
Card4Tab: CEDAR DEFINITIONS = BEGIN

Ref: TYPE = REF Card4TabRep;
Card4TabRep: TYPE = MONITORED RECORD [impl: REF Card4TabImplRep];
Card4TabImplRep: TYPE;

Key: TYPE = ARRAY [0 .. 3] OF CARD;
Val: TYPE = REF;

EqualProc: TYPE = PROC [key1, key2: Key] RETURNS [BOOL];
HashProc: TYPE = PROC [key: Key] RETURNS [CARDINAL];

Create: PROC [mod: NAT м 17, equal: EqualProc м NIL, hash: HashProc м NIL] RETURNS [Ref];


GetSize: PROC [x: Ref] RETURNS [INT];

Fetch: PROC [x: Ref, key: Key] RETURNS [found: BOOL, val: Val];

Replace: PROC [x: Ref, key: Key, val: Val] RETURNS [BOOL];

Store: PROC [x: Ref, key: Key, val: Val] RETURNS [BOOL];

Insert: PROC [x: Ref, key: Key, val: Val] RETURNS [BOOL];

Delete: PROC [x: Ref, key: Key] RETURNS [BOOL];

Erase: PROC [x: Ref];

EachPairAction: TYPE = PROC [key: Key, val: Val] RETURNS [quit: BOOL м FALSE];
Pairs: PROC [x: Ref, action: EachPairAction] RETURNS [BOOL];


UpdateOperation: TYPE = {none, store, delete};
UpdateAction: TYPE
= PROC [found: BOOL, val: Val]
RETURNS [op: UpdateOperation м none, new: Val м NIL];
Update: PROC [x: Ref, key: Key, action: UpdateAction];


Copy: PROC [x: Ref] RETURNS [Ref];


END.
   Д  
Card4Tab.mesa
Copyright ╙ 1990, 1992 by Xerox Corporation.  All rights reserved.
Last tweaked by Mike Spreitzer on July 13, 1990 8:03:51 am PDT
A Card4Tab is a hash table which associates pair-of-CARD keys with REF values.  Card4Tab is like RefTab and SymTab except for the Key type.

... creates new table with suggested hash size.
When equal=NIL, the keys are compared with `key1=key2'.
When hash=NIL, some reasonable hash function is used.
... returns number of key-value pairs in table (use this to properly deal with monitored data in preference to using the size field)
... looks up key in table, returns associated value (if any); if found = TRUE, val = value associated with given key; if found = FALSE, val = NIL
... replaces value for existing key; returns TRUE if previous value overwritten; if no previous value for key, returns FALSE without inserting new pair
... stores new key-value pair, overwriting previous value for given key; returns TRUE if new value, FALSE if previous value overwritten
... inserts new key-value pair, except if previous value for given key; returns TRUE if inserted, FALSE if previous value for key
... deletes key-value pair associated with given key; returns TRUE if deletion actually occurred, FALSE if no such key
... deletes all key-value pairs in the table


... enumerates pairs currently in symbol table in unspecified order; pairs inserted/deleted during enumeration may or may not be seen; applies action to each pair until action returns TRUE or no more pairs; returns TRUE if some action returns TRUE


... atomically performs an update action; looks up key and calls action, which returns the desired operation.  If op=none, the table is not changed; if op=store, the new value is stored; if op=delete, key is removed from the table.
... atomically copies the table.
Carl Hauser, January 14, 1988 2:27:48 pm PST
Folded in CedarChest7.0's RefTabExtras interface

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