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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) Manuel Novoa III <mjn3@codepoet.org>
* and Vladimir Oleynik <dzo@simtreas.ru>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
#define WANT_HEX_ESCAPES 1
/* Usual "this only works for ascii compatible encodings" disclaimer. */
#undef _tolower
#define _tolower(X) ((X)|((char) 0x20))
char FAST_FUNC bb_process_escape_sequence(const char **ptr)
{
/* bash builtin "echo -e '\ec'" interprets \e as ESC,
* but coreutils "/bin/echo -e '\ec'" does not.
* manpages tend to support coreutils way.
* Update: coreutils added support for \e on 28 Oct 2009. */
static const char charmap[] ALIGN1 = {
'a', 'b', 'e', 'f', 'n', 'r', 't', 'v', '\\', 0,
'\a', '\b', 27, '\f', '\n', '\r', '\t', '\v', '\\', '\\' };
const char *p;
const char *q;
unsigned num_digits;
unsigned r;
unsigned n;
unsigned d;
unsigned base;
num_digits = n = 0;
base = 8;
q = *ptr;
#ifdef WANT_HEX_ESCAPES
if (*q == 'x') {
++q;
base = 16;
++num_digits;
}
#endif
/* bash requires leading 0 in octal escapes:
* \02 works, \2 does not (prints \ and 2).
* We treat \2 as a valid octal escape sequence. */
do {
d = (unsigned char)(*q) - '0';
#ifdef WANT_HEX_ESCAPES
if (d >= 10) {
d = (unsigned char)(_tolower(*q)) - 'a' + 10;
}
#endif
if (d >= base) {
#ifdef WANT_HEX_ESCAPES
if ((base == 16) && (!--num_digits)) {
/* return '\\'; */
--q;
}
#endif
break;
}
r = n * base + d;
if (r > UCHAR_MAX) {
break;
}
n = r;
++q;
} while (++num_digits < 3);
if (num_digits == 0) { /* mnemonic escape sequence? */
p = charmap;
do {
if (*p == *q) {
q++;
break;
}
} while (*++p);
/* p points to found escape char or NUL,
* advance it and find what it translates to */
p += sizeof(charmap) / 2;
n = *p;
}
*ptr = q;
return (char) n;
}
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