RefTab.Mesa - definitions for REF table abstraction
Copyright © 1985 by Xerox Corporation. All rights reserved.
Paxton - August 19, 1982 9:24 am
Teitelman - August 31, 1982 2:20 pm
Rovner - May 13, 1983 10:39 am
Russ Atkinson (RRA) February 5, 1985 2:01:00 pm PST
Ref: TYPE = REF RefTabRep;
RefTabRep:
PUBLIC
TYPE =
MONITORED
RECORD [mod:
CARDINAL, size:
INT, data:
REF Seq];
Seq:
TYPE =
RECORD[nodes:
SEQUENCE max: SeqIndex
OF Node];
SeqIndex: TYPE = CARDINAL[0..4000);
Node: TYPE = REF NodeRep;
NodeRep: TYPE = RECORD [key: Key, val: Val, next: Node];
Key: TYPE = REF;
Val: TYPE = REF;
Create:
PROC [mod: SeqIndex ← 17]
RETURNS [Ref];
creates new table with suggested hash size
GetSize:
PROC [x: Ref]
RETURNS [
INT];
returns number of key-value pairs in table
Fetch:
PROC [x: Ref, key: Key]
RETURNS [found:
BOOLEAN, val: Val];
looks up key in table, returns associated value (if any)
if found is TRUE, val is value associated with given key
if found is FALSE, val is NIL
Replace:
PROC [x: Ref, key: Key, val: Val]
RETURNS [
BOOLEAN];
returns TRUE after overwriting old value for existing key-value pair
if no previous value for key, returns FALSE without inserting new pair
Store:
PROC [x: Ref, key: Key, val: Val]
RETURNS [
BOOLEAN];
returns TRUE after inserting new pair
returns FALSE after overwriting old value for existing key-value pair
Insert:
PROC [x: Ref, key: Key, val: Val]
RETURNS [
BOOLEAN];
returns TRUE after inserted new pair
if previous value existed for key, returns FALSE without changing value
Delete:
PROC [x: Ref, key: Key]
RETURNS [
BOOLEAN];
deletes key-value pair associated with given key
returns TRUE if deletion actually occurred, FALSE if no such key
Pairs:
PROC [x: Ref, action: EachPairAction]
RETURNS [
BOOLEAN];
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
EachPairAction: TYPE = PROC [key: Key, val: Val] RETURNS [quit: BOOLEAN];
END.