~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 "mysys_priv.h"

#include "mysys_err.h"

#include <errno.h>

/*

  Read a chunk of bytes from a file with retry's if needed

  The parameters are:

    File descriptor

    Buffer to hold at least Count bytes

    Bytes to read

    Flags on what to do on error

    Return:

      -1 on error

      0  if flag has bits MY_NABP or MY_FNABP set

      N  number of bytes read.

*/

size_t my_read(File Filedes, unsigned char *Buffer, size_t Count, myf MyFlags)

{

  size_t readbytes, save_count;

  save_count= Count;

  for (;;)

  {

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

    if ((readbytes= read(Filedes, Buffer, Count)) != Count)

    {

      my_errno= errno ? errno : -1;

      if ((readbytes == 0 || (int) readbytes == -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)) && !(MyFlags & MY_FULL_IO)))

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

      if (readbytes != (size_t) -1 && (MyFlags & MY_FULL_IO))

      {

        Buffer+= readbytes;

        Count-= readbytes;

        continue;

      }

    }

    if (MyFlags & (MY_NABP | MY_FNABP))

      readbytes= 0;			/* Ok on read */

    else if (MyFlags & MY_FULL_IO)

      readbytes= save_count;

    break;

  }

  return(readbytes);

} /* my_read */