Index Map

An indexmap is basically a managed array of pointers, but it allows you to derive relatively quickly the index from a pointer in the array. More...

Collaboration diagram for Index Map:

Data Structures
struct	t_indexmap_entry
	An indexmap element. More...
struct	t_indexmap
	An indexmap object. More...

Functions
t_indexmap *	indexmap_new (void)
	Create a new indexmap object. More...
void	indexmap_append (t_indexmap *x, void *data)
	Add an item to an indexmap. More...
t_max_err	indexmap_move (t_indexmap *x, void *data, long newindex)
	Move an item to a different position in an indexmap. More...
t_max_err	indexmap_delete (t_indexmap *x, void *data)
	Delete a specified item from an indexmap. More...
t_max_err	indexmap_delete_index (t_indexmap *x, long index)
	Delete an item from the indexmap by index. More...
t_max_err	indexmap_delete_multi (t_indexmap *x, long count, void **pdata)
	Delete multiple specified items from an indexmap. More...
t_max_err	indexmap_delete_index_multi (t_indexmap *x, long count, long *indices)
	Delete multiple items from an indexmap by index. More...
void *	indexmap_datafromindex (t_indexmap *x, long index)
	Get an item from an indexmap by index. More...
t_max_err	indexmap_indexfromdata (t_indexmap *x, void *data, long *index)
	Find the index of an item given a pointer to the item. More...
long	indexmap_getsize (t_indexmap *x)
	Return the number of items in an indexmap. More...
void	indexmap_clear (t_indexmap *x)
	Delete all items in an indexmap. More...
void	indexmap_sort (t_indexmap *x, t_cmpfn fn)
	Sort the items in an indexmap. More...

Detailed Description

An indexmap is basically a managed array of pointers, but it allows you to derive relatively quickly the index from a pointer in the array.

The index is assumed to be 0-N (where N is the current size of the array). You can sort the data and retain access to an index from the data relatively quickly. There is a hashtab which holds pieces of memory that hold indices that can be referenced by the data pointer. There is also an array of data pointers – this is in "index" order. When operations take place on the array (insert, delete, sort), the pointers in the hashtab are updated with new indices.

Function Documentation

void indexmap_append	(	t_indexmap *	x,
		void *	data
	)

Add an item to an indexmap.

Parameters

x	The indexmap instance.
data	The item to add.

void indexmap_clear

(

t_indexmap *

x

)

Delete all items in an indexmap.

Parameters

x	The indexmap instance.

void* indexmap_datafromindex	(	t_indexmap *	x,
		long	index
	)

Get an item from an indexmap by index.

Parameters

x	The indexmap instance.
index	The index from which to fetch a stored item.

Returns

The item stored at the specified index.

t_max_err indexmap_delete	(	t_indexmap *	x,
		void *	data
	)

Delete a specified item from an indexmap.

Parameters

x	The indexmap instance.
data	The item pointer to remove from the indexmap.

Returns

A Max error code.

t_max_err indexmap_delete_index	(	t_indexmap *	x,
		long	index
	)

Delete an item from the indexmap by index.

Parameters

x	The indexmap instance.
index	The index of the item to remove from the indexmap.

Returns

A Max error code.

t_max_err indexmap_delete_index_multi	(	t_indexmap *	x,
		long	count,
		long *	indices
	)

Delete multiple items from an indexmap by index.

Parameters

x	The indexmap instance.
count	The number of items to remove from the indexmap.
indices	The address of the first of an array of index numbers to remove the indexmap.

Returns

A Max error code.

t_max_err indexmap_delete_multi	(	t_indexmap *	x,
		long	count,
		void **	pdata
	)

Delete multiple specified items from an indexmap.

Parameters

x	The indexmap instance.
count	The number of items to remove from the indexmap.
pdata	The address of the first of an array of item pointers to remove from the indexmap.

Returns

A Max error code.

long indexmap_getsize

(

t_indexmap *

x

)

Return the number of items in an indexmap.

Parameters

x	The indexmap instance.

Returns

The number of items in the indexmap.

t_max_err indexmap_indexfromdata	(	t_indexmap *	x,
		void *	data,
		long *	index
	)

Find the index of an item given a pointer to the item.

Parameters

x	The indexmap instance.
data	The item whose index you wish to look up.
index	The address of a variable to hold the retrieved index.

Returns

A Max error code.

t_max_err indexmap_move	(	t_indexmap *	x,
		void *	data,
		long	newindex
	)

Move an item to a different position in an indexmap.

Parameters

x	The indexmap instance.
data	The item in the indexmap to move.
newindex	The new index to which to move the item.

Returns

A Max error code.

t_indexmap* indexmap_new

(

void

)

Create a new indexmap object.

Returns

Pointer to the new indexmap object.

void indexmap_sort	(	t_indexmap *	x,
		t_cmpfn	fn
	)

Sort the items in an indexmap.

Item are sorted using a t_cmpfn function that is passed in as an argument.

Parameters

x	The indexmap instance.
fn	The function used to sort the list.

See also

linklist_sort()