scummvm/engines/tony/mpal/memory.cpp
2021-12-26 18:48:43 +01:00

124 lines
3.3 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "common/algorithm.h"
#include "common/textconsole.h"
#include "tony/mpal/memory.h"
namespace Tony {
namespace MPAL {
/****************************************************************************\
* MemoryManager methods
\****************************************************************************/
/**
* Allocates a new memory block
* @return Returns a MemoryItem instance for the new block
*/
MpalHandle MemoryManager::allocate(uint32 size, uint flags) {
MemoryItem *newItem = (MemoryItem *)malloc(sizeof(MemoryItem) + size);
newItem->_id = BLOCK_ID;
newItem->_size = size;
newItem->_lockCount = 0;
// If requested, clear the allocated data block
if ((flags & GMEM_ZEROINIT) != 0) {
byte *dataP = newItem->_data;
Common::fill(dataP, dataP + size, 0);
}
return (MpalHandle)newItem;
}
/**
* Allocates a new memory block and returns its data pointer
* @return Data pointer to allocated block
*/
void *MemoryManager::alloc(uint32 size, uint flags) {
MemoryItem *item = (MemoryItem *)allocate(size, flags);
++item->_lockCount;
return &item->_data[0];
}
#define OFFSETOF(type, field) ((size_t) &(((type *) 0)->field))
/**
* Returns a reference to the MemoryItem for a gien byte pointer
* @param block Byte pointer
*/
MemoryItem *MemoryManager::getItem(MpalHandle handle) {
MemoryItem *rec = (MemoryItem *)((byte *)handle - OFFSETOF(MemoryItem, _data));
assert(rec->_id == BLOCK_ID);
return rec;
}
/**
* Returns a size of a memory block given its pointer
*/
uint32 MemoryManager::getSize(MpalHandle handle) {
MemoryItem *item = (MemoryItem *)handle;
assert(item->_id == BLOCK_ID);
return item->_size;
}
/**
* Erases a given item
*/
void MemoryManager::freeBlock(MpalHandle handle) {
MemoryItem *item = (MemoryItem *)handle;
assert(item->_id == BLOCK_ID);
free(item);
}
/**
* Erases a given item
*/
void MemoryManager::destroyItem(MpalHandle handle) {
MemoryItem *item = getItem(handle);
assert(item->_id == BLOCK_ID);
free(item);
}
/**
* Locks an item for access
*/
byte *MemoryManager::lockItem(MpalHandle handle) {
MemoryItem *item = (MemoryItem *)handle;
assert(item->_id == BLOCK_ID);
++item->_lockCount;
return &item->_data[0];
}
/**
* Unlocks a locked item
*/
void MemoryManager::unlockItem(MpalHandle handle) {
MemoryItem *item = (MemoryItem *)handle;
assert(item->_id == BLOCK_ID);
assert(item->_lockCount > 0);
--item->_lockCount;
}
} // end of namespace MPAL
} // end of namespace Tony