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
Size in bytes of the memory block to allocate. 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