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Blt_Tree(3) Blt Library Procedures Blt_Tree(3)
 

NAME

Blt_Tree - Tree data object.

SYNOPSIS

#include <bltTree.h>
struct Blt_Tree { Tcl_Alloc(size)
Tcl_Free(ptr)
char * Tcl_Realloc(ptr, size)

ARGUMENTS

int size (in)
Size in bytes of the memory block to allocate.
char *ptr (in)
Pointer to memory block to free or realloc.
    
 

DESCRIPTION

These procedures provide a platform and compiler independent interface for memory allocation. Programs that need to transfer ownership of memory blocks between Tcl and other modules should use these routines rather than the native malloc() and free() routines provided by the C run-time library.
Tcl_Alloc returns a pointer to a block of at least size bytes suitably aligned for any use.
Tcl_Free makes the space referred to by ptr available for further allocation.
Tcl_Realloc changes the size of the block pointed to by ptr to size bytes and returns a pointer to the new block. The contents will be unchanged up to the lesser of the new and old sizes. The returned location may be different from ptr.

TREE OBJECT ROUTINES

The following library routines allow you to create and destroy tree objects. Each tree object has a name that uniquely identifies it. Tree objects can also be shared. For example, the tree and hiertable commands may access the same tree data object. Each client grabs a token associated with the tree. When all tokens are released the tree data object is automatically destroyed.
Blt_TreeCreate
Create a tree data object and optionally obtains a token associated with it.
Blt_TreeExists
Indicates if a tree by a given name exists.
Blt_TreeGetToken
Obtains a token for an existing tree data object.
Blt_TreeReleaseToken
Releases a token for a tree data object. The tree object is deleted when all outstanding tokens have been released.
Blt_TreeName
Returns the name of the tree object.
Blt_TreeChangeRoot
Specifies a node as the new root to a tree.

TREENODE ROUTINES

Tree objects initially contain only a root node. You can add or delete nodes with the following routines.
Blt_TreeCreateNode
Creates a new child node for a given parent in the tree.
Blt_TreeDeleteNode
Deletes a node and its children.
Blt_TreeNodeId
Returns the unique node identifier for a node.
Blt_TreeGetNode
Gets a node based upon its identifier.
Blt_TreeFindChild
Searches for a child node given by its label in a parent node.
Blt_TreeNodeLabel
Returns the current label for a node.
Blt_TreeRelabelNode
Resets a node's label.
Blt_TreeNodePath
Returns the fullpath to a node.
Blt_TreeNodeDepth
Returns the depth of the node.
Blt_TreeNodeDegree
Returns the number of children for a node.
Blt_TreeIsLeaf
Indicates if a node has no children.
Blt_TreeIsBefore
Indicates if a node is before another node in depth-first search order.
Blt_TreeIsAncestor
Indicates if a node is an ancestor or another.
Blt_TreeSortNode
Sorts the children of a node.
Blt_TreeSize
Returns the number of nodes in a node and its descendants.
Blt_TreeMoveNode

NODE NAVIGATION

Each node can have zero or more children nodes. These routines let you navigate the tree hierarchy.
Blt_TreeNodeParent
Returns the parent node.
Blt_TreeFirstChild
Returns the first child of a parent node.
Blt_TreeLastChild
Returns the last child of a parent node.
Blt_TreeNextSibling
Returns the next sibling node in the parent's list of children.
Blt_TreePrevSibling
Returns the previous sibling node in the parent's list of children.
Blt_TreeRootNode
Returns the root node of the tree.
Blt_TreeNextNode
Returns the next node in depth-first order.
Blt_TreePrevNode
Returns the previous node in depth-first order.
Blt_TreeEndNode
Returns the last node in the tree as determined by depth-first order.
Blt_TreeApply
Walks through a node and all it descendants, applying a given callback procedure.
Blt_TreeApplyDFS
Walks through a node and all it descendants in depth-first search order, applying a given callback procedure.
Blt_TreeApplyBFS
Walks through a node and all it descendants in breadth-first search order, applying a given callback procedure.

NODE DATA VALUES

Data values can be stored at any node. Values have by both a string key and a Tcl_Obj value. Data value keys do not have to be homogenous across all nodes (i.e. nodes do not have to contain the same keys). There is also a special node array data type.
Blt_TreeGetValue
Gets the node data value given by a key.
Blt_TreeValueExists
Indicates if a node data value given by a key exists.
Blt_TreeSetValue
Sets a node's value of a key.
Blt_TreeUnsetValue
Remove the node data value and key.
Blt_TreeGetArrayValue
Gets the node data array value given by a key and an array index.
Blt_TreeSetArrayValue
Sets the node data array value given by a key and an array index.
Blt_TreeUnsetArrayValue
Remove the node data array value.
Blt_TreeArrayValueExists
Determines if an array element by a given index exists.
Blt_TreeFirstKey
Returns the key of the first value in the node.
Blt_TreeNextKey
Returns the key of the next value in the node.
Blt_TreePrivateValue
Lock the value to current client, making it private.
Blt_TreePublicValue
Unlock the value so that all clients can access it.
Blt_TreeGetKey

NODE TRACES

Blt_TreeCreateTrace
Sets up a trace callback to be invoked when the node value is read, set, or unset.
Blt_TreeDeleteTrace
Deletes an existing trace.

NODE EVENTS

Blt_TreeCreateEventHandler
Sets up a callback to be invoked when events (create, delete, relabel, etc) take place on a node.
Blt_TreeDeleteEventHandler
Deletes an existing node callback.

KEYWORDS

alloc, allocation, free, malloc, memory, realloc
2.5 BLT