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/* 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;
}
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