libctf/ctf-error.c

   1 /* Error table.
   2    Copyright (C) 2019-2021 Free Software Foundation, Inc.
   3
   4    This file is part of libctf.
   5
   6    libctf is free software; you can redistribute it and/or modify it under
   7    the terms of the GNU General Public License as published by the Free
   8    Software Foundation; either version 3, or (at your option) any later
   9    version.
  10
  11    This program is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  14    See the GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; see the file COPYING.  If not see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <ctf-impl.h>
  21 #include <stddef.h>
  22 #include <string.h>
  23
  24 /* This construct is due to Bruno Haible: much thanks.  */
  25
  26 /* Give each structure member a unique name.  The name does not matter, so we
  27    use the enum constant to uniquify them.  */
  28
  29 #define ERRSTRFIELD(N) ctf_errstr##N
  30
  31 /* In this file, we want to treat the first item of the ctf error
  32    macro like subsequent items.  */
  33 #define _CTF_FIRST(NAME, VALUE) _CTF_ITEM(NAME, VALUE)
  34
  35 /* The error message strings, each in a unique structure member precisely big
  36    enough for that error, plus a str member to access them all as a string
  37    table.  */
  38
  39 static const union _ctf_errlist_t
  40 {
  41   __extension__ struct
  42   {
  43 #define _CTF_ITEM(n, s) char ERRSTRFIELD (n) [sizeof (s)];
  44 _CTF_ERRORS
  45 #undef _CTF_ITEM
  46   };
  47   char str[1];
  48 } _ctf_errlist =
  49   {
  50    {
  51 #define _CTF_ITEM(n, s) N_(s),
  52 _CTF_ERRORS
  53 #undef _CTF_ITEM
  54    }
  55   };
  56
  57 /* Offsets to each member in the string table, computed using offsetof.  */
  58
  59 static const unsigned int _ctf_erridx[] =
  60   {
  61 #define _CTF_ITEM(n, s) [n - ECTF_BASE] = offsetof (union _ctf_errlist_t, ERRSTRFIELD (n)),
  62 _CTF_ERRORS
  63 #undef _CTF_ITEM
  64   };
  65
  66 const char *
  67 ctf_errmsg (int error)
  68 {
  69   const char *str;
  70
  71   if (error >= ECTF_BASE && (error - ECTF_BASE) < ECTF_NERR)
  72     str = _ctf_errlist.str + _ctf_erridx[error - ECTF_BASE];
  73   else
  74     str = (const char *) strerror (error);
  75
  76   return (str ? gettext (str) : _("Unknown error"));
  77 }
  78
  79 int
  80 ctf_errno (ctf_dict_t * fp)
  81 {
  82   return fp->ctf_errno;
  83 }