with System;
package Universal_Integer_Arithmetic is

    -- This package implements the Ada type Universal_integer.

    -- The operations defined on universal integers are those specified in
    -- chapter 4 of the RM.  Since the equality and inequality operators can
    -- not be overloaded, an equality operation is defined.  In addition,
    -- conversions between INTEGER, STRING and Universal_integer are defined.

    type Universal_Integer is private;

    function "+" (X, Y : Universal_Integer) return Universal_Integer;
    function "-" (X, Y : Universal_Integer) return Universal_Integer;
    function "*" (X, Y : Universal_Integer) return Universal_Integer;
    function "/" (X, Y : Universal_Integer) return Universal_Integer;
    function "mod" (X, Y : Universal_Integer) return Universal_Integer;
    function "rem" (X, Y : Universal_Integer) return Universal_Integer;

    function "**" (X : Universal_Integer; Y : Integer) return Universal_Integer;

    function "-" (X : Universal_Integer) return Universal_Integer;
    function "abs" (X : Universal_Integer) return Universal_Integer;

    function ">=" (X, Y : Universal_Integer) return Boolean;
    function ">" (X, Y : Universal_Integer) return Boolean;

    function "<=" (X, Y : Universal_Integer) return Boolean;
    function "<" (X, Y : Universal_Integer) return Boolean;
    function Eql (X, Y : Universal_Integer) return Boolean;

    function Int (X : Universal_Integer) return Integer;
    function Int (X : Universal_Integer) return Long_Integer;

    -- Converts a universal integer to a integer.  The exception
    -- NUMERIC_ERROR is raised if the universal integer x has a value
    -- outside the integer range.

    function Ui (I : Integer) return Universal_Integer;
    function Ui (I : Long_Integer) return Universal_Integer;

    -- Constructs a universal integer from an integer;

    function Image (X : Universal_Integer) return String;

    -- Converts the universal integer x into its string image, that is, a
    -- sequence of characters representing the value in display form.  The
    -- image of a universal integer value is the corresponding decimal
    -- literal; without underlines, leading zeros, exponent or trailing spaces;
    -- but with a single leading minus sign or space.  The lower bound of the
    -- image string is one.

    function Value (S : String) return Universal_Integer;

    -- Converts the string s int a universal integer value.  The string must
    -- have the syntax of an optionally signed decimal integer literal;
    -- otherwise, the exception CONSTRAINT_ERROR is raised.  The exponent of
    -- the decimal literal, if present, must not exceed INTEGER'LAST.

    function I_Zero return Universal_Integer;
    function I_One return Universal_Integer;
    function I_Two return Universal_Integer;
    function I_Ten return Universal_Integer;

    -- Conversion to/from pure-value form of Universal_Integer

    function Image (I : Universal_Integer) return System.Byte_String;
    function Value (S : System.Byte_String) return Universal_Integer;
    function Scaled_Value
                (X : Universal_Integer; Y : Universal_Integer) return Float;

    -- returns an approximation to X/Y expressed as a standard
    -- float value.  As much accuracy as possible is preserved.

private

    type Vector;

    type Universal_Integer is access Vector;

end Universal_Integer_Arithmetic;