hush/libbb/process_escape_sequence.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) tons of folks. Tracking down who wrote what
* isn't something I'm going to worry about... If you wrote something
* here, please feel free to acknowledge your work.
*
* 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
*
* Based in part on code from sash, Copyright (c) 1999 by David I. Bell
* Permission has been granted to redistribute this code under the GPL.
*
*/
#include <stdio.h>
#include <limits.h>
#include "libbb.h"
char process_escape_sequence(char **ptr)
{
static const char charmap[] = {
'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', 0,
'\a', '\b', '\f', '\n', '\r', '\t', '\v', '\\', '\\' };
const char *p;
char *q;
int num_digits;
unsigned int n;
n = 0;
q = *ptr;
for ( num_digits = 0 ; num_digits < 3 ; ++num_digits) {
if ((*q < '0') || (*q > '7')) { /* not a digit? */
break;
}
n = n * 8 + (*q++ - '0');
}
if (num_digits == 0) { /* mnemonic escape sequence? */
for (p=charmap ; *p ; p++) {
if (*p == *q) {
q++;
break;
}
}
n = *(p+(sizeof(charmap)/2));
}
/* doesn't hurt to fall through to here from mnemonic case */
if (n > UCHAR_MAX) { /* is octal code too big for a char? */
n /= 8; /* adjust value and */
--q; /* back up one char */
}
*ptr = q;
return (char) n;
}
/* END CODE */
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/