busybox/scripts/echo.c

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/* vi: set sw=4 ts=4: */
/*
* echo implementation for busybox - used as a helper for testsuite/*
* on systems lacking "echo -en"
*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*
* Original copyright notice is retained at the end of this file.
*/
/* BB_AUDIT SUSv3 compliant -- unless configured as fancy echo. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html */
/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
*
* Because of behavioral differences, implemented configurable SUSv3
* or 'fancy' gnu-ish behaviors. Also, reduced size and fixed bugs.
* 1) In handling '\c' escape, the previous version only suppressed the
* trailing newline. SUSv3 specifies _no_ output after '\c'.
* 2) SUSv3 specifies that octal escapes are of the form \0{#{#{#}}}.
* The previous version did not allow 4-digit octals.
*/
#include <stdio.h>
#include <string.h>
#include <limits.h>
#define WANT_HEX_ESCAPES 1
/* Usual "this only works for ascii compatible encodings" disclaimer. */
#undef _tolower
#define _tolower(X) ((X)|((char) 0x20))
static char bb_process_escape_sequence(const char **ptr)
{
static const char charmap[] = {
'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', 0,
'\a', '\b', '\f', '\n', '\r', '\t', '\v', '\\', '\\' };
const char *p;
const char *q;
unsigned int num_digits;
unsigned int r;
unsigned int n;
unsigned int d;
unsigned int base;
num_digits = n = 0;
base = 8;
q = *ptr;
#ifdef WANT_HEX_ESCAPES
if (*q == 'x') {
++q;
base = 16;
++num_digits;
}
#endif
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);
n = *(p + (sizeof(charmap)/2));
}
*ptr = q;
return (char) n;
}
int main(int argc, char **argv)
{
const char *arg;
const char *p;
char nflag = 1;
char eflag = 0;
/* We must check that stdout is not closed. */
if (dup2(1, 1) != 1)
return -1;
while (1) {
arg = *++argv;
if (!arg)
goto newline_ret;
if (*arg != '-')
break;
/* If it appears that we are handling options, then make sure
* that all of the options specified are actually valid.
* Otherwise, the string should just be echoed.
*/
p = arg + 1;
if (!*p) /* A single '-', so echo it. */
goto just_echo;
do {
if (!strrchr("neE", *p))
goto just_echo;
} while (*++p);
/* All of the options in this arg are valid, so handle them. */
p = arg + 1;
do {
if (*p == 'n')
nflag = 0;
if (*p == 'e')
eflag = '\\';
} while (*++p);
}
just_echo:
while (1) {
/* arg is already == *argv and isn't NULL */
int c;
if (!eflag) {
/* optimization for very common case */
fputs(arg, stdout);
} else while ((c = *arg++)) {
if (c == eflag) { /* Check for escape seq. */
if (*arg == 'c') {
/* '\c' means cancel newline and
* ignore all subsequent chars. */
goto ret;
}
{
/* Since SUSv3 mandates a first digit of 0, 4-digit octals
* of the form \0### are accepted. */
if (*arg == '0') {
/* NB: don't turn "...\0" into "...\" */
if (arg[1] && ((unsigned char)(arg[1]) - '0') < 8) {
arg++;
}
}
/* bb_process_escape_sequence handles NUL correctly
* ("...\" case. */
c = bb_process_escape_sequence(&arg);
}
}
putchar(c);
}
arg = *++argv;
if (!arg)
break;
putchar(' ');
}
newline_ret:
if (nflag) {
putchar('\n');
}
ret:
return fflush(NULL);
}
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
* ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
*
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)echo.c 8.1 (Berkeley) 5/31/93
*/