module acpi;

import c3os::util;

extern fn int memcmp(void*, void*, usz);

fn bool RootSystemDescriptionPointer.is_valid(&self)
{
	if (memcmp(&self.signature, "RSD PTR ", 8) != 0) return false;
	if (self.revision != 2) return false;
	char sum = 0;
	for (int i = 0; i < 20; i++) sum += ((char*)self)[i];
	if (sum != 0) return false;
	for (int i = 0; i < RootSystemDescriptionPointer::size; i++) sum += ((char*)self)[i];
	return (sum == 0);
}

fn bool ExtendedSystemDescriptionTable.is_valid(&self)
{
	if (memcmp(&self.signature, "XSDT", 4) != 0) return false;
	if (self.revision != 1) return false;
	char sum = 0;
	for (uint i = 0; i < self.length; i++) sum += ((char*)self)[i];
	if (sum != 0) return false;
	return true;
}

fn bool DescriptionHeader.is_valid(&self)
{
	if (catch excuse = self.sig()) return false;
	char sum = 0;
	for (uint i = 0; i < self.length; i++) sum += ((char*)self)[i];
	if (sum != 0) return false;
	return true;
}

fn DescriptionHeaderSignature? DescriptionHeader.sig(&self)
{
	foreach (i, name : DescriptionHeaderSignature::names)
	{
		if (memcmp(name, &self.signature, 4) == 0) return (DescriptionHeaderSignature)i;
	}
	return INVALID_DESCRIPTION_HEADER~;
}