Oracle clob column rtf2text function;

 Oracle clob column rtf2text function;

CREATE OR REPLACE FUNCTION Rtf2Txt
(
    pRtf varchar2
)
return nvarchar2 is
/*
Converts RTF text to TXT format by removing headers, commands, and formatting
*/
vPos1 int;
vPos2 int;
vPos3 int;
vPos4 int;
vTmp int;
vText varchar2(4000);
begin
vText := pRtf;
if vText is null then
    return vText;
end if;

-- Remove outer { and } pair
vPos1 := instr(vText, '{', +1);  -- The first {
vPos2 := instr(vText, '}', -1);  -- The last }
if vPos1 > 0 and vPos2 > 0 then
    vText := substr(vText, vPos1 +1, vPos2 - vPos1 -1);
end if;

-- Remove inner { and } pairs
while 1 = 1 loop
    vPos2 := instr(vText, '}', +1);  -- The first }
    vPos1 := instr(vText, '{', (length(vText) - vPos2) *-1 -1);  -- The last { before the found }
    if vPos1 > 0 and vPos2 > 0 and vPos1 < vPos2 then
        vText := substr(vText, 1, vPos1 -1) || substr(vText, vPos2 +1, length(vText) - vPos2);
    else
        exit;
    end if;
end loop;

-- Cleaning up
vText := replace(vText, '\pard', '');
vText := replace(vText, chr(13), '');
vText := replace(vText, chr(10), '');
vText := replace(vText, '\par', chr(13));
while length(vText) > 0 and substr(vText, 1, 1) IN (' ', CHR(13), CHR(10)) loop
    vText := substr(vText, 2, length(vText) -1);
end loop;
while length(vText) > 0 and substr(vText, length(vText), 1) IN (' ', CHR(13), CHR(10)) loop
    vText := substr(vText, 1, length(vText) -1);
end loop;

-- Remove \ commands and replace \'XX charactercoding
vPos2 := 1;
while 1 = 1 loop
      vPos1 := instr(vText, '\', vPos2);
      if vPos1 = 0 then
          exit;
      end if;
      if substr(vText, vPos1 +1, 1) = '\' then  -- Skip \\ escape sequence, when present
          vPos2 := vPos1 +2;
          continue;
      end if;
      if substr(vText, vPos1 +1, 1) = '''' then  -- Decode \' hex sequence
          vTmp := to_number(substr(vText, vPos1 +2, 2), 'xx');
          vText := substr(vText, 1, vPos1 -1) ||chr(vTmp)|| substr(vText, vPos1 +4, length(vText) - vPos1 -3);
          vPos2 := vPos1 +1;
          continue;
      end if;
      -- Skip \anything sequence
      vPos2 := instr(vText, '\', vPos1 +1);  -- The next \  
      vPos3 := instr(vText, ' ', vPos1 +1);  -- The next ' '
      vPos4 := instr(vText, chr(13), vPos1 +1);  -- The next Enter
      if vPos4 > 0 and vPos4 < vPos3 then
          vPos3 := vPos4;
      end if;
      if vPos2 = 0 and vPos3 = 0 then
          vPos3 := length(vText); 
      end if;
      if vPos2 > 0 and (vPos2 < vPos3 or vPos3 = 0) then
          vText := substr(vText, 1, vPos1 -1) || substr(vText, vPos2, length(vText) - vPos2 +1);
          vPos2 := vPos1;
      end if;
      if vPos3 > 0 and (vPos3 < vPos2  or vPos2 = 0) then
          vText := substr(vText, 1, vPos1 -1) || substr(vText, vPos3 +1, length(vText) - vPos3);
          vPos2 := vPos1;
      end if;
end loop;

return vText;

end;
/