67 lines
2.3 KiB
C
67 lines
2.3 KiB
C
/**************************************************************************/
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/* */
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/* OCaml */
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/* */
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/* Xavier Leroy, 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. */
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/* */
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/* All rights reserved. This file is distributed under the terms of */
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/* the GNU Lesser General Public License version 2.1, with the */
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/* special exception on linking described in the file LICENSE. */
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/* */
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/**************************************************************************/
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#define CAML_INTERNALS
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#include <errno.h>
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#include <sys/types.h>
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#include <caml/mlvalues.h>
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#include <caml/alloc.h>
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#include <caml/io.h>
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#include <caml/signals.h>
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#include "unixsupport.h"
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#ifdef HAS_UNISTD
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#include <unistd.h>
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#else
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#define SEEK_SET 0
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#define SEEK_CUR 1
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#define SEEK_END 2
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#endif
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#ifndef EOVERFLOW
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#define EOVERFLOW ERANGE
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#endif
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static int seek_command_table[] = {
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SEEK_SET, SEEK_CUR, SEEK_END
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};
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CAMLprim value unix_lseek(value fd, value ofs, value cmd)
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{
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file_offset ret;
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caml_enter_blocking_section();
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ret = lseek(Int_val(fd), Long_val(ofs),
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seek_command_table[Int_val(cmd)]);
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caml_leave_blocking_section();
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if (ret == -1) uerror("lseek", Nothing);
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if (ret > Max_long) unix_error(EOVERFLOW, "lseek", Nothing);
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return Val_long(ret);
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}
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CAMLprim value unix_lseek_64(value fd, value ofs, value cmd)
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{
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file_offset ret;
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/* [ofs] is an Int64, which is stored as a custom block; we must therefore
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extract its contents before dropping the runtime lock, or it might be
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moved. */
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file_offset ofs_c = File_offset_val(ofs);
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caml_enter_blocking_section();
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ret = lseek(Int_val(fd), ofs_c, seek_command_table[Int_val(cmd)]);
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caml_leave_blocking_section();
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if (ret == -1) uerror("lseek", Nothing);
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return Val_file_offset(ret);
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}
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