\ Hashed dictionaries 15jul94py
\ Copyright (C) 1995 Free Software Foundation, Inc.
\ This file is part of Gforth.
\ Gforth is free software; you can redistribute it and/or
\ modify it under the terms of the GNU General Public License
\ as published by the Free Software Foundation; either version 2
\ of the License, or (at your option) any later version.
\ This program is distributed in the hope that it will be useful,
\ but WITHOUT ANY WARRANTY; without even the implied warranty of
\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
\ GNU General Public License for more details.
\ You should have received a copy of the GNU General Public License
\ along with this program; if not, write to the Free Software
\ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
11 value hashbits
1 hashbits lshift Value Hashlen
Variable insRule insRule on
Variable revealed
\ Memory handling 10oct94py
Variable HashPointer
Variable HashIndex
0 Value HashTable
\ DelFix and NewFix are from bigFORTH 15jul94py
: DelFix ( addr root -- ) dup @ 2 pick ! ! ;
: NewFix ( root len # -- addr )
BEGIN 2 pick @ ?dup 0= WHILE 2dup * allocate throw
over 0 ?DO dup 4 pick DelFix 2 pick + LOOP drop
REPEAT >r drop r@ @ rot ! r@ swap erase r> ;
\ compute hash key 15jul94py
: hash ( addr len -- key )
hashbits (hashkey1) ;
\ (hashkey)
\ Hashlen 1- and ;
: bucket ( addr len wordlist -- bucket-addr )
\ @var{bucket-addr} is the address of a cell that points to the first
\ element in the list of the bucket for the string @var{addr len}
wordlist-extend @ -rot hash xor ( bucket# )
cells HashTable + ;
: hash-find ( addr len wordlist -- nfa / false )
>r 2dup r> bucket @ (hashfind) ;
\ hash vocabularies 16jul94py
: lastlink! ( addr link -- )
BEGIN dup @ dup WHILE nip REPEAT drop ! ;
: (reveal ( nfa wid -- )
dup wordlist-extend @ 0<
IF
2drop EXIT
THEN
over name>string rot bucket >r
HashPointer 2 Cells $400 NewFix
tuck cell+ ! r> insRule @
IF
dup @ 2 pick ! !
ELSE
lastlink!
THEN
revealed on ;
: hash-reveal ( nfa wid -- )
2dup (reveal) (reveal ;
: addall ( -- )
voclink
BEGIN @ dup @ WHILE dup 'initvoc REPEAT drop ;
: clearhash ( -- )
HashTable Hashlen cells bounds
DO I @
BEGIN dup WHILE
dup @ swap HashPointer DelFix
REPEAT I !
cell +LOOP HashIndex off ;
: re-hash clearhash addall ;
: (rehash) ( addr -- )
drop revealed @ IF re-hash revealed off THEN ;
Create hashsearch-map ( -- wordlist-map )
' hash-find A, ' hash-reveal A, ' (rehash) A,
\ hash allocate and vocabulary initialization 10oct94py
: hash-alloc ( addr -- addr ) HashTable 0= IF
Hashlen cells allocate throw TO HashTable
HashTable Hashlen cells erase THEN
HashIndex @ over ! 1 HashIndex +!
HashIndex @ Hashlen >=
IF HashTable >r clearhash
1 hashbits 1+ dup to hashbits lshift to hashlen
r> free >r 0 to HashTable
addall r> throw
THEN ;
: (initvoc) ( addr -- )
cell+ dup @ 0< IF drop EXIT THEN
dup 2 cells - @ hashsearch-map <> IF drop EXIT THEN
insRule @ >r insRule off hash-alloc 3 cells - dup
BEGIN @ dup WHILE 2dup swap (reveal REPEAT
2drop r> insRule ! ;
' (initvoc) IS 'initvoc
\ Hash-Find 01jan93py
: make-hash
Root hashsearch-map context @ cell+ !
Forth hashsearch-map context @ cell+ !
addall \ Baum aufbauen
;
make-hash \ Baumsuche ist installiert.
: hash-cold ( -- ) Defers 'cold
HashPointer off 0 TO HashTable HashIndex off
voclink
BEGIN @ dup @ WHILE
dup cell - @ >r
dup 'initvoc
r> over cell - !
REPEAT drop ;
' hash-cold ' 'cold >body !
: .words ( -- )
base @ >r hex HashTable Hashlen 0
DO cr i 2 .r ." : " dup i cells +
BEGIN @ dup WHILE
dup cell+ @ .name REPEAT drop
LOOP drop r> base ! ;
\ \ this stuff is for evaluating the hash function
\ : square dup * ;
\ : countwl ( -- sum sumsq )
\ \ gives the number of words in the current wordlist
\ \ and the sum of squares for the sublist lengths
\ 0 0
\ hashtable Hashlen cells bounds DO
\ 0 i BEGIN
\ @ dup WHILE
\ swap 1+ swap
\ REPEAT
\ drop
\ swap over square +
\ >r + r>
\ 1 cells
\ +LOOP ;
\ : chisq ( -- n )
\ \ n should have about the same size as Hashlen
\ countwl Hashlen 2 pick */ swap - ;
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