guideline

Use the case statement when measured performance indicates.

   subtype Small_Int is Integer range 1 .. 5;
   Switch : Small_Int;
   ...
   -- Case statement
   case Switch is
      when 1 => ...
      when 2 => ...
      when 3 => ...
      when 4 => ...
      when 5 => ...
   end case;

   -- "elsif construct"
   if Switch = 1 then
      ...
   elsif Switch = 2 then
      ...
   elsif Switch = 3 then
      ...
   elsif Switch = 4 then
      ...
   elsif Switch = 5 then
      ...
   end if;

rationale

Determine the impact of using case statements versus the elsif construct. If the case statement is implemented using a small jump table, then it may be significantly more efficient than the if .. then .. elsif construct.