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

** 

**

** 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.

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** as defined by Trolltech AS of Norway and appearing in the file

** LICENSE.QPL included in the packaging of this file.

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** This file may be distributed and/or modified under the terms of the

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** Foundation and appearing in the file LICENSE.GPL included in the

** packaging of this file.

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** licenses may use this file in accordance with the Qt Commercial License

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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=()

*/

QGArray &QGArray::duplicate( const char *d, uint len )

{

    char *data;

    if ( d == 0 || len == 0 ) {

	data = 0;

	len  = 0;

    } else {

	if ( shd->count == 1 && shd->len == len ) {

	    memcpy( shd->data, d, len );	// use same buffer

	    return *this;

	}

	data = NEW(char,len);

	CHECK_PTR( data );

	memcpy( data, d, len );

    }

    if ( shd->count > 1 ) {			// detach

	shd->count--;

	shd = newData();

	CHECK_PTR( shd );

    } else {					// just a single reference

	if ( shd->data )

	    DELETE(shd->data);

    }

    shd->data = data;

    shd->len  = len;

    return *this;

}

/*!

  \internal

  Resizes this array to \e len bytes and copies the \e len bytes at

  address \e into it.

  \warning This function disregards the reference count mechanism.  If

  other QGArrays reference the same data as this, all will be updated.

*/

void QGArray::store( const char *d, uint len )

{						// store, but not deref

    resize( len );

    memcpy( shd->data, d, len );

}

/*!

  \fn array_data *QGArray::sharedBlock() const

  \internal

  Returns a pointer to the shared array block.

  \warning

  Do not use this function.  Using it is begging for trouble.  We dare

  not remove it, for fear of breaking code, but we \e strongly

  discourage new use of it.

*/

/*!

  \fn void QGArray::setSharedBlock( array_data *p )

  \internal

  Sets the shared array block to \e p.

  \warning

  Do not use this function.  Using it is begging for trouble.  We dare

  not remove it, for fear of breaking code, but we \e strongly

  discourage new use of it.

*/

/*!

  \internal

  Sets raw data and returns a reference to the array.

  Dereferences the current array and sets the new array data to \e d and

  the new array size to \e len.	 Do not attempt to resize or re-assign the

  array data when raw data has been set.

  Call resetRawData(d,len) to reset the array.

  Setting raw data is useful because it set QArray data without allocating

  memory or copying data.

  Example of intended use:

  \code

    static uchar bindata[] = { 231, 1, 44, ... };

    QByteArray	a;

    a.setRawData( bindata, sizeof(bindata) );	// a points to bindata

    QDataStream s( a, IO_ReadOnly );		// open on a's data

    s >> <something>;				// read raw bindata

    s.close();

    a.resetRawData( bindata, sizeof(bindata) ); // finished

  \endcode

  Example of misuse (do not do this):

  \code

    static uchar bindata[] = { 231, 1, 44, ... };

    QByteArray	a, b;

    a.setRawData( bindata, sizeof(bindata) );	// a points to bindata

    a.resize( 8 );				// will crash

    b = a;					// will crash

    a[2] = 123;					// might crash

      // forget to resetRawData - will crash

  \endcode

  \warning If you do not call resetRawData(), QGArray will attempt to

  deallocate or reallocate the raw data, which might not be too good.

  Be careful.

*/

QGArray &QGArray::setRawData( const char *d, uint len )

{

    duplicate( 0, 0 );				// set null data

    shd->data = (char *)d;

    shd->len  = len;

    return *this;

}

/*!

  \internal

  Resets raw data.

  The arguments must be the data and length that were passed to

  setRawData().  This is for consistency checking.

*/

void QGArray::resetRawData( const char *d, uint len )

{

    if ( d != shd->data || len != shd->len ) {

#if defined(CHECK_STATE)

	qWarning( "QGArray::resetRawData: Inconsistent arguments" );

#endif

	return;

    }

    shd->data = 0;

    shd->len  = 0;

}

/*!

  \internal

  Finds the first occurrence of \e d in the array from position \e index,

  where \e sz is the size of the \e d element.

  Note that \e index is given in units of \e sz, not bytes.

  This function only compares whole cells, not bytes.

*/

int QGArray::find( const char *d, uint index, uint sz ) const

{

    index *= sz;

    if ( index >= shd->len ) {

#if defined(CHECK_RANGE)

	qWarning( "QGArray::find: Index %d out of range", index/sz );

#endif