90 lines
1.5 KiB
C
90 lines
1.5 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) Manuel Novoa III <mjn3@codepoet.org>
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* and Vladimir Oleynik <dzo@simtreas.ru>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include <stdio.h>
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#include <limits.h>
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#include <ctype.h>
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#include "libbb.h"
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#define WANT_HEX_ESCAPES 1
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/* Usual "this only works for ascii compatible encodings" disclaimer. */
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#undef _tolower
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#define _tolower(X) ((X)|((char) 0x20))
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char bb_process_escape_sequence(const char **ptr)
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{
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static const char charmap[] = {
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'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', 0,
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'\a', '\b', '\f', '\n', '\r', '\t', '\v', '\\', '\\' };
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const char *p;
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const char *q;
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unsigned int num_digits;
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unsigned int r;
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unsigned int n;
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unsigned int d;
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unsigned int base;
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num_digits = n = 0;
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base = 8;
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q = *ptr;
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#ifdef WANT_HEX_ESCAPES
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if (*q == 'x') {
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++q;
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base = 16;
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++num_digits;
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}
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#endif
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do {
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d = (unsigned int)(*q - '0');
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#ifdef WANT_HEX_ESCAPES
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if (d >= 10) {
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d = ((unsigned int)(_tolower(*q) - 'a')) + 10;
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}
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#endif
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if (d >= base) {
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#ifdef WANT_HEX_ESCAPES
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if ((base == 16) && (!--num_digits)) {
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/* return '\\'; */
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--q;
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}
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#endif
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break;
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}
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r = n * base + d;
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if (r > UCHAR_MAX) {
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break;
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}
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n = r;
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++q;
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} while (++num_digits < 3);
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if (num_digits == 0) { /* mnemonic escape sequence? */
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p = charmap;
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do {
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if (*p == *q) {
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q++;
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break;
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}
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} while (*++p);
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n = *(p+(sizeof(charmap)/2));
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}
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*ptr = q;
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return (char) n;
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}
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