wiki:Documentation/API/MUI_Datamap

Datamap.mui

Super class

Semaphore.mui

Background

The Datamap class serves as a simple data container, similar to Dataspace. They both are subclasses of Semaphore.mui. The data is sorted by the string key using btree.library. This makes lookups very fast.

Datamap is designed to store arbitrary data.

Attributes

Attribute Version ISG Type
MUIA_Datamap_AutoLock V20I..BOOL
MUIA_Datamap_CopyKeys V20I..BOOL
MUIA_Datamap_Pool V20I..APTR


Methods

Method Version
MUIM_Datamap_Clear V20
MUIM_Datamap_Find V20
MUIM_Datamap_Get V21
MUIM_Datamap_Iterate V20
MUIM_Datamap_IterationKey V20
MUIM_Datamap_Remove V20
MUIM_Datamap_Set V20


MUIA_Datamap_AutoLock

NAME

MUIA_Datamap_AutoLock — V20 [I..], BOOL, 0x8042fbe4

FUNCTION

Setting this attribute to TRUE ensures that Datamap methods are called under appropriate locks. Please note that this does not guarantee that the returned data will stay valid on return. It also does not protect the iteration methods. In case the Datamap is used by multiple threads, you must put the whole iteration into an exclusive lock.

MUIA_Datamap_CopyKeys

NAME

MUIA_Datamap_CopyKeys — V20 [I..], BOOL, 0x8042a179

FUNCTION

Setting this attribute to FALSE will skip the copying of the passed key to MUIM_Datamap_Set. Instead the key will be used directly for all tree related actions. It is up the the application to ensure the validity of the key as long as the corresponding entry is contained in the tree.

This attribute is very useful if your application uses static strings as keys for example.

MUIA_Datamap_Pool

NAME

MUIA_Datamap_Pool — V20 [I..], APTR, 0x80424724

FUNCTION

If set to a valid memory pool pointer created by exec/CreatePool() the datamap object will use this pool for all memory allocations instead of creating a private pool.

SEE ALSO

MUIM_Datamap_Set, exec.library/CreatePool

MUIM_Datamap_Clear

NAME

MUIM_Datamap_Clear — V20, 0x8042eebc

SYNOPSIS

DoMethod(obj, MUIM_Datamap_Clear);

FUNCTION

Remove and free all entries in the Datamap object.

MUIM_Datamap_Find

NAME

MUIM_Datamap_Find — V20, 0x8042d650

SYNOPSIS

DoMethod(obj, MUIM_Datamap_Find, CONST_STRPTR key);

FUNCTION

Look up an entry by a key.

INPUTS

CONST_STRPTR key
key to look up the entry by.

RESULT

Pointer to the stored data or NULL in case the key was not found.

SEE ALSO

MUIM_Datamap_Get, MUIM_Datamap_Iterate

MUIM_Datamap_Get

NAME

MUIM_Datamap_Get — V21, 0x8042c2ba

SYNOPSIS

DoMethod(obj, MUIM_Datamap_Get, CONST_STRPTR key, ULONG *size);

FUNCTION

Look up an entry by a key.

INPUTS

CONST_STRPTR key
key to look up the entry by.
ULONG *size
pointer to ULONG.

RESULT

Pointer to the stored data or NULL in case the key was not found. Additionally the size of the entry will be returned in the size parameter.

SEE ALSO

MUIM_Datamap_Set, MUIM_Datamap_Find, MUIM_Datamap_Get, MUIM_Datamap_Iterate

MUIM_Datamap_Iterate

NAME

MUIM_Datamap_Iterate — V20, 0x8042fda1

SYNOPSIS

DoMethod(obj, MUIM_Datamap_Iterate, ULONG *counter);

FUNCTION

This method iterates over all stored keys. It is perfectly legal to continue the iteration after removing the current item by calling MUIM_Datamap_Remove but calling MUIM_Datamap_Clear will make the iterator invalid.

INPUTS

ULONG *counter
pointer to a 32bit-sized storage for internal usage. This storage MUST be zeroed before starting the iteration.

RESULT

Pointer to the stored data or NULL after returning the last item

SEE ALSO

MUIM_Datamap_IterationKey

MUIM_Datamap_IterationKey

NAME

MUIM_Datamap_IterationKey — V20, 0x8042bc15

SYNOPSIS

DoMethod(obj, MUIM_Datamap_IterationKey, ULONG *counter);

FUNCTION

Returns the key associated with the current iteration stage.

INPUTS

ULONG *counter
pointer to the 32bit-sized storage used for MUIM_Datamap_Iterate.

RESULT

Pointer to a key or NULL if the counter doesn't contain a valid entry

EXAMPLE

Object o = DatamapObject, End;
APTR item;
ULONG counter;

/* assume data has been inserted into the map before */
counter = 0;
while((item = (APTR)DoMethod(o, MUIM_Datamap_Iterate, &counter)) != NULL)
{
  CONST_STRPTR key = (CONST_STRPTR)DoMethod(o, MUIM_Datamap_IterationKey, &counter);

  printf("key '%s', data %p\n", key, item);
}

SEE ALSO

MUIM_Datamap_Iterate

MUIM_Datamap_Remove

NAME

MUIM_Datamap_Remove — V20, 0x804203d8

SYNOPSIS

DoMethod(obj, MUIM_Datamap_Remove, CONST_STRPTR key);

FUNCTION

Removes the entry corresponding to the specified key.

INPUTS

CONST_STRPTR key
key to look up the entry by.

RESULT

NULL if no corresponding entry was not found.

SEE ALSO

MUIM_Datamap_Set

MUIM_Datamap_Set

NAME

MUIM_Datamap_Set — V20, 0x8042b84f

SYNOPSIS

DoMethod(obj, MUIM_Datamap_Set, CONST_APTR data, LONG len, CONST_STRPTR key);

FUNCTION

This method adds or changes an entry corresponding to the specified key. Keys are considered to be unique within a tree. Hence calling MUIM_Datamap_Set multiple times with the same key will overwrite the data set before.

INPUTS

CONST_APTR data
pointer to data to store.
LONG len
size of the data.
CONST_STRPTR key
the key to index the data by.

RESULT

NULL on failure or a non-NULL value on success.

SEE ALSO

MUIM_Datamap_Remove, MUIM_Datamap_Find, MUIM_Datamap_Iterate


Copyright © 1992-2006 by Stefan Stuntz
Copyright © 2006-2017 by Thore Böckelmann, Jens Maus

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Updated: 13-Dec-2017

Last modified 9 months ago Last modified on Mar 27, 2017, 4:00:32 PM