mirror of
git://git.suckless.org/sbase
synced 2026-01-26 13:43:17 +00:00
948e516190
unescape() is used by several tools, in particular printf(1) and
tr(1), which should stop the octal escape at a maximum of 3 digits:
printf(1)
> In addition to the escape sequences shown in XBD 5. File Format
> Notation ('\\', '\a', '\b', '\f', '\n', '\r', '\t', '\v'), "\ddd",
> where ddd is a one, two, or three-digit octal number, shall be
> written as a byte with the numeric value specified by the octal
> number.
tr(1)
> An octal sequence shall consist of a <backslash> followed by the
> longest sequence of one, two, or three-octal-digit characters.
Previously, the maximum was set to 4 (possibly a typo?), which meant
that printf '\0123' printed `S` instead of `<newline>3`.
To check that this doesn't break any other tools using unescape:
- cut: used for -d parameter, escapes are non-standard
- join: used for -t parameter, escapes are non-standard
- nl: used for -s parameter, escapes are non-standard
- paste: used for -d parameter, POSIX specifies \n, \t, \\, and \0,
\0 followed by a digit is unspecified
- sort: used for -t parameter, escapes are non-standard
59 lines
1.1 KiB
C
59 lines
1.1 KiB
C
/* See LICENSE file for copyright and license details. */
|
|
#include <ctype.h>
|
|
#include <string.h>
|
|
|
|
#include "../util.h"
|
|
|
|
#define is_odigit(c) ('0' <= c && c <= '7')
|
|
|
|
size_t
|
|
unescape(char *s)
|
|
{
|
|
static const char escapes[256] = {
|
|
['"'] = '"',
|
|
['\''] = '\'',
|
|
['\\'] = '\\',
|
|
['a'] = '\a',
|
|
['b'] = '\b',
|
|
['E'] = 033,
|
|
['e'] = 033,
|
|
['f'] = '\f',
|
|
['n'] = '\n',
|
|
['r'] = '\r',
|
|
['t'] = '\t',
|
|
['v'] = '\v'
|
|
};
|
|
size_t m, q;
|
|
char *r, *w;
|
|
|
|
for (r = w = s; *r;) {
|
|
if (*r != '\\') {
|
|
*w++ = *r++;
|
|
continue;
|
|
}
|
|
r++;
|
|
if (!*r) {
|
|
eprintf("null escape sequence\n");
|
|
} else if (escapes[(unsigned char)*r]) {
|
|
*w++ = escapes[(unsigned char)*r++];
|
|
} else if (is_odigit(*r)) {
|
|
for (q = 0, m = 3; m && is_odigit(*r); m--, r++)
|
|
q = q * 8 + (*r - '0');
|
|
*w++ = MIN(q, 255);
|
|
} else if (*r == 'x' && isxdigit(r[1])) {
|
|
r++;
|
|
for (q = 0, m = 2; m && isxdigit(*r); m--, r++)
|
|
if (isdigit(*r))
|
|
q = q * 16 + (*r - '0');
|
|
else
|
|
q = q * 16 + (tolower(*r) - 'a' + 10);
|
|
*w++ = q;
|
|
} else {
|
|
eprintf("invalid escape sequence '\\%c'\n", *r);
|
|
}
|
|
}
|
|
*w = '\0';
|
|
|
|
return w - s;
|
|
}
|