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author | Roland McGrath <roland@gnu.org> | 1995-02-18 01:27:10 +0000 |
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committer | Roland McGrath <roland@gnu.org> | 1995-02-18 01:27:10 +0000 |
commit | 28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch) | |
tree | 15f07c4c43d635959c6afee96bde71fb1b3614ee /stdio/fgets.c | |
download | glibc-28f540f45bbacd939bfd07f213bcad2bf730b1bf.tar.gz glibc-28f540f45bbacd939bfd07f213bcad2bf730b1bf.tar.xz glibc-28f540f45bbacd939bfd07f213bcad2bf730b1bf.zip |
initial import
Diffstat (limited to 'stdio/fgets.c')
-rw-r--r-- | stdio/fgets.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/stdio/fgets.c b/stdio/fgets.c new file mode 100644 index 0000000000..e9e53c88dd --- /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; +} |