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/*
StackZone.m
Copyright (C) 1995, 1996 Ovidiu Predescu and Mircea Oancea.
All rights reserved.
Author: Ovidiu Predescu <ovidiu@bx.logicnet.ro>
This file is part of libFoundation.
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, provided
that the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.
We disclaim all warranties with regard to this software, including all
implied warranties of merchantability and fitness, in no event shall
we be liable for any special, indirect or consequential damages or any
damages whatsoever resulting from loss of use, data or profits, whether in
an action of contract, negligence or other tortious action, arising out of
or in connection with the use or performance of this software.
*/
#include <Foundation/common.h>
#include <Foundation/StackZone.h>
#include <extensions/NSException.h>
@implementation StackZone
/* nextNode indicates to the next allocation node available. The `previous'
component of this node points to the node allocated before it.
When a new allocation is requested it is satisfied from the node pointed to
by nextNode and then nextNode is updated to point to the zone where the
next node will be allocated. The algorithm tries first to allocate memory
in the nodes below the current node if they are freed. */
+ alloc
{
return [self allocZoneInstance];
}
- init
{
return [self initForSize:64536 granularity:0 canFree:YES];
}
- initForSize:(unsigned)startSize granularity:(unsigned)granularity
canFree:(BOOL)canFree
{
[self setName:@"Default zone"];
memory = malloc(startSize);
nextNode = (AllocationNode*)memory;
nextNode->previous = NULL;
memorySize = startSize;
return self;
}
- (void*)malloc:(unsigned)size
{
AllocationNode* previous = nextNode->previous;
/* Try to use the nodes below the top of stack if they are freed */
while (previous && previous->freed == YES) {
nextNode = previous;
previous = previous->previous;
}
Assert (nextNode);
/* Check if the requested size can be handled */
if (((char*)nextNode) + size - memory
+ sizeof(AllocationNode) >= memorySize)
return NULL;
/* Prepare nextNode to be allocated */
nextNode->freed = NO;
/* Make nextNode to point to the next allocation node */
previous = nextNode;
nextNode = (void*)(((char*)nextNode) + sizeof(AllocationNode) + size);
nextNode->previous = previous;
/* Return the memory from the previous node */
return &(previous->allocatedMemory);
}
- (void*)calloc:(unsigned)numElems byteSize:(unsigned)byteSize
{
unsigned size = numElems * byteSize;
void* pointer = [self malloc:size];
memset (pointer, 0, size);
return pointer;
}
- (void*)realloc:(void*)pointer size:(unsigned)newSize
{
AllocationNode* currentNode = nextNode->previous;
unsigned size = ((char*)nextNode) - ((char*)currentNode)
- sizeof(AllocationNode);
void* newPointer;
/* If the pointer is NULL behave like a normal allocation */
if (!pointer)
return [self malloc:newSize];
while (currentNode && &(currentNode->allocatedMemory) != pointer) {
size = ((char*)currentNode) - ((char*)(currentNode->previous))
- sizeof(AllocationNode);
currentNode = currentNode->previous;
}
/* If the requested size is lower than the allocated pointer size, return
the old value. Otherwise allocate a new memory zone, copy the content of
the old one and return the address of the new pointer. The old zone is
marked as freed. */
if (currentNode && size >= newSize)
return pointer;
else {
newPointer = [self malloc:newSize];
if (newPointer)
memcpy(newPointer, pointer, size);
currentNode->freed = YES;
return newPointer;
}
}
- (void)recycle
{
}
- (BOOL)pointerInZone:(void*)pointer
{
return (char*)pointer > memory && (char*)pointer < memory + memorySize;
}
- (void)freePointer:(void*)pointer
{
AllocationNode* currentNode = nextNode->previous;
/* Identify the allocation node of pointer and mark it as freed. */
while (currentNode && &(currentNode->allocatedMemory) != pointer)
currentNode = currentNode->previous;
if (currentNode) {
if (currentNode->freed == YES)
NSLog(@"attempt to free an already freed pointer: %p\n", pointer);
else
currentNode->freed = YES;
}
else
NSLog(@"attempt to free an unexisting pointer in zone: pointer %p, "
@"zone %p (%@)", pointer, self, [self name]);
}
- (BOOL)checkZone
{
return YES;
}
@end /* StackZone */
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.