FreeBSD/Linux Kernel Cross Reference
sys/fs/jfs/jfs_btree.h

     /*
      *   Copyright (c) International Business Machines Corp., 2000-2001
      *
      *   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.
    */
   #define MAXTREEHEIGHT           8
   struct btframe {        /* stack frame */
           s64 bn;                 /* 8: */
           s16 index;              /* 2: */
           s16 lastindex;          /* 2: */
           struct metapage *mp;    /* 4: */
   };                              /* (16) */
   
   struct btstack {
           struct btframe *top;
           int nsplit;
           struct btframe stack[MAXTREEHEIGHT];
   };
   
   #define BT_CLR(btstack)\
           (btstack)->top = (btstack)->stack
   
   #define BT_PUSH(BTSTACK, BN, INDEX)\
   {\
           (BTSTACK)->top->bn = BN;\
           (BTSTACK)->top->index = INDEX;\
           ++(BTSTACK)->top;\
           assert((BTSTACK)->top != &((BTSTACK)->stack[MAXTREEHEIGHT]));\
   }
   
   #define BT_POP(btstack)\
           ( (btstack)->top == (btstack)->stack ? NULL : --(btstack)->top )
   
   #define BT_STACK(btstack)\
           ( (btstack)->top == (btstack)->stack ? NULL : (btstack)->top )
   
   /* 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 */

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