59 lines
1.1 KiB
C
59 lines
1.1 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <ctype.h>
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#include <string.h>
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#include "../util.h"
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#define is_odigit(c) ('0' <= c && c <= '7')
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size_t
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unescape(char *s)
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{
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static const char escapes[256] = {
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['"'] = '"',
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['\''] = '\'',
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['\\'] = '\\',
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['a'] = '\a',
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['b'] = '\b',
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['E'] = 033,
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['e'] = 033,
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['f'] = '\f',
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['n'] = '\n',
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['r'] = '\r',
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['t'] = '\t',
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['v'] = '\v'
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};
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size_t m, q;
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char *r, *w;
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for (r = w = s; *r;) {
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if (*r != '\\') {
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*w++ = *r++;
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continue;
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}
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r++;
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if (!*r) {
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eprintf("null escape sequence\n");
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} else if (escapes[(unsigned char)*r]) {
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*w++ = escapes[(unsigned char)*r++];
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} else if (is_odigit(*r)) {
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for (q = 0, m = 4; m && is_odigit(*r); m--, r++)
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q = q * 8 + (*r - '0');
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*w++ = MIN(q, 255);
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} else if (*r == 'x' && isxdigit(r[1])) {
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r++;
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for (q = 0, m = 2; m && isxdigit(*r); m--, r++)
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if (isdigit(*r))
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q = q * 16 + (*r - '0');
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else
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q = q * 16 + (tolower(*r) - 'a' + 10);
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*w++ = q;
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} else {
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eprintf("invalid escape sequence '\\%c'\n", *r);
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}
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}
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*w = '\0';
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return w - s;
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}
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