bencodeparser.cpp Example File

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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;
  }