// this function abstracts away the layout and mode details of a libc++ string
// and returns the address of the data and the size ready for callers to consume
static bool
ExtractLibcxxStringInfo (ValueObject& valobj,
ValueObjectSP &location_sp,
uint64_t& size)
{
ValueObjectSP D(valobj.GetChildAtIndexPath({0,0,0,0}));
if (!D)
return false;
ValueObjectSP layout_decider(D->GetChildAtIndexPath({0,0}));
// this child should exist
if (!layout_decider)
return false;
ConstString g_data_name("__data_");
ConstString g_size_name("__size_");
bool short_mode = false; // this means the string is in short-mode and the data is stored inline
LibcxxStringLayoutMode layout = (layout_decider->GetName() == g_data_name) ? eLibcxxStringLayoutModeDSC : eLibcxxStringLayoutModeCSD;
uint64_t size_mode_value = 0;
if (layout == eLibcxxStringLayoutModeDSC)
{
ValueObjectSP size_mode(D->GetChildAtIndexPath({1,1,0}));
if (!size_mode)
return false;
if (size_mode->GetName() != g_size_name)
{
// we are hitting the padding structure, move along
size_mode = D->GetChildAtIndexPath({1,1,1});
if (!size_mode)
return false;
}
size_mode_value = (size_mode->GetValueAsUnsigned(0));
short_mode = ((size_mode_value & 0x80) == 0);
}
else
{
ValueObjectSP size_mode(D->GetChildAtIndexPath({1,0,0}));
if (!size_mode)
return false;
size_mode_value = (size_mode->GetValueAsUnsigned(0));
short_mode = ((size_mode_value & 1) == 0);
}
if (short_mode)
{
ValueObjectSP s(D->GetChildAtIndex(1, true));
if (!s)
return false;
location_sp = s->GetChildAtIndex((layout == eLibcxxStringLayoutModeDSC) ? 0 : 1, true);
size = (layout == eLibcxxStringLayoutModeDSC) ? size_mode_value : ((size_mode_value >> 1) % 256);
return (location_sp.get() != nullptr);
}
else
{
