/*
   *   Copyright (C) International Business Machines Corp., 2000-2004
   *
   *   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
   */
  #ifndef	_H_JFS_BTREE
  #define _H_JFS_BTREE
  
  /*
   *	jfs_btree.h: B+-tree
   *
   * JFS B+-tree (dtree and xtree) common definitions
   */
  
  /*
   *	basic btree page - btpage
   *
  struct btpage {
  	s64 next;		right sibling bn
  	s64 prev;		left sibling bn
  
  	u8 flag;
  	u8 rsrvd[7];		type specific
  	s64 self;		self address
  
  	u8 entry[4064];
  };						*/
  
  /* btpaget_t flag */
  #define BT_TYPE		0x07	/* B+-tree index */
  #define	BT_ROOT		0x01	/* root page */
  #define	BT_LEAF		0x02	/* leaf page */
  #define	BT_INTERNAL	0x04	/* internal page */
  #define	BT_RIGHTMOST	0x10	/* rightmost page */
  #define	BT_LEFTMOST	0x20	/* leftmost page */
  #define	BT_SWAPPED	0x80	/* used by fsck for endian swapping */
  
  /* btorder (in inode) */
  #define	BT_RANDOM		0x0000
  #define	BT_SEQUENTIAL		0x0001
  #define	BT_LOOKUP		0x0010
  #define	BT_INSERT		0x0020
  #define	BT_DELETE		0x0040
  
  /*
   *	btree page buffer cache access
   */
  #define BT_IS_ROOT(MP) (((MP)->xflag & COMMIT_PAGE) == 0)
  
  /* get page from buffer page */
  #define BT_PAGE(IP, MP, TYPE, ROOT)\
  	(BT_IS_ROOT(MP) ? (TYPE *)&JFS_IP(IP)->ROOT : (TYPE *)(MP)->data)
  
  /* get the page buffer and the page for specified block address */
  #define BT_GETPAGE(IP, BN, MP, TYPE, SIZE, P, RC, ROOT)\
  {\
  	if ((BN) == 0)\
  	{\
  		MP = (struct metapage *)&JFS_IP(IP)->bxflag;\
  		P = (TYPE *)&JFS_IP(IP)->ROOT;\
  		RC = 0;\
  	}\
  	else\
  	{\
  		MP = read_metapage((IP), BN, SIZE, 1);\
  		if (MP) {\
  			RC = 0;\
  			P = (MP)->data;\
  		} else {\
  			P = NULL;\
  			jfs_err("bread failed!");\
  			RC = -EIO;\
  		}\
  	}\
  }
  
  #define BT_MARK_DIRTY(MP, IP)\
  {\
  	if (BT_IS_ROOT(MP))\
  		mark_inode_dirty(IP);\
  	else\
  		mark_metapage_dirty(MP);\
  }
  
  /* put the page buffer */
  #define BT_PUTPAGE(MP)\
  {\
  	if (! BT_IS_ROOT(MP)) \
  		release_metapage(MP); \
  }
  
  
  /*
   *	btree traversal stack
   *
   * record the path traversed during the search;
   * top frame record the leaf page/entry selected.
   */
  struct btframe {	/* stack frame */
  	s64 bn;			/* 8: */
  	s16 index;		/* 2: */
  	s16 lastindex;		/* 2: unused */
  	struct metapage *mp;	/* 4/8: */
  };				/* (16/24) */
  
  struct btstack {
  	struct btframe *top;
  	int nsplit;
  	struct btframe stack[MAXTREEHEIGHT];
  };
  
  #define BT_CLR(btstack)\
  	(btstack)->top = (btstack)->stack
  
  #define BT_STACK_FULL(btstack)\
  	( (btstack)->top == &((btstack)->stack[MAXTREEHEIGHT-1]))
  
  #define BT_PUSH(BTSTACK, BN, INDEX)\
  {\
  	assert(!BT_STACK_FULL(BTSTACK));\
  	(BTSTACK)->top->bn = BN;\
  	(BTSTACK)->top->index = INDEX;\
  	++(BTSTACK)->top;\
  }
  
  #define BT_POP(btstack)\
  	( (btstack)->top == (btstack)->stack ? NULL : --(btstack)->top )
  
  #define BT_STACK(btstack)\
  	( (btstack)->top == (btstack)->stack ? NULL : (btstack)->top )
  
  static inline void BT_STACK_DUMP(struct btstack *btstack)
  {
  	int i;
  	printk("btstack dump:
  ");
  	for (i = 0; i < MAXTREEHEIGHT; i++)
  		printk(KERN_ERR "bn = %Lx, index = %d
  ",
  		       (long long)btstack->stack[i].bn,
  		       btstack->stack[i].index);
  }
  
  /* retrieve search results */
  #define BT_GETSEARCH(IP, LEAF, BN, MP, TYPE, P, INDEX, ROOT)\
  {\
  	BN = (LEAF)->bn;\
  	MP = (LEAF)->mp;\
  	if (BN)\
  		P = (TYPE *)MP->data;\
  	else\
  		P = (TYPE *)&JFS_IP(IP)->ROOT;\
  	INDEX = (LEAF)->index;\
  }
  
  /* put the page buffer of search */
  #define BT_PUTSEARCH(BTSTACK)\
  {\
  	if (! BT_IS_ROOT((BTSTACK)->top->mp))\
  		release_metapage((BTSTACK)->top->mp);\
  }
  #endif				/* _H_JFS_BTREE */