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#include "q3membuf_p.h"

QT_BEGIN_NAMESPACE

// *******************************************************************

// QMembuf declaration and implementation

// *******************************************************************

/*  \internal

    This class implements an efficient buffering of data that is often used by

    asynchronous IO classes like QSocket, QHttp and QProcess.

*/

Q3Membuf::Q3Membuf() : _size(0), _index(0)

{

}

Q3Membuf::~Q3Membuf()

{

    while (!buf.isEmpty())

        delete buf.takeFirst();

}

/*! \internal

    This function consumes \a nbytes bytes of data from the

    buffer and copies it into \a sink. If \a sink is a 0 pointer

    the data goes into the nirvana.

*/

bool Q3Membuf::consumeBytes(Q_ULONG nbytes, char *sink)

{

    if (nbytes <= 0 || (qint64)nbytes > _size)

        return false;

    _size -= nbytes;

    while (!buf.isEmpty()) {

        QByteArray *a = buf.first();

        if ((int)(_index + nbytes) >= a->size()) {

            // Here we skip the whole byte array and get the next later

            int len = a->size() - _index;

            if (sink) {

                memcpy(sink, a->constData()+_index, len);

                sink += len;

            }

            nbytes -= len;

            buf.removeFirst();

	    delete a;

            _index = 0;

            if (nbytes == 0)

                break;

        } else {

            // Here we skip only a part of the first byte array

            if (sink)

                memcpy(sink, a->constData()+_index, nbytes);

            _index += nbytes;

            break;

        }

    }

    return true;

}

/*! \internal

    Scans for any occurrence of '\n' in the buffer. If \a store

    is not 0 the text up to the first '\n' (or terminating 0) is

    written to \a store, and a terminating 0 is appended to \a store

    if necessary. Returns true if a '\n' was found; otherwise returns

    false.

*/

bool Q3Membuf::scanNewline(QByteArray *store)

{

    if (_size == 0)

        return false;

    int i = 0; // index into 'store'

    QByteArray *a = 0;

    char *p;

    int n;

    bool retval = false;

    for (int j = 0; j < buf.size(); ++j) {

        a = buf.at(j);

        p = a->data();

        n = a->size();

        if (!j) {

            // first buffer

            p += _index;

            n -= _index;

        }

        if (store) {

            while (n-- > 0) {

                *(store->data()+i) = *p;

                if (++i == (int)store->size())

                    store->resize(store->size() < 256

                                   ? 1024 : store->size()*4);

                if (*p == '\n') {

                    retval = true;

                    goto end;

                }

                p++;

            }

        } else {

            while (n-- > 0) {

                if(*p == '\n')

                    return true;

                p++;

            }

        }

    }

 end:

    if (store)

        store->resize(i);

    return retval;

}

int Q3Membuf::ungetch(int ch)

{

    if (buf.isEmpty() || _index==0) {

        // we need a new QByteArray

        QByteArray *ba = new QByteArray;

        ba->resize(1);

        buf.prepend(ba);

        _size++;

        (*ba)[0] = ch;

    } else {

        // we can reuse a place in the buffer

        QByteArray *ba = buf.first();

        _index--;

        _size++;

        (*ba)[(int)_index] = ch;

    }

    return ch;

}

QT_END_NAMESPACE