Improve and complete cachet

cachet.opam

@@ -0,0 +1,23 @@
+opam-version: "2.0"
+name:         "cachet"
+maintainer:   [ "Romain Calascibetta <romain.calascibetta@gmail.com>"
+                "Reynir Björnsson <reynir@reynir.dk>" ]
+authors:      [ "Romain Calascibetta <romain.calascibetta@gmail.com>"
+                "Reynir Björnsson <reynir@reynir.dk>" ]
+homepage:     "https://git.robur.coop/robur/cachet"
+bug-reports:  "https://git.robur.coop/robur/cachet"
+dev-repo:     "git+https://git.robur.coop/robur/cachet"
+doc:          "https://robur-coop.github.io/cachet/"
+license:      "MIT"
+synopsis:     "A simple cache system for mmap"
+description: """A small library that provides a simple cache system for page-by-page read access on a block device."""
+
+build: [ "dune" "build" "-p" name "-j" jobs ]
+run-test: [ "dune" "runtest" "-p" name "-j" jobs ]
+
+depends: [
+  "ocaml"       {>= "4.14.0"}
+  "dune"        {>= "3.5.0"}
+  "bigstringaf" {with-test & >= "0.9.0"}
+  "alcotest"    {with-test & >= "1.7.0"}
+]

lib/cachet.ml

@@ -9,6 +9,7 @@ module Bstr = struct
   type t = bigstring
 
   let of_bigstring x = x
+  let empty = Bigarray.Array1.create Bigarray.char Bigarray.c_layout 0
   let length = Bigarray.Array1.dim
 
   external get : t -> int -> char = "%caml_ba_ref_1"
@@ -230,6 +231,54 @@ let get_string t ~len logical_address =
   blit_to_bytes t ~src_off:logical_address buf ~dst_off:0 ~len;
   Bytes.unsafe_to_string buf
 
+let get_uint16_ne t logical_address =
+  let str = get_string t ~len:2 logical_address in
+  String.get_uint16_ne str 0
+
+let get_uint16_le t logical_address =
+  let str = get_string t ~len:2 logical_address in
+  String.get_uint16_le str 0
+
+let get_uint16_be t logical_address =
+  let str = get_string t ~len:2 logical_address in
+  String.get_uint16_be str 0
+
+let get_int16_ne t logical_address =
+  let str = get_string t ~len:2 logical_address in
+  String.get_int16_ne str 0
+
+let get_int16_le t logical_address =
+  let str = get_string t ~len:2 logical_address in
+  String.get_int16_le str 0
+
+let get_int16_be t logical_address =
+  let str = get_string t ~len:2 logical_address in
+  String.get_int16_be str 0
+
+let get_int32_ne t logical_address =
+  let str = get_string t ~len:4 logical_address in
+  String.get_int32_ne str 0
+
+let get_int32_le t logical_address =
+  let str = get_string t ~len:4 logical_address in
+  String.get_int32_le str 0
+
+let get_int32_be t logical_address =
+  let str = get_string t ~len:4 logical_address in
+  String.get_int32_be str 0
+
+let get_int64_ne t logical_address =
+  let str = get_string t ~len:8 logical_address in
+  String.get_int64_ne str 0
+
+let get_int64_le t logical_address =
+  let str = get_string t ~len:8 logical_address in
+  String.get_int64_le str 0
+
+let get_int64_be t logical_address =
+  let str = get_string t ~len:8 logical_address in
+  String.get_int64_be str 0
+
 let rec get_seq t logical_address () =
   match load t logical_address with
   | Some { offset; payload; length; _ } ->

lib/cachet.mli

@@ -6,9 +6,20 @@ module Bstr : sig
 
   type t = private bigstring
 
+  val empty : t
+  (** [empty] is an empty bigstring. *)
+
   val of_bigstring : bigstring -> t
+
   val length : t -> int
+  (** [length bstr] is the number of bytes in [bstr]. *)
+
   val get : t -> int -> char
+  (** [get bstr i] is the byte of [bstr]' at index [i]. This is
+      equivalent to the [bstr.{i}] notation. 
+
+      @raise Invalid_argument if [i] is not an index of [bstr]. *)
+
   val get_int8 : t -> int -> int
   val get_uint8 : t -> int -> int
   val get_int16_ne : t -> int -> int
@@ -129,8 +140,13 @@ val invalidate : 'fd t -> off:int -> len:int -> unit
     zero-extend) their result. *)
 
 val get_int8 : 'fd t -> int -> int
+(** [get_int8 t logical_address] is [t]'s signed 8-bit integer starting at byte
+    index [logical_address]. *)
+
 val get_uint8 : 'fd t -> int -> int
-(*
+(** [get_uint8 t logical_address] is [t]'s unsigned 8-bit integer starting at byte
+    index [logical_address]. *)
+
 val get_uint16_ne : 'fd t -> int -> int
 val get_uint16_le : 'fd t -> int -> int
 val get_uint16_be : 'fd t -> int -> int
@@ -143,8 +159,6 @@ val get_int32_be : 'fd t -> int -> int32
 val get_int64_ne : 'fd t -> int -> int64
 val get_int64_le : 'fd t -> int -> int64
 val get_int64_be : 'fd t -> int -> int64
-*)
-
 val get_string : 'fd t -> len:int -> int -> string
 val get_seq : 'fd t -> int -> string Seq.t
 val next : 'fd t -> slice -> slice option

lib/dune

@@ -1,8 +1,12 @@
 (library
  (name cachet)
- (modes native)
+ (modes native byte)
- ; (foreign_stubs
+ (foreign_stubs
- ;   (language c)
+  (language c)
- ;   (mode byte)
+  (mode byte)
- ;   (names hash))
+  (names hash))
+ (foreign_stubs
+  (language c)
+  (mode native)
+  (names stub))
  (modules cachet))