Celestin Apprentice 5/Apprentice-Release5.iso/Environments/SmallEiffel 0.3.3/SmallEiffel PPC/lib_std/integer.e

Text File | 1996-06-13 | 6.2 KB | 311 lines | [TEXT/EDIT]

-- Part of SmallEiffel -- Read DISCLAIMER file -- Copyright (C)
-- Dominique COLNET and Suzanne COLLIN -- [e-mail]
--
expanded class INTEGER
--
-- Note : corresponding C type is "int"
--
inherit
   INTEGER_REF
      redefine
     infix "+", infix "-", infix "*", infix "/", infix "\\",
     infix "//", infix "^", infix "<", infix "<=", infix ">",
     infix ">=", compare, prefix "-", prefix "+", hash_code,
     one, zero, fill_tagged_out_memory
      end;

feature

   infix "+"(other: INTEGER): INTEGER is
     -- Add `other' to Current.
      external "CSE"
      end;

   infix "-" (other: INTEGER): INTEGER is
     -- Subtract `other' from Current.
      external "CSE"
      end;

   infix "*" (other: INTEGER): INTEGER is
     -- Multiply `other' by Current.
      external "CSE"
      end;

   infix "/" (other: INTEGER): DOUBLE is
     -- Divide Current by `other'.
      do
     Result := to_double / other.to_double;
      end;

   infix "//" (other: INTEGER): INTEGER is
     -- Divide Current by `other'.
     -- Note : Integer division
      external "CSE"
      end;

   infix "\\" (other: INTEGER): INTEGER is
     -- Remainder of division of Current by `other'.
      external "CSE"
      end;

   infix "^" (exp: INTEGER): INTEGER is
     -- Raise Current to `exp'-th power.
     --
     -- Note : written by Bruno MATHIEU
      do
     if exp = 0 then
        Result := 1;
     elseif exp \\ 2 = 0 then
        Result := (Current * Current) ^ (exp // 2);
     else
        Result := Current * (Current ^ (exp - 1));
     end;
      end; -- infix "^"

   abs: INTEGER is
      do
     if Current < 0 then
        Result := -Current;
     else
        Result := Current;
     end;
      end;

   infix "<" (other: INTEGER): BOOLEAN is
     -- Is 'Current' strictly less than 'other'?
      external "CSE"
      end;

   infix "<=" (other: INTEGER): BOOLEAN is
     -- Is 'Current' less or equal 'other'?
      external "CSE"
      end;

   infix ">" (other: INTEGER): BOOLEAN is
     -- Is 'Current' strictly greater than 'other'?
      external "CSE"
      end;

   infix ">=" (other: INTEGER): BOOLEAN is
     -- Is 'Current' greater or equal than 'other'?
      external "CSE"
      end;

   prefix "+": INTEGER is
      do
     Result := Current
      end;

   prefix "-": INTEGER is
     -- Unary minus of Current
      external "CSE"
      end;

   compare(other: INTEGER): INTEGER is
     -- Compare Current with `other'.
     -- '<' <==> Result < 0
     -- '>' <==> Result > 0
     -- Otherwise Result = 0
      do
     Result := Current - other
      end;

   hash_code: INTEGER is
      do
     if Current < 0 then
        Result := -Current
     else
        Result := Current
     end
      end;

   one: INTEGER is
      do
     Result := 1
      end;

   zero: INTEGER is
      do
     Result := 0
      end;

   sqrt: DOUBLE is
      -- Compute the square routine.
      do
     Result := to_double.sqrt;
      end;

  gcd(other: INTEGER): INTEGER is
     -- Great Common Divisor of `Current' and `other'.
      require
     Current >= 0;
         other >= 0;
      do
     if other = 0 then
        Result := Current
         else
            Result := other.gcd(Current \\ other);
         end;
      ensure
         Result = other.gcd(Current);
      end;

feature -- Conversions :

   to_real: REAL is
      do
     Result := Current;
      end;

   to_double: DOUBLE is
      do
     Result := Current;
      end;

   to_string: STRING is
     -- Convert the INTEGER into a new allocated STRING.
     -- Note: see `append_in' to save memory.
      do
     !!Result.make(0);
     append_in(Result);
      end;

   to_boolean: BOOLEAN is
      do
     if Current /= 0 then
        Result := true;
     end;
      end;

   append_in(str: STRING) is
     -- Append the equivalent of `to_string' at the end of
     -- `str'. Thus you can save memory because no other
     -- STRING is allocate for the job.
      require
     str /= Void;
      local
     val, i: INTEGER;
      do
     if Current = 0 then
        str.extend('0');
     else
        if Current < 0 then
           str.extend('-');
           (- Current).append_in(str);
        else
           from
          i := str.count + 1;
          val := Current;
           until
          val = 0
           loop
          str.extend((val \\ 10).digit);
          val := val // 10;
           end;
           from
          val := str.count;
           until
          i >= val
           loop
          str.swap(i,val);
          val := val - 1;
          i := i + 1;
           end;
        end;
     end;
      end;

   to_string_format(s: INTEGER): STRING is
     -- Same as `to_string' but the result is on `s' character and the
     -- number is right aligned.
     -- Note: see `append_in_format' to save memory.
      require
     to_string.count <= s;
      do
     from
        tmp_string.clear;
        append_in(tmp_string);
     until
        tmp_string.count >= s
     loop
        tmp_string.add_first(' ');
     end;
     Result := clone(tmp_string);
      ensure
     Result.count = s;
      end;

   append_in_format(str: STRING; s: INTEGER) is
     -- Append the equivalent of `to_string_format' at the end of
     -- `str'. Thus you can save memory because no other
     -- STRING is allocate for the job.
      do
     from
        tmp_string.clear;
        append_in(tmp_string);
     until
        tmp_string.count >= s
     loop
        tmp_string.add_first(' ');
     end;
     str.append(tmp_string);
      ensure
     str.count >= (old str.count) + s;
      end;

   digit: CHARACTER is
     -- Gives the corresponding CHARACTER for range 0..9.
      require
     0 <= Current;
     Current <= 9;
      do
     Result := ("0123456789").item(Current + 1);
      ensure
     ("0123456789").has(Result);
     Result.value = Current;
      end;

   to_character: CHARACTER is
     -- Return the coresponding ASCII character.
      require
     Current >= 0;
      external "CSE"
      end;

   to_octal: INTEGER is
      -- Gives the octal value.
      do
     if Current = 0 then
     elseif Current < 0 then
        Result := -((-Current).to_octal);
     else
        from
           tmp_string.clear;
           Result := Current;
        until
           Result = 0
        loop
           tmp_string.extend((Result \\ 8).digit);
           Result := Result // 8;
        end;
        tmp_string.reverse;
        Result := tmp_string.to_integer;
     end;
      end;

feature -- Object Printing :

   fill_tagged_out_memory is
      do
     Current.append_in(tagged_out_memory);
      end;

feature {NONE}

   tmp_string: STRING is
      once
     !!Result.make(128);
      end;

end -- INTEGER