/* $NetBSD: getdelim.c,v 1.14 2017/06/08 15:59:45 uwe 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 <sys/cdefs.h>
#include <sys/param.h>

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

#include "reentrant.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;

  _DIAGASSERT(fp != NULL);

  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, (size_t)fp->_r);
    if (p == NULL)
      len = fp->_r;
    else
      len = (p - fp->_p) + 1;

    newlen = off + len;
    /* Ensure we can handle it */
    if (newlen < off || newlen > SSIZE_MAX) {
      errno = EOVERFLOW;
      goto error;
    }
    newlen++; /* reserve space for the null terminator */
    if (newlen > *buflen) {
      if (newlen < MINBUF)
        newlen = MINBUF;
      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_T_MAX > 0xffffffffU
        newlen |= newlen >> 32;
#endif
        newlen++;
      }

      newb = realloc(*buf, newlen);
      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);

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

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

error:
  fp->_flags |= __SERR;
  return -1;
}

ssize_t getdelim(char **__restrict buf, size_t *__restrict buflen, int sep,
                 FILE *__restrict fp) {
  ssize_t n;

  FLOCKFILE(fp);
  n = __getdelim(buf, buflen, sep, fp);
  FUNLOCKFILE(fp);
  return n;
}
