1/* Quote a blob so that it can be used in C literals.
2 Copyright (C) 2018-2020 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
22char *
23support_quote_blob (const void *blob, size_t length)
24{
25 struct xmemstream out;
26 xopen_memstream (&out);
27
28 const unsigned char *p = blob;
29 for (size_t i = 0; i < length; ++i)
30 {
31 unsigned 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 '\a':
38 putc_unlocked ('\\', out.out);
39 putc_unlocked ('a', out.out);
40 break;
41 case '\b':
42 putc_unlocked ('\\', out.out);
43 putc_unlocked ('b', out.out);
44 break;
45 case '\f':
46 putc_unlocked ('\\', out.out);
47 putc_unlocked ('f', out.out);
48 break;
49 case '\n':
50 putc_unlocked ('\\', out.out);
51 putc_unlocked ('n', out.out);
52 break;
53 case '\r':
54 putc_unlocked ('\\', out.out);
55 putc_unlocked ('r', out.out);
56 break;
57 case '\t':
58 putc_unlocked ('\\', out.out);
59 putc_unlocked ('t', out.out);
60 break;
61 case '\v':
62 putc_unlocked ('\\', out.out);
63 putc_unlocked ('v', out.out);
64 break;
65 case '\\':
66 case '\'':
67 case '\"':
68 putc_unlocked ('\\', out.out);
69 putc_unlocked (ch, out.out);
70 break;
71 default:
72 if (ch < ' ' || ch > '~')
73 /* Use octal sequences because they are fixed width,
74 unlike hexadecimal sequences. */
75 fprintf (out.out, "\\%03o", ch);
76 else
77 putc_unlocked (ch, out.out);
78 }
79 }
80
81 xfclose_memstream (&out);
82 return out.buffer;
83}
84