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/*-

 * 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. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *      This product includes software developed by the University of

 *      California, Berkeley and its contributors.

 * 4. 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)

#if 0

static char sccsid[] = "@(#)fgetln.c    8.2 (Berkeley) 1/2/94";

#endif

static const char rcsid[] =

                "$\Id: fgetln.c,v 1.3 1996/06/22 10:33:08 jraynard Exp $";

#endif /* LIBC_SCCS and not lint */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "local.h"

/*

 * Expand the line buffer.  Return -1 on error.

#ifdef notdef

 * The `new size' does not account for a terminating '\0',

 * so we add 1 here.

#endif

 */

int

__slbexpand(fp, newsize)

        FILE *fp;

        size_t newsize;

{

        void *p;

#ifdef notdef

        ++newsize;

#endif

        if (fp->_lb._size >= newsize)

                return (0);

        if ((p = realloc(fp->_lb._base, newsize)) == NULL)

                return (-1);

        fp->_lb._base = p;

        fp->_lb._size = newsize;

        return (0);

}

/*

 * Get an input line.  The returned pointer often (but not always)

 * points into a stdio buffer.  Fgetln does not alter the text of

 * the returned line (which is thus not a C string because it will

 * not necessarily end with '\0'), but does allow callers to modify

 * it if they wish.  Thus, we set __SMOD in case the caller does.

 */

char *

fgetln(fp, lenp)

        register FILE *fp;

        size_t *lenp;

{

        register unsigned char *p;

        register size_t len;

        size_t off;

        /* make sure there is input */

        if (fp->_r <= 0 && __srefill(fp)) {

                *lenp = 0;

                return (NULL);

        }

        /* look for a newline in the input */

        if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) {

                register char *ret;

                /*

                 * Found one.  Flag buffer as modified to keep fseek from

                 * `optimising' a backward seek, in case the user stomps on

                 * the text.

                 */

                p++;            /* advance over it */

                ret = (char *)fp->_p;

                *lenp = len = p - fp->_p;

                fp->_flags |= __SMOD;

                fp->_r -= len;

                fp->_p = p;

                return (ret);

        }

        /*

         * We have to copy the current buffered data to the line buffer.

         * As a bonus, though, we can leave off the __SMOD.

         *

         * OPTIMISTIC is length that we (optimistically) expect will

         * accomodate the `rest' of the string, on each trip through the

         * loop below.

         */

#define OPTIMISTIC 80

        for (len = fp->_r, off = 0;; len += fp->_r) {

                register size_t diff;

                /*

                 * Make sure there is room for more bytes.  Copy data from

                 * file buffer to line buffer, refill file and look for

                 * newline.  The loop stops only when we find a newline.

                 */

                if (__slbexpand(fp, len + OPTIMISTIC))

                        goto error;

                (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,

                    len - off);

                off = len;

                if (__srefill(fp))

                        break;  /* EOF or error: return partial line */

                if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL)

                        continue;

                /* got it: finish up the line (like code above) */

                p++;

                diff = p - fp->_p;

                len += diff;

                if (__slbexpand(fp, len))

                        goto error;

                (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,

                    diff);

                fp->_r -= diff;

                fp->_p = p;

                break;

        }

        *lenp = len;

#ifdef notdef

        fp->_lb._base[len] = 0;

#endif

        return ((char *)fp->_lb._base);

error:

        *lenp = 0;              /* ??? */

        return (NULL);          /* ??? */

}