77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
/*
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* Copyright (c) 2011, 2012, 2013, 2014, 2015 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* stdio/fgetc_unlocked.c
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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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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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