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added add_link_abs()

This commit is contained in:
ariza 2020-02-06 16:11:58 -08:00
parent 07504569d5
commit 017cd945bf
1 changed files with 59 additions and 12 deletions
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71
src/hb-serialize.hh
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@ -70,7 +70,9 @@ struct hb_serialize_context_t
struct link_t
{
bool is_wide: 1;
unsigned position : 31;
bool is_signed: 1;
bool is_absolute: 1;
unsigned position;
unsigned bias;
objidx_t objidx;
};
@ -127,7 +129,7 @@ struct hb_serialize_context_t
template <typename T1, typename T2>
bool check_assign (T1 &v1, T2 &&v2)
{ return check_equal (v1 = v2, v2); }
{ return check_equal ((hb_remove_reference<T2>) (v1 = v2), v2); }
template <typename T> bool propagate_error (T &&obj)
{ return check_success (!hb_deref (obj).in_error ()); }
@ -286,11 +288,47 @@ struct hb_serialize_context_t
auto& link = *current->links.push ();
link.is_wide = sizeof (T) == 4;
link.is_signed = false;
link.is_absolute = false;
link.position = (const char *) &ofs - current->head;
link.bias = (const char *) base - current->head;
link.objidx = objidx;
}
/*
* Set a link to an object with an absolute offset.
* T may be signed or unsigned IntType.
*/
template <typename T>
void add_link_abs (T &ofs, objidx_t objidx)
{
static_assert (sizeof (T) == 2 || sizeof (T) == 4, "");
if (!objidx)
return;
assert (current);
assert (current->head <= (const char *) &ofs);
auto& link = *current->links.push ();
link.is_wide = sizeof (T) == 4;
link.is_signed = hb_is_signed (typename T::type);
link.is_absolute = true;
link.position = (const char *) &ofs - current->head;
link.bias = 0;
link.objidx = objidx;
}
private:
template <typename T>
void assign (const object_t* parent, const object_t::link_t &link, unsigned offset)
{
auto &off = * ((BEInt<T, sizeof (T)> *) (parent->head + link.position));
assert (0 == off);
check_assign (off, offset);
}
public:
void resolve_links ()
{
if (unlikely (in_error ())) return;
@ -302,20 +340,29 @@ struct hb_serialize_context_t
for (const object_t::link_t &link : parent->links)
{
const object_t* child = packed[link.objidx];
assert (link.bias <= (size_t) (parent->tail - parent->head));
unsigned offset = (child->head - parent->head) - link.bias;
if (link.is_wide)
if (unlikely (!child)) { err_other_error(); return; }
unsigned offset;
if (link.is_absolute)
offset = (head - start) + (child->head - tail);
else
{
auto &off = * ((BEInt<uint32_t, 4> *) (parent->head + link.position));
assert (0 == off);
check_assign (off, offset);
assert (link.bias <= (size_t) (parent->tail - parent->head));
offset = (child->head - parent->head) - link.bias;
}
if (link.is_signed)
{
if (link.is_wide)
assign<int32_t> (parent, link, offset);
else
assign<int16_t> (parent, link, offset);
}
else
{
auto &off = * ((BEInt<uint16_t, 2> *) (parent->head + link.position));
assert (0 == off);
check_assign (off, offset);
if (link.is_wide)
assign<uint32_t> (parent, link, offset);
else
assign<uint16_t> (parent, link, offset);
}
}
}