126 lines
3.7 KiB
C
126 lines
3.7 KiB
C
/****************************************************************************
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* libs/libc/stdio/lib_ungetwc.c
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*
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* Copyright © 2005-2014 Rich Felker, et al.
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <wchar.h>
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#include <limits.h>
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#include <ctype.h>
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#include <fcntl.h>
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#include <string.h>
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#ifdef CONFIG_FILE_STREAM
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: ungetwc_unlocked
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*
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* Description:
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* Put a wide character back to the stream without lock the stream
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*
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* Input Parameters:
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* wc - the wide character to be put back
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* f - the file stream to put the wide character back to
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*
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* Returned Value:
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* Return the wide character that put back to the stream on success,
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* return WEOF on failed, and keep the given stream remains unchanged.
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*
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****************************************************************************/
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wint_t ungetwc_unlocked(wint_t wc, FAR FILE *f)
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{
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char mbc[MB_LEN_MAX];
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int l = 1;
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/* Stream must be open for read access */
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if ((f->fs_oflags & O_RDOK) == 0)
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{
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return WEOF;
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}
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/* Try conversion early so we can fail without locking if invalid */
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if ((l = wctomb(mbc, wc)) < 0)
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{
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return WEOF;
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}
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#if CONFIG_NUNGET_CHARS > 0
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if (f->fs_nungotten + l <= CONFIG_NUNGET_CHARS)
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{
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memcpy(f->fs_ungotten + f->fs_nungotten, mbc, l);
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f->fs_nungotten += l;
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return wc;
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}
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else
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#endif
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{
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return WEOF;
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}
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}
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/****************************************************************************
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* Name: ungetwc
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*
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* Description:
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* Put a wide character back to the stream
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*
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* Input Parameters:
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* wc - the wide character that need to put back to the stream
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* f - pointer to a FILE object that identifies an input stream
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*
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* Returned Value:
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* Return the wide character that put back to the stream on success,
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* return WEOF on failed, and keep the given stream remains unchanged.
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*
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****************************************************************************/
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wint_t ungetwc(wint_t wc, FAR FILE *f)
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{
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wint_t ret;
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/* Verify that a non-NULL stream was provided and wc is not WEOF */
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if (!f || wc == WEOF)
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{
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return WEOF;
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}
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flockfile(f);
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ret = ungetwc_unlocked(wc, f);
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funlockfile(f);
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return ret;
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}
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#endif /* CONFIG_FILE_STREAM */
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