mirror of
https://gitlab.com/sortix/sortix.git
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66 lines
2.1 KiB
C++
66 lines
2.1 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014, 2015.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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stdio/ungetc_unlocked.cpp
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Inserts data in front of the current read queue, allowing applications to
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peek the incoming data and pretend they didn't.
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*******************************************************************************/
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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extern "C" int ungetc_unlocked(int c, FILE* fp)
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{
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if ( c == EOF )
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return EOF;
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if ( !(fp->flags & _FILE_READABLE) )
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return errno = EBADF, fp->flags |= _FILE_STATUS_ERROR, EOF;
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if ( !(fp->flags & _FILE_BUFFER_MODE_SET) )
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setvbuf_unlocked(fp, NULL, fp->buffer_mode, 0);
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if ( fp->flags & _FILE_LAST_WRITE )
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fflush_stop_writing_unlocked(fp);
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fp->flags |= _FILE_LAST_READ;
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// TODO: Is this a bug that ungetc doesn't work for unbuffered files?
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if ( fp->buffer_mode == _IONBF )
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return errno = EBADF, fp->flags |= _FILE_STATUS_ERROR, EOF;
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if ( fp->offset_input_buffer == 0 )
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{
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size_t amount = fp->amount_input_buffered - fp->offset_input_buffer;
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size_t offset = BUFSIZ - amount;
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if ( !offset )
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return EOF;
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memmove(fp->buffer + offset, fp->buffer, sizeof(fp->buffer[0]) * amount);
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fp->offset_input_buffer = offset;
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fp->amount_input_buffered = offset + amount;
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}
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fp->buffer[--fp->offset_input_buffer] = c;
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fp->flags &= ~_FILE_STATUS_EOF;
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return c;
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}
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