75 lines
1.9 KiB
C
75 lines
1.9 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <string.h>
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#include "../util.h"
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size_t
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unescape(char *s)
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{
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size_t len, i, off, m, factor, q;
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len = strlen(s);
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for (i = 0; i < len; i++) {
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if (s[i] != '\\')
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continue;
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off = 0;
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switch (s[i + 1]) {
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case '\\': s[i] = '\\'; off++; break;
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case '\'': s[i] = '\'', off++; break;
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case '"': s[i] = '"', off++; break;
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case 'a': s[i] = '\a'; off++; break;
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case 'b': s[i] = '\b'; off++; break;
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case 'e': s[i] = 033; off++; break;
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case 'f': s[i] = '\f'; off++; break;
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case 'n': s[i] = '\n'; off++; break;
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case 'r': s[i] = '\r'; off++; break;
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case 't': s[i] = '\t'; off++; break;
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case 'v': s[i] = '\v'; off++; break;
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case 'x':
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/* "\xH[H]" hexadecimal escape */
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for (m = i + 2; m < i + 1 + 3 && m < len; m++)
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if ((s[m] < '0' && s[m] > '9') &&
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(s[m] < 'A' && s[m] > 'F') &&
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(s[m] < 'a' && s[m] > 'f'))
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break;
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if (m == i + 2)
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eprintf("%s: invalid escape sequence '\\%c'\n", argv0, s[i + 1]);
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off += m - i - 1;
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for (--m, q = 0, factor = 1; m > i + 1; m--) {
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if (s[m] >= '0' && s[m] <= '9')
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q += (s[m] - '0') * factor;
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else if (s[m] >= 'A' && s[m] <= 'F')
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q += ((s[m] - 'A') + 10) * factor;
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else if (s[m] >= 'a' && s[m] <= 'f')
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q += ((s[m] - 'a') + 10) * factor;
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factor *= 16;
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}
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s[i] = q;
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break;
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case '\0':
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eprintf("%s: null escape sequence\n", argv0);
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default:
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/* "\O[OOO]" octal escape */
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for (m = i + 1; m < i + 1 + 4 && m < len; m++)
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if (s[m] < '0' || s[m] > '7')
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break;
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if (m == i + 1)
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eprintf("%s: invalid escape sequence '\\%c'\n", argv0, s[i + 1]);
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off += m - i - 1;
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for (--m, q = 0, factor = 1; m > i; m--) {
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q += (s[m] - '0') * factor;
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factor *= 8;
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}
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s[i] = (q > 255) ? 255 : q;
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}
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for (m = i + 1; m <= len - off; m++)
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s[m] = s[m + off];
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len -= off;
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}
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return len;
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}
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