xo-object2/src/object2/DList.cpp
Roland Conybeare 39ae54167f refactor: + narrower interface for gc pointer forwarding
add AGCObjectVisitor, instead of requiring ACollector.
2026-04-05 23:53:02 -04:00

198 lines
4.7 KiB
C++

/** @file DList.cpp
*
* @author Roland Conybeare, Dec 2025
**/
#include "DList.hpp"
#include "list/IPrintable_DList.hpp"
#include "list/IGCObject_DList.hpp"
#include <xo/alloc2/GCObject.hpp>
#include <xo/printable2/Printable.hpp>
#include <xo/facet/FacetRegistry.hpp>
#include <xo/facet/facet_implementation.hpp>
#include <xo/indentlog/print/pretty.hpp>
#include <xo/indentlog/print/tag.hpp>
namespace xo {
using xo::print::APrintable;
using xo::mm::AGCObject;
using xo::facet::FacetRegistry;
//using xo::facet::typeseq;
namespace scm {
static DList s_null(obj<AGCObject>(), nullptr);
DList *
DList::_nil()
{
return &s_null;
}
obj<AGCObject,DList>
DList::nil()
{
return obj<AGCObject,DList>(_nil());
}
DList *
DList::_cons(obj<AAllocator> mm,
obj<AGCObject> car,
DList * cdr)
{
void * mem = mm.alloc_for<DList>();
return new (mem) DList(car, cdr);
}
obj<AGCObject,DList>
DList::cons(obj<AAllocator> mm,
obj<AGCObject> car,
DList * cdr)
{
return obj<AGCObject,DList>(_cons(mm, car, cdr));
}
#ifdef OBSOLETE
DList *
DList::list(obj<AAllocator> mm,
obj<AGCObject> h1)
{
void * mem = mm.alloc(typeseq::id<DList>(), sizeof(DList));
return new (mem) DList(h1, DList::_nil());
}
DList *
DList::list(obj<AAllocator> mm,
obj<AGCObject> h1,
obj<AGCObject> h2)
{
void * mem = mm.alloc(typeseq::id<DList>(), sizeof(DList));
return new (mem) DList(h1, DList::list(mm, h2));
}
#endif
bool
DList::is_empty() const noexcept
{
return this == &s_null;
}
auto
DList::size() const noexcept -> size_type
{
const DList * l = this;
size_type z = 0;
while (l && l != &s_null) {
++z;
l = l->rest_;
}
return z;
}
auto
DList::at(size_type index) const -> obj<AGCObject>
{
size_type ix = index;
const DList * l = this;
while (l->rest_ && (ix > 0)) {
--ix;
l = l->rest_;
}
if (ix > 0) {
assert(l == nullptr);
throw std::runtime_error
(tostr("DList::at: out-of-range index where [0..z) expected",
xtag("index", index),
xtag("z", this->size())));
}
assert(l);
return l->head_;
}
void
DList::assign_head(obj<ACollector> gc, obj<AGCObject> rhs)
{
scope log(XO_DEBUG(true), xtag("gc.data", gc.data_));
mm_do_assign(gc, this, &head_, rhs);
}
void
DList::assign_rest(DList * r)
{
scope log(XO_DEBUG(true), "need write barrier");
this->rest_ = r;
}
bool
DList::pretty(const ppindentinfo & ppii) const
{
/* adapted from ppstate.pretty_struct(), see also */
using xo::print::ppstate;
ppstate * pps = ppii.pps();
if (ppii.upto()) {
/* perhaps print on one line */
pps->write("(");
/* TODO: probably use iterators here, when available */
const DList * l = this;
size_t i = 0;
while (!l->is_empty()) {
if (i > 0)
pps->write(" ");
obj<APrintable> elt
= FacetRegistry::instance().variant<APrintable, AGCObject>(l->head_);
assert(elt.data());
if (!pps->print_upto(elt))
return false;
l = l->rest_;
++i;
}
pps->write(")");
return true;
} else {
pps->write("(...)");
return false;
}
}
// ----- GCObject facet ------
DList *
DList::shallow_move(obj<ACollector> gc) noexcept
{
return gc.std_move_for(this);
}
void
DList::visit_gco_children(obj<AGCObjectVisitor> gc) noexcept
{
//scope log(XO_DEBUG(true));
gc.visit_child(&head_);
gc.visit_child(&rest_);
}
} /*namespace scm*/
} /*namespace xo*/
/* end DList.cpp */