qbuffer.cpp

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/****************************************************************************
** $Id: qbuffer.cpp,v 1.2 2003/07/10 02:40:11 llornkcor Exp $
**
** Implementation of QBuffer class
**
** Created : 930812
**
** Copyright (C) 1992-2002 Trolltech AS.  All rights reserved.
**
** This file is part of the tools module of the Qt GUI Toolkit.
**
** This file may be distributed under the terms of the Q Public License
** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.QPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** Licensees holding valid Qt Enterprise Edition or Qt Professional Edition
** licenses may use this file in accordance with the Qt Commercial License
** Agreement provided with the Software.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
**   information about Qt Commercial License Agreements.
** See http://www.trolltech.com/qpl/ for QPL licensing information.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
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**********************************************************************/

#include "qbuffer.h"
#include <stdlib.h>

QBuffer::QBuffer()
{
    setFlags( IO_Direct );
    a_inc = 16;                                 // initial increment
    a_len = 0;
    ioIndex = 0;
}


QBuffer::QBuffer( QByteArray buf ) : a(buf)
{
    setFlags( IO_Direct );
    a_len = a.size();
    a_inc = (a_len > 512) ? 512 : a_len;        // initial increment
    if ( a_inc < 16 )
        a_inc = 16;
    ioIndex = 0;
}

QBuffer::~QBuffer()
{
}


bool QBuffer::setBuffer( QByteArray buf )
{
    if ( isOpen() ) {
#if defined(QT_CHECK_STATE)
        qWarning( "QBuffer::setBuffer: Buffer is open" );
#endif
        return FALSE;
    }
    a = buf;
    a_len = a.size();
    a_inc = (a_len > 512) ? 512 : a_len;        // initial increment
    if ( a_inc < 16 )
        a_inc = 16;
    ioIndex = 0;
    return TRUE;
}

bool QBuffer::open( int m  )
{
    if ( isOpen() ) {                           // buffer already open
#if defined(QT_CHECK_STATE)
        qWarning( "QBuffer::open: Buffer already open" );
#endif
        return FALSE;
    }
    setMode( m );
    if ( m & IO_Truncate ) {                    // truncate buffer
        a.resize( 1 );
        a_len = 1;
    }
    if ( m & IO_Append ) {                      // append to end of buffer
        ioIndex = a.size();
    } else {
        ioIndex = 0;
    }
    a_inc = 16;
    setState( IO_Open );
    setStatus( 0 );
    return TRUE;
}

void QBuffer::close()
{
    if ( isOpen() ) {
        setFlags( IO_Direct );
        ioIndex = 0;
        a_inc = 16;
    }
}

void QBuffer::flush()
{
    return;
}


bool QBuffer::at( Offset pos )
{
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {
        qWarning( "QBuffer::at: Buffer is not open" );
        return FALSE;
    }
#endif
    if ( pos > a_len ) {
#if defined(QT_CHECK_RANGE)
#if defined(QT_LARGEFILE_SUPPORT) && defined(QT_ABI_64BITOFFSET)
        qWarning( "QBuffer::at: Index %llu out of range", pos );
#else
        qWarning( "QBuffer::at: Index %lu out of range", pos );
#endif
#endif
        return FALSE;
    }
    ioIndex = pos;
    return TRUE;
}


Q_LONG QBuffer::readBlock( char *p, Q_ULONG len )
{
#if defined(QT_CHECK_STATE)
    if ( !p ) {
        qWarning( "QBuffer::readBlock: Null pointer error" );
        return -1;
    }
    if ( !isOpen() ) {                          // buffer not open
        qWarning( "QBuffer::readBlock: Buffer not open" );
        return -1;
    }
    if ( !isReadable() ) {                      // reading not permitted
        qWarning( "QBuffer::readBlock: Read operation not permitted" );
        return -1;
    }
#endif
    if ( ioIndex + len > a.size() ) {   // overflow
        if ( ioIndex >= a.size() ) {
            return 0;
        } else {
            len = a.size() - ioIndex;
        }
    }
    memcpy( p, a.data()+ioIndex, len );
    ioIndex += len;
    return len;
}

Q_LONG QBuffer::writeBlock( const char *p, Q_ULONG len )
{
    if ( len == 0 )
        return 0;

#if defined(QT_CHECK_NULL)
    if ( p == 0 ) {
        qWarning( "QBuffer::writeBlock: Null pointer error" );
        return -1;
    }
#endif
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {                          // buffer not open
        qWarning( "QBuffer::writeBlock: Buffer not open" );
        return -1;
    }
    if ( !isWritable() ) {                      // writing not permitted
        qWarning( "QBuffer::writeBlock: Write operation not permitted" );
        return -1;
    }
#endif
    if ( ioIndex + len >= a_len ) {             // overflow
        Q_ULONG new_len = a_len + a_inc*((ioIndex+len-a_len)/a_inc+1);
        if ( !a.resize( new_len ) ) {           // could not resize
#if defined(QT_CHECK_NULL)
            qWarning( "QBuffer::writeBlock: Memory allocation error" );
#endif
            setStatus( IO_ResourceError );
            return -1;
        }
        a_inc *= 2;                             // double increment
        a_len = new_len;
        a.shd->len = ioIndex + len;
    }
    memcpy( a.data()+ioIndex, p, len );
    ioIndex += len;
    if ( a.shd->len < ioIndex )
        a.shd->len = ioIndex;                   // fake (not alloc'd) length
    return len;
}


Q_LONG QBuffer::readLine( char *p, Q_ULONG maxlen )
{
#if defined(QT_CHECK_NULL)
    if ( p == 0 ) {
        qWarning( "QBuffer::readLine: Null pointer error" );
        return -1;
    }
#endif
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {                          // buffer not open
        qWarning( "QBuffer::readLine: Buffer not open" );
        return -1;
    }
    if ( !isReadable() ) {                      // reading not permitted
        qWarning( "QBuffer::readLine: Read operation not permitted" );
        return -1;
    }
#endif
    if ( maxlen == 0 )
        return 0;
    Q_ULONG start = ioIndex;
    char *d = a.data() + ioIndex;
    maxlen--;                                   // make room for 0-terminator
    if ( a.size() - ioIndex < maxlen )
        maxlen = a.size() - ioIndex;
    while ( maxlen-- ) {
        if ( (*p++ = *d++) == '\n' )
            break;
    }
    *p = '\0';
    ioIndex = d - a.data();
    return ioIndex - start;
}


int QBuffer::getch()
{
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {                          // buffer not open
        qWarning( "QBuffer::getch: Buffer not open" );
        return -1;
    }
    if ( !isReadable() ) {                      // reading not permitted
        qWarning( "QBuffer::getch: Read operation not permitted" );
        return -1;
    }
#endif
    if ( ioIndex+1 > a.size() ) {               // overflow
        setStatus( IO_ReadError );
        return -1;
    }
    return uchar(*(a.data()+ioIndex++));
}

int QBuffer::putch( int ch )
{
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {                          // buffer not open
        qWarning( "QBuffer::putch: Buffer not open" );
        return -1;
    }
    if ( !isWritable() ) {                      // writing not permitted
        qWarning( "QBuffer::putch: Write operation not permitted" );
        return -1;
    }
#endif
    if ( ioIndex + 1 >= a_len ) {               // overflow
        char buf[1];
        buf[0] = (char)ch;
        if ( writeBlock(buf,1) != 1 )
            return -1;                          // write error
    } else {
        *(a.data() + ioIndex++) = (char)ch;
        if ( a.shd->len < ioIndex )
            a.shd->len = ioIndex;
    }
    return ch;
}

int QBuffer::ungetch( int ch )
{
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {                          // buffer not open
        qWarning( "QBuffer::ungetch: Buffer not open" );
        return -1;
    }
    if ( !isReadable() ) {                      // reading not permitted
        qWarning( "QBuffer::ungetch: Read operation not permitted" );
        return -1;
    }
#endif
    if ( ch != -1 ) {
        if ( ioIndex )
            ioIndex--;
        else
            ch = -1;
    }
    return ch;
}

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