/*      $OpenBSD: getdelim.c,v 1.6 2017/04/13 18:36:51 brynet Exp $     */
/* $NetBSD: getdelim.c,v 1.13 2011/07/22 23:12:30 joerg Exp $ */

/*
 * Copyright (c) 2009 The NetBSD Foundation, Inc.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Roy Marples.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <errno.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "local.h"

/* Minimum buffer size we create.
 * This should allow config files to fit into our power of 2 buffer growth
 * without the need for a realloc. */
#define MINBUF  128

ssize_t
getdelim(char **__restrict buf, size_t *__restrict buflen,
    int sep, FILE *__restrict fp)
{
        unsigned char *p;
        size_t len, newlen, off;
        char *newb;

        FLOCKFILE(fp);

        if (buf == NULL || buflen == NULL) {
                errno = EINVAL;
                goto error;
        }

        /* If buf is NULL, we have to assume a size of zero */
        if (*buf == NULL)
                *buflen = 0;

        _SET_ORIENTATION(fp, -1);
        off = 0;
        do {
                /* If the input buffer is empty, refill it */
                if (fp->_r <= 0 && __srefill(fp)) {
                        if (__sferror(fp))
                                goto error;
                        /* No error, so EOF. */
                        break;
                }

                /* Scan through looking for the separator */
                p = memchr(fp->_p, sep, fp->_r);
                if (p == NULL)
                        len = fp->_r;
                else
                        len = (p - fp->_p) + 1;

                /* Ensure we can handle it */
                if (off > SSIZE_MAX || len + 1 > SSIZE_MAX - off) {
                        errno = EOVERFLOW;
                        goto error;
                }
                newlen = off + len + 1; /* reserve space for NUL terminator */
                if (newlen > *buflen) {
                        if (newlen < MINBUF)
                                newlen = MINBUF;
#define powerof2(x) ((((x)-1)&(x))==0)
                        if (!powerof2(newlen)) {
                                /* Grow the buffer to the next power of 2 */
                                newlen--;
                                newlen |= newlen >> 1;
                                newlen |= newlen >> 2;
                                newlen |= newlen >> 4;
                                newlen |= newlen >> 8;
                                newlen |= newlen >> 16;
#if SIZE_MAX > 0xffffffffU
                                newlen |= newlen >> 32;
#endif
                                newlen++;
                        }

                        newb = recallocarray(*buf, *buflen, newlen, 1);
                        if (newb == NULL)
                                goto error;
                        *buf = newb;
                        *buflen = newlen;
                }

                (void)memcpy((*buf + off), fp->_p, len);
                /* Safe, len is never greater than what fp->_r can fit. */
                fp->_r -= (int)len;
                fp->_p += (int)len;
                off += len;
        } while (p == NULL);

        FUNLOCKFILE(fp);

        /* POSIX demands we return -1 on EOF. */
        if (off == 0)
                return -1;

        if (*buf != NULL)
                *(*buf + off) = '\0';
        return off;

error:
        fp->_flags |= __SERR;
        FUNLOCKFILE(fp);
        return -1;
}
DEF_WEAK(getdelim);