Method apply

src/jrd/sqz.cpp:517–567

}

ULONG Difference::apply(ULONG diffLength, ULONG outLength, UCHAR* const output)
{
/**************************************
 *
 *	Apply a differences (delta) to a record.
 *  Return the length.
 *
 **************************************/
	if (diffLength > MAX_DIFFERENCES)
		BUGCHECK(176);	// msg 176 bad difference record

	auto differences = m_differences;
	const auto end = differences + diffLength;
	auto p = output;
	const auto p_end = output + outLength;

	while (differences < end && p < p_end)
	{
		const int l = (signed char) *differences++;

		if (l > 0)
		{
			if (p + l > p_end)
				BUGCHECK(177);	// msg 177 applied differences will not fit in record

			if (differences + l > end)
				BUGCHECK(176);	// msg 176 bad difference record

			memcpy(p, differences, l);
			p += l;
			differences += l;
		}
		else
		{
			p += -l;
		}
	}

	while (differences < end)
	{
		if (*differences++)
			BUGCHECK(177);	// msg 177 applied differences will not fit in record
	}

	const auto length = p - output;

	if (length > outLength)
		BUGCHECK(177);	// msg 177 applied differences will not fit in record

	return length;
}

ULONG Difference::makeNoDiff(ULONG length)
{