| /* Copyright (C) 1991, 1992, 1995, 1996, 1997 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., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #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 * |
| fgets (s, n, stream) |
| char *s; |
| int n; |
| register FILE *stream; |
| { |
| register char *p = s; |
| |
| if (!__validfp (stream) || s == NULL || n <= 0) |
| { |
| __set_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 ((void *) 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; |
| } |