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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /stdio/fgets.c
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initial import
Diffstat (limited to 'stdio/fgets.c')
-rw-r--r--stdio/fgets.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/stdio/fgets.c b/stdio/fgets.c
new file mode 100644
index 0000000..e9e53c8
--- /dev/null
+++ b/stdio/fgets.c
@@ -0,0 +1,121 @@
+/* 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;
+}