adtools/clib2

/*
 * $Id: stdio_fgets.c,v 1.6 2006-01-08 12:04:24 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
 */

#ifndef _STDLIB_NULL_POINTER_CHECK_H
#include "stdlib_null_pointer_check.h"
#endif /* _STDLIB_NULL_POINTER_CHECK_H */

/****************************************************************************/

#ifndef _STDIO_HEADERS_H
#include "stdio_headers.h"
#endif /* _STDIO_HEADERS_H */

/****************************************************************************/

char *
fgets(char *s,int n,FILE *stream)
{
    char * result = s;
    int c;

    ENTER();

    SHOWPOINTER(s);
    SHOWVALUE(n);
    SHOWPOINTER(stream);

    assert( s != NULL && stream != NULL );

    if(__check_abort_enabled)
        __check_abort();

    flockfile(stream);

    #if defined(CHECK_FOR_NULL_POINTERS)
    {
        if(s == NULL || stream == NULL)
        {
            SHOWMSG("invalid parameters");

            __set_errno(EFAULT);
            result = NULL;
            goto out;
        }
    }
    #endif /* CHECK_FOR_NULL_POINTERS */

    if(n <= 0)
    {
        SHOWMSG("no work to be done");

        result = NULL;
        goto out;
    }

    /* Take care of the checks and data structure changes that
     * need to be handled only once for this stream.
     */
    if(__fgetc_check(stream) < 0)
    {
        result = NULL;
        goto out;
    }

    /* So that we can tell error and 'end of file' conditions apart. */
    clearerr(stream);

    /* One off for the terminating '\0'. */
    n--;

    while(n-- > 0)
    {
        c = __getc(stream);
        if(c == EOF)
        {
            if(ferror(stream))
            {
                /* Just to be on the safe side. */
                (*s) = '\0';

                result = NULL;
                goto out;
            }

            /* Make sure that we return NULL if we really
               didn't read anything at all */
            if(s == result)
                result = NULL;

            break;
        }

        (*s++) = c;

        if(c == '\n')
            break;
    }

    (*s) = '\0';

    SHOWSTRING(result);

 out:

    funlockfile(stream);

    RETURN(result);
    return(result);
}