PACKET to 16 DEFINES to 16 :


LET OLDRECORD = STRUCT (INT succ, pred, x, y, TEXT line) ,
    OLDFILE   = BOUND ROW 4075 OLDRECORD ;

LET free root = 1 ,
    used root = 2 ;

LET file type 16 = 1002 ;


FILE VAR file 17 ;
OLDFILE VAR file 16 ;
DATASPACE VAR file space ;


PROC to 16 :
  to 16 (last param)
ENDPROC to 16 ;

PROC to 16 (TEXT CONST file name) :

  last param (file name) ;
  file 17 := sequential file (input, file name) ;
  disable stop ;
  file space := nilspace ;
  file 16 := file space ;
  type (file space, file type 16) ;
  copy 17 to 16 ;
  IF NOT is error
    THEN replace 17 by 16 file
  FI ;
  forget (file space) .

replace 17 by 16 file :
  forget (file name, quiet) ;
  copy (file space, file name) .

ENDPROC to 16 ;

PROC copy 17 to 16 :

  enable stop ;
  build used record chain ;
  build free record chain .

build used record chain :
  copy all records ;
  construct used chains head and circular links .

copy all records :
  INT VAR line ;
  FOR line FROM 1 UPTO lines (file 17) REP
    copy one record ;
    cout (line)
  PER .

copy one record :
  INT VAR index := line + 2 ;
  TEXT VAR line 17;
  record.pred := index - 1 ;
  record.succ := index + 1 ;
  getline (file 17, line 17) ;
  change special 17 chars;
  record.line := line 17.

change special 17 chars: 
  change all (line 17, ""217"", ""225"");
  change all (line 17, ""218"", ""239"");
  change all (line 17, ""219"", ""245"");
  change all (line 17, ""214"", ""193"");
  change all (line 17, ""215"", ""207"");
  change all (line 17, ""216"", ""213"");
  change all (line 17, ""220"", ""235"");
  change all (line 17, ""221"", ""173"");
  change all (line 17, ""222"", ""163"");
  change all (line 17, ""223"", ""160"");
  change all (line 17, ""251"", ""194"").

construct used chains head and circular links :
  record.succ := used root ;
  used root record.pred := index ;
  used root record.succ := used root + 1 ;
  used root record.line := headline (file 17) .

build free record chain :
  free root record.pred := free root ;
  free root record.succ := free root ;
  free root record.y    := index + 1 ;
  free root record.line := "    0    1    1" ;
  free root record.line CAT text (maxlinelength (file 17), 5) .

record : CONCR (file 16) (index) .

used root record : CONCR (file 16) (used root) .

free root record : CONCR (file 16) (free root) .

ENDPROC copy 17 to 16 ;

ENDPACKET to 16 ;