COMMENT ⊗   VALID 00002 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	entry  filter
C00005 ENDMK
C⊗;
entry  filter;
begin

  comment  Filtering of a huge .seg (and .sseg) file to
  retain only longer segments.  This program also preserves
  seg to sseg mappings.
  January 24, 1979
  K Ramesh Babu
  Endcomment;

  require  "<babu>define.sai"  source!file;
  require  "<babu>seg.dcl"  source!file;
  require  "<babu>sseg.dcl"  source!file;

  internal  simple  procedure  filter;
  begin  "filter"
  integer  output, ssegfile;
  integer  c, k, ss, oss, kss;  real  minl;
    output := openfile(picture & ".seg1","wc");
    swdptr(output,hdrl);  wrecsz := rrecsz;
    Print("This filter will pass only those that are >, not >=, the minimum length.",crlf);
    c := 0;  k := 0;  rprmpt("min length",minl);
    ss := 0;  oss := 0;  kss := 0;
    while  c < segno  do
    begin
      sgin;  c := c + 1;  ss := seg:family[pseg];
      if  seg:length[pseg] > minl  then
      begin
        k := k + 1;  seg:name[pseg] := k;
      end;
      if  ss neq oss  then  kss := kss + 1;
      seg:pred[pseg] := 0;  seg:succ[pseg] := 0;
      seg:fork[pseg] := 0;  seg:family[pseg] := kss;
      arryout(output,seg:name[pseg],wrecsz);
      oss := ss;
    end;
    sghdr[34] := k;  sghdr[35] := kss;
    swdptr(output,0);  arryout(output,sghdr[0],hdrl);
    cfile(output);
  end  "filter" ;