diff options
Diffstat (limited to 'lib/libc/stdio/fgets.c')
| -rw-r--r-- | lib/libc/stdio/fgets.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/lib/libc/stdio/fgets.c b/lib/libc/stdio/fgets.c new file mode 100644 index 000000000000..9abf559bf108 --- /dev/null +++ b/lib/libc/stdio/fgets.c @@ -0,0 +1,109 @@ +/*- + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Chris Torek. + * + * 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. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)fgets.c 8.2 (Berkeley) 12/22/93"; +#endif /* LIBC_SCCS and not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "namespace.h" +#include <stdio.h> +#include <string.h> +#include "un-namespace.h" +#include "local.h" +#include "libc_private.h" + +/* + * Read at most n-1 characters from the given file. + * Stop when a newline has been read, or the count runs out. + * Return first argument, or NULL if no characters were read. + */ +char * +fgets(char * __restrict buf, int n, FILE * __restrict fp) +{ + size_t len; + char *s; + unsigned char *p, *t; + + if (n <= 0) /* sanity check */ + return (NULL); + + FLOCKFILE(fp); + ORIENT(fp, -1); + s = buf; + n--; /* leave space for NUL */ + while (n != 0) { + /* + * If the buffer is empty, refill it. + */ + if ((len = fp->_r) <= 0) { + if (__srefill(fp)) { + /* EOF/error: stop with partial or no line */ + if (s == buf) { + FUNLOCKFILE(fp); + return (NULL); + } + break; + } + len = fp->_r; + } + p = fp->_p; + + /* + * Scan through at most n bytes of the current buffer, + * looking for '\n'. If found, copy up to and including + * newline, and stop. Otherwise, copy entire chunk + * and loop. + */ + if (len > n) + len = n; + t = memchr((void *)p, '\n', len); + if (t != NULL) { + len = ++t - p; + fp->_r -= len; + fp->_p = t; + (void)memcpy((void *)s, (void *)p, len); + s[len] = 0; + FUNLOCKFILE(fp); + return (buf); + } + fp->_r -= len; + fp->_p += len; + (void)memcpy((void *)s, (void *)p, len); + s += len; + n -= len; + } + *s = 0; + FUNLOCKFILE(fp); + return (buf); +} |