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The mtr package
Multiway-branch tree manipulation
Fabio Somenzi
**********************************************************************
Mtr_AllocNode() Allocates new tree node.
Mtr_CopyTree() Makes a copy of tree.
Mtr_CreateFirstChild() Creates a new node and makes it the first child
of parent.
Mtr_CreateLastChild() Creates a new node and makes it the last child
of parent.
Mtr_DeallocNode() Deallocates tree node.
Mtr_DissolveGroup() Merges the children of `group' with the
children of its parent.
Mtr_FindGroup() Finds a group with size leaves starting at low,
if it exists.
Mtr_FreeTree() Disposes of tree rooted at node.
Mtr_InitGroupTree() Allocate new tree.
Mtr_InitTree() Initializes tree with one node.
Mtr_MakeFirstChild() Makes child the first child of parent.
Mtr_MakeGroup() Makes a new group with size leaves starting at
low.
Mtr_MakeLastChild() Makes child the last child of parent.
Mtr_MakeNextSibling() Makes second the next sibling of first.
Mtr_PrintGroups() Prints the groups as a parenthesized list.
Mtr_PrintTree() Prints a tree, one node per line.
Mtr_ReadGroups() Reads groups from a file and creates a group
tree.
Mtr_SwapGroups() Swaps two children of a tree node.
**********************************************************************
This package provides two layers of functions. Functions of the lower level
manipulate multiway-branch trees, implemented according to the classical
scheme whereby each node points to its first child and its previous and
next siblings. These functions are collected in mtrBasic.c. Functions
of the upper layer deal with group trees, that is the trees used by group
sifting to represent the grouping of variables. These functions are
collected in mtrGroup.c.
MtrNode *
Mtr_AllocNode(
)
Allocates new tree node. Returns pointer to node.
Side Effects: None
MtrNode *
Mtr_CopyTree(
MtrNode * node,
int expansion
)
Makes a copy of tree. If parameter expansion is greater than 1, it will
expand the tree by that factor. It is an error for expansion to be less than
1. Returns a pointer to the copy if successful; NULL otherwise.
Side Effects: None
MtrNode *
Mtr_CreateFirstChild(
MtrNode * parent
)
Creates a new node and makes it the first child of parent. Returns pointer
to new child.
Side Effects: None
MtrNode *
Mtr_CreateLastChild(
MtrNode * parent
)
Creates a new node and makes it the last child of parent. Returns pointer to
new child.
Side Effects: None
void
Mtr_DeallocNode(
MtrNode * node node to be deallocated
)
Deallocates tree node.
Side Effects: None
MtrNode *
Mtr_DissolveGroup(
MtrNode * group group to be dissolved
)
Merges the children of `group' with the children of its parent. Disposes of
the node pointed by group. If group is the root of the group tree, this
procedure leaves the tree unchanged. Returns the pointer to the parent of
`group' upon successful termination; NULL otherwise.
Side Effects: None
MtrNode *
Mtr_FindGroup(
MtrNode * root, root of the group tree
unsigned int low, lower bound of the group
unsigned int size upper bound of the group
)
Finds a group with size leaves starting at low, if it exists. This procedure
relies on the low and size fields of each node. It also assumes that the
children of each node are sorted in order of increasing low. Returns the
pointer to the root of the group upon successful termination; NULL
otherwise.
Side Effects: None
void
Mtr_FreeTree(
MtrNode * node
)
Disposes of tree rooted at node.
Side Effects: None
MtrNode *
Mtr_InitGroupTree(
int lower,
int size
)
Allocate new tree with one node, whose low and size fields are specified by
the lower and size parameters. Returns pointer to tree root.
Side Effects: None
MtrNode *
Mtr_InitTree(
)
Initializes tree with one node. Returns pointer to node.
Side Effects: None
void
Mtr_MakeFirstChild(
MtrNode * parent,
MtrNode * child
)
Makes child the first child of parent.
Side Effects: None
MtrNode *
Mtr_MakeGroup(
MtrNode * root, root of the group tree
unsigned int low, lower bound of the group
unsigned int size, upper bound of the group
unsigned int flags flags for the new group
)
Makes a new group with size leaves starting at low. If the new group
intersects an existing group, it must either contain it or be contained by
it. This procedure relies on the low and size fields of each node. It also
assumes that the children of each node are sorted in order of increasing
low. In case of a valid request, the flags of the new group are set to the
value passed in `flags.' This can also be used to change the flags of an
existing group. Returns the pointer to the root of the new group upon
successful termination; NULL otherwise. If the group already exists, the
pointer to its root is returned.
Side Effects: None
void
Mtr_MakeLastChild(
MtrNode * parent,
MtrNode * child
)
Makes child the last child of parent.
Side Effects: None
void
Mtr_MakeNextSibling(
MtrNode * first,
MtrNode * second
)
Makes second the next sibling of first. Second becomes a child of the parent
of first.
Side Effects: None
void
Mtr_PrintGroups(
MtrNode * root, root of the group tree
int silent flag to check tree syntax only
)
Prints the groups as a parenthesized list. After each group, the group's
flag are printed, preceded by a `|'. For each flag (except MTR_TERMINAL) a
character is printed. F: MTR_FIXED N: MTR_NEWNODE S:
MTR_SOFT The second argument, silent, if different from 0, causes
Mtr_PrintGroups to only check the syntax of the group tree.
Side Effects: None
void
Mtr_PrintTree(
MtrNode * node
)
Prints a tree, one node per line.
Side Effects: None
MtrNode *
Mtr_ReadGroups(
FILE * fp, file pointer
int nleaves number of leaves of the new tree
)
Reads groups from a file and creates a group tree. Each group is specified
by three fields: low size flags. Low and size are (short)
integers. Flags is a string composed of the following characters (with
associated translation): D: MTR_DEFAULT F: MTR_FIXED N:
MTR_NEWNODE S: MTR_SOFT T: MTR_TERMINAL Normally, the only
flags that are needed are D and F. Groups and fields are separated by white
space (spaces, tabs, and newlines). Returns a pointer to the group tree if
successful; NULL otherwise.
Side Effects: None
int
Mtr_SwapGroups(
MtrNode * first, first node to be swapped
MtrNode * second second node to be swapped
)
Swaps two children of a tree node. Adjusts the high and low fields of the
two nodes and their descendants. The two children must be adjacent. However,
first may be the younger sibling of second. Returns 1 in case of success; 0
otherwise.
Side Effects: None