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https://gitlab.com/sortix/sortix.git
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9ad7690c74
These changes aim to make the stdio functions much more stable, flexible, correct and bugfree.
69 lines
2 KiB
C++
69 lines
2 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
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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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fgetc.cpp
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Reads a single character from a FILE.
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*******************************************************************************/
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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extern "C" int fgetc(FILE* fp)
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{
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if ( fp->flags & _FILE_NO_BUFFER )
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{
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unsigned char c;
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if ( fread(&c, sizeof(c), 1, fp) != 1 )
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return EOF;
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return c;
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}
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if ( !fp->read_func )
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return EOF; // TODO: ferror doesn't report error!
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if ( fp->flags & _FILE_LAST_WRITE )
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fflush_stop_writing(fp);
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fp->flags |= _FILE_LAST_READ;
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if ( fp->offset_input_buffer < fp->amount_input_buffered )
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retry:
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return fp->buffer[fp->offset_input_buffer++];
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assert(fp->buffer && fp->buffersize);
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size_t pushback = _FILE_MAX_PUSHBACK;
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if ( fp->buffersize <= pushback )
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pushback = 0;
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size_t count = fp->buffersize - pushback;
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size_t size = sizeof(unsigned char);
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size_t numread = fp->read_func(fp->buffer + pushback, size, count, fp->user);
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if ( !numread )
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return EOF;
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fp->offset_input_buffer = pushback;
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fp->amount_input_buffered = pushback + numread;
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goto retry;
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}
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