~drizzle-trunk/drizzle/development

/* Copyright (C) 2000 MySQL AB

   This program 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; version 2 of the License.

   This program 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 program; if not, write to the Free Software

   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#include "myisamdef.h"

#include <mysys/mysys_err.h>

#include <errno.h>

#include <unistd.h>

/*

  Read a chunk of bytes from a file from a given position

  SYNOPSIOS

    my_pread()

    Filedes	File decsriptor

    Buffer	Buffer to read data into

    Count	Number of bytes to read

    offset	Position to read from

    MyFlags	Flags

  NOTES

    This differs from the normal pread() call in that we don't care

    to set the position in the file back to the original position

    if the system doesn't support pread().

  RETURN

    (size_t) -1   Error

    #             Number of bytes read

*/

size_t my_pread(File Filedes, unsigned char *Buffer, size_t Count, my_off_t offset,

                myf MyFlags)

{

  size_t readbytes;

  int error= 0;

  for (;;)

  {

    errno=0;					/* Linux doesn't reset this */

    if ((error= ((readbytes= pread(Filedes, Buffer, Count, offset)) != Count)))

      my_errno= errno ? errno : -1;

    if (error || readbytes != Count)

    {

      if ((readbytes == 0 || readbytes == (size_t) -1) && errno == EINTR)

      {

        continue;                              /* Interrupted */

      }

      if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))

      {

	if (readbytes == (size_t) -1)

	  my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG),

		   my_filename(Filedes),my_errno);

	else if (MyFlags & (MY_NABP | MY_FNABP))

	  my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG),

		   my_filename(Filedes),my_errno);

      }

      if (readbytes == (size_t) -1 || (MyFlags & (MY_FNABP | MY_NABP)))

	return(MY_FILE_ERROR);		/* Return with error */

    }

    if (MyFlags & (MY_NABP | MY_FNABP))

      return(0);				/* Read went ok; Return 0 */

    return(readbytes);			/* purecov: inspected */

  }

} /* my_pread */

/*

  Write a chunk of bytes to a file at a given position

  SYNOPSIOS

    my_pwrite()

    Filedes	File decsriptor

    Buffer	Buffer to write data from

    Count	Number of bytes to write

    offset	Position to write to

    MyFlags	Flags

  NOTES

    This differs from the normal pwrite() call in that we don't care

    to set the position in the file back to the original position

    if the system doesn't support pwrite()

  RETURN

    (size_t) -1   Error

    #             Number of bytes read

*/

size_t my_pwrite(int Filedes, const unsigned char *Buffer, size_t Count,

                 my_off_t offset, myf MyFlags)

{

  size_t writenbytes, written;

  uint32_t errors;

  errors= 0;

  written= 0;

  for (;;)

  {

    if ((writenbytes= pwrite(Filedes, Buffer, Count,offset)) == Count)

      break;

    my_errno= errno;

    if (writenbytes != (size_t) -1)

    {					/* Safegueard */

      written+=writenbytes;

      Buffer+=writenbytes;

      Count-=writenbytes;

      offset+=writenbytes;

    }

#ifndef NO_BACKGROUND

    if (my_thread_var->abort)

      MyFlags&= ~ MY_WAIT_IF_FULL;		/* End if aborted by user */

    if ((my_errno == ENOSPC || my_errno == EDQUOT) &&

        (MyFlags & MY_WAIT_IF_FULL))

    {

      if (!(errors++ % MY_WAIT_GIVE_USER_A_MESSAGE))

	my_error(EE_DISK_FULL,MYF(ME_BELL | ME_NOREFRESH),

		 my_filename(Filedes),my_errno,MY_WAIT_FOR_USER_TO_FIX_PANIC);

      sleep(MY_WAIT_FOR_USER_TO_FIX_PANIC);

      continue;

    }

    if ((writenbytes && writenbytes != (size_t) -1) || my_errno == EINTR)

      continue;					/* Retry */

#endif

    if (MyFlags & (MY_NABP | MY_FNABP))

    {

      if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))

      {

	my_error(EE_WRITE, MYF(ME_BELL | ME_WAITTANG),

		 my_filename(Filedes),my_errno);

      }

      return(MY_FILE_ERROR);		/* Error on read */

    }

    else

      break;					/* Return bytes written */

  }

  if (MyFlags & (MY_NABP | MY_FNABP))

    return(0);			/* Want only errors */

  return(writenbytes+written); /* purecov: inspected */

} /* my_pwrite */