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