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KDECore

kbufferedio.cpp

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/*
 *  This file is part of the KDE libraries
 *  Copyright (C) 2001 Thiago Macieira <thiago.macieira@kdemail.net>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 */

#include "config.h"

#include <string.h>

#include <qptrlist.h>
#include <qcstring.h>
#include "kbufferedio.h"

// constructor
KBufferedIO::KBufferedIO() :
  inBufIndex(0), outBufIndex(0)
{
  inBuf.setAutoDelete(true);
  outBuf.setAutoDelete(true);
}

// destructor
KBufferedIO::~KBufferedIO()
{
}

// sets the buffer sizes
// this implementation doesn't support setting the buffer sizes
// if any parameter is different than -1 or -2, fail
bool KBufferedIO::setBufferSize(int rsize, int wsize /* = -2 */)
{
  if (wsize != -2 && wsize != -1)
    return false;
  if (rsize != -2 && rsize != -1)
    return false;

  return true;
}

int KBufferedIO::bytesAvailable() const
{
  return readBufferSize();
}

int KBufferedIO::bytesToWrite() const
{
  return writeBufferSize();
}

// This function will scan the read buffer for a '\n'
bool KBufferedIO::canReadLine() const
{
  if (bytesAvailable() == 0)
    return false;       // no new line in here

  QByteArray* buf;

  // scan each QByteArray for the occurrence of '\n'
  QPtrList<QByteArray> &buflist = ((KBufferedIO*)this)->inBuf;
  buf = buflist.first();
  char *p = buf->data() + inBufIndex;
  int n = buf->size() - inBufIndex;
  while (buf != NULL)
    {
      while (n--)
    if (*p++ == '\n')
      return true;
      buf = buflist.next();
      if (buf != NULL)
    {
      p = buf->data();
      n = buf->size();
    }
    }

  return false;         // no new line found
}

// unreads the current data
// that is, writes into the read buffer, at the beginning
int KBufferedIO::unreadBlock(const char *data, uint len)
{
  return feedReadBuffer(len, data, true);
}

//
// protected member functions
//

unsigned KBufferedIO::consumeReadBuffer(unsigned nbytes, char *destbuffer, bool discard)
{
  {
    register unsigned u = readBufferSize();
    if (nbytes > u)
      nbytes = u;       // we can't consume more than there is
  }

  QByteArray *buf;
  unsigned copied = 0;
  unsigned index = inBufIndex;

  buf = inBuf.first();
  while (nbytes && buf)
    {
      // should we copy it all?
      unsigned to_copy = buf->size() - index;
      if (to_copy > nbytes)
    to_copy = nbytes;

      if (destbuffer)
    memcpy(destbuffer + copied, buf->data() + index, to_copy);
      nbytes -= to_copy;
      copied += to_copy;

      if (buf->size() - index > to_copy)
    {
      index += to_copy;
      break;    // we aren't copying everything, that means that's
            // all the user wants
    }
      else
    {
      index = 0;
      if (discard)
        {
          inBuf.remove();
          buf = inBuf.first();
        }
      else
        buf = inBuf.next();
    }
    }

  if (discard)
    inBufIndex = index;

  return copied;
}

void KBufferedIO::consumeWriteBuffer(unsigned nbytes)
{
  QByteArray *buf = outBuf.first();
  if (buf == NULL)
    return;         // nothing to consume

  if (nbytes < buf->size() - outBufIndex)
    // we want to consume less than there is in the first buffer
    outBufIndex += nbytes;
  else
    {
      nbytes -= buf->size() - outBufIndex;
      outBufIndex = 0;
      outBuf.remove();

      while ((buf = outBuf.current()) != NULL)
    if (buf->size() <= nbytes)
      {
        nbytes -= buf->size();
        outBuf.remove();
      }
    else
      {
        outBufIndex = nbytes;
        break;
      }
    }
}

unsigned KBufferedIO::feedReadBuffer(unsigned nbytes, const char *buffer, bool atBeginning)
{
  if (nbytes == 0)
    return 0;

  QByteArray *a = new QByteArray(nbytes);
  a->duplicate(buffer, nbytes);

  if (atBeginning)
    inBuf.prepend(a);
  else
    inBuf.append(a);

  return nbytes;
}

unsigned KBufferedIO::feedWriteBuffer(unsigned nbytes, const char *buffer)
{
  if (nbytes == 0)
    return 0;

  QByteArray *a = new QByteArray(nbytes);
  a->duplicate(buffer, nbytes);
  outBuf.append(a);
  return nbytes;
}

unsigned KBufferedIO::readBufferSize() const
{
  unsigned count = 0;
  QByteArray *buf = ((KBufferedIO*)this)->inBuf.first();
  while (buf != NULL)
    {
      count += buf->size();
      buf = ((KBufferedIO*)this)->inBuf.next();
    }

  return count - inBufIndex;
}

unsigned KBufferedIO::writeBufferSize() const
{
  unsigned count = 0;
  QByteArray *buf = ((KBufferedIO*)this)->outBuf.first();
  while (buf != NULL)
    {
      count += buf->size();
      buf = (const_cast<KBufferedIO*>(this))->outBuf.next();
    }

  return count - outBufIndex;
}

void KBufferedIO::virtual_hook( int id, void* data )
{ KAsyncIO::virtual_hook( id, data ); }

#include "kbufferedio.moc"

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