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