*************************************************************************
Copyright (C) Olivetti 1989
All Rights reserved
Use and copy of this software and preparation of derivative works based
upon this software are permitted to any person, provided this same
copyright notice and the following Olivetti warranty disclaimer are
included in any copy of the software or any modification thereof or
derivative work therefrom made by any person.
This software is made available AS IS and Olivetti disclaims all
warranties with respect to this software, whether expressed or implied
under any law, including all implied warranties of merchantibility and
fitness for any purpose. In no event shall Olivetti be liable for any
damages whatsoever resulting from loss of use, data or profits or
otherwise arising out of or in connection with the use or performance
of this software.
*************************************************************************
Copyright (C) 1994, Digital Equipment Corp.
MODULE M3CHash;
IMPORT Text, Word;
REVEAL
Table = TablePublic BRANDED OBJECT
size: CARDINAL;
idCreator: IdCreator;
ids: REF ARRAY OF Id;
OVERRIDES
init := InitTable;
enter := Enter;
lookup := Lookup;
setCreator := SetCreator;
enterCharsWithValue := EnterCharsWithValue;
enterTextWithValue := EnterTextWithValue;
END;
Id = IdPublic BRANDED OBJECT
next: Id;
text: Text.T;
OVERRIDES
toText := ToText;
END;
Value = ValuePublic BRANDED OBJECT
sum, sumOfSums := 0;
OVERRIDES
init := InitValue;
reset := ResetValue;
addCharToValue := AddCharToValue;
END;
<*INLINE*> PROCEDURE InitValue(v: Value): Value=
BEGIN
RETURN v;
END InitValue;
<*INLINE*> PROCEDURE ResetValue(v: Value)=
BEGIN
v.sum := 0; v.sumOfSums := 0;
END ResetValue;
<*INLINE*> PROCEDURE AddCharToValue(v: Value; ch: CHAR)=
BEGIN
v.sum := Word.Plus(v.sum, ORD(ch));
v.sumOfSums := Word.Plus(v.sumOfSums, v.sum);
END AddCharToValue;
<*INLINE*> PROCEDURE Create(
t: Table;
text: Text.T;
VAR list: Id)
: Id=
BEGIN
WITH new = t.idCreator.new(text) DO
new.next := list;
new.text := text;
list := new;
RETURN new;
END;
END Create;
<*INLINE*> PROCEDURE Equal(
t: Text.T;
READONLY chars: ARRAY OF CHAR)
: BOOLEAN
=
BEGIN
FOR i := 0 TO LAST(chars) DO
IF Text.GetChar(t, i) # chars[i] THEN RETURN FALSE END;
END;
RETURN TRUE;
END Equal;
<*INLINE*> PROCEDURE FindChars(
READONLY chars: ARRAY OF CHAR;
id: Id)
: Id=
BEGIN
WHILE id # NIL DO
IF Text.Length(id.text) = NUMBER(chars) AND Equal(id.text, chars) THEN
EXIT;
ELSE
id := id.next;
END;
END;
RETURN id;
END FindChars;
PROCEDURE EnterCharsWithValue(
t: Table;
v: Value;
READONLY chars: ARRAY OF CHAR)
: Id
=
BEGIN
WITH id = t.ids[v.sumOfSums MOD t.size], found = FindChars(chars, id) DO
IF found # NIL THEN
RETURN found;
ELSE
RETURN Create(t, Text.FromChars(chars), id);
END;
END;
END EnterCharsWithValue;
<*INLINE*> PROCEDURE FindText(text: Text.T; id: Id): Id=
BEGIN
WHILE id # NIL DO
IF Text.Equal(id.text, text) THEN
EXIT;
ELSE
id := id.next;
END;
END;
RETURN id;
END FindText;
PROCEDURE EnterTextWithValue(t: Table; v: Value; text: Text.T): Id=
BEGIN
WITH id = t.ids[v.sumOfSums MOD t.size], found = FindText(text, id) DO
IF found # NIL THEN
RETURN found;
ELSE
RETURN Create(t, text, id);
END;
END;
END EnterTextWithValue;
<*INLINE*> PROCEDURE TextValue(text: Text.T): Value=
VAR
v := NEW(Value).init();
BEGIN
FOR i := 0 TO Text.Length(text) - 1 DO
AddCharToValue(v, Text.GetChar(text, i));
END; (* for *)
RETURN v;
END TextValue;
<*INLINE*> PROCEDURE Enter(t: Table; text: Text.T): Id=
BEGIN
RETURN EnterTextWithValue(t, TextValue(text), text);
END Enter;
<*INLINE*> PROCEDURE Lookup(t: Table; text: Text.T; VAR id: Id): BOOLEAN=
VAR
tempId := FindText(text, t.ids[TextValue(text).sumOfSums MOD t.size]);
BEGIN
IF tempId # NIL THEN id := tempId; RETURN TRUE ELSE RETURN FALSE END;
END Lookup;
TYPE
DefaultIdCreator = IdCreator OBJECT OVERRIDES new := DefaultNewId END;
<*INLINE*> PROCEDURE DefaultNewId(<*UNUSED*> c: IdCreator;
<*UNUSED*> t: Text.T): Id=
BEGIN
RETURN NEW(Id);
END DefaultNewId;
<*INLINE*> PROCEDURE NewDefaultIdCreator(): DefaultIdCreator=
BEGIN
RETURN NEW(DefaultIdCreator);
END NewDefaultIdCreator;
VAR
gDefaultIdCreator := NewDefaultIdCreator();
PROCEDURE InitTable(
init: Table;
size: CARDINAL;
idCreator: IdCreator := NIL): Table=
BEGIN
IF idCreator = NIL THEN idCreator := gDefaultIdCreator END;
init.size := size;
init.idCreator := idCreator;
init.ids := NEW(REF ARRAY OF Id, size);
RETURN init;
END InitTable;
<*INLINE*> PROCEDURE SetCreator(t: Table; idCreator: IdCreator): IdCreator=
VAR
old := t.idCreator;
BEGIN
t.idCreator := idCreator;
RETURN old;
END SetCreator;
<*INLINE*> PROCEDURE ToText(id: Id): TEXT=
BEGIN
RETURN id.text;
END ToText;
BEGIN
END M3CHash.