Re: Unifont static compiled and stack size...

["Jeffrey R.Carter" <spam.jrcarter.not@spam.acm.org.not>]

On 2023-08-13 18:16, Micah Waddoups wrote:
> I tried to compile the Unifont hex file, converted with a script into variable Ada code, but it went on forever, gradually blowing up my memory.  I used an .ads file and aimed for a static build, but I suspect I would have hit the stack size limit for executables if I succeeded

As I understand it, the file in question is for code points 0 .. 16#FFFF#, with 
a maximum of 32 bytes per code point. A straightforward representation of this is

package Unifont is
    type Byte is mod 2 ** 8 with Size => 8;

    type Line is array (1 .. 2) of Byte with Size => 16;

    type Bitmap is array (1 .. 16) of Line with Size => 256;

    function Width_8 (Map : in Bitmap) return Boolean is
       (for all L of Map => L (2) = 0);

    type Code_Point is mod 16#FFFF# + 1;

    type Font_Map is array (Code_Point) of Bitmap with Size => 2 ** 24;

    Font : constant Font_Map := (others => (others => (others => 0) ) );
end Unifont;

Font will occupy 2 MB.

We can test this with

with Ada.Text_IO;
with Unifont;

procedure Unifont_Test is
    -- Empty
begin -- Unifont_Test
    Ada.Text_IO.Put_Line (Item => Unifont.Font (0) (1) (1)'Image);
end Unifont_Test;

and see what happens:

$ gnatmake -m -j0 -gnat12 -gnatan -gnato2 -O2 -fstack-check unifont_test.adb
x86_64-linux-gnu-gcc-12 -c -gnat12 -gnatan -gnato2 -O2 -fstack-check 
unifont_test.adb
x86_64-linux-gnu-gcc-12 -c -gnat12 -gnatan -gnato2 -O2 -fstack-check unifont.ads
x86_64-linux-gnu-gnatbind-12 -x unifont_test.ali
x86_64-linux-gnu-gnatlink-12 unifont_test.ali -O2 -fstack-check
$ ./unifont_test
  0

so this representation seems to be workable. It should be trivial to write a 
program to read the file and produce the real array aggregate for Font.

-- 
Jeff Carter
"I wave my private parts at your aunties."
Monty Python & the Holy Grail
13