Function find_page

src/jrd/btr.cpp:4936–5103

static ULONG find_page(btree_page* bucket, const temporary_key* key,
					   const index_desc* idx, RecordNumber find_record_number,
					   int retrieval)
{
/**************************************
 *
 *	f i n d _ p a g e
 *
 **************************************
 *
 * Functional description
 *	Find a page number in an index level.  Return either the
 *	node equal to the key or the last node less than the key.
 *	Note that this routine can be called only for non-leaf
 *	pages, because it assumes the first node on page is
 *	a degenerate, zero-length node.
 *
 **************************************/

	const bool leafPage = (bucket->btr_level == 0);
	bool firstPass = true;
	const bool descending = (idx->idx_flags & idx_descending);
	const bool primary = (idx->idx_flags & idx_primary);
	const bool unique = (idx->idx_flags & idx_unique);
	const bool key_all_nulls = (key->key_nulls == (1 << idx->idx_count) - 1);
	const bool validateDuplicates = (unique && !key_all_nulls) || primary;

	if (validateDuplicates)
		find_record_number = NO_VALUE;

	const UCHAR* const endPointer = (UCHAR*) bucket + bucket->btr_length;

	USHORT prefix = 0;	// last computed prefix against processed node

	// pointer where to start reading next node
	UCHAR* pointer = find_area_start_point(bucket, key, 0, &prefix,
										   descending, retrieval, find_record_number);

	IndexNode node;
	pointer = node.readNode(pointer, leafPage);
	// Check if pointer is still valid
	if (pointer > endPointer)
		BUGCHECK(204);	// msg 204 index inconsistent

	if (node.isEndBucket || node.isEndLevel)
	{
		pointer = bucket->btr_nodes + bucket->btr_jump_size;
		pointer = node.readNode(pointer, leafPage);

		// Check if pointer is still valid
		if (pointer > endPointer)
			BUGCHECK(204);	// msg 204 index inconsistent
	}

	if (node.isEndLevel)
		BUGCHECK(206);	// msg 206 exceeded index level

	ULONG previousNumber = node.pageNumber;