Qompress.Bas 1/

 BBS: Inland Empire Archive
Date: 02-23-93 (08:52)             Number: 322
From: QUINN TYLER JACKSON          Refer#: NONE
  To: ALL                           Recvd: NO  
Subj: Qompress.Bas          1/       Conf: (2) Quik_Bas

'           ***************************************************
'           *    QOMPRESS.BAS v1.0 (Public Domain Version)    *
'           *       WRITTEN  BY: Quinn Tyler Jackson of       *
'           *        JackMack Consulting & Development        *
'           *           DIALECT:    QuickBASIC 4.5            *
'           *               QBS:        YES!                  *
'           ***************************************************

' COMMENT:
'
'           Using simple substitution tables, this program compresses
'           English text based on one of three possible schemes:
'           full words, trigrams, or digrams, whichever is best.  It returns
'           the compressed string with a flag that indicates which method
'           was used.  If no compression method shows a minimum result, this
'           is shown.  If compression was achieved, the two bytes following
'           the compression type flag indicate the expanded length of the
'           original string.
'
'           Interface with other modules is through the main function
'           funQompress$(InText$).
'
'           This module is not meant to be fast.  It is meant to be
'           educational.  In fact, it is not even as tight as it could be.
'           Gotta leave something up to your imagination!

DEFINT A-Z
OPTION BASE 1

' Compression types
CONST WordType = 255            'Word compression was achieved.

CONST TrigramType = 254         'Trigram compression was acheived.

CONST DigramType = 253          'Digram compression was achieved.

CONST NoType = 254              'No reasonable compression was possible.
                                'The maximum amount that could be achieved
                                'follows the NoType byte.

DIM SHARED WordTable$(128 TO 228)
DIM SHARED TriTable$(128 TO 226)
DIM SHARED DiTable$(128 TO 227)


nul = fqjTableInit
OPEN "c:\test.txt" FOR INPUT AS #1


DO

LINE INPUT #1, Txt$
NewText$ = funQompress(Txt$)
NewLen = LEN(NewText$)
Ratio = (LEN(Txt$) - NewLen)
Saved = Saved + Ratio

SELECT CASE ASC(NewText$)
    CASE WordType
        PRINT "W: "; Ratio
    CASE TriType
        PRINT "T: "; Ratio
    CASE DiType
        PRINT "D: "; Ratio
    CASE NoType
        PRINT "N: "; Ratio
    CASE ELSE
END SELECT

LOOP UNTIL EOF(1)

PRINT "Saved"; Saved; "bytes on a file of"; LOF(1); "bytes."

CLOSE

END

EnglishWordData:

' Below are listed the hundred most frequently used words in English.
' Taken from fifteen English authors and many newspapers.  Compiled by
' Frank R. Fraprie.  Taken from Helen Gaines Fouche's _Cryptanalysis_,
' which is published by Dover Publications since 1956.

DATA the,of,and,to,a,in,that,is,I,it
DATA for,as,with,was,his,he,be,not,by,but
DATA have,you,which,are,on,or,her,had,at,from
DATA this,my,they,all,their,an,she,has,were,me
DATA been,him,one,so,if,will,there,who,no,we
DATA when,what,your,more,would,them,some,than,may,upon
DATA its,out,into,our,these,man,up,do,like,after
DATA shall,great,now,such,should,other,only,any,then,yet
DATA about,those,can,made,well,old,must,us,said,time,two
DATA time,even,new,could,very,much,own,most,might,first

EnglishTrigramData:

' The ninety-eight most frequent English trigrams, combining a count of
' 20,000 trigrams by Fletcher Pratt, in "Secret and Urgent," supposed not
' to include include overlaps between words, and 5,000 by Frank R. Fraprie,
' including overlaps.  Also taken from Fouche's _Crytanalysis_.

DATA the,ing,and,ion,ent,for,tio,ere,her,ate
DATA ver,ter,tha,ati,hat,ers,his,res,ill,are
DATA con,nce,all,eve,ith,ted,ain,est,man,red
DATA thi,ive,rea,wit,ons,ess,ave,per,ect,one
DATA und,int,ant,hou,men,was,oun,pro,sta,ine
DATA whi,ove,tin,ast,der,ous,rom,ven,ard,ear
DATA din,sti,not,ort,tho,day,ore,but,out,ure
DATA str,tic,ame,com,our,wer,ome,een,lar,les
DATA san,set,any,art,nte,rat,rut,ica,ich,nde
DATA pre,enc,has,whe,will,era,lin,tra

EnglishDigramData:

' One-hundred digrams from the same book, also compiled by
' Pratt and Fraprie from 20,000 trigrams.

DATA th,in,er,re,an,he,ar,en,ti,te
DATA at,on,ha,ou,it,es,st,or,nt,hi
DATA es,st,or,nt,hi,ea,ve,co,de,ra
DATA ro,li,ri,io,le,nd,ma,se,al,ic
DATA fo,il,ne,la,ta,el,me,ec,is,di
DATA si,ca,un,ut,nc,wi,ho,tr,be,ce
DATA wh,ll,fi,no,to,pe,as,wa,ur,lo
DATA pa,us,mo,om,ai,pr,we,ac,ee,et
DATA sa,ni,rt,na,ol,ev,ie,mi,ng,pl
DATA iv,po,ch,ei,ad,ss,il,os,ul,em

FUNCTION fqjSqueeze$ (InString$, Table$())

   s$ = InString$
   FOR ASCII = LBOUND(Table$) TO UBOUND(Table$)
      DO
         i = INSTR(s$, Table$(ASCII))
         IF i THEN

s$ = LEFT$(s$, i - 1) + CHR$(ASCII) + MID$(s$, i + LEN(Table$(ASCII)))

         END IF
      LOOP WHILE i
   NEXT

   fqjSqueeze$ = s$
>>> Continued to next message

 * SLMR 2.1a *

--- Maximus 2.01wb