Class DT_DURATION

Class DT_DURATION

note

description:

    "Durations"

library:    "Gobo Eiffel Time Library"
author:     "Eric Bezault <ericb@gobosoft.com>"
copyright:  "Copyright (c) 2000-2001, Eric Bezault and others"
license:    "MIT License"

deferred class interface

DT_DURATION

inherit

KL_PART_COMPARABLE
HASHABLE

feature -- Access

absolute_time (a_time: DT_ABSOLUTE_TIME): DT_ABSOLUTE_TIME
        -- Addition of current duration to a_time
        -- (Create a new object at each call.)
    require
        a_time_not_void: a_time /= Void
    ensure
        absolute_time_not_void: Result /= Void
        definition: Result.is_equal (a_time + Current)

hash_code: INTEGER
        -- Hash code value
        -- (From HASHABLE.)
    deferred
    ensure
        good_hash_value: Result >= 0

feature -- Basic operations

infix "+" (other: like Current): like Current
        -- Sum of current duration with other
    require
        other_not_void: other /= Void
    deferred
    ensure
        addition_not_void: Result /= Void

infix "-" (other: like Current): like Current
        -- Difference with other
    require
        other_not_void: other /= Void
    deferred
    ensure
        subtraction_not_void: Result /= Void

prefix "+": like Current
        -- Unary plus
    ensure
        unary_plus_not_void: Result /= Void
        same_object: Result = Current

prefix "-": like Current
        -- Unary minus
    deferred
    ensure
        unary_minus_not_void: Result /= Void

feature -- Comparison

infix "<" (other: like Current): BOOLEAN
        -- Is current object less than other?
        -- (From KL_PART_COMPARABLE.)
    require
        other_not_void: other /= Void
    deferred

infix "<=" (other: like Current): BOOLEAN
        -- Is current object less than or equal to other?
        -- (From KL_PART_COMPARABLE.)
    require
        other_not_void: other /= Void
    ensure
        definition: Result = ((Current < other) or is_equal (other))

infix ">=" (other: like Current): BOOLEAN
        -- Is current object greater than or equal to other?
        -- (From KL_PART_COMPARABLE.)
    require
        other_not_void: other /= Void
    ensure
        definition: Result = (other <= Current)

infix ">" (other: like Current): BOOLEAN
        -- Is current object greater than other?
        -- (From KL_PART_COMPARABLE.)
    require
        other_not_void: other /= Void
    ensure
        definition: Result = ((other < Current) or is_equal (other))

is_equal (other: like Current): BOOLEAN
        -- Is other attached to an object considered equal
        -- to current object?
        -- (From GENERAL.)
    require
        other_not_void: other /= Void
    ensure
        symmetric: Result implies other.is_equal (Current)
        consistent: standard_is_equal (other) implies Result

feature -- Duplication

copy (other: like Current)
        -- Copy other to current duration.
        -- (From GENERAL.)
    require
        other_not_void: other /= Void
        type_identity: same_type (other)
    ensure
        is_equal: is_equal (other)

end -- class DT_DURATION