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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 source tree.
*/
#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)
{
const char *q;
unsigned num_digits;
unsigned n;
unsigned base;
num_digits = n = 0;
base = 8;
q = *ptr;
if (WANT_HEX_ESCAPES && *q == 'x') {
++q;
base = 16;
++num_digits;
}
/* 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 {
unsigned r;
#if !WANT_HEX_ESCAPES
unsigned d = (unsigned char)(*q) - '0';
#else
unsigned d = (unsigned char)_tolower(*q) - '0';
if (d >= 10)
d += ('0' - 'a' + 10);
#endif
if (d >= base) {
if (WANT_HEX_ESCAPES && base == 16) {
--num_digits;
if (num_digits == 0) {
/* \x<bad_char>: return '\',
* leave ptr pointing to x */
return '\\';
}
}
break;
}
r = n * base + d;
if (r > UCHAR_MAX) {
break;
}
n = r;
++q;
} while (++num_digits < 3);
if (num_digits == 0) {
/* Not octal or hex escape sequence.
* Is it one-letter one? */
/* 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', '\\',
'\a', '\b', 27, '\f', '\n', '\r', '\t', '\v', '\\',
};
const char *p = charmap;
do {
if (*p == *q) {
q++;
break;
}
} while (*++p != '\\');
/* p points to found escape char or '\',
* advance it and find what it translates to.
* Note that \NUL and unrecognized sequence \z return '\'
* and leave ptr pointing to NUL or z. */
n = p[sizeof(charmap) / 2];
}
*ptr = q;
return (char) n;
}
char* FAST_FUNC strcpy_and_process_escape_sequences(char *dst, const char *src)
{
while (1) {
char c, c1;
c = c1 = *src++;
if (c1 == '\\')
c1 = bb_process_escape_sequence(&src);
*dst = c1;
if (c == '\0')
return dst;
dst++;
}
}
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