path: root/libio/libioP.h

/* Copyright (C) 1993, 1997, 1998, 1999 Free Software Foundation, Inc.
   This file is part of the GNU IO Library.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This library is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this library; see the file COPYING.  If not, write to
   the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
   MA 02111-1307, USA.

   As a special exception, if you link this library with files
   compiled with a GNU compiler to produce an executable, this does
   not cause the resulting executable to be covered by the GNU General
   Public License.  This exception does not however invalidate any
   other reasons why the executable file might be covered by the GNU
   General Public License.  */

#include <errno.h>
#ifndef __set_errno
# define __set_errno(Val) errno = (Val)
#endif
#if defined __GLIBC__ && __GLIBC__ >= 2
# include <bits/libc-lock.h>
#else
/*# include <comthread.h>*/
#endif

#include "iolibio.h"

#ifdef __cplusplus
extern "C" {
#endif

#define _IO_seek_set 0
#define _IO_seek_cur 1
#define _IO_seek_end 2

/* THE JUMPTABLE FUNCTIONS.

 * The _IO_FILE type is used to implement the FILE type in GNU libc,
 * as well as the streambuf class in GNU iostreams for C++.
 * These are all the same, just used differently.
 * An _IO_FILE (or FILE) object is allows followed by a pointer to
 * a jump table (of pointers to functions).  The pointer is accessed
 * with the _IO_JUMPS macro.  The jump table has a eccentric format,
 * so as to be compatible with the layout of a C++ virtual function table.
 * (as implemented by g++).  When a pointer to a streambuf object is
 * coerced to an (_IO_FILE*), then _IO_JUMPS on the result just
 * happens to point to the virtual function table of the streambuf.
 * Thus the _IO_JUMPS function table used for C stdio/libio does
 * double duty as the virtual function table for C++ streambuf.
 *
 * The entries in the _IO_JUMPS function table (and hence also the
 * virtual functions of a streambuf) are described below.
 * The first parameter of each function entry is the _IO_FILE/streambuf
 * object being acted on (i.e. the 'this' parameter).
 */

#if (!defined _IO_USE_OLD_IO_FILE \
     && (!defined _G_IO_NO_BACKWARD_COMPAT || _G_IO_NO_BACKWARD_COMPAT == 0))
# define _IO_JUMPS_OFFSET 1
#endif

#define _IO_JUMPS(THIS) ((struct _IO_FILE_plus *) (THIS))->vtable
#define _IO_WIDE_JUMPS(THIS) ((struct _IO_FILE *) (THIS))->_wide_data->_wide_vtable
#if _IO_JUMPS_OFFSET
# define _IO_JUMPS_FUNC(THIS) \
 (*(struct _IO_jump_t **) ((void *) &((struct _IO_FILE_plus *) (THIS))->vtable\
			   + (THIS)->_vtable_offset))
#else
# define _IO_JUMPS_FUNC(THIS) _IO_JUMPS(THIS)
#endif
#define _IO_WIDE_JUMPS_FUNC(THIS) _IO_WIDE_JUMPS(THIS)
#ifdef _G_USING_THUNKS
# define JUMP_FIELD(TYPE, NAME) TYPE NAME
# define JUMP0(FUNC, THIS) _IO_JUMPS_FUNC(THIS)->FUNC (THIS)
# define JUMP1(FUNC, THIS, X1) _IO_JUMPS_FUNC(THIS)->FUNC (THIS, X1)
# define JUMP2(FUNC, THIS, X1, X2) _IO_JUMPS_FUNC(THIS)->FUNC (THIS, X1, X2)
# define JUMP3(FUNC, THIS, X1,X2,X3) _IO_JUMPS_FUNC(THIS)->FUNC (THIS, X1,X2, X3)
# define JUMP_INIT(NAME, VALUE) VALUE
# define JUMP_INIT_DUMMY JUMP_INIT(dummy, 0), JUMP_INIT (dummy2, 0)

# define WJUMP0(FUNC, THIS) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC (THIS)
# define WJUMP1(FUNC, THIS, X1) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC (THIS, X1)
# define WJUMP2(FUNC, THIS, X1, X2) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC (THIS, X1, X2)
# define WJUMP3(FUNC, THIS, X1,X2,X3) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC (THIS, X1,X2, X3)
#else
/* These macros will change when we re-implement vtables to use "thunks"! */
# define JUMP_FIELD(TYPE, NAME) struct { short delta1, delta2; TYPE pfn; } NAME
# define JUMP0(FUNC, THIS) _IO_JUMPS_FUNC(THIS)->FUNC.pfn (THIS)
# define JUMP1(FUNC, THIS, X1) _IO_JUMPS_FUNC(THIS)->FUNC.pfn (THIS, X1)
# define JUMP2(FUNC, THIS, X1, X2) _IO_JUMPS_FUNC(THIS)->FUNC.pfn (THIS, X1, X2)
# define JUMP3(FUNC, THIS, X1,X2,X3) _IO_JUMPS_FUNC(THIS)->FUNC.pfn (THIS, X1,X2,X3)
# define JUMP_INIT(NAME, VALUE) {0, 0, VALUE}
# define JUMP_INIT_DUMMY JUMP_INIT(dummy, 0)

# define WJUMP0(FUNC, THIS) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC.pfn (THIS)
# define WJUMP1(FUNC, THIS, X1) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC.pfn (THIS, X1)
# define WJUMP2(FUNC, THIS, X1, X2) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC.pfn (THIS, X1, X2)
# define WJUMP3(FUNC, THIS, X1,X2,X3) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC.pfn (THIS, X1,X2,X3)
#endif

/* The 'finish' function does any final cleaning up of an _IO_FILE object.
   It does not delete (free) it, but does everything else to finalize it.
   It matches the streambuf::~streambuf virtual destructor.  */
typedef void (*_IO_finish_t) __PMT ((_IO_FILE *, int)); /* finalize */
#define _IO_FINISH(FP) JUMP1 (__finish, FP, 0)
#define _IO_WFINISH(FP) WJUMP1 (__finish, FP, 0)

/* The 'overflow' hook flushes the buffer.
   The second argument is a character, or EOF.
   It matches the streambuf::overflow virtual function. */
typedef int (*_IO_overflow_t) __PMT ((_IO_FILE *, int));
#define _IO_OVERFLOW(FP, CH) JUMP1 (__overflow, FP, CH)
#define _IO_WOVERFLOW(FP, CH) WJUMP1 (__overflow, FP, CH)

/* The 'underflow' hook tries to fills the get buffer.
   It returns the next character (as an unsigned char) or EOF.  The next
   character remains in the get buffer, and the get position is not changed.
   It matches the streambuf::underflow virtual function. */
typedef int (*_IO_underflow_t) __PMT ((_IO_FILE *));
#define _IO_UNDERFLOW(FP) JUMP0 (__underflow, FP)
#define _IO_WUNDERFLOW(FP) WJUMP0 (__underflow, FP)

/* The 'uflow' hook returns the next character in the input stream
   (cast to unsigned char), and increments the read position;
   EOF is returned on failure.
   It matches the streambuf::uflow virtual function, which is not in the
   cfront implementation, but was added to C++ by the ANSI/ISO committee. */
#define _IO_UFLOW(FP) JUMP0 (__uflow, FP)
#define _IO_WUFLOW(FP) WJUMP0 (__uflow, FP)

/* The 'pbackfail' hook handles backing up.
   It matches the streambuf::pbackfail virtual function. */
typedef int (*_IO_pbackfail_t) __PMT ((_IO_FILE *, int));
#define _IO_PBACKFAIL(FP, CH) JUMP1 (__pbackfail, FP, CH)
#define _IO_W