26
Ranges library
[ranges]
26.5
Range utilities
[range.utility]
26.5.4
Sub-ranges
[range.subrange]
26.5.4.1
General
[range.subrange.general]
1
#
The
subrange
class template combines together an iterator and a sentinel into a single object that models the
view
concept
.
Additionally, it models the
sized_
range
concept when the final template parameter is
subrange_
kind
::
sized
.
🔗
namespace
std
::
ranges
{
template
<
class
From,
class
To
>
concept
uses-nonqualification-pointer-conversion
=
//
exposition only
is_pointer_v
<
From
>
&
&
is_pointer_v
<
To
>
&
&
!
convertible_
to
<
remove_pointer_t
<
From
>
(
*
)
[
]
, remove_pointer_t
<
To
>
(
*
)
[
]
>
;
template
<
class
From,
class
To
>
concept
convertible-to-non-slicing
=
//
exposition only
convertible_
to
<
From, To
>
&
&
!
uses-nonqualification-pointer-conversion
<
decay_t
<
From
>
, decay_t
<
To
>
>
;
template
<
class
T,
class
U,
class
V
>
concept
pair-like-convertible-from
=
//
exposition only
!
range
<
T
>
&
&
!
is_reference_v
<
T
>
&
&
pair-like
<
T
>
&
&
constructible_
from
<
T, U, V
>
&
&
convertible-to-non-slicing
<
U, tuple_element_t
<
0
, T
>
>
&
&
convertible_
to
<
V, tuple_element_t
<
1
, T
>
>
;
template
<
input_
or_
output_
iterator
I,
sentinel_
for
<
I
>
S
=
I, subrange_kind K
=
sized_
sentinel_
for
<
S, I
>
?
subrange_kind
::
sized
:
subrange_kind
::
unsized
>
requires
(
K
=
=
subrange_kind
::
sized
|
|
!
sized_
sentinel_
for
<
S, I
>
)
class
subrange
:
public
view_interface
<
subrange
<
I, S, K
>
>
{
private
:
static
constexpr
bool
StoreSize
=
//
exposition only
K
=
=
subrange_kind
::
sized
&
&
!
sized_
sentinel_
for
<
S, I
>
; I
begin_
=
I
(
)
;
//
exposition only
S
end_
=
S
(
)
;
//
exposition only
make-unsigned-like-t
<
iter_difference_t
<
I
>
>
size_
=
0
;
//
exposition only
; present only
// if
StoreSize
is
true
public
:
subrange
(
)
requires
default_
initializable
<
I
>
=
default
;
constexpr
subrange
(
convertible-to-non-slicing
<
I
>
auto
i, S s
)
requires
(
!
StoreSize
)
;
constexpr
subrange
(
convertible-to-non-slicing
<
I
>
auto
i, S s,
make-unsigned-like-t
<
iter_difference_t
<
I
>
>
n
)
requires
(
K
=
=
subrange_kind
::
sized
)
;
template
<
different-from
<
subrange
>
R
>
requires
borrowed_
range
<
R
>
&
&
convertible-to-non-slicing
<
iterator_t
<
R
>
, I
>
&
&
convertible_
to
<
sentinel_t
<
R
>
, S
>
constexpr
subrange
(
R
&
&
r
)
requires
(
!
StoreSize
|
|
sized_
range
<
R
>
)
;
template
<
borrowed_
range
R
>
requires
convertible-to-non-slicing
<
iterator_t
<
R
>
, I
>
&
&
convertible_
to
<
sentinel_t
<
R
>
, S
>
constexpr
subrange
(
R
&
&
r,
make-unsigned-like-t
<
iter_difference_t
<
I
>
>
n
)
requires
(
K
=
=
subrange_kind
::
sized
)
:
subrange
{
ranges
::
begin
(
r
)
, ranges
::
end
(
r
)
, n
}
{
}
template
<
different-from
<
subrange
>
PairLike
>
requires
pair-like-convertible-from
<
PairLike,
const
I
&
,
const
S
&
>
constexpr
operator
PairLike
(
)
const
;
constexpr
I begin
(
)
const
requires
copyable
<
I
>
;
constexpr
I begin
(
)
requires
(
!
copyable
<
I
>
)
;
constexpr
S end
(
)
const
;
constexpr
bool
empty
(
)
const
;
constexpr
make-unsigned-like-t
<
iter_difference_t
<
I
>
>
size
(
)
const
requires
(
K
=
=
subrange_kind
::
sized
)
;
constexpr
subrange next
(
iter_difference_t
<
I
>
n
=
1
)
const
&
requires
forward_
iterator
<
I
>
;
constexpr
subrange next
(
iter_difference_t
<
I
>
n
=
1
)
&
&
;
constexpr
subrange prev
(
iter_difference_t
<
I
>
n
=
1
)
const
requires
bidirectional_
iterator
<
I
>
;
constexpr
subrange
&
advance
(
iter_difference_t
<
I
>
n
)
;
}
;
template
<
input_
or_
output_
iterator
I,
sentinel_
for
<
I
>
S
>
subrange
(
I, S
)
-
>
subrange
<
I, S
>
;
template
<
input_
or_
output_
iterator
I,
sentinel_
for
<
I
>
S
>
subrange
(
I, S,
make-unsigned-like-t
<
iter_difference_t
<
I
>
>
)
-
>
subrange
<
I, S, subrange_kind
::
sized
>
;
template
<
borrowed_
range
R
>
subrange
(
R
&
&
)
-
>
subrange
<
iterator_t
<
R
>
, sentinel_t
<
R
>
,
(
sized_
range
<
R
>
|
|
sized_
sentinel_
for
<
sentinel_t
<
R
>
, iterator_t
<
R
>
>
)
?
subrange_kind
::
sized
:
subrange_kind
::
unsized
>
;
template
<
borrowed_
range
R
>
subrange
(
R
&
&
,
make-unsigned-like-t
<
range_difference_t
<
R
>
>
)
-
>
subrange
<
iterator_t
<
R
>
, sentinel_t
<
R
>
, subrange_kind
::
sized
>
;
}