~drizzle-trunk/drizzle/development

/* Copyright (C) 2000-2004, 2006 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 */

/* Read and write key blocks */

#include "myisam_priv.h"

using namespace drizzled;

	/* Fetch a key-page in memory */

unsigned char *_mi_fetch_keypage(register MI_INFO *info, MI_KEYDEF *keyinfo,

			 internal::my_off_t page, int level,

                         unsigned char *buff, int return_buffer)

{

  unsigned char *tmp;

  uint32_t page_size;

  tmp=(unsigned char*) key_cache_read(info->s->key_cache,

                             info->s->kfile, page, level, (unsigned char*) buff,

			     (uint) keyinfo->block_length,

			     (uint) keyinfo->block_length,

			     return_buffer);

  if (tmp == info->buff)

    info->buff_used=1;

  else if (!tmp)

  {

    info->last_keypage=HA_OFFSET_ERROR;

    mi_print_error(info->s, HA_ERR_CRASHED);

    errno=HA_ERR_CRASHED;

    return(0);

  }

  info->last_keypage=page;

  page_size=mi_getint(tmp);

  if (page_size < 4 || page_size > keyinfo->block_length)

  {

    info->last_keypage = HA_OFFSET_ERROR;

    mi_print_error(info->s, HA_ERR_CRASHED);

    errno = HA_ERR_CRASHED;

    tmp = 0;

  }

  return(tmp);

} /* _mi_fetch_keypage */

	/* Write a key-page on disk */

int _mi_write_keypage(register MI_INFO *info, register MI_KEYDEF *keyinfo,

		      internal::my_off_t page, int level, unsigned char *buff)

{

  register uint32_t length;

#ifndef FAST					/* Safety check */

  if (page < info->s->base.keystart ||

      page+keyinfo->block_length > info->state->key_file_length ||

      (page & (MI_MIN_KEY_BLOCK_LENGTH-1)))

  {

    errno=EINVAL;

    return((-1));

  }

#endif

  if ((length=keyinfo->block_length) > IO_SIZE*2 &&

      info->state->key_file_length != page+length)

    length= ((mi_getint(buff)+IO_SIZE-1) & (uint) ~(IO_SIZE-1));

#ifdef HAVE_purify

  {

    length=mi_getint(buff);

    memset(buff+length, 0, keyinfo->block_length-length);

    length=keyinfo->block_length;

  }

#endif

  return((key_cache_write(info->s->key_cache,

                         info->s->kfile,page, level, (unsigned char*) buff,length,

			 (uint) keyinfo->block_length,

			 (int) ((info->lock_type != F_UNLCK) ||

				info->s->delay_key_write))));

} /* mi_write_keypage */

	/* Remove page from disk */

int _mi_dispose(register MI_INFO *info, MI_KEYDEF *keyinfo, internal::my_off_t pos,

                int level)

{

  internal::my_off_t old_link;

  unsigned char buff[8];

  old_link= info->s->state.key_del[keyinfo->block_size_index];

  info->s->state.key_del[keyinfo->block_size_index]= pos;

  mi_sizestore(buff,old_link);

  info->s->state.changed|= STATE_NOT_SORTED_PAGES;

  return(key_cache_write(info->s->key_cache,

                              info->s->kfile, pos , level, buff,

			      sizeof(buff),

			      (uint) keyinfo->block_length,

			      (int) (info->lock_type != F_UNLCK)));

} /* _mi_dispose */

	/* Make new page on disk */

internal::my_off_t _mi_new(register MI_INFO *info, MI_KEYDEF *keyinfo, int level)

{

  internal::my_off_t pos;

  unsigned char buff[8];

  if ((pos= info->s->state.key_del[keyinfo->block_size_index]) ==

      HA_OFFSET_ERROR)

  {

    if (info->state->key_file_length >=

	info->s->base.max_key_file_length - keyinfo->block_length)

    {

      errno=HA_ERR_INDEX_FILE_FULL;

      return(HA_OFFSET_ERROR);

    }

    pos=info->state->key_file_length;

    info->state->key_file_length+= keyinfo->block_length;

  }

  else

  {

    if (!key_cache_read(info->s->key_cache,

                        info->s->kfile, pos, level,

			buff,

			(uint) sizeof(buff),

			(uint) keyinfo->block_length,0))

      pos= HA_OFFSET_ERROR;

    else

      info->s->state.key_del[keyinfo->block_size_index]= mi_sizekorr(buff);

  }

  info->s->state.changed|= STATE_NOT_SORTED_PAGES;

  return(pos);

} /* _mi_new */