mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-27 05:00:15 +00:00
122 lines
2.9 KiB
C
122 lines
2.9 KiB
C
/* Copyright (C) 1991, 1992, 1995 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public License as
|
|
published by the Free Software Foundation; either version 2 of the
|
|
License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If
|
|
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
|
|
Cambridge, MA 02139, USA. */
|
|
|
|
#include <ansidecl.h>
|
|
#include <errno.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
/* Reads characters from STREAM into S, until either a newline character
|
|
is read, N - 1 characters have been read, or EOF is seen. Returns
|
|
the newline, unlike gets. Finishes by appending a null character and
|
|
returning S. If EOF is seen before any characters have been written
|
|
to S, the function returns NULL without appending the null character.
|
|
If there is a file error, always return NULL. */
|
|
char *
|
|
DEFUN(fgets, (s, n, stream), char *s AND int n AND register FILE *stream)
|
|
{
|
|
register char *p = s;
|
|
|
|
if (!__validfp(stream) || s == NULL || n <= 0)
|
|
{
|
|
errno = EINVAL;
|
|
return NULL;
|
|
}
|
|
|
|
if (ferror (stream))
|
|
return NULL;
|
|
|
|
if (stream->__buffer == NULL && stream->__userbuf)
|
|
{
|
|
/* Unbuffered stream. Not much optimization to do. */
|
|
register int c = 0;
|
|
while (--n > 0 && (c = getc (stream)) != EOF)
|
|
if ((*p++ = c) == '\n')
|
|
break;
|
|
if (c == EOF && (p == s || ferror (stream)))
|
|
return NULL;
|
|
*p = '\0';
|
|
return s;
|
|
}
|
|
|
|
/* Leave space for the null. */
|
|
--n;
|
|
|
|
if (n > 0 &&
|
|
(!stream->__seen || stream->__buffer == NULL || stream->__pushed_back))
|
|
{
|
|
/* Do one with getc to allocate a buffer. */
|
|
int c = getc (stream);
|
|
if (c == EOF)
|
|
return NULL;
|
|
*p++ = c;
|
|
if (c == '\n')
|
|
{
|
|
*p = '\0';
|
|
return s;
|
|
}
|
|
else
|
|
--n;
|
|
}
|
|
|
|
while (n > 0)
|
|
{
|
|
size_t i;
|
|
char *found;
|
|
|
|
i = stream->__get_limit - stream->__bufp;
|
|
if (i == 0)
|
|
{
|
|
/* Refill the buffer. */
|
|
int c = __fillbf (stream);
|
|
if (c == EOF)
|
|
break;
|
|
*p++ = c;
|
|
--n;
|
|
if (c == '\n')
|
|
{
|
|
*p = '\0';
|
|
return s;
|
|
}
|
|
i = stream->__get_limit - stream->__bufp;
|
|
}
|
|
|
|
if (i > n)
|
|
i = n;
|
|
|
|
found = (char *) __memccpy ((PTR) p, stream->__bufp, '\n', i);
|
|
|
|
if (found != NULL)
|
|
{
|
|
stream->__bufp += found - p;
|
|
p = found;
|
|
break;
|
|
}
|
|
|
|
stream->__bufp += i;
|
|
n -= i;
|
|
p += i;
|
|
}
|
|
|
|
if (p == s)
|
|
return NULL;
|
|
|
|
*p = '\0';
|
|
return ferror (stream) ? NULL : s;
|
|
}
|