EmbeddedPkg: Extend NvVarStoreFormattedLib LIBRARY_CLASS

[mirror_edk2.git] / StdLib / LibC / Stdio / ungetc.c

/** @file\r
    Implementation of ungetc as declared in <stdio.h>.\r
\r
    Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>\r
    This program and the accompanying materials are licensed and made available\r
    under the terms and conditions of the BSD License that accompanies this\r
    distribution.  The full text of the license may be found at\r
    http://opensource.org/licenses/bsd-license.\r
\r
    THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
    WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
    Copyright (c) 1990, 1993\r
    The Regents of the University of California.  All rights reserved.\r
\r
    This code is derived from software contributed to Berkeley by\r
    Chris Torek.\r
\r
    Redistribution and use in source and binary forms, with or without\r
    modification, are permitted provided that the following conditions\r
    are met:\r
      - Redistributions of source code must retain the above copyright\r
        notice, this list of conditions and the following disclaimer.\r
      - Redistributions in binary form must reproduce the above copyright\r
        notice, this list of conditions and the following disclaimer in the\r
        documentation and/or other materials provided with the distribution.\r
      - Neither the name of the University nor the names of its contributors\r
        may be used to endorse or promote products derived from this software\r
        without specific prior written permission.\r
\r
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"\r
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE\r
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE\r
    ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE\r
    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR\r
    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF\r
    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS\r
    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN\r
    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)\r
    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE\r
    POSSIBILITY OF SUCH DAMAGE.\r
\r
    NetBSD: ungetc.c,v 1.14 2003/08/07 16:43:34 agc Exp\r
    ungetc.c  8.2 (Berkeley) 11/3/93\r
**/\r
#include  <LibConfig.h>\r
\r
#include <assert.h>\r
#include <errno.h>\r
#include <stdio.h>\r
#include <stdlib.h>\r
#include <string.h>\r
#include "reentrant.h"\r
#include "local.h"\r
\r
static int __submore(FILE *);\r
/*\r
 * Expand the ungetc buffer `in place'.  That is, adjust fp->_p when\r
 * the buffer moves, so that it points the same distance from the end,\r
 * and move the bytes in the buffer around as necessary so that they\r
 * are all at the end (stack-style).\r
 */\r
static int\r
__submore(FILE *fp)\r
{\r
  int i;\r
  unsigned char *p;\r
\r
  _DIAGASSERT(fp != NULL);\r
  if(fp == NULL) {\r
    errno = EINVAL;\r
    return (EOF);\r
  }\r
\r
  if (_UB(fp)._base == fp->_ubuf) {\r
    /*\r
     * Get a new buffer (rather than expanding the old one).\r
     */\r
    if ((p = malloc((size_t)BUFSIZ)) == NULL)\r
      return (EOF);\r
    _UB(fp)._base = p;\r
    _UB(fp)._size = BUFSIZ;\r
    p += BUFSIZ - sizeof(fp->_ubuf);\r
    for (i = sizeof(fp->_ubuf); --i >= 0;)\r
      p[i] = fp->_ubuf[i];\r
    fp->_p = p;\r
    return (0);\r
  }\r
  i = _UB(fp)._size;\r
  p = realloc(_UB(fp)._base, (size_t)(i << 1));\r
  if (p == NULL)\r
    return (EOF);\r
  /* no overlap (hence can use memcpy) because we doubled the size */\r
  (void)memcpy((void *)(p + i), (void *)p, (size_t)i);\r
  fp->_p = p + i;\r
  _UB(fp)._base = p;\r
  _UB(fp)._size = i << 1;\r
  return (0);\r
}\r
\r
int\r
ungetc(int c, FILE *fp)\r
{\r
  _DIAGASSERT(fp != NULL);\r
  if(fp == NULL) {\r
    errno = EINVAL;\r
    return (EOF);\r
  }\r
\r
  if (c == EOF)\r
    return (EOF);\r
  if (!__sdidinit)\r
    __sinit();\r
  FLOCKFILE(fp);\r
  _SET_ORIENTATION(fp, -1);\r
  if ((fp->_flags & __SRD) == 0) {\r
    /*\r
     * Not already reading: no good unless reading-and-writing.\r
     * Otherwise, flush any current write stuff.\r
     */\r
    if ((fp->_flags & __SRW) == 0) {\r
      FUNLOCKFILE(fp);\r
      return (EOF);\r
    }\r
    if (fp->_flags & __SWR) {\r
      if (__sflush(fp)) {\r
        FUNLOCKFILE(fp);\r
        return (EOF);\r
      }\r
      fp->_flags &= ~__SWR;\r
      fp->_w = 0;\r
      fp->_lbfsize = 0;\r
    }\r
    fp->_flags |= __SRD;\r
  }\r
  c = (unsigned char)c;\r
\r
  /*\r
   * If we are in the middle of ungetc'ing, just continue.\r
   * This may require expanding the current ungetc buffer.\r
   */\r
  if (HASUB(fp)) {\r
    if (fp->_r >= _UB(fp)._size && __submore(fp)) {\r
      FUNLOCKFILE(fp);\r
      return (EOF);\r
    }\r
    *--fp->_p = (unsigned char)c;\r
    fp->_r++;\r
    FUNLOCKFILE(fp);\r
    return (c);\r
  }\r
  fp->_flags &= ~__SEOF;\r
\r
  /*\r
   * If we can handle this by simply backing up, do so,\r
   * but never replace the original character.\r
   * (This makes sscanf() work when scanning `const' data.)\r
   */\r
  if (fp->_bf._base != NULL && fp->_p > fp->_bf._base &&\r
      fp->_p[-1] == c) {\r
    fp->_p--;\r
    fp->_r++;\r
    FUNLOCKFILE(fp);\r
    return (c);\r
  }\r
\r
  /*\r
   * Create an ungetc buffer.\r
   * Initially, we will use the `reserve' buffer.\r
   */\r
  fp->_ur = fp->_r;\r
  fp->_up = fp->_p;\r
  _UB(fp)._base = fp->_ubuf;\r
  _UB(fp)._size = sizeof(fp->_ubuf);\r
  fp->_ubuf[sizeof(fp->_ubuf) - 1] = (unsigned char)c;\r
  fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1];\r
  fp->_r = 1;\r
  FUNLOCKFILE(fp);\r
  return (c);\r
}\r