module Iobuf: Iobuf
include ??
include ??
type (+'data_perm_read_write, +'seek_permission)
t
To allow read_write
or read_only
access, a function's type uses _
rather than
read_only
as the type argument to t
. Analogously, to allow no_seek
or seek
access, a function's type uses _
rather than no_seek
as the type argument to t
.
Using _
allows the function to be directly applied to either permission. Using
a specific permission would require code to use coercion :>
.
include Invariant.S2
val create : len:int -> ('a, 'b) t
create ~len
creates a new iobuf, backed by a bigstring of length len
,
with the limits and window set to the entire bigstring.val of_bigstring : ?pos:int -> ?len:int -> Bigstring.t -> ('a, 'b) t
of_bigstring bigstring ~pos ~len
returns an iobuf backed by bigstring
, with the
window and limits specified starting at pos
and of length len
.val of_string : string -> ('a, 'b) t
of_string s
returns a new iobuf whose contents are s
.val sub : ?pos:int -> ?len:int -> ('d, 'a) t -> ('d, 'b) t
sub t ~pos ~len
returns a new iobuf with limits and window set to the subrange of
t
specified by pos
and len
. sub
preserves data permissions, but allows
arbitrary seek permissions on the resulting iobuf.val set_bounds_and_buffer : src:(Common.read_write, 'a) t -> dst:('b, seek) t -> unit
set_bounds_and_buffer ~src ~dst
copies bounds (ie limits + window) and shallowly
copies the buffer from src
to dst
. read_write
access is required on src
because the caller might have read_write
access to dst
, and would after the call
then effectively have read_write
access to src
.val set_bounds_and_buffer_sub : ?pos:int ->
?len:int ->
src:(Common.read_write, 'a) t -> dst:('b, seek) t -> unit -> unit
set_bounds_and_buffer_sub ?pos ?len ~src ~dst ()
is a more efficient version of:
set_bounds_and_buffer ~src:(Iobuf.sub ?pos ?len src) ~dst
.
set_bounds_and_buffer ~src ~dst
is not the same as
set_bounds_and_buffer_sub ~dst ~src ()
, because the limits are narrowed in the
latter case.
val capacity : ('a, 'b) t -> int
capacity t
returns the size of t
's limits subrange. The capacity of an iobuf can
be reduced via narrow
.val length : ('a, 'b) t -> int
length t
returns the size of t
's window.val is_empty : ('a, 'b) t -> bool
is_empty t
is length t = 0
.val narrow : ('a, seek) t -> unit
narrow t
sets t
's limits to the current window.Lo_bound.window t
to get a snapshot of the lower bound of the
window, and then later restore that snapshot with Lo_bound.restore
. This is
useful for speculatively parsing, and then rewinding when there isn't enough data to
finish.
Similarly for Hi_bound.window
and Lo_bound.restore
.
Using a snapshot with a different iobuf, even a sub iobuf of the snapshotted one, has
unspecified results. An exception may be raised, or a silent error may occur.
However, the safety guarantees of the iobuf will not be violated, i.e., the attempt
will not enlarge the limits of the subject iobuf.
module type Bound =Bound
with type ('d, 'w) iobuf := ('d, 'w) t
module Lo_bound:Bound
module Hi_bound:Bound
val advance : ('a, seek) t -> int -> unit
advance t amount
advances the lower bound of the window by amount
. It is an error
to advance past the upper bound of the window or the lower limit.val resize : ('a, seek) t -> len:int -> unit
resize t
sets the length of t
's window, provided it does not exceed limits.val rewind : ('a, seek) t -> unit
rewind t
sets the lower bound of the window to the lower limit.val reset : ('a, seek) t -> unit
reset t
sets the window to the limits.val flip_lo : ('a, seek) t -> unit
flip_lo t
sets the window to range from the lower limit to the lower bound of the
old window. This is typically called after a series of Fill
s, to reposition the
window in preparation to Consume
the newly written data.
The bounded version narrows the effective limit. This can preserve some data near the
limit, such as an hypothetical packet header, in the case of bounded_flip_lo
or
unfilled suffix of a buffer, in bounded_flip_hi
.
val bounded_flip_lo : ('a, seek) t -> Lo_bound.t -> unit
val compact : (Common.read_write, seek) t -> unit
compact t
copies data from the window to the lower limit of the iobuf and sets the
window to range from the end of the copied data to the upper limit. This is typically
called after a series of Consume
s to save unread data and prepare for the next
series of Fill
s and flip_lo
.val bounded_compact : (Common.read_write, seek) t -> Lo_bound.t -> Hi_bound.t -> unit
val flip_hi : ('a, seek) t -> unit
flip_hi t
sets the window to range from the the upper bound of the current window to
the upper limit. This operation is dual to flip_lo
and is typically called when the
data in the current (narrowed) window has been processed and the window needs to be
positioned over the remaining data in the buffer. For example:
(* ... determine initial_data_len ... *)
Iobuf.resize buf ~len:initial_data_len;
(* ... and process initial data ... *)
Iobuf.flip_hi buf;
Now the window of buf
ranges over the remainder of the data.
val bounded_flip_hi : ('a, seek) t -> Hi_bound.t -> unit
val to_string : ?len:int -> ('a, 'b) t -> string
to_string t
returns the bytes in t
as a string. It does not alter the window.val consume_into_string : ?pos:int -> ?len:int -> ('a, seek) t -> string -> unit
consume_into_string t s ~pos ~len
reads len
bytes from t
, advancing t
's window
accordingly, and writes them into s
starting at pos
. By default pos = 0
and
len = String.length s - pos
. It is an error if pos
and len
don't specify a
valid region of s
or len > length t
.val consume_into_bigstring : ?pos:int -> ?len:int -> ('a, seek) t -> Bigstring.t -> unit
module Consume:Accessors
with type ('a, 'd, 'w) t = ('d, seek) t -> 'a
with type 'a bin_prot := 'a Bin_prot.Type_class.reader
Consume.string t ~len
reads len
characters (all, by default) from t
into a new
string and advances the lower bound of the window accordingly.
module Fill:Accessors
with type ('a, 'd, 'w) t = (read_write, seek) t -> 'a -> unit
with type 'a bin_prot := 'a Bin_prot.Type_class.writer
Fill.bin_prot X.bin_write_t t x
writes x
to t
in bin-prot form, advancing past
the bytes written.
module Peek:Accessors
with type ('a, 'd, 'w) t = ('d, 'w) t -> pos:int -> 'a
with type 'a bin_prot := 'a Bin_prot.Type_class.reader
Peek
and Poke
functions access a value at pos
from the lower bound of the window
and do not advance.
module Poke:Accessors
with type ('a, 'd, 'w) t = (read_write, 'w) t -> pos:int -> 'a -> unit
with type 'a bin_prot := 'a Bin_prot.Type_class.writer
Poke.bin_prot X.bin_write_t t x
writes x
to the beginning of t
in binary form
without advancing.
module Unsafe:sig
..end
Unsafe
has submodules that are like their corresponding module, except with no range
checks.
val fill_bin_prot : (Common.read_write, seek) t ->
'a Bin_prot.Type_class.writer -> 'a -> unit Or_error.t
fill_bin_prot
writes a bin-prot value to the lower bound of the window, prefixed by
its length, and advances by the amount written. fill_bin_prot
returns an error if
the window is too small to write the value.
consume_bin_prot t reader
reads a bin-prot value from the lower bound of the window,
which should have been written using fill_bin_prot
, and advances the window by the
amount read. consume_bin_prot
returns an error if there is not a complete message
in the window and in that case the window is left unchanged.
val consume_bin_prot : ('b, seek) t -> 'a Bin_prot.Type_class.reader -> 'a Or_error.t
val transfer : ?len:int ->
src:('a, seek) t -> dst:(Common.read_write, seek) t -> unit
transfer
blits len
bytes from src
to dst
, advancing the lower bounds of both
windows. It is an error if len > length src || len > length dst || phys_equal src
dst
.val memmove : (Common.read_write, 'a) t ->
src_pos:int -> dst_pos:int -> len:int -> unit
memmove
blits len
bytes from src_pos
to dst_pos
in an iobuf, both relative to
the lower bound of the window. The window is not advanced.val read_assume_fd_is_nonblocking : (Common.read_write, seek) t -> Iobuf_intf.Unix.File_descr.t -> int
Iobuf
has analogs of various Bigstring
functions. These analogs advance by the
amount written/read.val pread_assume_fd_is_nonblocking : (Common.read_write, seek) t ->
Iobuf_intf.Unix.File_descr.t -> offset:int -> int
val recvfrom_assume_fd_is_nonblocking : (Common.read_write, seek) t ->
Iobuf_intf.Unix.File_descr.t -> int * Iobuf_intf.Unix.sockaddr
val recvmmsg_assume_fd_is_nonblocking : (Iobuf_intf.Unix.File_descr.t ->
?count:int ->
?srcs:Iobuf_intf.Unix.sockaddr array ->
(Common.read_write, seek) t array -> int)
Or_error.t
val recvmmsg_assume_fd_is_nonblocking_no_options : (Iobuf_intf.Unix.File_descr.t ->
count:int -> (Common.read_write, seek) t array -> int)
Or_error.t
val send_nonblocking_no_sigpipe : unit ->
(('a, seek) t -> Iobuf_intf.Unix.File_descr.t -> int option) Or_error.t
val sendto_nonblocking_no_sigpipe : unit ->
(('a, seek) t ->
Iobuf_intf.Unix.File_descr.t -> Iobuf_intf.Unix.sockaddr -> int option)
Or_error.t
val write_assume_fd_is_nonblocking : ('a, seek) t -> Iobuf_intf.Unix.File_descr.t -> int
val pwrite_assume_fd_is_nonblocking : ('a, seek) t -> Iobuf_intf.Unix.File_descr.t -> offset:int -> int
val sexp_of_seek : seek -> Sexplib.Sexp.t
val sexp_of_no_seek : no_seek -> Sexplib.Sexp.t
val sexp_of_t : ('data_perm_read_write -> Sexplib.Sexp.t) ->
('seek_permission -> Sexplib.Sexp.t) ->
('data_perm_read_write, 'seek_permission) t -> Sexplib.Sexp.t
To allow read_write
or read_only
access, a function's type uses _
rather than
read_only
as the type argument to t
. Analogously, to allow no_seek
or seek
access, a function's type uses _
rather than no_seek
as the type argument to t
.
Using _
allows the function to be directly applied to either permission. Using
a specific permission would require code to use coercion :>
.
create ~len
creates a new iobuf, backed by a bigstring of length len
,
with the limits and window set to the entire bigstring.of_bigstring bigstring ~pos ~len
returns an iobuf backed by bigstring
, with the
window and limits specified starting at pos
and of length len
.0
Bigstring.length bigstring - pos
of_string s
returns a new iobuf whose contents are s
.sub t ~pos ~len
returns a new iobuf with limits and window set to the subrange of
t
specified by pos
and len
. sub
preserves data permissions, but allows
arbitrary seek permissions on the resulting iobuf.set_bounds_and_buffer ~src ~dst
copies bounds (ie limits + window) and shallowly
copies the buffer from src
to dst
. read_write
access is required on src
because the caller might have read_write
access to dst
, and would after the call
then effectively have read_write
access to src
.set_bounds_and_buffer_sub ?pos ?len ~src ~dst ()
is a more efficient version of:
set_bounds_and_buffer ~src:(Iobuf.sub ?pos ?len src) ~dst
.
set_bounds_and_buffer ~src ~dst
is not the same as
set_bounds_and_buffer_sub ~dst ~src ()
, because the limits are narrowed in the
latter case.
capacity t
returns the size of t
's limits subrange. The capacity of an iobuf can
be reduced via narrow
.length t
returns the size of t
's window.is_empty t
is length t = 0
.narrow t
sets t
's limits to the current window.Lo_bound.window t
to get a snapshot of the lower bound of the
window, and then later restore that snapshot with Lo_bound.restore
. This is
useful for speculatively parsing, and then rewinding when there isn't enough data to
finish.
Similarly for Hi_bound.window
and Lo_bound.restore
.
Using a snapshot with a different iobuf, even a sub iobuf of the snapshotted one, has
unspecified results. An exception may be raised, or a silent error may occur.
However, the safety guarantees of the iobuf will not be violated, i.e., the attempt
will not enlarge the limits of the subject iobuf.
advance t amount
advances the lower bound of the window by amount
. It is an error
to advance past the upper bound of the window or the lower limit.
resize t
sets the length of t
's window, provided it does not exceed limits.
rewind t
sets the lower bound of the window to the lower limit.
reset t
sets the window to the limits.
flip_lo t
sets the window to range from the lower limit to the lower bound of the
old window. This is typically called after a series of Fill
s, to reposition the
window in preparation to Consume
the newly written data.
The bounded version narrows the effective limit. This can preserve some data near the
limit, such as an hypothetical packet header, in the case of bounded_flip_lo
or
unfilled suffix of a buffer, in bounded_flip_hi
.
compact t
copies data from the window to the lower limit of the iobuf and sets the
window to range from the end of the copied data to the upper limit. This is typically
called after a series of Consume
s to save unread data and prepare for the next
series of Fill
s and flip_lo
.
flip_hi t
sets the window to range from the the upper bound of the current window to
the upper limit. This operation is dual to flip_lo
and is typically called when the
data in the current (narrowed) window has been processed and the window needs to be
positioned over the remaining data in the buffer. For example:
(* ... determine initial_data_len ... *)
Iobuf.resize buf ~len:initial_data_len;
(* ... and process initial data ... *)
Iobuf.flip_hi buf;
Now the window of buf
ranges over the remainder of the data.
to_string t
returns the bytes in t
as a string. It does not alter the window.consume_into_string t s ~pos ~len
reads len
bytes from t
, advancing t
's window
accordingly, and writes them into s
starting at pos
. By default pos = 0
and
len = String.length s - pos
. It is an error if pos
and len
don't specify a
valid region of s
or len > length t
.Consume.string t ~len
reads len
characters (all, by default) from t
into a new
string and advances the lower bound of the window accordingly.
Consume.bin_prot X.bin_read_t t
returns the initial X.t
in t
, advancing past the
bytes read.
Fill.bin_prot X.bin_write_t t x
writes x
to t
in bin-prot form, advancing past
the bytes written.
Peek
and Poke
functions access a value at pos
from the lower bound of the window
and do not advance.
Peek.bin_prot X.bin_read_t t
returns the initial X.t
in t
without advancing.
Following the bin_prot
protocol, the representation of x
is X.bin_size_t x
bytes
long. Peek.
, Poke.
, Consume.
, and Fill.bin_prot
do not add any size prefix or
other framing to the bin_prot
representation.
Poke.bin_prot X.bin_write_t t x
writes x
to the beginning of t
in binary form
without advancing. You can use X.bin_size_t
to tell how long it was.
X.bin_write_t
is only allowed to write that portion of the buffer to which you have
access.
Unsafe
has submodules that are like their corresponding module, except with no range
checks. Hence, mistaken uses can cause segfaults. Be careful!
fill_bin_prot
writes a bin-prot value to the lower bound of the window, prefixed by
its length, and advances by the amount written. fill_bin_prot
returns an error if
the window is too small to write the value.
consume_bin_prot t reader
reads a bin-prot value from the lower bound of the window,
which should have been written using fill_bin_prot
, and advances the window by the
amount read. consume_bin_prot
returns an error if there is not a complete message
in the window and in that case the window is left unchanged.
transfer
blits len
bytes from src
to dst
, advancing the lower bounds of both
windows. It is an error if len > length src || len > length dst || phys_equal src
dst
.
default is min (length src) (length dst)
memmove
blits len
bytes from src_pos
to dst_pos
in an iobuf, both relative to
the lower bound of the window. The window is not advanced.
Iobuf
has analogs of various Bigstring
functions. These analogs advance by the
amount written/read.