read.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 232 行

/****************************************************************************
*
*                            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:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
*               DESCRIBE IT HERE!
*
****************************************************************************/


#include "variety.h"
#include <stdio.h>
#include <io.h>
#include <fcntl.h>
#include <errno.h>
#if defined(__NT__)
    #include <windows.h>
#elif defined(__WINDOWS__)
    #include <windows.h>
    #include "tinyio.h"
#elif defined(__OS2__)
    #include "tinyos2.h"
    #define INCL_DOSMEMMGR
    #include <wos2.h>
#else
    #include "tinyio.h"
#endif
#include "iomode.h"
#include "fileacc.h"
#include "rtcheck.h"
#include "rtdata.h"
#include "seterrno.h"
#include "defwin.h"
#include "lseek.h"


#if defined(__WINDOWS_386__)
  static int __read( int handle, void *buf, unsigned len )
#else
  _WCRTLINK int read( int handle, void *buf, unsigned len )
#endif
{
    unsigned read_len, total_len;
    unsigned reduce_idx, finish_idx;
    unsigned iomode_flags;
    char *buffer = buf;
#if defined(__NT__)
    DWORD   amount_read;
    BOOL    rc;
    HANDLE  h;
#elif defined(__WARP__)
    ULONG amount_read;
#elif defined(__OS2_286__)
    USHORT amount_read;
#else
    unsigned amount_read;
#endif
#if !defined(__NT__)
    tiny_ret_t rc;
#endif
#ifdef DEFAULT_WINDOWING
    LPWDATA res;
#endif

    __handle_check( handle, -1 );
    __ChkTTYIOMode( handle );
    iomode_flags = __GetIOMode( handle );
    if( iomode_flags == 0 ) {
#if defined( __WINDOWS__ ) || defined( __WINDOWS_386__ )
        return( _lread( handle, buffer, len ) );
#else
        __set_errno( EBADF );
        return( -1 );
#endif
    }
    if( !(iomode_flags & _READ) ) {
        __set_errno( EACCES );     /* changed from EBADF to EACCES 23-feb-89 */
        return( -1 );
    }
#ifdef __NT__
    h = __getOSHandle( handle );
#endif
    if( iomode_flags & _BINARY ) {       /* if binary mode */
#ifdef DEFAULT_WINDOWING
        if( _WindowsStdin != 0 &&
                (res = _WindowsIsWindowedHandle( handle )) != 0 ) {
            total_len = _WindowsStdin( res, buffer, len );
            rc = 0;
        } else
#endif
        {
#if defined(__NT__)
            rc = ReadFile( h, buffer, len, &amount_read, NULL );
            total_len = amount_read;
            if( !rc ) {
                if (GetLastError() == ERROR_BROKEN_PIPE)
                    return total_len;

                return( __set_errno_nt() );
            }
#elif defined( __OS2__ )
            rc = DosRead( handle, buffer, len, &amount_read );
            total_len = amount_read;
#else
            rc = TinyRead( handle, buffer, len );
            total_len = TINY_LINFO( rc );
#endif
        }
#if !defined(__NT__)
        if( TINY_ERROR( rc ) ) {
            return( __set_errno_dos( TINY_INFO( rc ) ) );
        }
#endif
    } else {
        _AccessFileH( handle );
        total_len = 0;
        read_len = len;
        do {
#ifdef DEFAULT_WINDOWING
            if( _WindowsStdin != 0 &&
                    (res = _WindowsIsWindowedHandle( handle )) != 0L ) {
                amount_read = _WindowsStdin( res, buffer, read_len );
                rc = 0;
            } else
#endif
            {
#if defined(__NT__)
                rc = ReadFile( h, buffer, read_len, &amount_read, NULL );
                if( !rc ) {
                    _ReleaseFileH( handle );

                    if( GetLastError() == ERROR_BROKEN_PIPE )
                        return total_len;

                    return( __set_errno_nt() );
                }
#elif defined( __OS2__ )
                rc = DosRead( handle, buffer, read_len, &amount_read );
#else
                rc = TinyRead( handle, buffer, read_len );
                amount_read = TINY_LINFO( rc );
#endif
            }
#if !defined(__NT__)
            if( TINY_ERROR( rc ) ) {
                _ReleaseFileH( handle );
                return( __set_errno_dos( TINY_INFO( rc ) ) );
            }
#endif
            if( amount_read == 0 ) {                    /* EOF */
                break;
            }
            reduce_idx = 0;
            finish_idx = reduce_idx;
            for( ; reduce_idx < amount_read; ++reduce_idx ) {
                if( buffer[ reduce_idx ] == 0x1a ) {    /* EOF */
                    __lseek( handle,
                           ((long)reduce_idx - (long)amount_read)+1L,
                           SEEK_CUR );
                    total_len += finish_idx;
                    _ReleaseFileH( handle );
                    return( total_len );
                }
                if( buffer[ reduce_idx ] != '\r' ) {
                    buffer[ finish_idx++ ] = buffer[ reduce_idx ];
                }
            }
            total_len += finish_idx;
            buffer += finish_idx;
            read_len -= finish_idx;
            if( iomode_flags & _ISTTY ) {
                break;  /* 04-feb-88, FWC */
            }
        } while( read_len != 0 );
        _ReleaseFileH( handle );
    }
    return( total_len );
}

#if defined( __WINDOWS_386__ )
#define MAXBUFF 0x8000
_WCRTLINK int read( int handle, void *buffer, unsigned len )
{
    unsigned    total = 0;
    unsigned    readamt;
    int         rc;

    __handle_check( handle, -1 );

    while( len > 0 ) {
        if( len > MAXBUFF ) {
            readamt = MAXBUFF;
        } else {
            readamt = len;
        }
        rc = __read( handle, buffer, readamt );
        if( rc == -1 )
            return( rc );
        total += (unsigned)rc;
        if( rc != readamt )
            return( total );

        len -= readamt;
        buffer = ((char *)buffer) + readamt;
    }
    return( total );

}
#endif