String type based on Bigarray, for use in I/O and C-bindings
Types and exceptions
type t = (char, Bigarray.int8_unsigned_elt, Bigarray.c_layout) Bigarray.Array1.t
Type of bigstrings
Creation and string conversion
val create : ?max_mem_waiting_gc:Byte_units.t -> int -> t
create length
max_mem_waiting_gc : default = 256 M in OCaml <= 3.12, 1 G otherwise. As the total allocation of calls to create approach max_mem_waiting_gc, the pressure in the garbage collector to be more agressive will increase.
Returns a new bigstring having length. Content is undefined.
val init : int -> f:(int -> char) -> t
init n ~f creates a bigstring t of length n, with t.{i} = f i
val of_string : ?pos:int -> ?len:int -> string -> t
of_string ?pos ?len str
pos : default = 0
len : default = String.length str - pos
Returns a new bigstring that is equivalent to the substring of length len in str starting at position pos.
val to_string : ?pos:int -> ?len:int -> t -> string
to_string ?pos ?len bstr
pos : default = 0
len : default = length bstr - pos
Raises Invalid_argument if the string would exceed runtime limits.
Returns a new string that is equivalent to the substring of length len in bstr starting at position pos.
Checking
val check_args : loc:string -> pos:int -> len:int -> t -> unit
check_args ~loc ~pos ~len bstr checks the position and length arguments pos and len for bigstrings bstr. Raises Invalid_argument if these arguments are illegal for the given bigstring using loc to indicate the calling context.
val get_opt_len : t -> pos:int -> int option -> int
get_opt_len bstr ~pos opt_len Returns the length of a subbigstring in bstr starting at position pos and given optional length opt_len. This function does not check the validity of its arguments. Use check_args for that purpose.
Accessors
val length : t -> int
length bstr Returns the length of bigstring bstr.
val sub_shared : ?pos:int -> ?len:int -> t -> t
sub_shared ?pos ?len bstr
pos : default = 0
len : default = Bigstring.length bstr - pos
Returns the sub-bigstring in bstr that starts at position pos and has length len. The sub-bigstring shares the same memory region, i.e. modifying it will modify the original bigstring. Holding on to the sub-bigstring will also keep the (usually bigger) original one around.
val get : t -> int -> char
get t pos returns the character at pos
val set : t -> int -> char -> unit
set t pos sets the character at pos
val is_mmapped : t -> bool
is_mmapped bstr Returns whether the bigstring bstr is memory-mapped.
Blitting
blit ~src ?src_pos ?src_len ~dst ?dst_pos () blits src_len characters from src starting at position src_pos to dst at position dst_pos. Raises Invalid_argument if the designated ranges are out of bounds.
include Blit.S with type t := t
module To_string : Blit.S_distinct with type src := t with type dst := string
module From_string : Blit.S_distinct with type src := string with type dst := t
Memory mapping
val map_file : shared:bool -> Unix.file_descr -> int -> t
map_file shared fd n memory-maps n characters of the data associated with descriptor fd to a bigstring. Iff shared is true, all changes to the bigstring will be reflected in the file.
Search
val find : ?pos:int -> ?len:int -> char -> t -> int option
find ?pos ?len char t returns Some i for the smallest i >= pos such that t.{i} = char, or None if there is no such i.
pos : default = 0
len : default = length bstr - pos
Destruction
val unsafe_destroy : t -> unit
unsafe_destroy bstr destroys the bigstring by deallocating its associated data or, if memory-mapped, unmapping the corresponding file, and setting all dimensions to zero. This effectively frees the associated memory or address-space resources instantaneously. This feature helps working around a bug in the current OCaml runtime, which does not correctly estimate how aggressively to reclaim such resources.

This operation is safe unless you have passed the bigstring to another thread that is performing operations on it at the same time. Access to the bigstring after this operation will yield array bounds exceptions.

Raises Failure if the bigstring has already been deallocated (or deemed "external", which is treated equivalently), or if it has proxies, i.e. other bigstrings referring to the same data.
val unsafe_get_int8 : t -> pos:int -> int
val unsafe_set_int8 : t -> pos:int -> int -> unit
val unsafe_get_uint8 : t -> pos:int -> int
val unsafe_set_uint8 : t -> pos:int -> int -> unit
val unsafe_get_int16_le : t -> pos:int -> int
val unsafe_get_int16_be : t -> pos:int -> int
val unsafe_set_int16_le : t -> pos:int -> int -> unit
val unsafe_set_int16_be : t -> pos:int -> int -> unit
val unsafe_get_uint16_le : t -> pos:int -> int
val unsafe_get_uint16_be : t -> pos:int -> int
val unsafe_set_uint16_le : t -> pos:int -> int -> unit
val unsafe_set_uint16_be : t -> pos:int -> int -> unit
val unsafe_get_int32_le : t -> pos:int -> int
val unsafe_get_int32_be : t -> pos:int -> int
val unsafe_set_int32_le : t -> pos:int -> int -> unit
val unsafe_set_int32_be : t -> pos:int -> int -> unit
val unsafe_get_uint32_le : t -> pos:int -> int
val unsafe_get_uint32_be : t -> pos:int -> int
val unsafe_set_uint32_le : t -> pos:int -> int -> unit
val unsafe_set_uint32_be : t -> pos:int -> int -> unit
val unsafe_get_int64_le_exn : t -> pos:int -> int
val unsafe_get_int64_be_exn : t -> pos:int -> int
val unsafe_set_int64_le : t -> pos:int -> int -> unit
val unsafe_set_int64_be : t -> pos:int -> int -> unit
val unsafe_get_int32_t_le : t -> pos:int -> Int32.t
val unsafe_get_int32_t_be : t -> pos:int -> Int32.t
val unsafe_set_int32_t_le : t -> pos:int -> Int32.t -> unit
val unsafe_set_int32_t_be : t -> pos:int -> Int32.t -> unit
val unsafe_get_int64_t_le : t -> pos:int -> Int64.t
val unsafe_get_int64_t_be : t -> pos:int -> Int64.t
val unsafe_set_int64_t_le : t -> pos:int -> Int64.t -> unit
val unsafe_set_int64_t_be : t -> pos:int -> Int64.t -> unit
val get_padded_fixed_string : padding:char -> t -> pos:int -> len:int -> unit -> string
val set_padded_fixed_string : padding:char -> t -> pos:int -> len:int -> string -> unit
val t_of_sexp : Sexplib.Sexp.t -> t
val sexp_of_t : t -> Sexplib.Sexp.t
val bin_t : t Bin_prot.Type_class.t
val bin_read_t : t Bin_prot.Read.reader
val __bin_read_t__ : (int -> t) Bin_prot.Read.reader
val bin_reader_t : t Bin_prot.Type_class.reader
val bin_size_t : t Bin_prot.Size.sizer
val bin_write_t : t Bin_prot.Write.writer
val bin_writer_t : t Bin_prot.Type_class.writer