Method writeNode

src/jrd/btn.cpp:396–631

UCHAR* IndexNode::writeNode(UCHAR* pagePointer, bool leafNode, bool withData)
{
/**************************************
 *
 *	w r i t e N o d e
 *
 **************************************
 *
 * Functional description
 *	Write a leaf/page node to the page by the
 *  given page_pointer.
 *
 **************************************/
	nodePointer = pagePointer;

	// AB: 2004-02-22
	// To allow as much as compression possible we
	// store numbers per 7 bit and the 8-th bit tell us
	// if we need to go on reading or we're done.
	// Also for duplicate node entries (length and prefix
	// are zero) we don't store the length and prefix
	// information. This will save at least 2 bytes per node.

	if (!withData)
	{
		// First move data so we can't override it.
		// For older structure node was always the same, but length
		// from new structure depends on the values.
		const USHORT offset = getNodeSize(leafNode) - length;
		pagePointer += offset; // set pointer to right position
		memmove(pagePointer, data, length);
		pagePointer -= offset; // restore pointer to original position
	}

	// Internal flags
	UCHAR internalFlags = 0;
	if (isEndLevel) {
		internalFlags = BTN_END_LEVEL_FLAG;
	}
	else if (isEndBucket) {
		internalFlags = BTN_END_BUCKET_FLAG;
	}
	else if (length == 0)
	{
		if (prefix == 0) {
			internalFlags = BTN_ZERO_PREFIX_ZERO_LENGTH_FLAG;
		}
		else {
			internalFlags = BTN_ZERO_LENGTH_FLAG;
		}
	}
	else if (length == 1) {
		internalFlags = BTN_ONE_LENGTH_FLAG;
	}

	SINT64 number = recordNumber.getValue();
	if (number < 0) {
		number = 0;