language-Modula2-0.1: examples/Modula-2_Libraries/C.-Lins_Modula-2_Software_Component_Library/Vol4/hashing/ohash.mod
IMPLEMENTATION MODULE OHash;
(*==============================================================
Version : 2.0 16 Sep 1990 C. Lins
Compiler : Generic pc Modula-2
Component: Hash Table - Sequential Bounded Managed Iterator
Collision resolution using double hashing
REVISION HISTORY
v1.00 22 Apr 1989 C. Lins:
Initial Modula-2 implementation
v1.01 30 Jun 1989 C. Lins:
Removed separation of key and data.
v1.02 21 Aug 1989 C. Lins:
Added HashOf selector.
v1.03 29 Aug 1989 C. Lins:
Added HashOf selector.
v1.04 03 Sep 1989 C. Lins:
Copy hashing function to target hash table in Assign.
v1.05 19 Sep 1989 C. Lins:
Pass back result from hash table for key from searches
instead of key parameter.
v2.00 16 Sep 1990 C. Lins
Created generic pc version
(C) Copyright 1990 Charles A. Lins
==============================================================*)
FROM SCLStorage IMPORT
(*--proc*) Allocate, Deallocate;
FROM Relations IMPORT
(*--type*) Relation;
FROM HashTypes IMPORT
(*--type*) Exceptions, Operations, ComponentID,
FoundProc, NotFoundProc, UpdateProc, LoopProc,
AccessProc, HashFunction, States, Key, Data;
FROM Items IMPORT
(*--cons*) NullItem,
(*--type*) Item, AssignProc, CompareProc, DisposeProc;
FROM ErrorHandling IMPORT
(*--cons*) NullHandler,
(*--type*) HandlerProc,
(*--proc*) Raise;
FROM TypeManager IMPORT
(*--cons*) NullType,
(*--type*) TypeID,
(*--proc*) AssignOf, CompareOf, DisposeOf;
(*-------------------------*)
VAR tableError : Exceptions;
VAR handlers : ARRAY Exceptions OF HandlerProc;
PROCEDURE TableError () : Exceptions (*--out *);
BEGIN
RETURN tableError;
END TableError;
(*-------------------------*)
PROCEDURE SetHandler ( theError : Exceptions (*--in *);
theHandler : HandlerProc (*--in *));
BEGIN
handlers[theError] := theHandler;
END SetHandler;
(*-------------------------*)
PROCEDURE GetHandler ( theError : Exceptions (*--in *))
: HandlerProc (*--out *);
BEGIN
RETURN handlers[theError];
END GetHandler;
(*-------------------------*)
PROCEDURE RaiseErrIn ( theRoutine : Operations (*--in *);
theError : Exceptions (*--in *));
BEGIN
tableError := theError;
Raise(ComponentID + ModuleID, theRoutine, theError, handlers[theError]);
END RaiseErrIn;
(*-------------------------*)
TYPE HashTable = POINTER TO BoundedHashTable;
TYPE TableEntry = RECORD
state : States;
key : Key;
data : Data;
END (*-- TableEntry --*);
TYPE HashingTable = ARRAY [0..0] OF TableEntry;
TYPE BoundedHashTable = RECORD
keyID : TypeID;
dataID : TypeID;
h : HashFunction;
size : CARDINAL;
extent : CARDINAL;
table : HashingTable;
END (*-- BoundedHashTable --*);
PROCEDURE InitToEmpty ( theTable : HashTable (*--inout*));
VAR index : CARDINAL;
BEGIN
WITH theTable^ DO
FOR index := 0 TO size-1 DO
table[index].state := empty;
END (*--for*);
END (*--with*);
END InitToEmpty;
(*-------------------------*)
PROCEDURE FreeTableEntry ( theTable : HashTable (*--in *);
theEntry : TableEntry (*--inout*));
VAR free : DisposeProc; (*-- key/data disposal routine *)
BEGIN
free := DisposeOf(theTable^.keyID);
free(theEntry.key);
free := DisposeOf(theTable^.dataID);
free(theEntry.data);
END FreeTableEntry;
(*-------------------------*)
PROCEDURE Hash ( hashAddress: CARDINAL (*--in *);
tableSize : CARDINAL (*--in *);
VAR theBucket : CARDINAL (*--out *);
VAR increment : CARDINAL (*--out *));
BEGIN
theBucket := hashAddress MOD tableSize;
increment := hashAddress DIV tableSize;
IF (increment = 0) THEN
increment := 1;
END (*--if*);
END Hash;
(*-------------------------*)
(*
Search the given hash table for the given key returning the index
into the hash table where the key was found. Finding an empty
slot in the table causes the index to the last empty or deleted
slot encountered during the search.
*)
PROCEDURE Search ( theTable : HashTable (*--in *);
theKey : Key (*--in *);
VAR theBucket : CARDINAL (*--out *))
: BOOLEAN (*--out *);
VAR index : CARDINAL; (*-- loop index over table entries *)
incr : CARDINAL; (*-- increment *)
last : CARDINAL; (*-- last table entry to examine *)
compare : CompareProc; (*-- key comparison routine *)
comparison: Relation; (*-- compare result *)
BEGIN
theBucket := 0;
WITH theTable^ DO
compare := CompareOf(keyID);
Hash(h(theKey), size, index, incr);
last := (index + (size - 1) * incr) MOD size;
WHILE (index # last) DO
WITH table[index] DO
CASE state OF
empty:
IF (theBucket = 0) THEN
theBucket := index;
END (*--if*);
RETURN FALSE;
| deleted:
IF (theBucket = 0) THEN
theBucket := index;
END (*--if*);
| used:
comparison := compare(theKey, key);
IF (comparison = equal) THEN
theBucket := index;
RETURN TRUE;
ELSIF (comparison = greater) THEN
theBucket := index;
RETURN FALSE;
END (*--if*);
END (*--case*);
END (*--with*);
index := (index + incr) MOD size;
END (*--while*);
END (*--with*);
RETURN FALSE;
END Search;
(*-------------------------*)
PROCEDURE AddTableEntry ( theTable : HashTable (*--inout*);
theKey : Key (*--in *);
theData : Data (*--in *);
theProc : Operations (*--in *));
VAR index : CARDINAL; (*-- bucket where to insert *)
incr : CARDINAL; (*-- increment value *)
compare : CompareProc;
comparison: Relation;
tempData : Item;
BEGIN
WITH theTable^ DO
compare := CompareOf(keyID);
Hash(h(theKey), size, index, incr);
LOOP
WITH table[index] DO
IF (state = used) THEN
comparison := compare(key, theKey);
IF (comparison = equal) THEN
RaiseErrIn(theProc, duplicatekey);
EXIT (*--loop*);
ELSIF (comparison = greater) THEN
tempData := theKey;
theKey := key;
key := tempData;
tempData := theData;
theData := data;
data := tempData;
END (*--if*);
ELSE
(*-- empty or deleted --*)
state := used;
key := theKey;
data := theData;
INC(extent);
EXIT (*--loop*);
END (*--if*);
END (*--with*);
index := (index + incr) MOD size;
END (*--loop*);
END (*--with*);
END AddTableEntry;
(*-------------------------*)
PROCEDURE Create ( keyTypeID : TypeID (*--in *);
dataTypeID : TypeID (*--in *);
theSize : CARDINAL (*--in *);
hashFunc : HashFunction (*--in *))
: HashTable (*--out *);
CONST baseSize = SIZE(BoundedHashTable) - SIZE(HashingTable);
CONST entrySize = SIZE(TableEntry);
VAR newTable : HashTable; (*--temporary for new hash table object *)
BEGIN
tableError := noerr;
Allocate(newTable, baseSize + theSize * entrySize);
IF (newTable = NullTable) THEN
RaiseErrIn(create, overflow);
ELSE
WITH newTable^ DO
keyID := keyTypeID;
dataID := dataTypeID;
extent := 0;
size := theSize;
h := hashFunc;
END (*--with*);
InitToEmpty(newTable);
END (*--if*);
RETURN newTable;
END Create;
(*-------------------------*)
PROCEDURE Destroy (VAR theTable : HashTable (*--inout*));
CONST baseSize = SIZE(BoundedHashTable) - SIZE(HashingTable);
CONST entrySize = SIZE(TableEntry);
BEGIN
Clear(theTable);
IF (tableError = noerr) THEN
Deallocate(theTable, baseSize + theTable.size * entrySize);
END (*--if*);
END Destroy;
(*-------------------------*)
PROCEDURE Clear ( theTable : HashTable (*--inout*));
VAR index : CARDINAL;
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(clear, undefined);
ELSE
WITH theTable^ DO
FOR index := 0 TO size-1 DO
IF (table[index].state = used) THEN
FreeTableEntry(theTable, table[index]);
END (*--if*);
END (*--for*);
extent := 0;
END (*--with*);
InitToEmpty(theTable);
END (*--if*);
END Clear;
(*-------------------------*)
PROCEDURE Assign ( theTable : HashTable (*--in *);
VAR toTable : HashTable (*--inout*));
PROCEDURE RecreateTarget () : BOOLEAN (*--out *);
BEGIN
IF (theTable = NullTable) THEN
RaiseErrIn(assign, undefined);
ELSIF (toTable = NullTable) THEN
WITH theTable^ DO
toTable := Create(keyID, dataID, size, h);
END (*--with*);
ELSIF (toTable = theTable) THEN
RETURN FALSE;
ELSIF (toTable^.size >= theTable^.extent) THEN
Clear(toTable);
WITH theTable^ DO
toTable^.keyID := keyID;
toTable^.dataID := dataID;
toTable^.h := h;
END (*--with*);
ELSE
RaiseErrIn(assign, overflow);
END (*--if*);
RETURN tableError = noerr;
END RecreateTarget;
VAR assignKey : AssignProc; (*-- key assignment routine *)
assignData : AssignProc; (*-- data assignment routine *)
index : CARDINAL; (*-- loop index over table entries *)
BEGIN
tableError := noerr;
IF RecreateTarget() THEN
WITH theTable^ DO
assignKey := AssignOf(keyID);
assignData := AssignOf(dataID);
FOR index := 0 TO size-1 DO
WITH table[index] DO
IF (state = used) THEN
Insert(toTable, assignKey(key), assignData(data));
END (*--if*);
END (*--with*);
END (*--for*);
END (*--with*);
END (*--if*);
END Assign;
(*-------------------------*)
PROCEDURE Insert ( theTable : HashTable (*--inout*);
theKey : Key (*--in *);
theData : Data (*--in *));
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(insert, undefined);
ELSIF (theTable^.extent >= theTable^.size) THEN
RaiseErrIn(insert, overflow);
ELSE
AddTableEntry(theTable, theKey, theData, insert);
END (*--if*);
END Insert;
(*-------------------------*)
PROCEDURE Remove ( theTable : HashTable (*--inout*);
theKey : Key (*--in *);
notFound : NotFoundProc (*--in *));
VAR index : CARDINAL; (*-- bucket where key was found *)
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(remove, undefined);
ELSIF Search(theTable, theKey, index) THEN
WITH theTable^ DO
FreeTableEntry(theTable, table[index]);
table[index].state := deleted;
DEC(extent);
END (*--with*);
ELSE
notFound(theKey);
END (*--if*);
END Remove;
(*-------------------------*)
PROCEDURE Update ( theTable : HashTable (*--inout*);
theKey : Key (*--in *);
theData : Data (*--in *);
updateEntry: UpdateProc (*--in *));
VAR index : CARDINAL; (*-- bucket where key was found *)
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(remove, undefined);
ELSIF Search(theTable, theKey, index) THEN
updateEntry(theTable^.table[index].key, theTable^.table[index].data, theData);
ELSIF (theTable^.extent >= theTable^.size) THEN
RaiseErrIn(update, overflow);
ELSE
AddTableEntry(theTable, theKey, theData, update);
END (*--if*);
END Update;
(*-------------------------*)
PROCEDURE IsDefined ( theTable : HashTable (*--in *))
: BOOLEAN (*--out *);
BEGIN
RETURN (theTable # NullTable);
END IsDefined;
(*-------------------------*)
PROCEDURE IsEmpty ( theTable : HashTable (*--in *))
: BOOLEAN (*--out *);
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(isempty, undefined);
RETURN TRUE;
END (*--if*);
RETURN theTable^.extent = 0;
END IsEmpty;
(*-------------------------*)
PROCEDURE KeyTypeOf ( theTable : HashTable (*--in *))
: TypeID (*--out *);
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(typeof, undefined);
RETURN NullType;
END (*--if*);
RETURN theTable^.keyID;
END KeyTypeOf;
(*-------------------------*)
PROCEDURE DataTypeOf( theTable : HashTable (*--in *))
: TypeID (*--out *);
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(typeof, undefined);
RETURN NullType;
END (*--if*);
RETURN theTable^.dataID;
END DataTypeOf;
(*-------------------------*)
PROCEDURE HashOf ( theTable : HashTable (*--in *))
: HashFunction (*--out *);
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(hashof, undefined);
RETURN VAL(HashFunction, NIL);
END (*--if*);
RETURN theTable^.h;
END HashOf;
(*-------------------------*)
PROCEDURE SizeOf ( theTable : HashTable (*--in *))
: CARDINAL (*--out *);
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(sizeof, undefined);
RETURN 0;
END (*--if*);
RETURN theTable^.size;
END SizeOf;
(*-------------------------*)
PROCEDURE ExtentOf ( theTable : HashTable (*--in *))
: CARDINAL (*--out *);
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(extentof, undefined);
RETURN 0;
END (*--if*);
RETURN theTable^.extent;
END ExtentOf;
(*-------------------------*)
PROCEDURE IsPresent( theTable : HashTable (*--in *);
theKey : Key (*--in *);
found : FoundProc (*--in *);
notFound : NotFoundProc (*--in *));
VAR index : CARDINAL; (*-- bucket where item was found *)
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(ispresent, undefined);
ELSIF Search(theTable, theKey, index) THEN
found(theTable^.table[index].key, theTable^.table[index].data);
ELSE
notFound(theKey);
END (*--if*);
END IsPresent;
(*-------------------------*)
PROCEDURE LoopOver ( theTable : HashTable (*--in *);
process : LoopProc (*--in *));
VAR index : CARDINAL; (*-- loop index over hashing table *)
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(loopover, undefined);
ELSE
WITH theTable^ DO
FOR index := 0 TO size-1 DO
WITH table[index] DO
IF (state = used) & ~process(key, data) THEN
RETURN;
END (*--if*);
END (*--with*);
END (*--for*);
END (*--with*);
END (*--if*);
END LoopOver;
(*-------------------------*)
PROCEDURE Traverse ( theTable : HashTable (*--in *);
process : AccessProc (*--in *));
VAR index : CARDINAL; (*-- loop index over hashing table *)
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(traverse, undefined);
ELSE
WITH theTable^ DO
FOR index := 0 TO size-1 DO
WITH table[index] DO
IF (state = used) THEN
process(key, data);
END (*--if*);
END (*--with*);
END (*--for*);
END (*--with*);
END (*--if*);
END Traverse;
(*-------------------------*)
PROCEDURE Iterate ( theTable : HashTable (*--in *);
process : IterateProc (*--in *));
VAR index : CARDINAL; (*-- loop index over hashing table *)
BEGIN
tableError := noerr;
IF (theTable = NullTable) THEN
RaiseErrIn(traverse, undefined);
ELSE
WITH theTable^ DO
FOR index := 0 TO size-1 DO
WITH table[index] DO
CASE state OF
used:
process(index, state, key, data);
| empty, deleted:
process(index, state, NullItem, NullItem);
END (*--case*);
END (*--with*);
END (*--for*);
END (*--with*);
END (*--if*);
END Iterate;
(*-------------------------*)
BEGIN
FOR tableError := MIN(Exceptions) TO MAX(Exceptions) DO
SetHandler(tableError, NullHandler);
END (*--for*);
SetHandler(noerr, NullHandler);
tableError := noerr;
NullTable := NIL;
END OHash.