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Files
amiga-clib2/library/stdio_ungetc.c
Olaf Barthel 2ced1d3293 - Modified the locale-aware isalnum(), isalpha(), iscntrl(),
isdigit(), isgraph(), islower(), isprint(), ispunct(), isspace(),
  isupper(), isxdigit(), tolower() and toupper() functions
  to clamp the input parameter to the "unsigned char" range before
  it is submitted to the respective locale.library function. This
  should be in sync with what the specs demand, which state that
  if the input parameter is neither EOF nor in the range of an
  "unsigned char" variable, then the results are undefined.

- ungetc() now returns the input character, clamped to an unsigned
  char value, upon success. Previously, if the input parameter was
  negative and not EOF, the result was identical to the input, which
  could have had negative side-effects.


git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@14958 87f5fb63-7c3d-0410-a384-fd976d0f7a62
2005-05-29 09:56:09 +00:00

146 lines
3.7 KiB
C

/*
* $Id: stdio_ungetc.c,v 1.6 2005-05-29 09:56:09 obarthel Exp $
*
* :ts=4
*
* Portable ISO 'C' (1994) runtime library for the Amiga computer
* Copyright (c) 2002-2005 by Olaf Barthel <olsen@sourcery.han.de>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Neither the name of Olaf Barthel nor the names of contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
*/
#ifndef _STDLIB_NULL_POINTER_CHECK_H
#include "stdlib_null_pointer_check.h"
#endif /* _STDLIB_NULL_POINTER_CHECK_H */
/****************************************************************************/
#ifndef _STDIO_HEADERS_H
#include "stdio_headers.h"
#endif /* _STDIO_HEADERS_H */
/****************************************************************************/
int
ungetc(int c,FILE *stream)
{
struct iob * file = (struct iob *)stream;
int result = EOF;
assert( stream != NULL );
if(__check_abort_enabled)
__check_abort();
flockfile(stream);
#if defined(CHECK_FOR_NULL_POINTERS)
{
if(stream == NULL)
{
SHOWMSG("null file pointer!");
__set_errno(EFAULT);
goto out;
}
}
#endif /* CHECK_FOR_NULL_POINTERS */
assert( __is_valid_iob(file) );
assert( FLAG_IS_SET(file->iob_Flags,IOBF_IN_USE) );
assert( file->iob_BufferSize > 0 );
if(FLAG_IS_CLEAR(file->iob_Flags,IOBF_IN_USE))
{
SHOWMSG("this file is not even in use");
SET_FLAG(file->iob_Flags,IOBF_ERROR);
__set_errno(EBADF);
goto out;
}
/* Pushing back characters only works for files that can be read from. */
if(FLAG_IS_CLEAR(file->iob_Flags,IOBF_READ))
{
SHOWMSG("can't even read from this file");
SET_FLAG(file->iob_Flags,IOBF_ERROR);
__set_errno(EACCES);
goto out;
}
/* Pushing back an EOF is forbidden. */
if(c == EOF)
{
SHOWMSG("cannot push back an EOF");
SET_FLAG(file->iob_Flags,IOBF_ERROR);
__set_errno(EINVAL);
goto out;
}
/* Get rid of the write buffer, if it's still around. */
if(__iob_write_buffer_is_valid(file) > 0 && __flush_iob_write_buffer(file) < 0)
{
SHOWMSG("could not flush write buffer");
goto out;
}
/* We need to replace one of the characters in the buffer, which must
* have been read before. The ISO standard requires that it must
* be possible to push back at least one single character.
*/
if(file->iob_BufferPosition == 0)
{
SHOWMSG("no room to push back");
SET_FLAG(file->iob_Flags,IOBF_ERROR);
__set_errno(ENOBUFS);
goto out;
}
CLEAR_FLAG(file->iob_Flags,IOBF_EOF_REACHED);
/* Replace the character just read. */
file->iob_Buffer[--file->iob_BufferPosition] = c;
/* Clamp the result to an unsigned 8 bit value. */
result = (c & 255);
out:
funlockfile(stream);
return(result);
}