82 lines
2.4 KiB
C++
82 lines
2.4 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/fgetc_unlocked.cpp
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Reads a single character from a FILE.
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*******************************************************************************/
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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extern "C" int fgetc_unlocked(FILE* fp)
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{
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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->buffer_mode == _IONBF )
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{
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unsigned char c;
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if ( fread_unlocked(&c, sizeof(c), 1, fp) != 1 )
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return EOF;
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return (int) c;
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}
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if ( !fp->read_func )
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return errno = EBADF, fp->flags |= _FILE_STATUS_ERROR, EOF;
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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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fp->flags &= ~_FILE_STATUS_EOF;
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if ( !(fp->offset_input_buffer < fp->amount_input_buffered) )
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{
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assert(fp->buffer && BUFSIZ);
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size_t pushback = _FILE_MAX_PUSHBACK;
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if ( BUFSIZ <= pushback )
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pushback = 0;
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size_t count = BUFSIZ - pushback;
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if ( (size_t) SSIZE_MAX < count )
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count = SSIZE_MAX;
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ssize_t numread = fp->read_func(fp->user, fp->buffer + pushback, count);
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if ( numread < 0 )
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return fp->flags |= _FILE_STATUS_ERROR, EOF;
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if ( numread == 0 )
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return fp->flags |= _FILE_STATUS_EOF, EOF;
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fp->offset_input_buffer = pushback;
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fp->amount_input_buffered = pushback + numread;
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}
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return fp->buffer[fp->offset_input_buffer++];
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}
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