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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 << qVariantFromValue<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, qVariantFromValue<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;

}