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|
(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Francois Rouaix, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the GNU Library General Public License, with *)
(* the special exception on linking described in file ../../LICENSE. *)
(* *)
(***********************************************************************)
(* $Id: db.ml,v 1.1.1.1 2002/10/01 00:10:14 yminsky Exp $ *)
(* Module [Db]: interface to the DB databases *)
(* this collides with Unix *)
type open_flag =
O_CREAT
| O_EXCL
| O_RDONLY
| O_RDWR
| O_TRUNC
type routine_flag =
R_CURSOR
| R_FIRST
| R_LAST
| R_NEXT
| R_NOOVERWRITE
| R_PREV
| R_SETCURSOR
(* All other fields have default values *)
type btree_flag =
Duplicates (* means R_DUP *)
| Cachesize of int
type file_perm = int
exception DB_error of string
(* Raised by the following functions when an error is encountered. *)
external caml_db_init : unit -> unit
= "caml_db_init"
let _ = Callback.register_exception "dberror" (DB_error "")
let _ = caml_db_init()
type key = string
type data = string
type t
(* Raw access *)
external dbopen : string -> open_flag list -> file_perm -> btree_flag list -> t
= "caml_db_open"
(* [dbopen file flags mode dupentries] *)
(* The common subset of available primitives *)
external close : t -> unit
= "caml_db_close"
external del : t -> key -> routine_flag list -> unit
= "caml_db_del"
(* raise Not_found if the key was not in the file *)
external get : t -> key -> routine_flag list -> data
= "caml_db_get"
(* raise Not_found if the key was not in the file *)
external put : t -> key:key -> data:data -> routine_flag list -> unit
= "caml_db_put"
external seq : t -> key -> routine_flag list -> (key * data)
= "caml_db_seq"
external sync : t -> unit
= "caml_db_sync"
(* Wrap-up as for other table-like types *)
let add db ~key:x ~data:v = put db x v [R_NOOVERWRITE]
let find db x = get db x []
let find_all db x =
try
match seq db x [R_CURSOR] with
k, v when k = x ->
let l = ref [v] in
begin
try
while true do
let k, v = seq db x [R_NEXT] in
if k = x then l := v :: !l
else raise Exit
done;
!l
with
Exit | Not_found -> !l
end
| _ -> (* its greater than x *) []
with
Not_found -> []
let remove db x = del db x []
let iter ~f db =
let rec walk = function
None -> ()
| Some(k, v) ->
f ~key:k ~data:v;
walk (try Some(seq db k [R_NEXT]) with Not_found -> None)
in
walk (try Some(seq db "" [R_FIRST]) with Not_found -> None)
|
