#pypp 0
#include "kernel.hh"

// TODO: avoid recursion.
bool Memory::use ():
	if used >= limit:
		return false
	if !parent || parent->use ():
		++used
		return true
	return false

void Memory::unuse ():
	--used
	return parent->unuse ()

unsigned Memory::palloc ():
	if !use ():
		return NULL
	FreePage *ret = junk_pages
	if !ret:
		ret = zero_pages
		zero_pages = ret->next
	else:
		junk_pages = ret->next
	return (unsigned)ret
	
unsigned Memory::zalloc ():
	if !use ():
		return NULL
	FreePage *ret = zero_pages
	if !ret:
		ret = junk_pages
		for unsigned i = 1; i < PAGE_SIZE; ++i:
			((unsigned *)ret)[i] = 0
		junk_pages = ret->next
	else:
		zero_pages = ret->next
	ret->next = NULL
	return (unsigned)ret

void Memory::pfree (unsigned page):
	FreePage *p = (FreePage *)page
	p->next = junk_pages
	junk_pages = p

void Memory::zfree (unsigned page):
	FreePage *p = (FreePage *)page
	p->next = zero_pages
	zero_pages = p

void *Memory::search_free (unsigned size, void **first):
	Free *f
	unsigned s = 0
	for f = frees; f; f = f->next:
		if f->next_obj:
			s = (unsigned)f->next_obj - (unsigned)f
		else:
			s = PAGE_SIZE - ((unsigned)f & ~PAGE_MASK)
		if s >= size:
			break
	if !f:
		f = (Free *)palloc ()
		if !f:
			return NULL
		f->marker = ~0
		f->next = frees
		f->prev = NULL
		frees = f
		if f->next:
			f->next->prev = f
		f->next_obj = NULL
		f->prev_obj = NULL
		s = PAGE_SIZE
	// We have a free block, possibly too large.
	if s >= size + sizeof (Free):
		// Create the new object at the end and keep the Free.
		Free *obj = (Free *)((unsigned)f + s - size)
		obj->next_obj = f->next_obj
		if obj->next_obj:
			obj->next_obj->prev_obj = obj
		obj->prev_obj = f
		f->next_obj = obj
		f = obj
	else:
		if f->prev:
			f->prev->next = f->next
		else:
			frees = f->next
		if f->next:
			f->next->prev = f->prev
	f->next = (Free *)*first
	f->prev = NULL
	if f->next:
		f->next->prev = f
	*first = f
	return f

void Object_base::free_obj (Memory *parent):
	Free *self
	// Merge with previous, if it exists and is a Free.
	if prev_obj && prev_obj->is_free ():
		self = (Free *)prev_obj
		self->next_obj = next_obj
		if next_obj:
			next_obj->prev_obj = self
	else:
		self = (Free *)this
		self->next = parent->frees
		self->prev = NULL
		if self->next:
			self->next->prev = self
		parent->frees = self
		self->marker = ~0
	// Merge with next, if it exists and is a Free.
	if self->next_obj && self->next_obj->is_free ():
		self->next_obj = self->next_obj->next_obj
		if self->next_obj:
			self->next_obj->prev_obj = self
	// Free page if the resulting object is the only thing in it.
	if !self->prev_obj && !self->next_obj:
		if self->next:
			self->next->prev = self->prev
		if self->prev:
			self->prev->next = self->next
		else:
			parent->frees = self->next
		parent->pfree ((unsigned)self)

Page *Memory::alloc_page ():
	Page *ret = (Page *)search_free (sizeof (Page), (void **)&pages)
	ret->physical = 0
	return ret

Thread *Memory::alloc_thread ():
	Thread *ret = (Thread *)search_free (sizeof (Thread), (void **)&threads)
	ret->address_space = this
	ret->pc = 0
	ret->sp = 0
	Thread_arch_init (ret)
	ret->schedule_prev = NULL
	ret->schedule_next = NULL
	return ret

Message *Memory::alloc_message (Capability *source):
	Message *ret = (Message *)search_free (sizeof (Message), (void **)&source->target->messages)
	for unsigned i = 0; i < 4; ++i:
		ret->capabilities[i] = NULL
		ret->data[i] = 0
	ret->protected_data = source->protected_data
	return ret

Receiver *Memory::alloc_receiver ():
	Receiver *ret = (Receiver *)search_free (sizeof (Receiver), (void **)&receivers)
	ret->owner = NULL
	ret->prev_owned = NULL
	ret->next_owned = NULL
	ret->capabilities = NULL
	ret->messages = NULL
	return ret

Capability *Memory::alloc_capability (Receiver *target, Capability **parent, unsigned protected_data):
	Capability *ret = (Capability *)search_free (sizeof (Capability), (void **)&capabilities)
	ret->target = target
	ret->children = NULL
	ret->sibling_prev = NULL
	ret->sibling_next = parent ? *parent : NULL
	if ret->sibling_next:
		ret->sibling_next->sibling_prev = ret
	ret->protected_data = protected_data
	return ret

Memory *Memory::alloc_memory ():
	Memory *ret = (Memory *)search_free (sizeof (Memory), (void **)&memories)
	ret->parent = this
	ret->frees = NULL
	ret->pages = NULL
	ret->threads = NULL
	ret->memories = NULL
	ret->limit = ~0
	ret->used = 0
	Memory_arch_init (ret)
	return ret

void Memory::free_page (Page *page):
	if page->prev:
		page->prev->next = page->next
	else:
		pages = page->next
	if page->next:
		page->next->prev = page->prev
	unuse ()
	pfree (page->physical)
	page->free_obj (this)

void Memory::free_thread (Thread *thread):
	if thread->prev:
		thread->prev->next = thread->next
	else:
		threads = thread->next
	if thread->next:
		thread->next->prev = thread->prev
	// Unschedule.
	if thread->schedule_prev:
		thread->schedule_prev->schedule_next = thread->schedule_next
	else if first_scheduled == thread:
		first_scheduled = thread->schedule_next
	if thread->schedule_next:
		thread->schedule_next->schedule_prev = thread->schedule_prev
	thread->free_obj (this)

void Memory::free_message (Message *message):
	for unsigned i = 0; i < 4; ++i:
		free_capability (message->capabilities[i])
	message->free_obj (this)

void Memory::free_receiver (Receiver *receiver):
	if receiver->prev_owned:
		receiver->prev_owned->next_owned = receiver->next_owned
	else:
		receiver->owner->receivers = receiver->next_owned
	if receiver->next_owned:
		receiver->next_owned->prev_owned = receiver->prev_owned
	while receiver->capabilities:
		receiver->capabilities->invalidate ()
	while receiver->messages:
		free_message (receiver->messages)
	receiver->free_obj (this)

void Memory::free_capability (Capability *capability):
	if capability->sibling_prev:
		capability->sibling_prev->sibling_next = capability->sibling_next
	else:
		capability->target->capabilities = capability->sibling_next
	if capability->sibling_next:
		capability->sibling_next->sibling_prev = capability->sibling_prev
	// The sibling_prev link is used here to point to the parent.
	// This method is used to avoid recursion.
	capability->sibling_prev = NULL
	Capability *c = capability
	while c->children:
		c->children->sibling_prev = c
		c = c->children
	while c:
		Capability *next = c->sibling_next
		if !next:
			next = c->sibling_prev
		if next:
			next->sibling_prev = c->sibling_prev
		c->free_obj (this)
		c = next

void Capability::invalidate ():
	if sibling_prev:
		sibling_prev->sibling_next = sibling_next
	else:
		target->capabilities = sibling_next
	if sibling_next:
		sibling_next->sibling_prev = sibling_prev
	// The sibling_prev link is used here to point to the parent.
	// This method is used to avoid recursion.
	sibling_prev = NULL
	Capability *c = this
	while c->children:
		c->children->sibling_prev = c
		c = c->children
	while c:
		Capability *next = c->sibling_next
		if !next:
			next = c->sibling_prev
		if next:
			next->sibling_prev = c->sibling_prev
		c->target = NULL
		c->children = NULL
		c->sibling_prev = NULL
		c->sibling_next = NULL
		c->protected_data = 0
		c = next

void Memory::free_memory (Memory *mem):
	if mem->prev:
		mem->prev->next = mem->next
	else:
		memories = mem->next
	if mem->next:
		mem->next->prev = mem->prev
	while mem->pages:
		free_page (mem->pages)
	while mem->threads:
		free_thread (mem->threads)
	while mem->memories:
		free_memory (mem->memories)
	Memory_arch_free (mem)
	mem->free_obj (this)