Реализации echo.c в разных ОС
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Команда echo в Unix предназначена для отображения строки текста. Она просто выводит текст на стандартное устройство вывода. Далее представлена небольшая подборка реализаций этой команды на языке С в различных ОС. Интересно сравнить количество кода.
UNIX V5
main(argc, argv)
int argc;
char *argv[];
{
int i;
argc--;
for(i=1; i<=argc; i++)
printf("%s%c", argv[i], i==argc? '\n': ' ');
}
OpenBSD
/* $OpenBSD: echo.c,v 1.7 2009/10/27 23:59:21 deraadt Exp $ */
/* $NetBSD: echo.c,v 1.6 1995/03/21 09:04:27 cgd Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* 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. 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* ARGSUSED */
int
main(int argc, char *argv[])
{
int nflag;
/* This utility may NOT do getopt(3) option parsing. */
if (*++argv && !strcmp(*argv, "-n")) {
++argv;
nflag = 1;
}
else
nflag = 0;
while (*argv) {
(void)fputs(*argv, stdout);
if (*++argv)
putchar(' ');
}
if (!nflag)
putchar('\n');
return 0;
}
Plan 9
#include <u.h>
#include <libc.h>
void
main(int argc, char *argv[])
{
int nflag;
int i, len;
char *buf, *p;
nflag = 0;
if(argc > 1 && strcmp(argv[1], "-n") == 0)
nflag = 1;
len = 1;
for(i = 1+nflag; i < argc; i++)
len += strlen(argv[i])+1;
buf = malloc(len);
if(buf == 0)
exits("no memory");
p = buf;
for(i = 1+nflag; i < argc; i++){
strcpy(p, argv[i]);
p += strlen(p);
if(i < argc-1)
*p++ = ' ';
}
if(!nflag)
*p++ = '\n';
if(write(1, buf, p-buf) < 0){
fprint(2, "echo: write error: %r\n");
exits("write error");
}
exits((char *)0);
}
FreeBSD
/*-
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* 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.
* 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.
*/
#if 0
#ifndef lint
static char const copyright[] =
"@(#) Copyright (c) 1989, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)echo.c 8.1 (Berkeley) 5/31/93";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/uio.h>
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/*
* Report an error and exit.
* Use it instead of err(3) to avoid linking-in stdio.
*/
static __dead2 void
errexit(const char *prog, const char *reason)
{
char *errstr = strerror(errno);
write(STDERR_FILENO, prog, strlen(prog));
write(STDERR_FILENO, ": ", 2);
write(STDERR_FILENO, reason, strlen(reason));
write(STDERR_FILENO, ": ", 2);
write(STDERR_FILENO, errstr, strlen(errstr));
write(STDERR_FILENO, "\n", 1);
exit(1);
}
int
main(int argc, char *argv[])
{
int nflag; /* if not set, output a trailing newline. */
int veclen; /* number of writev arguments. */
struct iovec *iov, *vp; /* Elements to write, current element. */
char space[] = " ";
char newline[] = "\n";
char *progname = argv[0];
/* This utility may NOT do getopt(3) option parsing. */
if (*++argv && !strcmp(*argv, "-n")) {
++argv;
--argc;
nflag = 1;
} else
nflag = 0;
veclen = (argc >= 2) ? (argc - 2) * 2 + 1 : 0;
if ((vp = iov = malloc((veclen + 1) * sizeof(struct iovec))) == NULL)
errexit(progname, "malloc");
while (argv[0] != NULL) {
size_t len;
len = strlen(argv[0]);
/*
* If the next argument is NULL then this is this
* the last argument, therefore we need to check
* for a trailing \c.
*/
if (argv[1] == NULL) {
/* is there room for a '\c' and is there one? */
if (len >= 2 &&
argv[0][len - 2] == '\\' &&
argv[0][len - 1] == 'c') {
/* chop it and set the no-newline flag. */
len -= 2;
nflag = 1;
}
}
vp->iov_base = *argv;
vp++->iov_len = len;
if (*++argv) {
vp->iov_base = space;
vp++->iov_len = 1;
}
}
if (!nflag) {
veclen++;
vp->iov_base = newline;
vp++->iov_len = 1;
}
/* assert(veclen == (vp - iov)); */
while (veclen) {
int nwrite;
nwrite = (veclen > IOV_MAX) ? IOV_MAX : veclen;
if (writev(STDOUT_FILENO, iov, nwrite) == -1)
errexit(progname, "write");
iov += nwrite;
veclen -= nwrite;
}
return 0;
}
GNU coreutils
/* echo.c, derived from code echo.c in Bash.
Copyright (C) 1987, 1989, 1991-1997, 1999-2005, 2007-2011 Free Software
Foundation, Inc.
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 3 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, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include "system.h"
/* The official name of this program (e.g., no `g' prefix). */
#define PROGRAM_NAME "echo"
#define AUTHORS \
proper_name ("Brian Fox"), \
proper_name ("Chet Ramey")
/* If true, interpret backslash escapes by default. */
#ifndef DEFAULT_ECHO_TO_XPG
enum { DEFAULT_ECHO_TO_XPG = false };
#endif
void
usage (int status)
{
if (status != EXIT_SUCCESS)
fprintf (stderr, _("Try `%s --help' for more information.\n"),
program_name);
else
{
printf (_("\
Usage: %s [SHORT-OPTION]... [STRING]...\n\
or: %s LONG-OPTION\n\
"), program_name, program_name);
fputs (_("\
Echo the STRING(s) to standard output.\n\
\n\
-n do not output the trailing newline\n\
"), stdout);
fputs (_(DEFAULT_ECHO_TO_XPG
? N_("\
-e enable interpretation of backslash escapes (default)\n\
-E disable interpretation of backslash escapes\n")
: N_("\
-e enable interpretation of backslash escapes\n\
-E disable interpretation of backslash escapes (default)\n")),
stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
fputs (_("\
\n\
If -e is in effect, the following sequences are recognized:\n\
\n\
"), stdout);
fputs (_("\
\\\\ backslash\n\
\\a alert (BEL)\n\
\\b backspace\n\
\\c produce no further output\n\
\\e escape\n\
\\f form feed\n\
\\n new line\n\
\\r carriage return\n\
\\t horizontal tab\n\
\\v vertical tab\n\
"), stdout);
fputs (_("\
\\0NNN byte with octal value NNN (1 to 3 digits)\n\
\\xHH byte with hexadecimal value HH (1 to 2 digits)\n\
"), stdout);
printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
emit_ancillary_info ();
}
exit (status);
}
/* Convert C from hexadecimal character to integer. */
static int
hextobin (unsigned char c)
{
switch (c)
{
default: return c - '0';
case 'a': case 'A': return 10;
case 'b': case 'B': return 11;
case 'c': case 'C': return 12;
case 'd': case 'D': return 13;
case 'e': case 'E': return 14;
case 'f': case 'F': return 15;
}
}
/* Print the words in LIST to standard output. If the first word is
`-n', then don't print a trailing newline. We also support the
echo syntax from Version 9 unix systems. */
int
main (int argc, char **argv)
{
bool display_return = true;
bool allow_options =
(! getenv ("POSIXLY_CORRECT")
|| (! DEFAULT_ECHO_TO_XPG && 1 < argc && STREQ (argv[1], "-n")));
/* System V machines already have a /bin/sh with a v9 behavior.
Use the identical behavior for these machines so that the
existing system shell scripts won't barf. */
bool do_v9 = DEFAULT_ECHO_TO_XPG;
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
atexit (close_stdout);
/* We directly parse options, rather than use parse_long_options, in
order to avoid accepting abbreviations. */
if (allow_options && argc == 2)
{
if (STREQ (argv[1], "--help"))
usage (EXIT_SUCCESS);
if (STREQ (argv[1], "--version"))
{
version_etc (stdout, PROGRAM_NAME, PACKAGE_NAME, Version, AUTHORS,
(char *) NULL);
exit (EXIT_SUCCESS);
}
}
--argc;
++argv;
if (allow_options)
while (argc > 0 && *argv[0] == '-')
{
char const *temp = argv[0] + 1;
size_t i;
/* 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. */
for (i = 0; temp[i]; i++)
switch (temp[i])
{
case 'e': case 'E': case 'n':
break;
default:
goto just_echo;
}
if (i == 0)
goto just_echo;
/* All of the options in TEMP are valid options to ECHO.
Handle them. */
while (*temp)
switch (*temp++)
{
case 'e':
do_v9 = true;
break;
case 'E':
do_v9 = false;
break;
case 'n':
display_return = false;
break;
}
argc--;
argv++;
}
just_echo:
if (do_v9)
{
while (argc > 0)
{
char const *s = argv[0];
unsigned char c;
while ((c = *s++))
{
if (c == '\\' && *s)
{
switch (c = *s++)
{
case 'a': c = '\a'; break;
case 'b': c = '\b'; break;
case 'c': exit (EXIT_SUCCESS);
case 'e': c = '\x1B'; break;
case 'f': c = '\f'; break;
case 'n': c = '\n'; break;
case 'r': c = '\r'; break;
case 't': c = '\t'; break;
case 'v': c = '\v'; break;
case 'x':
{
unsigned char ch = *s;
if (! isxdigit (ch))
goto not_an_escape;
s++;
c = hextobin (ch);
ch = *s;
if (isxdigit (ch))
{
s++;
c = c * 16 + hextobin (ch);
}
}
break;
case '0':
c = 0;
if (! ('0' <= *s && *s <= '7'))
break;
c = *s++;
/* Fall through. */
case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
c -= '0';
if ('0' <= *s && *s <= '7')
c = c * 8 + (*s++ - '0');
if ('0' <= *s && *s <= '7')
c = c * 8 + (*s++ - '0');
break;
case '\\': break;
not_an_escape:
default: putchar ('\\'); break;
}
}
putchar (c);
}
argc--;
argv++;
if (argc > 0)
putchar (' ');
}
}
else
{
while (argc > 0)
{
fputs (argv[0], stdout);
argc--;
argv++;
if (argc > 0)
putchar (' ');
}
}
if (display_return)
putchar ('\n');
exit (EXIT_SUCCESS);
}
Mac OS X
/*-
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* 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.
* 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.
*/
#if 0
#ifndef lint
static char const copyright[] =
"@(#) Copyright (c) 1989, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)echo.c 8.1 (Berkeley) 5/31/93";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/bin/echo/echo.c,v 1.18 2005/01/10 08:39:22 imp Exp $");
#include <sys/types.h>
#include <sys/uio.h>
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/*
* Report an error and exit.
* Use it instead of err(3) to avoid linking-in stdio.
*/
static void
errexit(const char *prog, const char *reason)
{
char *errstr = strerror(errno);
write(STDERR_FILENO, prog, strlen(prog));
write(STDERR_FILENO, ": ", 2);
write(STDERR_FILENO, reason, strlen(reason));
write(STDERR_FILENO, ": ", 2);
write(STDERR_FILENO, errstr, strlen(errstr));
write(STDERR_FILENO, "\n", 1);
exit(1);
}
int
main(int argc, char *argv[])
{
int nflag; /* if not set, output a trailing newline. */
int veclen; /* number of writev arguments. */
struct iovec *iov, *vp; /* Elements to write, current element. */
char space[] = " ";
char newline[] = "\n";
char *progname = argv[0];
/* This utility may NOT do getopt(3) option parsing. */
if (*++argv && !strcmp(*argv, "-n")) {
++argv;
--argc;
nflag = 1;
} else
nflag = 0;
veclen = (argc >= 2) ? (argc - 2) * 2 + 1 : 0;
if ((vp = iov = malloc((veclen + 1) * sizeof(struct iovec))) == NULL)
errexit(progname, "malloc");
while (argv[0] != NULL) {
size_t len;
len = strlen(argv[0]);
/*
* If the next argument is NULL then this is this
* the last argument, therefore we need to check
* for a trailing \c.
*/
if (argv[1] == NULL) {
/* is there room for a '\c' and is there one? */
if (len >= 2 &&
argv[0][len - 2] == '\\' &&
argv[0][len - 1] == 'c') {
/* chop it and set the no-newline flag. */
len -= 2;
nflag = 1;
}
}
vp->iov_base = *argv;
vp++->iov_len = len;
if (*++argv) {
vp->iov_base = space;
vp++->iov_len = 1;
}
}
if (!nflag) {
veclen++;
vp->iov_base = newline;
vp++->iov_len = 1;
}
/* assert(veclen == (vp - iov)); */
while (veclen) {
int nwrite;
nwrite = (veclen > IOV_MAX) ? IOV_MAX : veclen;
if (writev(STDOUT_FILENO, iov, nwrite) == -1)
errexit(progname, "write");
iov += nwrite;
veclen -= nwrite;
}
return 0;
}
NetBSD
/* $NetBSD: echo.c,v 1.18 2008/09/18 05:42:08 dholland Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* 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. 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT(
"@(#) Copyright (c) 1989, 1993\
The Regents of the University of California. All rights reserved.");
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)echo.c 8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: echo.c,v 1.18 2008/09/18 05:42:08 dholland Exp $");
#endif
#endif /* not lint */
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int, char *[]);
/* ARGSUSED */
int
main(int argc, char *argv[])
{
int nflag;
setprogname(argv[0]);
(void)setlocale(LC_ALL, "");
/* This utility may NOT do getopt(3) option parsing. */
if (*++argv && !strcmp(*argv, "-n")) {
++argv;
nflag = 1;
}
else
nflag = 0;
while (*argv) {
(void)printf("%s", *argv);
if (*++argv)
(void)putchar(' ');
}
if (nflag == 0)
(void)putchar('\n');
fflush(stdout);
if (ferror(stdout))
exit(1);
exit(0);
/* NOTREACHED */
}
Код взят с GitHub Gist.
2К открытий2К показов
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