mirror of
https://gitlab.com/sortix/sortix.git
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85 lines
2.6 KiB
C++
85 lines
2.6 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/fread_unlocked.cpp
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Reads data from a FILE.
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*******************************************************************************/
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#include <sys/types.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdint.h>
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#include <stdio.h>
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extern "C"
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size_t fread_unlocked(void* ptr,
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size_t element_size,
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size_t num_elements,
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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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unsigned char* buf = (unsigned char*) ptr;
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size_t count = element_size * num_elements;
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if ( count == 0 )
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return num_elements;
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if ( fp->buffer_mode == _IONBF )
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{
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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->read_func )
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return errno = EBADF, fp->flags |= _FILE_STATUS_ERROR, 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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fp->flags &= ~_FILE_STATUS_EOF;
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size_t sofar = 0;
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while ( sofar < count )
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{
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size_t request = count - sofar;
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if ( (size_t) SSIZE_MAX < request )
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request = SSIZE_MAX;
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ssize_t amount = fp->read_func(fp->user, buf + sofar, request);
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if ( amount < 0 )
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return fp->flags |= _FILE_STATUS_ERROR, sofar / num_elements;
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if ( amount == 0 )
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return fp->flags |= _FILE_STATUS_EOF, sofar / num_elements;
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sofar += amount;
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}
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return sofar / element_size;
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}
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for ( size_t n = 0; n < num_elements; n++ )
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{
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size_t offset = n * element_size;
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for ( size_t i = 0; i < element_size; i++ )
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{
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int c = fgetc_unlocked(fp);
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if ( c == EOF )
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return n;
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buf[offset + i] = (unsigned char) c;
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}
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}
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return num_elements;
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}
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