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(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 2000 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the Q Public License version 1.0. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* Handling of sections in bytecode executable files *)
(* List of all sections, in reverse order *)
let section_table = ref ([] : (string * int) list)
(* Recording sections *)
let section_beginning = ref 0
let init_record outchan =
section_beginning := pos_out outchan;
section_table := []
let record outchan name =
let pos = pos_out outchan in
section_table := (name, pos - !section_beginning) :: !section_table;
section_beginning := pos
let write_toc_and_trailer outchan =
List.iter
(fun (name, len) ->
output_string outchan name; output_binary_int outchan len)
(List.rev !section_table);
output_binary_int outchan (List.length !section_table);
output_string outchan Config.exec_magic_number;
section_table := [];
(* Read the table of sections from a bytecode executable *)
exception Bad_magic_number
let read_toc ic =
let pos_trailer = in_channel_length ic - 16 in
seek_in ic pos_trailer;
let num_sections = input_binary_int ic in
let header = String.create(String.length Config.exec_magic_number) in
really_input ic header 0 (String.length Config.exec_magic_number);
if header <> Config.exec_magic_number then raise Bad_magic_number;
seek_in ic (pos_trailer - 8 * num_sections);
section_table := [];
for i = 1 to num_sections do
let name = String.create 4 in
really_input ic name 0 4;
let len = input_binary_int ic in
section_table := (name, len) :: !section_table
done
(* Return the current table of contents *)
let toc () = List.rev !section_table
(* Position ic at the beginning of the section named "name",
and return the length of that section. Raise Not_found if no
such section exists. *)
let seek_section ic name =
let rec seek_sec curr_ofs = function
[] -> raise Not_found
| (n, len) :: rem ->
if n = name
then begin seek_in ic (curr_ofs - len); len end
else seek_sec (curr_ofs - len) rem in
seek_sec (in_channel_length ic - 16 - 8 * List.length !section_table)
!section_table
(* Return the contents of a section, as a string *)
let read_section_string ic name =
let len = seek_section ic name in
let res = String.create len in
really_input ic res 0 len;
res
(* Return the contents of a section, as marshalled data *)
let read_section_struct ic name =
ignore (seek_section ic name);
input_value ic
(* Return the position of the beginning of the first section *)
let pos_first_section ic =
in_channel_length ic - 16 - 8 * List.length !section_table -
List.fold_left (fun total (name, len) -> total + len) 0 !section_table
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