package io_utils - useful conversion functions

USE std.textio.ALL;
PACKAGE io_utils IS
PROCEDURE write_string(l : INOUT line;value : IN string;justified : IN side := right;field : IN width := 0);
TYPE radix IS (binary, octal, decimal, hex);
-- read a number from the line
-- use this if you have hex numbers that are not in VHDL pound-sign format
PROCEDURE read(l : INOUT line; value : OUT integer; radix : IN positive);
-- read a number that might be in VHDL pound-sign format
PROCEDURE read_based(l : INOUT line; value : OUT integer);
PROCEDURE write(l : INOUT line;
value : IN bit_vector;
justified : IN side := right;
field : IN width := 0;
base : IN radix;
use_pound : boolean := false);
PROCEDURE write(l : INOUT line;
value : IN integer;
justified : IN side := right;
field : IN width := 0;
base : IN radix;
use_pound : boolean := false);
END io_utils;
PACKAGE BODY io_utils IS
PROCEDURE write_string(l : INOUT line;
value : IN string;
justified : IN side := right;
field : IN width := 0)
IS
BEGIN
write(l, value, justified, field);
END;
PROCEDURE shrink_line(l : INOUT line; pos : integer) IS
VARIABLE tmpl : line;
BEGIN
tmpl := l;
l := NEW string'(tmpl(pos TO tmpl'high));
deallocate(tmpl);
END;
PROCEDURE read(l : INOUT line;
value : OUT integer;
radix : IN positive)
IS
CONSTANT not_digit : integer := -999;
-- convert a character to a value from 0 to 15
FUNCTION digit_value(c : character) RETURN integer IS
BEGIN
IF (c >= '0') AND (c <= '9') THEN
RETURN (character'pos(c) - character'pos('0'));
ELSIF (c >= 'a') AND (c <= 'f') THEN
RETURN (character'pos(c) - character'pos('a') + 10);
ELSIF (c >= 'a') AND (c <= 'f') THEN
RETURN (character'pos(c) - character'pos('a') + 10);
ELSE
RETURN not_digit;
END IF;
END;
-- skip leading white space in the line
PROCEDURE skip_white(VARIABLE l : IN line; pos : OUT integer) IS
BEGIN
pos := l'low;
FOR i IN l'low TO l'high LOOP
CASE l(i) IS
WHEN ' ' | ht =>
pos := i + 1;
WHEN OTHERS =>
EXIT;
END CASE;
END LOOP;
END;
VARIABLE digit : integer;
VARIABLE result : integer := 0;
VARIABLE pos : integer;
BEGIN
-- skip white space
skip_white(l, pos);
-- calculate the value
FOR i IN pos TO l'right LOOP
digit := digit_value(l(i));
EXIT WHEN (digit = not_digit) OR (digit >= radix);
result := result * radix + digit;
pos := i + 1;
END LOOP;
value := result;
-- remove the "used" characters from the line
shrink_line(l, pos);
END;
PROCEDURE read_based(l : INOUT line; value : OUT integer) IS
VARIABLE digit : integer;
VARIABLE num : integer;
VARIABLE base : integer;
BEGIN
read(l, num, 10);
IF (l'length > 1) AND (l(l'left) = '#') THEN
shrink_line(l, l'left+1);
base := num;
read(l, num, base);
IF (l'length >= 1) AND (l(l'left) = '#') THEN
shrink_line(l, l'left+1);
END IF;
END IF;
value := num;
END;
PROCEDURE write(l : INOUT line;value : IN bit_vector;justified : IN side := right;field : IN width := 0;
base : IN radix;
use_pound : boolean := false)
IS
FUNCTION to_int(bv : bit_vector) RETURN integer
IS
VARIABLE result : integer := 0;
BEGIN
FOR i IN bv'RANGE LOOP
result := result * 2;
IF (bv(i) = '1') THEN
result := result + 1;
END IF;
END LOOP;
RETURN result;
END;
TYPE array_of_widths IS ARRAY(radix) OF natural;
CONSTANT nibble_widths : array_of_widths := (
binary => 1,
octal => 3,
hex => 4,
decimal=> 32);
CONSTANT hex_digit : string(1 TO 16) := "0123456789ABCDEF";
ALIAS input_val : bit_vector(value'length DOWNTO 1) IS value;
CONSTANT nibble_width : natural := nibble_widths(base);
CONSTANT result_width : natural := (value'length + nibble_width - 1)/nibble_width;
VARIABLE result : string(1 TO result_width); -- longest possible value
VARIABLE result_pos : positive := 1;
VARIABLE nibble_val : integer;
VARIABLE bitcnt : integer;
BEGIN
IF base = decimal THEN
write(l, to_int(value), justified, field, base, use_pound);
RETURN;
END IF;
bitcnt := value'length MOD nibble_width;
IF (bitcnt = 0) THEN
bitcnt := nibble_width;
END IF;
FOR i IN input_val'RANGE LOOP
nibble_val := nibble_val * 2;
IF (input_val(i) = '1') THEN
nibble_val := nibble_val + 1;
END IF;
bitcnt := bitcnt - 1;
IF (bitcnt = 0) THEN
result(result_pos) := hex_digit(nibble_val + 1);
result_pos := result_pos + 1;
nibble_val := 0;
bitcnt := nibble_width;
END IF;
END LOOP;
write(l, result, justified, field);
END;
PROCEDURE write(l : INOUT line;
value : IN integer;
justified : IN side := right;
field : IN width := 0;
base : IN radix;
use_pound : boolean := false)
IS
FUNCTION to_bv(int : integer) RETURN bit_vector
IS
VARIABLE bv : bit_vector(32 DOWNTO 1) := (OTHERS => '0');
VARIABLE pos : integer := 0;
VARIABLE tmpval : integer := int;
BEGIN
FOR i IN 1 TO 32 LOOP
pos := pos + 1;
IF (tmpval MOD 2) = 1 THEN
bv(i) := '1';
END IF;
tmpval := tmpval / 2;
EXIT WHEN tmpval = 0;
END LOOP;
RETURN bv(pos DOWNTO 1);
END;
VARIABLE tmp : line;
BEGIN
IF (base = decimal) THEN
IF (use_pound) THEN
write_string(tmp, "10#");
END IF;
write(tmp, value);
IF (use_pound) THEN
write_string(tmp, "#");
END IF;
write(l, tmp.ALL, justified, field);
deallocate(tmp);
ELSE
write(l, to_bv(value), justified, field, base, use_pound);
END IF;
END;
END io_utils;

-- test the hex number reader

ENTITY test IS END;
USE std.textio.ALL;
USE work.io_utils.ALL;
ARCHITECTURE hex_test OF test IS
BEGIN
PROCESS
VARIABLE val : integer;
FILE myfile : text IS IN "values";
VARIABLE inline : line;
VARIABLE outline : line;
BEGIN
WHILE NOT endfile(myfile) LOOP
END LOOP;
WAIT;
END PROCESS;
END;