support/support_quote_blob_main.c

   1 /* Quote a blob so that it can be used in C literals.
   2    Copyright (C) 2018-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <support/support.h>
  20 #include <support/xmemstream.h>
  21
  22 char *
  23 SUPPORT_QUOTE_BLOB (const void *blob, size_t length)
  24 {
  25   struct xmemstream out;
  26   xopen_memstream (&out);
  27
  28   const CHAR *p = blob;
  29   for (size_t i = 0; i < length; ++i)
  30     {
  31       CHAR ch = p[i];
  32
  33       /* Use C backslash escapes for those control characters for
  34          which they are defined.  */
  35       switch (ch)
  36         {
  37         case L_('\a'):
  38           putc_unlocked ('\\', out.out);
  39           putc_unlocked ('a', out.out);
  40           break;
  41         case L_('\b'):
  42           putc_unlocked ('\\', out.out);
  43           putc_unlocked ('b', out.out);
  44           break;
  45         case L_('\f'):
  46           putc_unlocked ('\\', out.out);
  47           putc_unlocked ('f', out.out);
  48           break;
  49         case L_('\n'):
  50           putc_unlocked ('\\', out.out);
  51           putc_unlocked ('n', out.out);
  52           break;
  53         case L_('\r'):
  54           putc_unlocked ('\\', out.out);
  55           putc_unlocked ('r', out.out);
  56           break;
  57         case L_('\t'):
  58           putc_unlocked ('\\', out.out);
  59           putc_unlocked ('t', out.out);
  60           break;
  61         case L_('\v'):
  62           putc_unlocked ('\\', out.out);
  63           putc_unlocked ('v', out.out);
  64           break;
  65         case L_('\\'):
  66         case L_('\''):
  67         case L_('\"'):
  68           putc_unlocked ('\\', out.out);
  69           putc_unlocked (ch, out.out);
  70           break;
  71         default:
  72           if (ch < L_(' ') || ch > L_('~'))
  73             /* For narrow characters, use octal sequences because they
  74                are fixed width, unlike hexadecimal sequences.  For
  75                wide characters, use N2785 delimited escape
  76                sequences.  */
  77             if (WIDE)
  78               fprintf (out.out, "\\x{%x}", (unsigned int) ch);
  79             else
  80               fprintf (out.out, "\\%03o", (unsigned int) ch);
  81           else
  82             putc_unlocked (ch, out.out);
  83         }
  84     }
  85
  86   xfclose_memstream (&out);
  87   return out.buffer;
  88 }