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Module Netpagebuffer

module Netpagebuffer: sig .. end
Buffer for page-aligned I/O


This kind of buffer uses page-aligned bigarrays. Data can only be added to the end, or deleted at the beginning of the buffer.

The idea of this buffer is that input data is added to the last page of the buffer only (with add_inplace). If then all previous input was already a multiple of the page size, it is ensured that the new input is added at a page boundary. This kind of input operation can often be accelerated by the OS ("zero copy network I/O").

type t 
val create : int -> t
create blocksize: creates new buffer with this blocksize, which must be a whole multiple of the page size of the OS

The blocksize is normally either

These cases are optimized, and the buffer is allocated in a shared pool.
val contents : t -> string
Returns the contents as string
val to_bytes : t -> Bytes.t
Returns the contents of the buffer as fresh string.
val to_tstring_poly : t -> 's Netstring_tstring.tstring_kind -> 's
Return the buffer in the format as selected by the arg
val to_tstring : t -> 'a Netstring_tstring.tstring_kind -> Netsys_types.tstring
Returns the buffer as tagged string, selecting the chosen representation
val length : t -> int
The length
val sub : t -> int -> int -> string
Returns a substring
val sub_bytes : t -> int -> int -> Bytes.t
Same for bytes
val blit_to_bytes : t -> int -> Bytes.t -> int -> int -> unit
Blits contents to a string
val blit_to_string : t -> int -> Bytes.t -> int -> int -> unit
Deprecated."Use blit_to_bytes instead."
val blit_to_memory : t -> int -> Netsys_mem.memory -> int -> int -> unit
Blits contents to another memory buffer
val blit_to_tbuffer : t -> int -> Netsys_types.tbuffer -> int -> int -> unit
Blits contents to a tagged buffer
val blit : t -> int -> Bytes.t -> int -> int -> unit
Compatibility name for blit_to_bytes
val add_string : t -> string -> unit
Adds a string to the end of the buffer
val add_bytes : t -> Bytes.t -> unit
Same for bytes
val add_tstring : t -> Netsys_types.tstring -> unit
Same for tagged string
val add_substring : t -> string -> int -> int -> unit
Adds a sub string to the end of the buffer
val add_sub_string : t -> string -> int -> int -> unit
Deprecated."Use add_substring instead."
val add_subbytes : t -> Bytes.t -> int -> int -> unit
Adds a sub string to the end of the buffer
val add_submemory : t -> Netsys_mem.memory -> int -> int -> unit
Adds a sub memory buffer to the end of the buffer
val add_sub_memory : t -> Netsys_mem.memory -> int -> int -> unit
Deprecated."Use add_submemory instead."
val add_subtstring : t -> Netsys_types.tstring -> int -> int -> unit
Adds a sub tstring to the end of the buffer
val add_inplace : t -> (Netsys_mem.memory -> int -> int -> int) -> int
add_inplace b f: Calls f m pos len where m is the last page of the buffer, and pos is the first free byte on the page, and len is the number of free bytes on the page. The function f is expected to store new data in m from pos to pos+n-1 and to return n. The number n is also returned as final result.

It is ensured that f is called with a value of len>=1.

val page_for_additions : t -> Netsys_mem.memory * int * int
let (m,pos,len) = page_for_additions b: Returns the last page in m, the first free byte on the page in pos, and the number of free bytes on the page in len. (The same values the function f would have got as arguments in add_inplace.)
val advance : t -> int -> unit
advance b n: Marks further n bytes in the last page of the buffer as used. These bytes are not modified in any way - it is expected that the user calls page_for_additions first, and sets these n bytes to new values directly.
val page_for_consumption : t -> Netsys_mem.memory * int * int
let (m,pos,len) = page_for_consumption b: Returns the first page in m, the first used byte on the page in pos, and the number of used bytes on the page in len.
val delete_hd : t -> int -> unit
delete_hd b n: Deletes n bytes from the beginning of the buffer
val clear : t -> unit
Deletes all contents of the buffer

Searching


val index_from : t -> int -> char -> int
index_from nb k c: Searches the character c in the buffer beginning at position k. If found, the position of the left-most occurence is returned. Otherwise, Not_found is raised.
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