CREATE OR REPLACE FUNCTION pl.decode(selector text, clauses text)
  RETURNS text AS
$BODY$

######################################################################
+##########
##      decode( selector text , clauses text )
##
##              plperlu rendition of Oracle's decode() function.
##
##      Takes 2 args:
##
##              1. (selector).  The item to check, and
##              2. (clauses) .  A double comma (,,) separated string l
+isting of
##                 items to match and items to return if the match is 
+successful.
##                 The last entry in the string is the final "else" re
+turn value.
##                 The match sections may include standard perl boolea
+n
##                 operations.
##
##      USE DOLLAR QUOTING to setup the test/result string,
##      it WILL save you much hair pulling.
##
##      If you want a return item to be NULL for an option, use one of
+ the
##      following (case INSENSITVE) return values:
##              null()   or
##              undef()
##
##      decode() uses its own Safe.pm compartment for the reevalution 
+of the
##      match clauses.
##
######################################################################
+##########


use Safe;

my $vault;

# get / setup a safe "vault"  from / in %_SHARED to reduce function st
+art up time on a per session level

if ( exists( $_SHARED{pl_vault} ) && defined( $_SHARED{pl_vault} ) ){

    $vault = $_SHARED{pl_vault};
    #elog( NOTICE , "plperlu: Preloaded safety vault being used." );
}
else {
    # setup a safe vault using the same parameters as the SAFE_OK macr
+o in postgresql's
    # http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/p
+lperl.c?rev=1.105

    $vault = Safe->new;
    $vault->permit_only( qw/ :default :base_math !:base_io time sort /
+ );

    $_SHARED{pl_vault} = $vault;
    #elog( NOTICE , "plperlu: Setting up session safety vault.");
}

my $selector   = $_[0];
my @in_clauses = split( /,,/ , $_[1] );

#reject @in_clauses argument if it doesn't contain an odd number of en
+tries: ie - 
#            ( '>10' , 'return#1' , 'final else' ) or ( '>10' , 'retur
+n#1' , '<10' , 'return#2' , 'final else' )  is OK 
#            ( '>10' , 'return#1' ) is not

die   "pl.decode(): invalid clause argument, the number of entries was
+ not odd.\n"
    unless ( scalar( @in_clauses ) % 2 );

my $final_else = pop @in_clauses;
my $retval     = undef;
my $have_match = undef;

ITERATIONS:
while ( @in_clauses ){
    my $match_clause = shift @in_clauses;
    my $then_clause  = shift @in_clauses;
    my $result       = $vault->reval( $selector . $match_clause );

    if ( my $error = $@ ){
        # safe reval error...clean up the error message then elog() an
+d ignore it,
        #                    then move on and try the next set of matc
+h/result clauses...
        
        $error =~ s/ at line.+//;
        $error =~ s/trapped.+/deemed unsafe/;
        chomp $error;
        elog( NOTICE , "pl.decode(): potentially dangerous operation f
+ound, "
                             . $error
                             . ", skipping clause..."
                             );
        next ITERATIONS;
    }
    if ( $result ){ # we have the winner...set $retval and bail out...
+we only grab the first true result...

        $retval     = $then_clause;
        $have_match = "yes";
        last ITERATIONS;
    }
    # no $result? oh well try the next set...
}

if ( defined( $have_match ) ){
        # last check to see if we've matched anything...
        # and if so return it...accounting for the case where
        # the wanted return is NULL... 
    if ( $retval =~ m/^ (?: null || undef ) \( \) $ /ix ) {
        $retval=undef;
    }
    return $retval;
}

# if we get here we are returning the "default" result value
# also accounting for the case where the wanted return is NULL...
if ( $final_else =~ m/^ (?: null || undef ) \( \) $ /ix ) {
       $final_else=undef;
}

return $final_else;

$BODY$
  LANGUAGE 'plperlu' IMMUTABLE SECURITY DEFINER;
GRANT EXECUTE ON FUNCTION pl.decode(selector text, clauses text) TO pu
+blic;
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