--- /dev/null
+(* Copyright (C) 2005, HELM Team.
+ *
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ *
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ *
+ * For details, see the HELM World-Wide-Web page,
+ * http://helm.cs.unibo.it/
+ *)
+
+exception Corrupt_file of string
+exception Format_mismatch of string
+exception Version_mismatch of string
+
+let ensure_path_exists fname = HExtlib.mkdir (Filename.dirname fname)
+let marshal_flags = []
+
+let save ~fmt ~version ~fname data =
+ ensure_path_exists fname;
+ let oc = open_out fname in
+ let marshalled = Marshal.to_string data marshal_flags in
+ output_binary_int oc (Hashtbl.hash fmt); (* field 1 *)
+ output_binary_int oc version; (* field 2 *)
+ output_string oc fmt; (* field 3 *)
+ output_string oc (string_of_int version); (* field 4 *)
+ output_binary_int oc (Hashtbl.hash marshalled); (* field 5 *)
+ output_string oc marshalled; (* field 6 *)
+ close_out oc
+
+let expect ic fname s =
+ let len = String.length s in
+ let buf = String.create len in
+ really_input ic buf 0 len;
+ if buf <> s then raise (Corrupt_file fname)
+
+let load ~fmt ~version ~fname =
+ let ic = open_in fname in
+ HExtlib.finally
+ (fun () -> close_in ic)
+ (fun () ->
+ try
+ let fmt' = input_binary_int ic in (* field 1 *)
+ if fmt' <> Hashtbl.hash fmt then raise (Format_mismatch fname);
+ let version' = input_binary_int ic in (* field 2 *)
+ if version' <> version then raise (Version_mismatch fname);
+ expect ic fname fmt; (* field 3 *)
+ expect ic fname (string_of_int version); (* field 4 *)
+ let checksum' = input_binary_int ic in (* field 5 *)
+ let marshalled' = HExtlib.input_all ic in (* field 6 *)
+ if checksum' <> Hashtbl.hash marshalled' then
+ raise (Corrupt_file fname);
+ Marshal.from_string marshalled' 0
+ with End_of_file -> raise (Corrupt_file fname))
+ ()
+
--- /dev/null
+(* Copyright (C) 2005, HELM Team.
+ *
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ *
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ *
+ * For details, see the HELM World-Wide-Web page,
+ * http://helm.cs.unibo.it/
+ *)
+
+(** {2 Marshalling with version/consistency checks} *)
+
+(** {3 File formats}
+ *
+ * Files saved/loaded by this module share a common format:
+ *
+ * | n | Field name | Field type | Description |
+ * +---+-------------+------------+---------------------------------------+
+ * | 1 | format | integer | hash value of the 'fmt' parameter |
+ * | 2 | version | integer | 'version' parameter |
+ * | 3 | format dsc | string | extended 'fmt' parameter |
+ * | 4 | version dsc | string | extended 'version' parameter |
+ * | 5 | checksum | integer | hash value of the _field_ below |
+ * | 6 | data | raw | ocaml marshalling of 'data' parameter |
+ *
+ *)
+
+exception Corrupt_file of string (** checksum mismatch, or file too short *)
+exception Format_mismatch of string
+exception Version_mismatch of string
+
+ (** Marhsal some data according to the file format above.
+ * @param fmt format name
+ * @param version version number
+ * @param fname file name to which marshal data
+ * @param data data to be marshalled on disk *)
+val save: fmt:string -> version:int -> fname:string -> 'a -> unit
+
+ (** parameters as above
+ * @raise Corrupt_file
+ * @raise Format_mismatch
+ * @raise Version_mismatch *)
+val load: fmt:string -> version:int -> fname:string -> 'a
+
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