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ktorrent/libktorrent/torrent/bdecoder.cpp

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/***************************************************************************
* Copyright (C) 2005 by Joris Guisson *
* joris.guisson@gmail.com *
* *
* 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., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#include <util/log.h>
#include <util/error.h>
#include <klocale.h>
#include "bdecoder.h"
#include "bnode.h"
#include "globals.h"
namespace bt
{
BDecoder::BDecoder(const TQByteArray & data,bool verbose,Uint32 off)
: data(data),pos(off),verbose(verbose)
{
}
BDecoder::~BDecoder()
{}
BNode* BDecoder::decode()
{
if (pos >= data.size())
return 0;
if (data[pos] == 'd')
{
return parseDict();
}
else if (data[pos] == 'l')
{
return parseList();
}
else if (data[pos] == 'i')
{
return parseInt();
}
else if (data[pos] >= '0' && data[pos] <= '9')
{
return parseString();
}
else
{
throw Error(i18n("Illegal token: %1").arg(data[pos]));
}
}
BDictNode* BDecoder::parseDict()
{
Uint32 off = pos;
// we're now entering a dictionary
BDictNode* curr = new BDictNode(off);
pos++;
if (verbose) Out() << "DICT" << endl;
try
{
while (pos < data.size() && data[pos] != 'e')
{
if (verbose) Out() << "Key : " << endl;
BNode* kn = decode();
BValueNode* k = dynamic_cast<BValueNode*>(kn);
if (!k || k->data().getType() != Value::STRING)
{
delete kn;
throw Error(i18n("Decode error"));
}
TQByteArray key = k->data().toByteArray();
delete kn;
BNode* data = decode();
curr->insert(key,data);
}
pos++;
}
catch (...)
{
delete curr;
throw;
}
if (verbose) Out() << "END" << endl;
curr->setLength(pos - off);
return curr;
}
BListNode* BDecoder::parseList()
{
Uint32 off = pos;
if (verbose) Out() << "LIST" << endl;
BListNode* curr = new BListNode(off);
pos++;
try
{
while (pos < data.size() && data[pos] != 'e')
{
BNode* n = decode();
curr->append(n);
}
pos++;
}
catch (...)
{
delete curr;
throw;
}
if (verbose) Out() << "END" << endl;
curr->setLength(pos - off);
return curr;
}
BValueNode* BDecoder::parseInt()
{
Uint32 off = pos;
pos++;
TQString n;
// look for e and add everything between i and e to n
while (pos < data.size() && data[pos] != 'e')
{
n += data[pos];
pos++;
}
// check if we aren't at the end of the data
if (pos >= data.size())
{
throw Error(i18n("Unexpected end of input"));
}
// try to decode the int
bool ok = true;
int val = 0;
val = n.toInt(&ok);
if (ok)
{
pos++;
if (verbose) Out() << "INT = " << val << endl;
BValueNode* vn = new BValueNode(Value(val),off);
vn->setLength(pos - off);
return vn;
}
else
{
Int64 bi = 0LL;
bi = n.toLongLong(&ok);
if (!ok)
throw Error(i18n("Cannot convert %1 to an int").arg(n));
pos++;
if (verbose) Out() << "INT64 = " << n << endl;
BValueNode* vn = new BValueNode(Value(bi),off);
vn->setLength(pos - off);
return vn;
}
}
BValueNode* BDecoder::parseString()
{
Uint32 off = pos;
// string are encoded 4:spam (length:string)
// first get length by looking for the :
TQString n;
while (pos < data.size() && data[pos] != ':')
{
n += data[pos];
pos++;
}
// check if we aren't at the end of the data
if (pos >= data.size())
{
throw Error(i18n("Unexpected end of input"));
}
// try to decode length
bool ok = true;
int len = 0;
len = n.toInt(&ok);
if (!ok)
{
throw Error(i18n("Cannot convert %1 to an int").arg(n));
}
// move pos to the first part of the string
pos++;
if (pos + len > data.size())
throw Error(i18n("Torrent is incomplete!"));
TQByteArray arr(len);
for (unsigned int i = pos;i < pos + len;i++)
arr.at(i-pos) = data[i];
pos += len;
// read the string into n
// pos should be positioned right after the string
BValueNode* vn = new BValueNode(Value(arr),off);
vn->setLength(pos - off);
if (verbose)
{
if (arr.size() < 200)
Out() << "STRING " << TQString(arr) << endl;
else
Out() << "STRING " << "really long string" << endl;
}
return vn;
}
}