kolibrios/programs/develop/open watcom/trunk/clib/streamio/fread.c
Sergey Semyonov (Serge) 3be3768ce0 update CLib
git-svn-id: svn://kolibrios.org@614 a494cfbc-eb01-0410-851d-a64ba20cac60
2007-08-28 10:31:46 +00:00

166 lines
5.1 KiB
C

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