Oracle plsql rtf varchar2 field to plain text format

I need to convert a rich formatted text of a VARCHAR2 field to plain text.

For example:

{\rtf1\ansi\ansicpg1252\deff0{\fonttbl{\f0\fnil Tahoma;}{\f1\fnil\fcharset0 Tahoma;}}
{\colortbl ;\red0\green0\blue255;}
\viewkind4\uc1\pard\cf1\lang1031\b\f0\fs16 NUMBER_A\cf0\b0\f1 *\cf1\b\protect NUMBER_B\cf0\b0\protect0\f0\par
}

should be converted to:

NUMBER_A * NUMBER_B

I have tried to parse the 开发者_高级运维RTF-string char by char but this isn't a very smart solution. A PL/SQL utilities method for any RTF-text would be the nicest way. Is there a native solution? Any ideas how to convert the rtf-text?

Thx for sharing your time and ideas.

Apparently this can be done via Oracle Text - see this AskTom question

I made it with simple PL/SQL. Based on this SQL source, but completly rewritten. (Backslash + Apostrofe confuses code coloring here)

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;
/

I dont'have the repuation to comment CLS's posting, but I would like to advise that the line

  if vPos1 = 0 then

should be changed to

  if nvl(vPos1,0)=0 then

otherwise with not well formed RTFs the function will be stuck in the while loop forever

Bye Andreas