StdLib/LibC/Stdio/fgetstr.c

/*
    Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
    This program and the accompanying materials are licensed and made available
    under the terms and conditions of the BSD License that accompanies this
    distribution.  The full text of the license may be found at
    http://opensource.org/licenses/bsd-license.

    THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
    WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

 * 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. 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.

    $NetBSD: fgetstr.c,v 1.4 2006/11/24 19:46:58 christos Exp $
    fgetline.c  8.1 (Berkeley) 6/4/93
*/

/*-
 */
#include  <LibConfig.h>
#include <sys/EfiCdefs.h>

#include "namespace.h"

#include <assert.h>
#include  <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "reentrant.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(FILE *fp, size_t newsize)
{
  void *p;

#ifdef notdef
  ++newsize;
#endif
  _DIAGASSERT(fp != NULL);
  if(fp == NULL) {
    errno = EINVAL;
    return (-1);
  }

  if ((size_t)fp->_lb._size >= newsize)
    return (0);
  if ((p = realloc(fp->_lb._base, newsize)) == NULL)
    return (-1);
  fp->_lb._base = p;
  fp->_lb._size = (int)newsize;
  return (0);
}

/*
 * Get an input line.  The returned pointer often (but not always)
 * points into a stdio buffer.  Fgetline 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 *
__fgetstr(FILE *fp, size_t *lenp, int sep)
{
  unsigned char *p;
  size_t len;
  size_t off;

  _DIAGASSERT(fp != NULL);
  _DIAGASSERT(lenp != NULL);
  if(fp == NULL) {
    errno = EINVAL;
    return (NULL);
  }

  /* 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, sep, (size_t)fp->_r)) != NULL) {
    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 -= (int)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
   * accommodate the `rest' of the string, on each trip through the
   * loop below.
   */
#define OPTIMISTIC 80

  for (len = fp->_r, off = 0;; len += fp->_r) {
    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, sep, (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 -= (int)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);    /* ??? */
}