open_toontown_panda3d/dtool/src/dtoolbase/deletedBufferChain.cxx

140 lines
4.0 KiB
C++

/**
* PANDA 3D SOFTWARE
* Copyright (c) Carnegie Mellon University. All rights reserved.
*
* All use of this software is subject to the terms of the revised BSD
* license. You should have received a copy of this license along
* with this source code in a file named "LICENSE."
*
* @file deletedBufferChain.cxx
* @author drose
* @date 2007-07-20
*/
#include "deletedBufferChain.h"
#include "memoryHook.h"
/**
* Use the global MemoryHook to get a new DeletedBufferChain of the
* appropriate size.
*/
DeletedBufferChain::
DeletedBufferChain(size_t buffer_size) {
_deleted_chain = nullptr;
_buffer_size = buffer_size;
// We must allocate at least this much space for bookkeeping reasons.
_buffer_size = std::max(_buffer_size, sizeof(ObjectNode));
}
/**
* Allocates the memory for a new buffer of the indicated size (which must be
* no greater than the fixed size associated with the DeletedBufferChain).
*/
void *DeletedBufferChain::
allocate(size_t size, TypeHandle type_handle) {
#ifdef USE_DELETED_CHAIN
// TAU_PROFILE("void *DeletedBufferChain::allocate(size_t, TypeHandle)", "
// ", TAU_USER);
assert(size <= _buffer_size);
// Determine how much space to allocate.
const size_t alloc_size = _buffer_size + flag_reserved_bytes + MEMORY_HOOK_ALIGNMENT - 1;
ObjectNode *obj;
_lock.lock();
if (_deleted_chain != nullptr) {
obj = _deleted_chain;
_deleted_chain = _deleted_chain->_next;
_lock.unlock();
#ifdef USE_DELETEDCHAINFLAG
assert(obj->_flag == (AtomicAdjust::Integer)DCF_deleted);
obj->_flag = DCF_alive;
#endif // USE_DELETEDCHAINFLAG
void *ptr = node_to_buffer(obj);
#ifdef DO_MEMORY_USAGE
// type_handle.dec_memory_usage(TypeHandle::MC_deleted_chain_inactive,
// alloc_size);
type_handle.inc_memory_usage(TypeHandle::MC_deleted_chain_active, alloc_size);
#endif // DO_MEMORY_USAGE
return ptr;
}
_lock.unlock();
// If we get here, the deleted_chain is empty; we have to allocate a new
// object from the system pool.
// Allocate memory, and make sure the object starts at the proper alignment.
void *mem = NeverFreeMemory::alloc(alloc_size);
uintptr_t aligned = ((uintptr_t)mem + flag_reserved_bytes + MEMORY_HOOK_ALIGNMENT - 1) & ~(MEMORY_HOOK_ALIGNMENT - 1);
obj = (ObjectNode *)(aligned - flag_reserved_bytes);
#ifdef USE_DELETEDCHAINFLAG
obj->_flag = DCF_alive;
#endif // USE_DELETEDCHAINFLAG
void *ptr = node_to_buffer(obj);
#ifndef NDEBUG
assert(((uintptr_t)ptr % MEMORY_HOOK_ALIGNMENT) == 0);
#endif
#ifdef DO_MEMORY_USAGE
type_handle.inc_memory_usage(TypeHandle::MC_deleted_chain_active, alloc_size);
#endif // DO_MEMORY_USAGE
return ptr;
#else // USE_DELETED_CHAIN
return PANDA_MALLOC_SINGLE(_buffer_size);
#endif // USE_DELETED_CHAIN
}
/**
* Frees the memory for a buffer previously allocated via allocate().
*/
void DeletedBufferChain::
deallocate(void *ptr, TypeHandle type_handle) {
#ifdef USE_DELETED_CHAIN
// TAU_PROFILE("void DeletedBufferChain::deallocate(void *, TypeHandle)", "
// ", TAU_USER);
assert(ptr != nullptr);
#ifdef DO_MEMORY_USAGE
const size_t alloc_size = _buffer_size + flag_reserved_bytes + MEMORY_HOOK_ALIGNMENT - 1;
type_handle.dec_memory_usage(TypeHandle::MC_deleted_chain_active, alloc_size);
// type_handle.inc_memory_usage(TypeHandle::MC_deleted_chain_inactive,
// _buffer_size + flag_reserved_bytes);
#endif // DO_MEMORY_USAGE
ObjectNode *obj = buffer_to_node(ptr);
#ifdef USE_DELETEDCHAINFLAG
AtomicAdjust::Integer orig_flag = AtomicAdjust::compare_and_exchange(obj->_flag, DCF_alive, DCF_deleted);
// If this assertion is triggered, you double-deleted an object.
assert(orig_flag != (AtomicAdjust::Integer)DCF_deleted);
// If this assertion is triggered, you tried to delete an object that was
// never allocated, or you have heap corruption.
assert(orig_flag == (AtomicAdjust::Integer)DCF_alive);
#endif // USE_DELETEDCHAINFLAG
_lock.lock();
obj->_next = _deleted_chain;
_deleted_chain = obj;
_lock.unlock();
#else // USE_DELETED_CHAIN
PANDA_FREE_SINGLE(ptr);
#endif // USE_DELETED_CHAIN
}