLength(s.length() - 1);
s.append("]");
return s.toString();
}
@Override
public void toStream(OutputStream os) throws IOException {
os.write(_l);
for (final BObject bo: this.l) bo.toStream(os);
os.write(_e);
}
}
public static class BDictionaryObject extends BDfltObject implements BObject {
private Map<String, BObject> m;
public BDictionaryObject(Map<String, BObject> m) {
this.m = m;
}
@Override
public BType getType() {
return BType.dictionary;
}
@Override
public Map<String, BObject> getMap() {
return this.m;
}
@Override
public String toString() {
StringBuilder s = new StringBuilder(m.size() * 40 + 1);
s.append('{');
for (final Map.Entry<String, BObject> e: m.entrySet()) s.append(e.getKey()).append(':').append(e.getValue().toString()).append(',');
s.setLength(s.length() - 1);
s.append('}');
return s.toString();
}
@Override
public void toStream(OutputStream os) throws IOException {
os.write(_d);
for (final Map.Entry<String, BObject> e: this.m.entrySet()) {
BStringObject.toStream(os, e.getKey());
e.getValue().toStream(os);
}
os.write(_e);
}
public static void toStream(OutputStream os, String key, byte[] value) throws IOException {
os.write(_d);
BStringObject.toStream(os, key);
BStringObject.toStream(os, value);
os.write(_e);
}
}
public static class BIntegerObject extends BDfltObject implements BObject {
private long i;
private BIntegerObject(long i) {
this.i = i;
}
@Override
public BType getType() {
return BType.integer;
}
@Override
public long getInteger() {
return this.i;
}
@Override
public String toString() {
return Long.toString(this.i);
}
@Override
public void toStream(OutputStream os) throws IOException {
os.write(_i);
os.write(ASCII.getBytes(Long.toString(this.i)));
os.write(_e);
}
}
private Map<String, BObject> convertToMap(final List<BObject> list) {
final Map<String, BObject> m = new LinkedHashMap<String, BObject>();
final int length = list.size();
byte[] key;
BObject value;
for (int i = 0; i < length; i += 2) {
key = list.get(i).getString();
value = null;
if (i + 1 < length) {
value = list.get(i + 1);
}
m.put(UTF8.String(key), value);
}
return m;
}
private List<BObject> readList() {
final List<BObject> list = new ArrayList<BObject>();
char ch = (char) b[pos];
BObject bo;
while (ch != 'e') {
bo = parse();
if (bo == null) {pos++; break;}
list.add(bo);
ch = (char) b[pos];
}
pos++;
return list;
}
public BObject parse() {
if (pos >= b.length) return null;
char ch = (char) b[pos];
if ((ch >= '0') && (ch <= '9')) {
int end = pos;
end++;
while (b[end] != ':') ++end;
final int len = Integer.parseInt(ASCII.String(b, pos, end - pos));
final byte[] s = new byte[len];
System.arraycopy(b, end + 1, s, 0, len);
pos = end + len + 1;
return new BStringObject(s);
} else if (ch == 'l') {
pos++;
return new BListObject(readList());
} else if (ch == 'd') {
pos++;
return new BDictionaryObject(convertToMap(readList()));
} else if (ch == 'i') {
pos++;
int end = pos;
while (b[end] != 'e') ++end;
BIntegerObject io = new BIntegerObject(Long.parseLong(UTF8.String(b, pos, end - pos)));
pos = end + 1;
return io;
} else {
return null;
}
}
private static void print(BObject bo, int t) {
for (int i = 0; i < t; i++) System.out.print(" ");
if (bo.getType() == BType.integer) System.out.println(bo.getInteger());
if (bo.getType() == BType.string) System.out.println(bo.getString());
if (bo.getType() == BType.list) {
System.out.println("[");
//for (int i = 0; i < t + 1; i++) System.out.print(" ");
for (final BObject o: bo.getList()) print(o, t + 1);
for (int i = 0; i < t; i++) System.out.print(" ");
System.out.println("]");
}
if (bo.getType() == BType.dictionary) {
System.out.println("{");
for (final Map.Entry<String, BObject> e: bo.getMap().entrySet()) {
for (int i = 0; i < t + 1; i++) System.out.print(" ");
System.out.print(e.getKey());
System.out.println(":");
print(e.getValue(), t + 2);
}
for (int i = 0; i < t; i++) System.out.print(" ");
System.out.println("}");
}
}
public static void main(String[] args) {
try {
byte[] b = FileUtils.read(new File(args[0]));
BDecoder bdecoder = new BDecoder(b);
BObject o = bdecoder.parse();
print(o, 0);
System.out.println("Object: " + o.toString());
} catch (final IOException e) {
e.printStackTrace();
}
}
}