Class DS_INDEXABLE PreviousNext

note
description:

    "Data structures that can be traversed and %
    %modified through integer access"

library:    "Gobo Eiffel Structure Library"
author:     "Eric Bezault <ericb@gobosoft.com>"
copyright:  "Copyright (c) 1999-2001, Eric Bezault and others"
license:    "MIT License"
deferred class interface
DS_INDEXABLE [G]
inherit
DS_SORTABLE [G]
    DS_CONTAINER [G]
feature {NONE} -- Initialization
make_default
        -- Create an empty container.
        -- (From DS_CONTAINER.)
    deferred
    ensure
        empty: is_empty
feature -- Access
infix "@", item (i: INTEGER): G
        -- Item at index i
    require
        valid_index: 1 <= i and i <= count
    deferred
first: G
        -- First item in container
    require
        not_empty: not is_empty
    deferred
    ensure
        definition: Result = item (1)
last: G
        -- Last item in container
    require
        not_empty: not is_empty
    deferred
    ensure
        definition: Result = item (count)
feature -- Measurement
count: INTEGER
        -- Number of items in container
        -- (From DS_CONTAINER.)
    deferred
feature -- Status report
is_empty: BOOLEAN
        -- Is container empty?
        -- (From DS_CONTAINER.)
extendible (n: INTEGER): BOOLEAN
        -- May container be extended with n items?
    require
        positive_n: n >= 0
    deferred
sorted (a_sorter: DS_SORTER [G]): BOOLEAN
        -- Is container sorted according to a_sorter's criterion?
        -- (From DS_SORTABLE.)
    require
        a_sorter_not_void: a_sorter /= Void
feature -- Comparison
is_equal (other: like Current): BOOLEAN
        -- Is current container equal to other?
        -- (From GENERAL.)
    require
        other_not_void: other /= Void
    deferred
    ensure
        consistent: standard_is_equal (other) implies Result
        same_type: Result implies same_type (other)
        symmetric: Result implies other.is_equal (Current)
        same_count: Result implies count = other.count
feature -- Duplication
copy (other: like Current)
        -- Copy other to current container.
        -- (From GENERAL.)
    require
        other_not_void: other /= Void
        type_identity: same_type (other)
    deferred
    ensure
        is_equal: is_equal (other)
feature -- Sort
sort (a_sorter: DS_SORTER [G])
        -- Sort container using a_sorter's algorithm.
        -- (From DS_SORTABLE.)
    require
        a_sorter_not_void: a_sorter /= Void
    ensure
        sorted: sorted (a_sorter)
feature -- Element change
put_first (v: G)
        -- Add v to beginning of container.
    require
        extendible: extendible (1)
    deferred
    ensure
        one_more: count = old count + 1
        inserted: first = v
put_last (v: G)
        -- Add v to end of container.
    require
        extendible: extendible (1)
    deferred
    ensure
        one_more: count = old count + 1
        inserted: last = v
put (v: G; i: INTEGER)
        -- Add v at i-th position.
    require
        extendible: extendible (1)
        valid_index: 1 <= i and i <= (count + 1)
    deferred
    ensure
        one_more: count = old count + 1
        inserted: item (i) = v
force_first (v: G)
        -- Add v to beginning of container.
    deferred
    ensure
        one_more: count = old count + 1
        inserted: first = v
force_last (v: G)
        -- Add v to end of container.
    deferred
    ensure
        one_more: count = old count + 1
        inserted: last = v
force (v: G; i: INTEGER)
        -- Add v at i-th position.
    require
        valid_index: 1 <= i and i <= (count + 1)
    deferred
    ensure
        one_more: count = old count + 1
        inserted: item (i) = v
replace (v: G; i: INTEGER)
        -- Replace item at i-th position by v.
    require
        valid_index: 1 <= i and i <= count
    deferred
    ensure
        same_count: count = old count
        replaced: item (i) = v
swap (i, j: INTEGER)
        -- Exchange items at indexes i and j.
    require
        valid_i: 1 <= i and i <= count
        valid_j: 1 <= j and j <= count
    ensure
        same_count: count = old count
        new_i: item (i) = old item (j)
        new_j: item (j) = old item (i)
extend_first (other: DS_LINEAR [G])
        -- Add items of other to beginning of container.
        -- Keep items of other in the same order.
    require
        other_not_void: other /= Void
        extendible: extendible (other.count)
    deferred
    ensure
        new_count: count = old count + other.count
        same_order: (not other.is_empty) implies (first = other.first)
extend_last (other: DS_LINEAR [G])
        -- Add items of other to end of container.
        -- Keep items of other in the same order.
    require
        other_not_void: other /= Void
        extendible: extendible (other.count)
    deferred
    ensure
        new_count: count = old count + other.count
        same_order: (not other.is_empty) implies (item (old count + 1) = other.first)
extend (other: DS_LINEAR [G]; i: INTEGER)
        -- Add items of other at i-th position.
        -- Keep items of other in the same order.
    require
        other_not_void: other /= Void
        extendible: extendible (other.count)
        valid_index: 1 <= i and i <= (count + 1)
    deferred
    ensure
        new_count: count = old count + other.count
        same_order: (not other.is_empty) implies (item (i) = other.first)
append_first (other: DS_LINEAR [G])
        -- Add items of other to beginning of container.
        -- Keep items of other in the same order.
    require
        other_not_void: other /= Void
    deferred
    ensure
        new_count: count = old count + other.count
        same_order: (not other.is_empty) implies (first = other.first)
append_last (other: DS_LINEAR [G])
        -- Add items of other to end of container.
        -- Keep items of other in the same order.
    require
        other_not_void: other /= Void
    deferred
    ensure
        new_count: count = old count + other.count
        same_order: (not other.is_empty) implies (item (old count + 1) = other.first)
append (other: DS_LINEAR [G]; i: INTEGER)
        -- Add items of other at i-th position.
        -- Keep items of other in the same order.
    require
        other_not_void: other /= Void
        valid_index: 1 <= i and i <= (count + 1)
    deferred
    ensure
        new_count: count = old count + other.count
        same_order: (not other.is_empty) implies (item (i) = other.first)
feature -- Removal
remove_first
        -- Remove first item from container.
    require
        not_empty: not is_empty
    deferred
    ensure
        one_less: count = old count - 1
remove_last
        -- Remove last item from container.
    require
        not_empty: not is_empty
    deferred
    ensure
        one_less: count = old count - 1
remove (i: INTEGER)
        -- Remove item at i-th position.
    require
        not_empty: not is_empty
        valid_index: 1 <= i and i <= count
    deferred
    ensure
        one_less: count = old count - 1
prune_first (n: INTEGER)
        -- Remove n first items from container.
    require
        valid_n: 0 <= n and n <= count
    deferred
    ensure
        new_count: count = old count - n
prune_last (n: INTEGER)
        -- Remove n last items from container.
    require
        valid_n: 0 <= n and n <= count
    deferred
    ensure
        new_count: count = old count - n
prune (n: INTEGER; i: INTEGER)
        -- Remove n items at and after i-th position.
    require
        valid_index: 1 <= i and i <= count
        valid_n: 0 <= n and n <= (count - i + 1)
    deferred
    ensure
        new_count: count = old count - n
keep_first (n: INTEGER)
        -- Keep n first items in container.
    require
        valid_n: 0 <= n and n <= count
    deferred
    ensure
        new_count: count = n
keep_last (n: INTEGER)
        -- Keep n last items in container.
    require
        valid_n: 0 <= n and n <= count
    deferred
    ensure
        new_count: count = n
wipe_out
        -- Remove all items from container.
        -- (From DS_CONTAINER.)
    deferred
    ensure
        wiped_out: is_empty
invariant
positive_count: count >= 0
empty_definition: is_empty = (count = 0)
    -- (From DS_CONTAINER.)
end -- class DS_INDEXABLE

Copyright 1999-2001, Eric Bezault
mailto:
ericb@gobosoft.com
http:
//www.gobosoft.com
Last Updated: 31 March 2001

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