qgarray.cpp

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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
	return -1;
    }
    register uint i;
    uint ii;
    switch ( sz ) {
	case 1: {				// 8 bit elements
	    register char *x = data() + index;
	    char v = *d;
	    for ( i=index; i<shd->len; i++ ) {
		if ( *x++ == v )
		    break;
	    }
	    ii = i;
	    }
	    break;
	case 2: {				// 16 bit elements
	    register Q_INT16 *x = (Q_INT16*)(data() + index);
	    Q_INT16 v = *((Q_INT16*)d);
	    for ( i=index; i<shd->len; i+=2 ) {
		if ( *x++ == v )
		    break;
	    }
	    ii = i/2;
	    }
	    break;
	case 4: {				// 32 bit elements
	    register Q_INT32 *x = (Q_INT32*)(data() + index);
	    Q_INT32 v = *((Q_INT32*)d);
	    for ( i=index; i<shd->len; i+=4 ) {
		if ( *x++ == v )
		    break;
	    }
	    ii = i/4;
	    }
	    break;
	default: {				// any size elements
	    for ( i=index; i<shd->len; i+=sz ) {
		if ( memcmp( d, &shd->data[i], sz ) == 0 )
		    break;
	    }
	    ii = i/sz;
	    }
	    break;
    }
    return i<shd->len ? (int)ii : -1;
}

/*!
  \internal
  Returns the number of occurrences of \e d in the array, where \e sz is
  the size of the \e d element.

  This function only compares whole cells, not bytes.
*/

int QGArray::contains( const char *d, uint sz ) const
{
    register uint i = shd->len;
    int count = 0;
    switch ( sz ) {
	case 1: {				// 8 bit elements
	    register char *x = data();
	    char v = *d;
	    while ( i-- ) {
		if ( *x++ == v )
		    count++;
	    }
	    }
	    break;
	case 2: {				// 16 bit elements
	    register Q_INT16 *x = (Q_INT16*)data();
	    Q_INT16 v = *((Q_INT16*)d);
	    i /= 2;
	    while ( i-- ) {
		if ( *x++ == v )
		    count++;
	    }
	    }
	    break;
	case 4: {				// 32 bit elements
	    register Q_INT32 *x = (Q_INT32*)data();
	    Q_INT32 v = *((Q_INT32*)d);
	    i /= 4;
	    while ( i-- ) {
		if ( *x++ == v )
		    count++;
	    }
	    }
	    break;
	default: {				// any size elements
	    for ( i=0; i<shd->len; i+=sz ) {
		if ( memcmp(d, &shd->data[i], sz) == 0 )
		    count++;
	    }
	    }
	    break;
    }
    return count;
}

static int cmp_item_size = 0;

#if defined(Q_C_CALLBACKS)
extern "C" {
#endif

static int cmp_arr( const void *n1, const void *n2 )
{
    return ( n1 && n2 ) ? memcmp( n1, n2, cmp_item_size ) 
	                : (int)((long)n1 - (long)n2);
    // Qt 3.0: Add a virtual compareItems() method and call that instead
}

#if defined(Q_C_CALLBACKS)
}
#endif

/*!
  \internal

  Sort the array.
*/

void QGArray::sort( uint sz )
{
    int numItems = size() / sz;
    if ( numItems < 2 )
	return;
    cmp_item_size = sz;
    qsort( shd->data, numItems, sz, cmp_arr );
}

/*!
  \internal

  Binary search; assumes sorted array
*/

int QGArray::bsearch( const char *d, uint sz ) const
{
    int numItems = size() / sz;
    if ( !numItems )
	return -1;
    cmp_item_size = sz;
    char* r = (char*)::bsearch( d, shd->data, numItems, sz, cmp_arr );
    if ( !r )
	return -1;
    while( (r >= shd->data + sz) && (cmp_arr( r - sz, d ) == 0) )
	r -= sz;	// search to first of equal elements; bsearch is undef 
    return (int)(( r - shd->data ) / sz);
}


/*!
  \fn char *QGArray::at( uint index ) const
  \internal
  Returns a pointer to the byte at offset \e index in the array.
*/

/*!
  \internal
  Expand the array if necessary, and copies (the first part of) its
  contents from the \e index*zx bytes at \e d.

  Returns TRUE if the operation succeeds, FALSE if it runs out of
  memory.

  \warning This function disregards the reference count mechanism.  If
  other QGArrays reference the same data as this, all will be changed.
*/

bool QGArray::setExpand( uint index, const char *d, uint sz )
{
    index *= sz;
    if ( index >= shd->len ) {
	if ( !resize( index+sz ) )		// no memory
	    return FALSE;
    }
    memcpy( data() + index, d, sz );
    return TRUE;
}


/*!
  \internal
  Prints a warning message if at() or [] is given a bad index.
*/

void QGArray::msg_index( uint index )
{
#if defined(CHECK_RANGE)
    qWarning( "QGArray::at: Absolute index %d out of range", index );
#else
    Q_UNUSED( index )
#endif
}


/*!
  \internal
  Returns a new shared array block.
*/

QGArray::array_data * QGArray::newData()
{
    return new array_data;
}


/*!
  \internal
  Deletes the shared array block.
*/

void QGArray::deleteData( array_data *p )
{
    delete p;
    p = 0;
}