bitstring_helpers--1.0.sql

CREATE OR REPLACE FUNCTION shuffled_ints(bigint) RETURNS bigint[] 
	AS '$libdir/bitstring_helpers', 'shuffled_ints' LANGUAGE C STRICT; 
COMMENT ON FUNCTION shuffled_ints(bigint) IS 'Create an array of user definable size ''n'' of shuffled integers (1 to n)';

CREATE OR REPLACE FUNCTION popcount(bit varying) RETURNS int 
	AS '$libdir/bitstring_helpers', 'popcount' LANGUAGE C STRICT IMMUTABLE; 
COMMENT ON FUNCTION popcount(bit varying) IS 'Count the number of 1''s in a bitstring'; 

CREATE OR REPLACE FUNCTION hamming_distance(bit varying,bit varying) RETURNS int 
	AS $$
		SELECT popcount($1 # $2);
	$$ LANGUAGE 'SQL' STRICT IMMUTABLE;
COMMENT ON FUNCTION hamming_distance(bit varying, bit varying) IS 'Calculate the hamming distance between two bitstrings';

CREATE OR REPLACE FUNCTION neighbours(bit varying) RETURNS SETOF bit varying 
	AS $$
  		SELECT $1 # (pg_catalog.bit(1,length($1)) << generate_series(0,length($1)-1,1));
	$$ LANGUAGE 'SQL' STRICT IMMUTABLE;
COMMENT ON FUNCTION neighbours(bit varying) IS 'Return all the 1-bit mutation neighbours of the given bitstring';


--casts
CREATE OR REPLACE FUNCTION text2bitstring(text) RETURNS bit varying 
	AS $$
		SELECT bit_in(textout('B'::text||$1),67,length($1));
	$$ LANGUAGE 'SQL';
COMMENT ON FUNCTION text2bitstring(text) IS 'Convert text (contianing 1''s and 0''s only) to a bit varying type.';
CREATE CAST (text AS bit varying) WITH FUNCTION text2bitstring (text);

CREATE OR REPLACE FUNCTION bit2text(bit varying) RETURNS text 
	AS $$
  		SELECT textin(bit_out($1));
	$$ LANGUAGE 'SQL';
COMMENT ON FUNCTION bit2text(bit varying) IS 'Convert bits to text';
CREATE CAST (bit varying AS text) WITH FUNCTION bit2text(bit varying);

/*
CREATE OR REPLACE FUNCTION textarray2bitvaryingarray(text[]) RETURNS bit varying[] 
	AS $$
		DECLARE
  			out bit varying[];
		BEGIN
			FOR i IN 1..array_upper($1, 1) LOOP
				IF (i=1) THEN
					out:=array[$1[i]::bit varying];
				ELSE
					out:=array_append(out,$1[i]::bit varying);
				END IF;
			END LOOP;
			RETURN out;
		END;
	$$ LANGUAGE 'plpgsql';
--select textarray2bitvaryingarray(array['010011','0010101','010100101100']);
CREATE CAST (text[] AS bit varying[]) WITH FUNCTION textarray2bitvaryingarray(text[]);
*/


--aggregates

CREATE AGGREGATE aconcat (
	BASETYPE = anyelement,
	SFUNC = array_append,
	STYPE = anyarray,
	INITCOND = '{}'
);

CREATE AGGREGATE concat(
	BASETYPE=text,
	SFUNC=textcat,
	STYPE=text
);

CREATE AGGREGATE concat(
	BASETYPE=bit,
	SFUNC=bitcat,
	STYPE=bit varying
);