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/* yes - output a string repeatedly until killed
Copyright (C) 1991-2020 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 <https://www.gnu.org/licenses/>. */
/* David MacKenzie <djm@gnu.ai.mit.edu> */
#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include "system.h"
#include "error.h"
#include "full-write.h"
#include "long-options.h"
/* The official name of this program (e.g., no 'g' prefix). */
#define PROGRAM_NAME "yes"
#define AUTHORS proper_name ("David MacKenzie")
void
usage (int status)
{
if (status != EXIT_SUCCESS)
emit_try_help ();
else
{
printf (_("\
Usage: %s [STRING]...\n\
or: %s OPTION\n\
"),
program_name, program_name);
fputs (_("\
Repeatedly output a line with all specified STRING(s), or 'y'.\n\
\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
emit_ancillary_info (PROGRAM_NAME);
}
exit (status);
}
int
main (int argc, char **argv)
{
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
atexit (close_stdout);
parse_gnu_standard_options_only (argc, argv, PROGRAM_NAME, PACKAGE_NAME,
Version, true, usage, AUTHORS,
(char const *) NULL);
char **operands = argv + optind;
char **operand_lim = argv + argc;
if (optind == argc)
*operand_lim++ = bad_cast ("y");
/* Buffer data locally once, rather than having the
large overhead of stdio buffering each item. */
size_t bufalloc = 0;
bool reuse_operand_strings = true;
char **operandp = operands;
do
{
size_t operand_len = strlen (*operandp);
bufalloc += operand_len + 1;
if (operandp + 1 < operand_lim
&& *operandp + operand_len + 1 != operandp[1])
reuse_operand_strings = false;
}
while (++operandp < operand_lim);
/* Improve performance by using a buffer size greater than BUFSIZ / 2. */
if (bufalloc <= BUFSIZ / 2)
{
bufalloc = BUFSIZ;
reuse_operand_strings = false;
}
/* Fill the buffer with one copy of the output. If possible, reuse
the operands strings; this wins when the buffer would be large. */
char *buf = reuse_operand_strings ? *operands : xmalloc (bufalloc);
size_t bufused = 0;
operandp = operands;
do
{
size_t operand_len = strlen (*operandp);
if (! reuse_operand_strings)
memcpy (buf + bufused, *operandp, operand_len);
bufused += operand_len;
buf[bufused++] = ' ';
}
while (++operandp < operand_lim);
buf[bufused - 1] = '\n';
/* If a larger buffer was allocated, fill it by repeating the buffer
contents. */
size_t copysize = bufused;
for (size_t copies = bufalloc / copysize; --copies; )
{
memcpy (buf + bufused, buf, copysize);
bufused += copysize;
}
/* Repeatedly output the buffer until there is a write error; then fail. */
while (full_write (STDOUT_FILENO, buf, bufused) == bufused)
continue;
error (0, errno, _("standard output"));
return EXIT_FAILURE;
}
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