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/********************************************************************************
* *
* G e n e r i c A r r a y *
* *
*********************************************************************************
* Copyright (C) 1997,2022 by Jeroen van der Zijp. All Rights Reserved. *
*********************************************************************************
* This library is free software; you can redistribute it and/or modify *
* it under the terms of the GNU Lesser General Public License as published by *
* the Free Software Foundation; either version 3 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 Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/> *
********************************************************************************/
#include "xincs.h"
#include "fxver.h"
#include "fxdefs.h"
#include "FXElement.h"
#include "FXArray.h"
/*
Notes:
- FXArrayBase manages the gory details of the buffer representation: an item count
followed by the items themselves.
- The chosen representation allows an empty array to take up very minimal space
only; basically, just a pointer to the memory buffer.
- The buffer pointer is never NULL; thus its always safe to reference the buffer
pointer.
- Alignment is assumed to be 8 for 64-bit systems and 4 for 32-bit systems, same
as malloc() returns.
- Note sizeof(FXival) == sizeof(FXptr).
*/
// Special empty array value
#define EMPTY (const_cast<void*>((const void*)(__array__empty__+1)))
using namespace FX;
/*******************************************************************************/
namespace FX {
// Empty array value
extern const FXival __array__empty__[];
const FXival __array__empty__[2]={0,0};
// Copying empty array uses same empty-array pointer regardless of
// subclass; if array is non-empty, subclass does the actual copying.
FXArrayBase::FXArrayBase():ptr(EMPTY){
}
// Resize the array to num elements of size sz; if size becomes zero,
// substitute special empty-array pointer again which contains zero
// elements of any type.
FXbool FXArrayBase::resize(FXival num,FXival sz){
FXival old=*(((FXival*)ptr)-1);
if(__likely(old!=num)){
FXptr p;
if(0<num){
if(ptr!=EMPTY){
if(__unlikely((p=::realloc(((FXival*)ptr)-1,sizeof(FXival)+num*sz))==nullptr)) return false;
}
else{
if(__unlikely((p=::malloc(sizeof(FXival)+num*sz))==nullptr)) return false;
}
ptr=((FXival*)p)+1;
*(((FXival*)ptr)-1)=num;
}
else{
if(ptr!=EMPTY){
::free(((FXival*)ptr)-1);
ptr=EMPTY;
}
}
}
return true;
}
// Destructor
FXArrayBase::~FXArrayBase(){
resize(0,0);
ptr=(void*)-1L;
}
}
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