Btree Functions

:Associate with "Btree Functions" More...

Typedefs
typedef int(*)	BTreeDumpFunc (void *data, INT32 *tagnum, void *username)
typedef int(*)	BTreeTestFunc (void *, void *, void *)
Functions
GEOMLIBEXPORT void *	BTreeAlloc (int numitems, int datasize, BTreeTestFunc testfunc, void *userdata)
GEOMLIBEXPORT int	BTreeClear (void *item)
GEOMLIBEXPORT int	BTreeDump (void *tree, BTreeDumpFunc, void *userdata)
GEOMLIBEXPORT int	BTreeDumpT (void *tree, BTreeDumpFunc, void *userdata)
GEOMLIBEXPORT INT32	BTreeFindKey (void *tree, void *data, INT32 tagnum, int *add)
GEOMLIBEXPORT int	BTreeFree (void *tree)
GEOMLIBEXPORT void *	BTreeGetUserData (void *tree)
GEOMLIBEXPORT int	BTreeNewFunc (void *tree, BTreeTestFunc, void *userdata)
GEOMLIBEXPORT INT32	BTreeSearchKey (void *tree, void *data)
GEOMLIBEXPORT void	BTreeSetTestFunc (void *btree, BTreeTestFunc Test, void *userdata, bool TestFuncIsConst)

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Detailed Description

:Associate with "Btree Functions"

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Typedef Documentation

typedef int(*) BTreeDumpFunc(void *data,INT32 *tagnum,void *username)

Callback used to return data.

Definition at line 96 of file btreefun.h.

typedef int(*) BTreeTestFunc(void *, void *, void *)

Tree comparison function used in searching/adding.

Returns:

>, ==, < 0.

Definition at line 89 of file btreefun.h.

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Function Documentation

GEOMLIBEXPORT void* BTreeAlloc	(	int	numitems,
		int	datasize,
		BTreeTestFunc	testfunc,
		void *	userdata
	)

Allocate a "balanced tree".

Returns:

Handle to tree instance.

Note. At the current time, it is assumed that the test function may modify the data, forcing the tree to do more work that it should have to. You should not rely on this assumption, as it was an obscure, undocumented side effect and likely to change some day. Instead, you should call BTreeSetTestFunc() and tell it if your test function can modify the data.

Parameters:

numitems	Number of items to store per node
datasize	Size of data to tree in bytes
testfunc	Comparison function used in searching/adding
userdata	Data passed to comparison function

GEOMLIBEXPORT int BTreeClear

(

void *

item

)

Clears item from "balanced tree".

Parameters:

item	Item to be cleared from tree

GEOMLIBEXPORT int BTreeDump	(	void *	tree,
		BTreeDumpFunc	,
		void *	userdata
	)

Dump a "balanced tree" in "random" order.

NOTE: This function transverses the tree as it is stored, no order is at all guaranteed!

Parameters:

tree	Handle to tree instance
userdata	User data passed to Dump()

GEOMLIBEXPORT int BTreeDumpT	(	void *	tree,
		BTreeDumpFunc	,
		void *	userdata
	)

Dump a "balanced tree" in "traversal" order.

NOTE: This function transverses the tree and dumps the data in the order that the comparison function (see BTreeAlloc()) stipulated.

Parameters:

tree	Handle to tree instance
userdata	User data passed to Dump()

GEOMLIBEXPORT INT32 BTreeFindKey	(	void *	tree,
		void *	data,
		INT32	tagnum,
		int *	add
	)

Search "balanced tree" for a specified key, add if no match found.

Returns:

tag number assigned to the data if (>=0), else error

Parameters:

tree	Handle to tree instance
data	Data to find and add if necessary
tagnum	Number to tag data with
add	Set if data was added to tree

GEOMLIBEXPORT int BTreeFree

(

void *

tree

)

Free a "balanced tree".

Parameters:

tree	Handle to tree instance

GEOMLIBEXPORT void* BTreeGetUserData

(

void *

tree

)

Get the userdata associated with 'tree'.

Parameters:

tree	Handle to tree instance

GEOMLIBEXPORT int BTreeNewFunc	(	void *	tree,
		BTreeTestFunc	,
		void *	userdata
	)

Change test function for a "balanced tree".

Parameters:

tree	Handle to tree instance
userdata	Data passed to comparison function

GEOMLIBEXPORT INT32 BTreeSearchKey	(	void *	tree,
		void *	data
	)

Search "balanced tree" for a specified key.

Returns:

-1 = Not found, < -1 Error, else the tag number associated with the data. See BTreeFindKey().

Parameters:

tree	Handle to tree instance
data	Data to find if exists

GEOMLIBEXPORT void BTreeSetTestFunc	(	void *	btree,
		BTreeTestFunc	Test,
		void *	userdata,
		bool	TestFuncIsConst
	)

Change test function for a "balanced tree".

This is similar to BTreeNewFunc, but allows you to tell the BTree that the function won't modify the data it's passed. The default behaviour for btrees is to assume that the test function can modify the data passed.

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