/*
* Copyright (c) 2008-2025 Jonathan Schleifer <js@nil.im>
*
* All rights reserved.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License version 3.0 only,
* as published by the Free Software Foundation.
*
* This program 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
* version 3.0 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3.0 along with this program. If not, see
* <https://www.gnu.org/licenses/>.
*/
#import "ObjFWRT.h"
#import "private.h"
#define numTaggedPointerBits 4
#define maxNumTaggedPointerClasses (1 << (numTaggedPointerBits - 1))
Class _objc_taggedPointerClasses[maxNumTaggedPointerClasses];
static int taggedPointerClassesCount;
uintptr_t _objc_taggedPointerSecret;
void
objc_setTaggedPointerSecret(uintptr_t secret)
{
_objc_taggedPointerSecret = secret & ~(uintptr_t)1;
}
int
objc_registerTaggedPointerClass(Class class)
{
int i;
_objc_globalMutex_lock();
if (taggedPointerClassesCount == maxNumTaggedPointerClasses) {
_objc_globalMutex_unlock();
return -1;
}
i = taggedPointerClassesCount++;
_objc_taggedPointerClasses[i] = class;
_objc_globalMutex_unlock();
return i;
}
bool
object_isTaggedPointer(id object)
{
uintptr_t pointer = (uintptr_t)object;
return pointer & 1;
}
Class
_object_getTaggedPointerClass(id object)
{
uintptr_t pointer = (uintptr_t)object ^ _objc_taggedPointerSecret;
pointer &= (1 << numTaggedPointerBits) - 1;
pointer >>= 1;
if (pointer >= maxNumTaggedPointerClasses)
return Nil;
return _objc_taggedPointerClasses[pointer];
}
uintptr_t
object_getTaggedPointerValue(id object)
{
uintptr_t pointer = (uintptr_t)object ^ _objc_taggedPointerSecret;
pointer >>= numTaggedPointerBits;
return pointer;
}
id
objc_createTaggedPointer(int class, uintptr_t value)
{
uintptr_t pointer;
if (class < 0 || class >= maxNumTaggedPointerClasses)
return nil;
if (value > (UINTPTR_MAX >> numTaggedPointerBits))
return nil;
pointer = (class << 1) | 1;
pointer |= (value << numTaggedPointerBits);
return (id)(pointer ^ _objc_taggedPointerSecret);
}