Qt 5.6 | Qt Network | Torrent Example | bencodeparser.cpp Example File

Qt 5.6.2 Reference Documentation

# bencodeparser.cpp Example File

torrent/bencodeparser.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
      **
      ** This file is part of the examples of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** You may use this file under the terms of the BSD license as follows:
      **
      ** "Redistribution and use in source and binary forms, with or without
      ** modification, are permitted provided that the following conditions are
      ** met:
      **   * Redistributions of source code must retain the above copyright
      **     notice, this list of conditions and the following disclaimer.
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      **     notice, this list of conditions and the following disclaimer in
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      **     contributors may be used to endorse or promote products derived
      **     from this software without specific prior written permission.
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      #include "bencodeparser.h"

      #include <QList>
      #include <QMetaType>

      BencodeParser::BencodeParser()
      {
      }

      bool BencodeParser::parse(const QByteArray &content)
      {
          if (content.isEmpty()) {
              errString = QString("No content");
              return false;
          }

          this->content = content;
          index = 0;
          infoStart = 0;
          infoLength = 0;
          return getDictionary(&dictionaryValue);
      }

      QString BencodeParser::errorString() const
      {
          return errString;
      }

      QMap<QByteArray, QVariant> BencodeParser::dictionary() const
      {
          return dictionaryValue;
      }

      QByteArray BencodeParser::infoSection() const
      {
          return content.mid(infoStart, infoLength);
      }

      bool BencodeParser::getByteString(QByteArray *byteString)
      {
          const int contentSize = content.size();
          int size = -1;
          do {
              char c = content.at(index);
              if (c < '0' || c > '9') {
                  if (size == -1)
                      return false;
                  if (c != ':') {
                      errString = QString("Unexpected character at pos %1: %2")
                              .arg(index).arg(c);
                      return false;
                  }
                  ++index;
                  break;
              }
              if (size == -1)
                  size = 0;
              size *= 10;
              size += c - '0';
          } while (++index < contentSize);

          if (byteString)
              *byteString = content.mid(index, size);
          index += size;
          return true;
      }

      bool BencodeParser::getInteger(qint64 *integer)
      {
          const int contentSize = content.size();
          if (content.at(index) != 'i')
              return false;

          ++index;
          qint64 num = -1;
          bool negative = false;

          do {
              char c = content.at(index);
              if (c < '0' || c > '9') {
                  if (num == -1) {
                      if (c != '-' || negative)
                          return false;
                      negative = true;
                      continue;
                  } else {
                      if (c != 'e') {
                          errString = QString("Unexpected character at pos %1: %2")
                                  .arg(index).arg(c);
                          return false;
                      }
                      ++index;
                      break;
                  }
              }
              if (num == -1)
                  num = 0;
              num *= 10;
              num += c - '0';
          } while (++index < contentSize);

          if (integer)
              *integer = negative ? -num : num;
          return true;
      }

      bool BencodeParser::getList(QList<QVariant> *list)
      {
          const int contentSize = content.size();
          if (content.at(index) != 'l')
              return false;

          QList<QVariant> tmp;
          ++index;

          do {
              if (content.at(index) == 'e') {
                  ++index;
                  break;
              }

              qint64 number;
              QByteArray byteString;
              QList<QVariant> tmpList;
              QMap<QByteArray, QVariant> dictionary;

              if (getInteger(&number))
                  tmp << number;
              else if (getByteString(&byteString))
                  tmp << byteString;
              else if (getList(&tmpList))
                  tmp << tmpList;
              else if (getDictionary(&dictionary))
                  tmp << QVariant::fromValue<QMap<QByteArray, QVariant> >(dictionary);
              else {
                  errString = QString("error at index %1").arg(index);
                  return false;
              }
          } while (index < contentSize);

          if (list)
              *list = tmp;
          return true;
      }

      bool BencodeParser::getDictionary(QMap<QByteArray, QVariant> *dictionary)
      {
          const int contentSize = content.size();
          if (content.at(index) != 'd')
              return false;

          QMap<QByteArray, QVariant> tmp;
          ++index;

          do {
              if (content.at(index) == 'e') {
                  ++index;
                  break;
              }

              QByteArray key;
              if (!getByteString(&key))
                  break;

              if (key == "info")
                  infoStart = index;

              qint64 number;
              QByteArray byteString;
              QList<QVariant> tmpList;
              QMap<QByteArray, QVariant> dictionary;

              if (getInteger(&number))
                  tmp.insert(key, number);
              else if (getByteString(&byteString))
                  tmp.insert(key, byteString);
              else if (getList(&tmpList))
                  tmp.insert(key, tmpList);
              else if (getDictionary(&dictionary))
                  tmp.insert(key, QVariant::fromValue<QMap<QByteArray, QVariant> >(dictionary));
              else {
                  errString = QString("error at index %1").arg(index);
                  return false;
              }

              if (key == "info")
                  infoLength = index - infoStart;

          } while (index < contentSize);

          if (dictionary)
              *dictionary = tmp;
          return true;
      }