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
22char *
23SUPPORT_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}
89