166 lines
5.1 KiB
C
166 lines
5.1 KiB
C
/****************************************************************************
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*
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* Open Watcom Project
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*
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* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
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*
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* ========================================================================
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*
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* This file contains Original Code and/or Modifications of Original
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* Code as defined in and that are subject to the Sybase Open Watcom
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* Public License version 1.0 (the 'License'). You may not use this file
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* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
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* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
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* provided with the Original Code and Modifications, and is also
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* available at www.sybase.com/developer/opensource.
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*
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* The Original Code and all software distributed under the License are
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* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
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* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
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* NON-INFRINGEMENT. Please see the License for the specific language
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* governing rights and limitations under the License.
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*
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* ========================================================================
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*
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* Description: Implementation of fread() - read data from stream.
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*
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****************************************************************************/
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#include "variety.h"
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#include <stdio.h>
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#include <unistd.h>
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#include "fileacc.h"
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#include <string.h>
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#include <errno.h>
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#include "rtdata.h"
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#include "seterrno.h"
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#include "qread.h"
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#include "streamio.h"
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#define DOS_EOF_CHAR 0x1a
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extern int __fill_buffer( FILE * ); /* located in fgetc */
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_WCRTLINK size_t fread( void *_buf, size_t size, size_t n, FILE *fp )
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{
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char *buf = _buf;
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size_t len_read;
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_ValidFile( fp, 0 );
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_AccessFile( fp );
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if( (fp->_flag & _READ) == 0 ) {
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__set_errno( EBADF );
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fp->_flag |= _SFERR;
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_ReleaseFile( fp );
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return( 0 );
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}
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#if 0
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/*** If the buffer is _DIRTY, resync it before reading ***/
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if( fp->_flag & (_WRITE | _UNGET) ) {
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if( fp->_flag & _DIRTY ) {
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fseek( fp, 0, SEEK_CUR );
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}
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}
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#endif
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n *= size;
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if( n == 0 ) {
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_ReleaseFile( fp );
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return( n );
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}
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if( _FP_BASE(fp) == NULL ) {
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__ioalloc( fp ); /* allocate buffer */
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}
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len_read = 0;
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#if !defined( __UNIX__ )
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if( fp->_flag & _BINARY )
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#endif
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{
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size_t bytes_left = n, bytes;
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for( ;; ) {
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if( fp->_cnt != 0 ) {
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bytes = fp->_cnt;
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if( bytes > bytes_left ) {
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bytes = bytes_left;
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}
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memcpy( buf, fp->_ptr, bytes );
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fp->_ptr += bytes;
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buf += bytes;
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fp->_cnt -= bytes;
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bytes_left -= bytes;
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len_read += bytes;
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}
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if( bytes_left == 0 ) break;
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/* if user's buffer is larger than our buffer, OR
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_IONBF is set, then read directly into user's buffer. */
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if( (bytes_left >= fp->_bufsize) || (fp->_flag & _IONBF) ) {
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bytes = bytes_left;
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fp->_ptr = _FP_BASE(fp);
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fp->_cnt = 0;
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if( !(fp->_flag & _IONBF) ) {
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/* if more than a sector, set to multiple of sector size*/
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if( bytes > 512 ) {
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bytes &= -512;
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}
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}
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n = __qread( fileno(fp), buf, bytes );
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if( n == -1 ) {
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fp->_flag |= _SFERR;
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break;
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} else if( n == 0 ) {
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fp->_flag |= _EOF;
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break;
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}
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buf += n;
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bytes_left -= n;
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len_read += n;
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} else {
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if( __fill_buffer( fp ) == 0 ) break;
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}
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} /* end for */
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#if !defined(__UNIX__)
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} else {
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for( ;; ) {
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int c;
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// ensure non-empty buffer
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if( fp->_cnt == 0 ) {
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if( __fill_buffer( fp ) == 0 ) break;
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}
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// get character
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--fp->_cnt;
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c = *fp->_ptr++ & 0xff;
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// perform new-line translation
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if( c == '\r' ) {
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// ensure non-empty buffer
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if( fp->_cnt == 0 ) {
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if( __fill_buffer( fp ) == 0 ) break;
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}
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// get character
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--fp->_cnt;
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c = *fp->_ptr++ & 0xff;
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}
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// check for DOS end of file marker
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if( c == DOS_EOF_CHAR ) {
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fp->_flag |= _EOF;
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break;
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}
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// store chracter
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buf[len_read] = (char)c;
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++len_read;
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if( len_read == n ) break;
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}
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#endif
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}
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_ReleaseFile( fp );
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return( len_read / size );
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}
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