/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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; either version 2 of the License, or
   (at your option) any later version.

   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 */

	/* Functions to handle fixed-length-records */

#include "isamdef.h"


int _nisam_write_static_record(N_INFO *info, const byte *record)
{
  uchar temp[4];				/* Not sizeof(long) */

  if (info->s->state.dellink != NI_POS_ERROR)
  {
    ulong filepos=info->s->state.dellink;
    info->rec_cache.seek_not_done=1;		/* We have done a seek */
    VOID(my_seek(info->dfile,info->s->state.dellink+1,MY_SEEK_SET,MYF(0)));

    if (my_read(info->dfile,(char*) &temp[0],sizeof(temp), MYF(MY_NABP)))
      goto err;
    info->s->state.dellink=uint4korr(temp);
    if (info->s->state.dellink == (uint32) ~0)	/* Fix for 64 bit long */
      info->s->state.dellink=NI_POS_ERROR;
    info->s->state.del--;
    info->s->state.empty-=info->s->base.reclength;
    VOID(my_seek(info->dfile,filepos,MY_SEEK_SET,MYF(0)));
    if (my_write(info->dfile, (char*) record, info->s->base.reclength,
		 MYF(MY_NABP)))
      goto err;
  }
  else
  {
    if (info->s->state.data_file_length > info->s->base.max_data_file_length)
    {
      my_errno=HA_ERR_RECORD_FILE_FULL;
      return(2);
    }
    if (info->opt_flag & WRITE_CACHE_USED)
    {				/* Cash in use */
      if (my_b_write(&info->rec_cache, (byte*) record, info->s->base.reclength))
	goto err;
    }
    else
    {
      info->rec_cache.seek_not_done=1;		/* We have done a seek */
      VOID(my_seek(info->dfile,info->s->state.data_file_length,
		   MY_SEEK_SET,MYF(0)));
      if (my_write(info->dfile,(char*) record,info->s->base.reclength,
		   MYF(MY_NABP | MY_WAIT_IF_FULL)))
	goto err;
    }
    info->s->state.data_file_length+=info->s->base.reclength;
    info->s->state.splitt++;
  }
  return 0;
 err:
  return 1;
}

int _nisam_update_static_record(N_INFO *info, ulong pos, const byte *record)
{
  info->rec_cache.seek_not_done=1;		/* We have done a seek */
  VOID(my_seek(info->dfile,pos,MY_SEEK_SET,MYF(0)));
  return (my_write(info->dfile,(char*) record,info->s->base.reclength,
		   MYF(MY_NABP)) != 0);
}


int _nisam_delete_static_record(N_INFO *info)
{
  uchar temp[5];				/* 1+sizeof(uint32) */

  info->s->state.del++;
  info->s->state.empty+=info->s->base.reclength;
  temp[0]= '\0';			/* Mark that record is deleted */
  int4store(temp+1,info->s->state.dellink);
  info->s->state.dellink = info->lastpos;
  info->rec_cache.seek_not_done=1;
  VOID(my_seek(info->dfile,info->lastpos,MY_SEEK_SET,MYF(0)));
  return (my_write(info->dfile,(byte*) temp,(uint) sizeof(temp),
		   MYF(MY_NABP)) != 0);
}


int _nisam_cmp_static_record(register N_INFO *info, register const byte *old)
{
  DBUG_ENTER("_nisam_rectest");

  /* We are going to do changes; dont let anybody disturb */
  dont_break();				/* Dont allow SIGHUP or SIGINT */

  if (info->opt_flag & WRITE_CACHE_USED)
  {
    if (flush_io_cache(&info->rec_cache))
    {
      DBUG_RETURN(-1);
    }
    info->rec_cache.seek_not_done=1;		/* We have done a seek */
  }

  if ((info->opt_flag & READ_CHECK_USED))
  {						/* If check isn't disabled  */
    info->rec_cache.seek_not_done=1;		/* We have done a seek */
    VOID(my_seek(info->dfile,info->lastpos,MY_SEEK_SET,MYF(0)));
    if (my_read(info->dfile, (char*) info->rec_buff, info->s->base.reclength,
		MYF(MY_NABP)))
      DBUG_RETURN(-1);
    if (memcmp((byte*) info->rec_buff, (byte*) old,
	       (uint) info->s->base.reclength))
    {
      DBUG_DUMP("read",old,info->s->base.reclength);
      DBUG_DUMP("disk",info->rec_buff,info->s->base.reclength);
      my_errno=HA_ERR_RECORD_CHANGED;		/* Record have changed */
      DBUG_RETURN(1);
    }
  }
  DBUG_RETURN(0);
}

	/* Read a fixed-length-record */
	/* Returns 0 if Ok. */
	/*	   1 if record is deleted */
	/*	  MY_FILE_ERROR on read-error or locking-error */

int _nisam_read_static_record(register N_INFO *info, register ulong pos,
			   register byte *record)
{
  int error;

  if (pos != NI_POS_ERROR)
  {
    if (info->opt_flag & WRITE_CACHE_USED &&
	info->rec_cache.pos_in_file <= pos &&
	flush_io_cache(&info->rec_cache))
      return(-1);
    info->rec_cache.seek_not_done=1;	/* We have done a seek */

    error=my_pread(info->dfile,(char*) record,info->s->base.reclength,
		   pos,MYF(MY_NABP)) != 0;
    if (info->s->r_locks == 0 && info->s->w_locks == 0)
      VOID(_nisam_writeinfo(info,0));
    if (! error)
    {
      if (!*record) return(1);		/* Record is deleted */
      info->update|= HA_STATE_AKTIV;	/* Record is read */
      my_errno=HA_ERR_RECORD_DELETED;
      return(0);
    }
    return(-1);				/* Error on read */
  }
  VOID(_nisam_writeinfo(info,0));	/* No such record */
  return(-1);
} /* _nisam_read_record */


int _nisam_read_rnd_static_record(N_INFO *info, byte *buf,
				  register ulong filepos,
				  int skipp_deleted_blocks)
{
  int locked,error,cache_read;
  uint cache_length;
  ISAM_SHARE *share=info->s;
  DBUG_ENTER("_nisam_read_rnd_static_record");

  cache_read=0;
  LINT_INIT(cache_length);
  if (info->opt_flag & WRITE_CACHE_USED &&
      (info->rec_cache.pos_in_file <= filepos || skipp_deleted_blocks) &&
      flush_io_cache(&info->rec_cache))
    DBUG_RETURN(-1);
  if (info->opt_flag & READ_CACHE_USED)
  {						/* Cash in use */
    if (filepos == my_b_tell(&info->rec_cache) &&
	(skipp_deleted_blocks || !filepos))
    {
      cache_read=1;				/* Read record using cache */
      cache_length=(uint) (info->rec_cache.read_end - info->rec_cache.read_pos);
    }
    else
      info->rec_cache.seek_not_done=1;		/* Filepos is changed */
  }
#ifndef NO_LOCKING
  locked=0;
  if (info->lock_type == F_UNLCK)
  {
    if (filepos >= share->state.data_file_length)
    {						/* Test if new records */
      if (_nisam_readinfo(info,F_RDLCK,0))
	DBUG_RETURN(-1);
      locked=1;
    }
    else
    {						/* We don't nead new info */
#ifndef UNSAFE_LOCKING
      if ((! cache_read || share->base.reclength > cache_length) &&
	  share->r_locks == 0 && share->w_locks == 0)
      {						/* record not in cache */
	if (my_lock(share->kfile,F_RDLCK,0L,F_TO_EOF,
		    MYF(MY_SEEK_NOT_DONE) | info->lock_wait))
	  DBUG_RETURN(-1);
	locked=1;
      }
#else
      info->tmp_lock_type=F_RDLCK;
#endif
    }
  }
#endif
  if (filepos >= share->state.data_file_length)
  {
#ifndef NO_LOCKING
    DBUG_PRINT("test",("filepos: %ld (%ld)  records: %ld  del: %ld",
		       filepos/share->base.reclength,filepos,
		       share->state.records, share->state.del));
    VOID(_nisam_writeinfo(info,0));
#endif
    my_errno=HA_ERR_END_OF_FILE;
    DBUG_RETURN(-1);
  }
  info->lastpos= filepos;
  info->nextpos= filepos+share->base.reclength;

  if (! cache_read)			/* No cacheing */
  {
    error=_nisam_read_static_record(info,filepos,buf);
    if (error > 0)
      my_errno=HA_ERR_RECORD_DELETED;
    DBUG_RETURN(error);
  }

	/* Read record with cacheing */
  error=my_b_read(&info->rec_cache,(byte*) buf,share->base.reclength);

#ifndef NO_LOCKING
  if (locked)
    VOID(_nisam_writeinfo(info,0));		/* Unlock keyfile */
#endif
  if (!error)
  {
    if (!buf[0])
    {						/* Record is removed */
      my_errno=HA_ERR_RECORD_DELETED;
      DBUG_RETURN(1);
    }
						/* Found and may be updated */
    info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED;
    DBUG_RETURN(0);
  }
  if (info->rec_cache.error != -1 || my_errno == 0)
    my_errno=HA_ERR_WRONG_IN_RECORD;
  DBUG_RETURN(-1);				/* Something wrong (EOF?) */
}