qgarray.cpp

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/****************************************************************************
** $Id: qt/src/tools/qgarray.cpp   2.2.3   edited 2000-08-25 $
**
** Implementation of QGArray class
**
** Created : 930906
**
** Copyright (C) 1992-2000 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 [e-mail] 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 [e-mail] if any conditions of this licensing are
** not clear to you.
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**********************************************************************/

#define	 QGARRAY_CPP
#include "qgarray.h"
#include "qstring.h"
#include <stdlib.h>

#define USE_MALLOC				// comment to use new/delete

#undef NEW
#undef DELETE

#if defined(USE_MALLOC)
#define NEW(type,size)	((type*)malloc(size*sizeof(type)))
#define DELETE(array)	(free((char*)array))
#else
#define NEW(type,size)	(new type[size])
#define DELETE(array)	(delete[] array)
#define DONT_USE_REALLOC			// comment to use realloc()
#endif


// NOT REVISED
/*!
  \class QShared qshared.h
  \brief The QShared struct is internally used for implementing shared classes.

  It only contains a reference count and member functions to increment and
  decrement it.

  Shared classes normally have internal classes that inherit QShared and
  add the shared data.

  \sa \link shclass.html Shared Classes\endlink
*/


/*!
  \class QGArray qgarray.h
  \brief The QGArray class is an internal class for implementing the QArray class.

  QGArray is a strictly internal class that acts as base class for the
  QArray template array.

  It contains an array of bytes and has no notion of an array element.
*/


/*!
  \internal
  Constructs a null array.
*/

QGArray::QGArray()
{
    shd = newData();
    CHECK_PTR( shd );
}

/*!
  \internal
  Dummy constructor; does not allocate any data.

  This constructor does not initialize any array data so subclasses
  must do it. The intention is to make the code more efficient.
*/

QGArray::QGArray( int, int )
{
}

/*!
  \internal
  Constructs an array with room for \e size bytes.
*/

QGArray::QGArray( int size )
{
    if ( size < 0 ) {
#if defined(CHECK_RANGE)
	qWarning( "QGArray: Cannot allocate array with negative length" );
#endif
	size = 0;
    }
    shd = newData();
    CHECK_PTR( shd );
    if ( size == 0 )				// zero length
	return;
    shd->data = NEW(char,size);
    CHECK_PTR( shd->data );
    shd->len = size;
}

/*!
  \internal
  Constructs a shallow copy of \e a.
*/

QGArray::QGArray( const QGArray &a )
{
    shd = a.shd;
    shd->ref();
}

/*!
  \internal
  Dereferences the array data and deletes it if this was the last
  reference.
*/

QGArray::~QGArray()
{
    if ( shd && shd->deref() ) {		// delete when last reference
	if ( shd->data )			// is lost
	    DELETE(shd->data);
	deleteData( shd );
    }
}


/*!
  \fn QGArray &QGArray::operator=( const QGArray &a )
  \internal
  Assigns a shallow copy of \e a to this array and returns a reference to
  this array.  Equivalent to assign().
*/

/*!
  \fn void QGArray::detach()
  \internal
  Detaches this array from shared array data.
*/

/*!
  \fn char *QGArray::data() const
  \internal
  Returns a pointer to the actual array data.
*/

/*!
  \fn uint QGArray::nrefs() const
  \internal
  Returns the reference count.
*/

/*!
  \fn uint QGArray::size() const
  \internal
  Returns the size of the array, in bytes.
*/


/*!
  \internal
  Returns TRUE if this array is equal to \e a, otherwise FALSE.
  The comparison is bitwise, of course.
*/

bool QGArray::isEqual( const QGArray &a ) const
{
    if ( size() != a.size() )			// different size
	return FALSE;
    if ( data() == a.data() )			// has same data
	return TRUE;
    return (size() ? memcmp( data(), a.data(), size() ) : 0) == 0;
}


/*!
  \internal
  Resizes the array to \e newsize bytes.
*/

bool QGArray::resize( uint newsize )
{
    if ( newsize == shd->len )			// nothing to do
	return TRUE;
    if ( newsize == 0 ) {			// remove array
	duplicate( 0, 0 );
	return TRUE;
    }
    if ( shd->data ) {				// existing data
#if defined(DONT_USE_REALLOC)
	char *newdata = NEW(char,newsize);	// manual realloc
	memcpy( newdata, shd->data, QMIN(shd->len,newsize) );
	DELETE(shd->data);
	shd->data = newdata;
#else
	shd->data = (char *)realloc( shd->data, newsize );
#endif
    } else {
	shd->data = NEW(char,newsize);
    }
    CHECK_PTR( shd->data );
    if ( !shd->data )				// no memory
	return FALSE;
    shd->len = newsize;
    return TRUE;
}

/*!
  \internal
  Fills the array with the repeated occurrences of \e d, which is
  \e sz bytes long.
  If \e len is specified as different from -1, then the array will be
  resized to \e len*sz before it is filled.

  Returns TRUE if successful, or FALSE if the memory cannot be allocated
  (only when \e len != -1).

  \sa resize()
*/

bool QGArray::fill( const char *d, int len, uint sz )
{
    if ( len < 0 )
	len = shd->len/sz;			// default: use array length
    else if ( !resize( len*sz ) )
	return FALSE;
    if ( sz == 1 )				// 8 bit elements
	memset( data(), *d, len );
    else if ( sz == 4 ) {			// 32 bit elements
	register Q_INT32 *x = (Q_INT32*)data();
	Q_INT32 v = *((Q_INT32*)d);
	while ( len-- )
	    *x++ = v;
    } else if ( sz == 2 ) {			// 16 bit elements
	register Q_INT16 *x = (Q_INT16*)data();
	Q_INT16 v = *((Q_INT16*)d);
	while ( len-- )
	    *x++ = v;
    } else {					// any other size elements
	register char *x = data();
	while ( len-- ) {			// more complicated
	    memcpy( x, d, sz );
	    x += sz;
	}
    }
    return TRUE;
}

/*!
  \internal
  Shallow copy. Dereference the current array and references the data
  contained in \e a instead. Returns a reference to this array.
  \sa operator=()
*/

QGArray &QGArray::assign( const QGArray &a )
{
    a.shd->ref();				// avoid 'a = a'
    if ( shd->deref() ) {			// delete when last reference
	if ( shd->data )			// is lost
	    DELETE(shd->data);
	deleteData( shd );
    }
    shd = a.shd;
    return *this;
}

/*!
  \internal
  Shallow copy. Dereference the current array and references the
  array data \e d, which contains \e len bytes.
  Returns a reference to this array.

  Do not delete \e d later, because QGArray takes care of that.
*/

QGArray &QGArray::assign( const char *d, uint len )
{
    if ( shd->count > 1 ) {			// disconnect this
	shd->count--;
	shd = newData();
	CHECK_PTR( shd );
    } else {
	if ( shd->data )
	    DELETE(shd->data);
    }
    shd->data = (char *)d;
    shd->len = len;
    return *this;
}

/*!
  \internal
  Deep copy. Dereference the current array and obtains a copy of the data
  contained in \e a instead. Returns a reference to this array.
  \sa assign(), operator=()
*/

QGArray &QGArray::duplicate( const QGArray &a )
{
    if ( a.shd == shd ) {			// a.duplicate(a) !
	if ( shd->count > 1 ) {
	    shd->count--;
	    register array_data *n = newData();
	    CHECK_PTR( n );
	    if ( (n->len=shd->len) ) {
		n->data = NEW(char,n->len);
		CHECK_PTR( n->data );
		if ( n->data )
		    memcpy( n->data, shd->data, n->len );
	    } else {
		n->data = 0;
	    }
	    shd = n;
	}
	return *this;
    }
    char *oldptr = 0;
    if ( shd->count > 1 ) {			// disconnect this
	shd->count--;
	shd = newData();
	CHECK_PTR( shd );
    } else {					// delete after copy was made
	oldptr = shd->data;
    }
    if ( a.shd->len ) {				// duplicate data
	shd->data = NEW(char,a.shd->len);
	CHECK_PTR( shd->data );
	if ( shd->data )
	    memcpy( shd->data, a.shd->data, a.shd->len );
    } else {
	shd->data = 0;
    }
    shd->len = a.shd->len;
    if ( oldptr )
	DELETE(oldptr);
    return *this;
}

/*!
  \internal
  Deep copy. Dereferences the current array and obtains a copy of the
  array data \e d instead.  Returns a reference to this array.
  \sa assign(), operator=()
*/