genops.c

vxworks源码源码解读是学习vxworks的最佳途径

/* This has been copied from the gnu source tree */
/* Make all changes there, not here! */
#ifdef __cplusplus
extern "C" {
#endif
#ifndef _N_
char __genops_o = 0;
#else
char _N_ = 0;
#endif
#ifdef __cplusplus
}
#endif
#include "vxWorks.h"
/* Copyright (C) 1993, 1995, 1997 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.  */

/* Generic or default I/O operations. */

#include "libioP.h"
#ifdef __STDC__
#include <stdlib.h>
#endif
#include <string.h>

void
_IO_un_link (fp)
     _IO_FILE *fp;
{
  if (fp->_flags & _IO_LINKED)
    {
      _IO_FILE **f;
      for (f = &_IO_list_all; *f != NULL; f = &(*f)->_chain)
	{
	  if (*f == fp)
	    {
	      *f = fp->_chain;
	      break;
	    }
	}
      fp->_flags &= ~_IO_LINKED;
    }
}

void
_IO_link_in (fp)
     _IO_FILE *fp;
{
    if ((fp->_flags & _IO_LINKED) == 0)
      {
	fp->_flags |= _IO_LINKED;
	fp->_chain = _IO_list_all;
	_IO_list_all = fp;
      }
}

/* Return minimum _pos markers
   Assumes the current get area is the main get area. */
static _IO_size_t _IO_least_marker __P ((_IO_FILE *fp));

static _IO_size_t
_IO_least_marker (fp)
     _IO_FILE *fp;
{
  _IO_ssize_t least_so_far = fp->_IO_read_end - fp->_IO_read_base;
  struct _IO_marker *mark;
  for (mark = fp->_markers; mark != NULL; mark = mark->_next)
    if (mark->_pos < least_so_far)
      least_so_far = mark->_pos;
  return least_so_far;
}

/* Switch current get area from backup buffer to (start of) main get area. */

void
_IO_switch_to_main_get_area (fp)
     _IO_FILE *fp;
{
  char *tmp;
  fp->_flags &= ~_IO_IN_BACKUP;
  /* Swap _IO_read_end and _IO_save_end. */
  tmp = fp->_IO_read_end;
  fp->_IO_read_end = fp->_IO_save_end;
  fp->_IO_save_end= tmp;
  /* Swap _IO_read_base and _IO_save_base. */
  tmp = fp->_IO_read_base;
  fp->_IO_read_base = fp->_IO_save_base;
  fp->_IO_save_base = tmp;

  fp->_IO_read_ptr = fp->_IO_read_base;
}

/* Switch current get area from main get area to (end of) backup area. */

void
_IO_switch_to_backup_area (fp)
     _IO_FILE *fp;
{
  char *tmp;
  fp->_flags |= _IO_IN_BACKUP;
  /* Swap _IO_read_end and _IO_save_end. */
  tmp = fp->_IO_read_end;
  fp->_IO_read_end = fp->_IO_save_end;
  fp->_IO_save_end = tmp;
  /* Swap _gbase and _IO_save_base. */
  tmp = fp->_IO_read_base;
  fp->_IO_read_base = fp->_IO_save_base;
  fp->_IO_save_base = tmp;

  fp->_IO_read_ptr = fp->_IO_read_end;
}

int
_IO_switch_to_get_mode (fp)
     _IO_FILE *fp;
{
  if (fp->_IO_write_ptr > fp->_IO_write_base)
    if (_IO_OVERFLOW (fp, EOF) == EOF)
      return EOF;
  if (_IO_in_backup (fp))
    fp->_IO_read_base = fp->_IO_backup_base;
  else
    {
      fp->_IO_read_base = fp->_IO_buf_base;
      if (fp->_IO_write_ptr > fp->_IO_read_end)
	fp->_IO_read_end = fp->_IO_write_ptr;
    }
  fp->_IO_read_ptr = fp->_IO_write_ptr;

  fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end = fp->_IO_read_ptr;

  fp->_flags &= ~_IO_CURRENTLY_PUTTING;
  return 0;
}

void
_IO_free_backup_area (fp)
     _IO_FILE *fp;
{
  if (_IO_in_backup (fp))
    _IO_switch_to_main_get_area (fp);  /* Just in case. */
  free (fp->_IO_save_base);
  fp->_IO_save_base = NULL;
  fp->_IO_save_end = NULL;
  fp->_IO_backup_base = NULL;
}

#if 0
int
_IO_switch_to_put_mode (fp)
     _IO_FILE *fp;
{
  fp->_IO_write_base = fp->_IO_read_ptr;
  fp->_IO_write_ptr = fp->_IO_read_ptr;
  /* Following is wrong if line- or un-buffered? */
  fp->_IO_write_end = (fp->_flags & _IO_IN_BACKUP
		       ? fp->_IO_read_end : fp->_IO_buf_end);

  fp->_IO_read_ptr = fp->_IO_read_end;
  fp->_IO_read_base = fp->_IO_read_end;

  fp->_flags |= _IO_CURRENTLY_PUTTING;
  return 0;
}
#endif

int
__overflow (f, ch)
     _IO_FILE *f;
     int ch;
{
  return _IO_OVERFLOW (f, ch);
}

static int save_for_backup __P ((_IO_FILE *fp));

     static int
save_for_backup (fp)
     _IO_FILE *fp;
{
  /* Append [_IO_read_base.._IO_read_end] to backup area. */
  int least_mark = _IO_least_marker (fp);
  /* needed_size is how much space we need in the backup area. */
  int needed_size = (fp->_IO_read_end - fp->_IO_read_base) - least_mark;
  int current_Bsize = fp->_IO_save_end - fp->_IO_save_base;
  int avail; /* Extra space available for future expansion. */
  int delta;
  struct _IO_marker *mark;
  if (needed_size > current_Bsize)
    {
      char *new_buffer;
      avail = 100;
      new_buffer = (char *) malloc (avail + needed_size);
      if (new_buffer == NULL)
	return EOF;		/* FIXME */
      if (least_mark < 0)
	{
	  memcpy (new_buffer + avail,
		  fp->_IO_save_end + least_mark,
		  -least_mark);
	  memcpy (new_buffer + avail - least_mark,
		  fp->_IO_read_base,
		  fp->_IO_read_end - fp->_IO_read_base);
	}
      else
	memcpy (new_buffer + avail,
		fp->_IO_read_base + least_mark,
		needed_size);
      if (fp->_IO_save_base)
	free (fp->_IO_save_base);
      fp->_IO_save_base = new_buffer;
      fp->_IO_save_end = new_buffer + avail + needed_size;
    }
  else
    {
      avail = current_Bsize - needed_size;
      if (least_mark < 0)
	{
	  memmove (fp->_IO_save_base + avail,
		   fp->_IO_save_end + least_mark,
		   -least_mark);
	  memcpy (fp->_IO_save_base + avail - least_mark,
		  fp->_IO_read_base,
		  fp->_IO_read_end - fp->_IO_read_base);
	}
      else if (needed_size > 0)
	memcpy (fp->_IO_save_base + avail,
		fp->_IO_read_base + least_mark,
		needed_size);
    }
  /* FIXME: Dubious arithmetic if pointers are NULL */
  fp->_IO_backup_base = fp->_IO_save_base + avail;
  /* Adjust all the streammarkers. */
  delta = fp->_IO_read_end - fp->_IO_read_base;
  for (mark = fp->_markers; mark != NULL; mark = mark->_next)
    mark->_pos -= delta;
  return 0;
}

int
__underflow (fp)
     _IO_FILE *fp;
{
  if (_IO_in_put_mode (fp))
    if (_IO_switch_to_get_mode (fp) == EOF)
      return EOF;
  if (fp->_IO_read_ptr < fp->_IO_read_end)
    return *(unsigned char *) fp->_IO_read_ptr;
  if (_IO_in_backup (fp))
    {
      _IO_switch_to_main_get_area (fp);
      if (fp->_IO_read_ptr < fp->_IO_read_end)
	return *fp->_IO_read_ptr;
    }
  if (_IO_have_markers (fp))
    {
      if (save_for_backup (fp))
	return EOF;
    }
  else if (_IO_have_backup (fp))
    _IO_free_backup_area (fp);
  return _IO_UNDERFLOW (fp);
}

int
__uflow (fp)
     _IO_FILE *fp;
{
  if (_IO_in_put_mode (fp))
    if (_IO_switch_to_get_mode (fp) == EOF)
      return EOF;
  if (fp->_IO_read_ptr < fp->_IO_read_end)
    return *(unsigned char *) fp->_IO_read_ptr++;
  if (_IO_in_backup (fp))
    {
      _IO_switch_to_main_get_area (fp);
      if (fp->_IO_read_ptr < fp->_IO_read_end)
	return *fp->_IO_read_ptr++;
    }
  if (_IO_have_markers (fp))
    {
      if (save_for_backup (fp))
	return EOF;
    }
  else if (_IO_have_backup (fp))
    _IO_free_backup_area (fp);
  return _IO_UFLOW (fp);
}

void
_IO_setb (f, b, eb, a)
     _IO_FILE *f;
      char *b;
     char *eb;
     int a;
{
  if (f->_IO_buf_base && !(f->_flags & _IO_USER_BUF))
    FREE_BUF (f->_IO_buf_base, _IO_blen (f));
  f->_IO_buf_base = b;
  f->_IO_buf_end = eb;
  if (a)
    f->_flags &= ~_IO_USER_BUF;
  else
    f->_flags |= _IO_USER_BUF;
}

void
_IO_doallocbuf (fp)
     _IO_FILE *fp;
{
  if (fp->_IO_buf_base)
    return;
  if (!(fp->_flags & _IO_UNBUFFERED))
    if (_IO_DOALLOCATE (fp) != EOF)
      return;
  _IO_setb (fp, fp->_shortbuf, fp->_shortbuf+1, 0);
}

int
_IO_default_underflow (fp)
     _IO_FILE *fp;
{
  return EOF;
}

int
_IO_default_uflow (fp)
     _IO_FILE *fp;
{
  int ch = _IO_UNDERFLOW (fp);
  if (ch == EOF)
    return EOF;
  return *(unsigned char *) fp->_IO_read_ptr++;
}

_IO_size_t
_IO_default_xsputn (f, data, n)
     _IO_FILE *f;
     const void *data;
     _IO_size_t n;
{
  const char *s = (char *) data;
  _IO_size_t more = n;
  if (more <= 0)
    return 0;
  for (;;)
    {
      /* Space available. */
      _IO_ssize_t count = f->_IO_write_end - f->_IO_write_ptr;
      if (count > 0)
	{
	  if ((_IO_size_t) count > more)
	    count = more;
	  if (count > 20)
	    {
	      memcpy (f->_IO_write_ptr, s, count);
	      s += count;
	      f->_IO_write_ptr += count;
            }
	  else if (count <= 0)
	    count = 0;
	  else
	    {
	      char *p = f->_IO_write_ptr;
	      _IO_ssize_t i;
	      for (i = count; --i >= 0; )
		*p++ = *s++;
	      f->_IO_write_ptr = p;
            }
	  more -= count;
        }
      if (more == 0 || __overflow (f, (unsigned char) *s++) == EOF)
	break;
      more--;
    }
  return n - more;
}

_IO_size_t
_IO_sgetn (fp, data, n)
     _IO_FILE *fp;
     void *data;
     _IO_size_t n;
{
  /* FIXME handle putback buffer here! */
  return _IO_XSGETN (fp, data, n);
}

_IO_size_t
_IO_default_xsgetn (fp, data, n)
     _IO_FILE *fp;
     void *data;
     _IO_size_t n;
{
  _IO_size_t more = n;
  char *s = (char*) data;
  for (;;)
    {
      /* Data available. */
      _IO_ssize_t count = fp->_IO_read_end - fp->_IO_read_ptr;
      if (count > 0)
	{
	  if ((_IO_size_t) count > more)
	    count = more;
	  if (count > 20)
	    {
	      memcpy (s, fp->_IO_read_ptr, count);
	      s += count;
	      fp->_IO_read_ptr += count;
	    }
	  else if (count <= 0)
	    count = 0;
	  else
	    {
	      char *p = fp->_IO_read_ptr;
	      int i = (int) count;
	      while (--i >= 0)
		*s++ = *p++;
	      fp->_IO_read_ptr = p;
            }
            more -= count;
        }
      if (more == 0 || __underflow (fp) == EOF)
	break;
    }
  return n - more;
}

#if 0
/* Seems not to be needed. --drepper */
int
_IO_sync (fp)
     _IO_FILE *fp;
{
  return 0;
}
#endif

_IO_FILE *
_IO_default_setbuf (fp, p, len)
     _IO_FILE *fp;
     char *p;
     _IO_ssize_t len;
{
    if (_IO_SYNC (fp) == EOF)
	return NULL;
    if (p == NULL || len == 0)
      {
	fp->_flags |= _IO_UNBUFFERED;
	_IO_setb (fp, fp->_shortbuf, fp->_shortbuf+1, 0);
      }
    else
      {
	fp->_flags &= ~_IO_UNBUFFERED;
	_IO_setb (fp, p, p+len, 0);
      }
    fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end = 0;
    fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_read_end = 0;