libctf/ctf-error.c

   1 /* Error table.
   2    Copyright (C) 2019-2020 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
  23 /* This construct is due to Bruno Haible: much thanks.  */
  24
  25 /* Give each structure member a unique name.  The name does not matter, so we
  26    use the line number in ctf-error.h to uniquify them.  */
  27
  28 #define ERRSTRFIELD(line) ERRSTRFIELD1 (line)
  29 #define ERRSTRFIELD1(line) ctf_errstr##line
  30
  31 /* The error message strings, each in a unique structure member precisely big
  32    enough for that error, plus a str member to access them all as a string
  33    table.  */
  34
  35 static const union _ctf_errlist_t
  36 {
  37   __extension__ struct
  38   {
  39 #define _CTF_STR(n, s) char ERRSTRFIELD (__LINE__) [sizeof (s)];
  40 #include "ctf-error.h"
  41 #undef _CTF_STR
  42   };
  43   char str[1];
  44 } _ctf_errlist =
  45   {
  46    {
  47 #define _CTF_STR(n, s) s,
  48 #include "ctf-error.h"
  49 #undef _CTF_STR
  50    }
  51   };
  52
  53 /* Offsets to each member in the string table, computed using offsetof.  */
  54
  55 static const unsigned int _ctf_erridx[] =
  56   {
  57 #define _CTF_STR(n, s) [n - ECTF_BASE] = offsetof (union _ctf_errlist_t, ERRSTRFIELD (__LINE__)),
  58 #include "ctf-error.h"
  59 #undef _CTF_STR
  60   };
  61
  62 const char *
  63 ctf_errmsg (int error)
  64 {
  65   const char *str;
  66
  67   if (error >= ECTF_BASE && (error - ECTF_BASE) < ECTF_NERR)
  68     str = _ctf_errlist.str + _ctf_erridx[error - ECTF_BASE];
  69   else
  70     str = ctf_strerror (error);
  71
  72   return (str ? str : "Unknown error");
  73 }
  74
  75 int
  76 ctf_errno (ctf_file_t * fp)
  77 {
  78   return fp->ctf_errno;
  79 }