hfscommon/BTree/BTreeAllocate.c

99 Function:	Searches the map records for the first free node, marks it "in use" and
100 			returns the node number found. This routine should really only be called
112 Output:		nodeNum		- number of node allocated
123 	BlockDescriptor	 node;
132 	nodeNumber		= 0;				// first node number of header map record
133 	node.buffer		= nil;				// clear node.buffer to get header node
135 	node.blockHeader = nil;
139 		err = GetMapNode (btreePtr, &node, &mapPtr, &mapSize);
143 		ModifyBlockStart(btreePtr->fileRefNum, &node);
193 	*pos |= SWAP_BE16 (mask);				// set the map bit for the node
195 	err = UpdateNode (btreePtr, &node, 0, kLockTransaction);
201 	/* Account for allocations from node reserve */
212 	(void) ReleaseNode (btreePtr, &node);
222 Routine:	FreeNode	-	Clear allocation bit for node.
224 Function:	Finds the bit representing the node specified by nodeNum in the node
229 			nodeNum		- number of node to mark free
234 			fsBTNoMoreMapNodesErr	- node number is beyond end of node map
241 	BlockDescriptor	 node;
249 	nodeIndex			= 0;				// first node number of header map record
250 	node.buffer			= nil;				// invalidate node.buffer to get header node
251 	node.blockHeader    = nil;
255 		err = GetMapNode (btreePtr, &node, &mapPos, &mapSize);
264 	ModifyBlockStart(btreePtr->fileRefNum, &node);
272 	err = UpdateNode (btreePtr, &node, 0, kLockTransaction);
282 	(void) ReleaseNode (btreePtr, &node);
426 		((BTNodeDescriptor*)newNode.buffer)->fLink = nodeNum;	// point to next map node
519 Routine:	GetMapNode	-	Get the next map node and pointer to the map record.
521 Function:	Given a BlockDescriptor to a map node in nodePtr, GetMapNode releases
522 			it and gets the next node. If nodePtr->buffer is nil, then the header
523 			node is retrieved.
527 			nodePtr		- pointer to a BlockDescriptor of a map node
529 Output:		nodePtr		- pointer to the BlockDescriptor for the next map node
530 			mapPtr		- pointer to the map record within the map node
535 			fsBTInvalidNodeErr			- bad node, or not node type kMapNode
675 						continue;				/* This node is in use. */
685 					 * node.  Since we'll probably be writing a lot of nodes,
693 						printf("hfs: BTZeroUnusedNodes: unable to read node %u\n", nodeNumber + bitNumber);
700 						 * This node is already part of a transaction and will be written when