busybox/libbb/process_escape_sequence.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
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* Copyright (C) Manuel Novoa III <mjn3@codepoet.org>
* and Vladimir Oleynik <dzo@simtreas.ru>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
*/
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#include <string.h>
#include <stdio.h>
#include <limits.h>
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#include <ctype.h>
#include "libbb.h"
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#define isodigit(c) ((c) >= '0' && (c) <= '7')
#define hextobin(c) ((c)>='a'&&(c)<='f' ? (c)-'a'+10 : (c)>='A'&&(c)<='F' ? (c)-'A'+10 : (c)-'0')
#define octtobin(c) ((c) - '0')
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char bb_process_escape_sequence(const char **ptr)
{
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const char *p, *q;
unsigned int num_digits, r, n, hexescape;
static const char charmap[] = {
'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', 0,
'\a', '\b', '\f', '\n', '\r', '\t', '\v', '\\', '\\' };
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n = r = hexescape = num_digits = 0;
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q = *ptr;
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if (*q == 'x') {
hexescape++;
++q;
}
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do {
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if (hexescape && isxdigit(*q)) {
r = n * 16 + hextobin(*q);
} else if (isodigit(*q)) {
r = n * 8 + octtobin(*q);
} else {
break;
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}
if (r <= UCHAR_MAX) {
n = r;
++q;
if (++num_digits < 3) {
continue;
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}
}
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break;
} while (1);
if (num_digits == 0) { /* mnemonic escape sequence? */
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p = charmap;
do {
if (*p == *q) {
q++;
break;
}
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} while (*++p);
n = *(p+(sizeof(charmap)/2));
}
*ptr = q;
return (char) n;
}
/* END CODE */
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/