libv – assert_equal, str, etc.

procedure assert_equal (
    prefix'event : string;
     got, expected : integer; 
    level : severity_level := error) is 
begin 
  assert got = expected 
    report prefix & " wrong. Got " & integer'image(got) & " expected " 
    & integer'image(expected) 
    & "(difference=" & integer'image(got-expected) &")" 
    severity level; end procedure assert_equal; 

In addition, the same API can be used for comparing more complex types (like the integer_vector type which is also part of libv):

procedure assert_equal ( prefix : string; 
                         got, expected : integer_vector; 
                         level : severity_level := error) is 
  variable g,e : integer; 
begin -- procedure assert_equal
  assert got'length = expected'length 
      report prefix & " length wrong. Got " & integer'image(got'length) 
      & " expected " & integer'image(expected'length) 
      & "(difference=" & integer'image(got'length-expected'length) &")" 
  severity level; 
  for i in 0 to got'length-1 loop 
     g := got(got'low+i); 
     e := expected(expected'low+i); 
     assert g = e 
       report prefix & " got(" & integer'image(got'low+i) & ") = " 
       & integer'image(g) & CR 
       & " expected(" & integer'image(expected'low+i) 
       & ") = " & integer'image(e) 
       severity level; 
  end loop; -- i 
end procedure assert_equal; 

or indeed a similar function for `pixel_array`:

procedure assert_equal (
prefix : string;
expected, got : pixel_array;
level : severity_level := error) is
begin -- procedure assert_equal
    assert_equal(prefix & "(width)", expected'length(1), got'length(1), level);
    assert_equal(prefix & "(height)", expected'length(2), got'length(2), level);
    for y in expected'range(2) loop
       for x in expected'range(1) loop
          assert expected(x,y)=got(x,y)
            report prefix &"(" & str(x) & "," & str(y)  &")" & 
                str(expected(x,y)) & "/=" & str(got(x,y))
            severity level;
       end loop; -- x
    end loop; -- y
end procedure assert_equal;

You’ll notice I got bored of writing integer'image and wrote a str function which takes an integer and an optional length argument and returns a string, left-padded with spaces if the length argument is longer than the integer requires:

 function str (val : integer; length : natural := 0) return string is 
   constant chars_needed : natural := num_chars(val); 
   variable s : string(1 to max(length, chars_needed)) := (others => ' '); 
 begin -- function str 
    if length = 0 then 
       return integer'image(val); 
    end if; 
    if chars_needed > length then 
       report "Can't fit " & integer'image(val) & " into " 
              & integer'image(length) & " character(s) - returning full width"
              severity warning; 
       return integer'image(val); 
    end if; 
    s(s'high-(chars_needed-1) to s'high) := integer'image(val); 
    return s; 
end function str; 

Again, this can be a standard API and we can have a str function for other types; For example, boolean:

 function str (val : boolean; length:natural range 0 to 1 := 0) return string is 
 begin -- function str 
     if length = 0 then 
       return boolean'image(val); 
     end if; 
     if length = 1 then 
       if val then 
         return "T"; 
       else 
         return "F"; 
       end if; 
     end if; 
 end function str;