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570 lines
20 KiB
570 lines
20 KiB
3 years ago
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/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996, 1997, 1998, 1999
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* Sleepycat Software. All rights reserved.
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*
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* @(#)db_page.h 11.2 (Sleepycat) 8/19/99
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*/
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#ifndef _DB_PAGE_H_
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#define _DB_PAGE_H_
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/*
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* DB page formats.
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*
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* !!!
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* This implementation requires that values within the following structures
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* NOT be padded -- note, ANSI C permits random padding within structures.
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* If your compiler pads randomly you can just forget ever making DB run on
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* your system. In addition, no data type can require larger alignment than
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* its own size, e.g., a 4-byte data element may not require 8-byte alignment.
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*
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* Note that key/data lengths are often stored in db_indx_t's -- this is
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* not accidental, nor does it limit the key/data size. If the key/data
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* item fits on a page, it's guaranteed to be small enough to fit into a
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* db_indx_t, and storing it in one saves space.
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*/
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#define PGNO_INVALID 0 /* Invalid page number in any database. */
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#define PGNO_BASE_MD 0 /* Base database: metadata page number. */
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/* Page types. */
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#define P_INVALID 0 /* Invalid page type. */
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#define P_DUPLICATE 1 /* Duplicate. */
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#define P_HASH 2 /* Hash. */
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#define P_IBTREE 3 /* Btree internal. */
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#define P_IRECNO 4 /* Recno internal. */
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#define P_LBTREE 5 /* Btree leaf. */
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#define P_LRECNO 6 /* Recno leaf. */
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#define P_OVERFLOW 7 /* Overflow. */
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#define P_HASHMETA 8 /* Hash metadata page. */
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#define P_BTREEMETA 9 /* Btree metadata page. */
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#define P_QAMMETA 10 /* Queue metadata page. */
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#define P_QAMDATA 11 /* Queue data page. */
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/*
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* These page types are artificially built by io compression
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* when trying to access a page number that is not the
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* beginning of a page compression chain.
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* Utilities that walk the file by incrementing the page
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* number can make use of these page types or safely consider
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* them as equivalent to P_INVALID.
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*/
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#define P_CMPR_INTERNAL 12 /* Compression internal page. */
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#define P_CMPR_FREE 13 /* Compression free page. */
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/*
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* When we create pages in mpool, we ask mpool to clear some number of bytes
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* in the header. This number must be at least as big as the regular page
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* headers and cover enough of the btree and hash meta-data pages to obliterate
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* the page type.
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*/
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#define DB_PAGE_DB_LEN 32
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#define DB_PAGE_QUEUE_LEN 0
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/************************************************************************
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GENERIC METADATA PAGE HEADER
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*
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* !!!
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* The magic and version numbers have to be in the same place in all versions
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* of the metadata page as the application may not have upgraded the database.
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************************************************************************/
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typedef struct _dbmeta {
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DB_LSN lsn; /* 00-07: LSN. */
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db_pgno_t pgno; /* 08-11: Current page number. */
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u_int32_t magic; /* 12-15: Magic number. */
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u_int32_t version; /* 16-19: Version. */
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u_int32_t pagesize; /* 20-23: Pagesize. */
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u_int8_t unused1[1]; /* 24: Unused. */
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u_int8_t type; /* 25: Page type. */
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u_int8_t unused2[2]; /* 26-27: Unused. */
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u_int32_t free; /* 28-31: Free list page number. */
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u_int32_t flags; /* 32-35: Flags: unique to each AM. */
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/* 36-55: Unique file ID. */
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u_int8_t uid[DB_FILE_ID_LEN];
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} DBMETA;
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/************************************************************************
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BTREE METADATA PAGE LAYOUT
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************************************************************************/
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typedef struct _btmeta {
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#define BTM_DUP 0x001 /* Duplicates. */
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#define BTM_RECNO 0x002 /* Recno tree. */
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#define BTM_RECNUM 0x004 /* Btree: maintain record count. */
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#define BTM_FIXEDLEN 0x008 /* Recno: fixed length records. */
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#define BTM_RENUMBER 0x010 /* Recno: renumber on insert/delete. */
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#define BTM_SUBDB 0x020 /* Subdatabases. */
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#define BTM_MASK 0x03f
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DBMETA dbmeta; /* 00-55: Generic meta-data header. */
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u_int32_t maxkey; /* 56-59: Btree: Maxkey. */
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u_int32_t minkey; /* 60-63: Btree: Minkey. */
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u_int32_t re_len; /* 64-67: Recno: fixed-length record length. */
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u_int32_t re_pad; /* 68-71: Recno: fixed-length record pad. */
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u_int32_t root; /* 72-75: Root page. */
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/*
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* Minimum page size is 128.
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*/
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} BTMETA;
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/************************************************************************
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HASH METADATA PAGE LAYOUT
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************************************************************************/
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typedef struct _hashmeta {
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#define DB_HASH_DUP 0x01 /* Duplicates. */
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#define DB_HASH_SUBDB 0x02 /* Subdatabases. */
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DBMETA dbmeta; /* 00-55: Generic meta-data page header. */
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u_int32_t max_bucket; /* 56-59: ID of Maximum bucket in use */
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u_int32_t high_mask; /* 60-63: Modulo mask into table */
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u_int32_t low_mask; /* 64-67: Modulo mask into table lower half */
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u_int32_t ffactor; /* 68-71: Fill factor */
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u_int32_t nelem; /* 72-75: Number of keys in hash table */
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u_int32_t h_charkey; /* 76-79: Value of hash(CHARKEY) */
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#define NCACHED 32 /* number of spare points */
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/* 80-207: Spare pages for overflow */
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u_int32_t spares[NCACHED];
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/*
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* Minimum page size is 256.
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*/
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} HMETA;
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/************************************************************************
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QUEUE METADATA PAGE LAYOUT
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************************************************************************/
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/*
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* QAM Meta data page structure
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*
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*/
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typedef struct _qmeta {
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DBMETA dbmeta; /* 00-55: Generic meta-data header. */
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u_int32_t start; /* 56-59: Start offset. */
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u_int32_t first_recno; /* 60-63: First not deleted record. */
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u_int32_t cur_recno; /* 64-67: Last recno allocated. */
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u_int32_t re_len; /* 68-71: Fixed-length record length. */
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u_int32_t re_pad; /* 72-75: Fixed-length record pad. */
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u_int32_t rec_page; /* 76-79: Records Per Page. */
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/*
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* Minimum page size is 128.
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*/
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} QMETA;
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/************************************************************************
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BTREE/HASH MAIN PAGE LAYOUT
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************************************************************************/
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/*
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* +-----------------------------------+
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* | lsn | pgno | prev pgno |
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* +-----------------------------------+
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* | next pgno | entries | hf offset |
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* +-----------------------------------+
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* | level | type | index |
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* +-----------------------------------+
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* | index | free --> |
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* +-----------+-----------------------+
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* | F R E E A R E A |
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* +-----------------------------------+
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* | <-- free | item |
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* +-----------------------------------+
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* | item | item | item |
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* +-----------------------------------+
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*
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* sizeof(PAGE) == 26 bytes, and the following indices are guaranteed to be
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* two-byte aligned.
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*
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* For hash and btree leaf pages, index items are paired, e.g., inp[0] is the
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* key for inp[1]'s data. All other types of pages only contain single items.
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*/
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typedef struct _db_page {
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DB_LSN lsn; /* 00-07: Log sequence number. */
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db_pgno_t pgno; /* 08-11: Current page number. */
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db_pgno_t prev_pgno; /* 12-15: Previous page number. */
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db_pgno_t next_pgno; /* 16-19: Next page number. */
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db_indx_t entries; /* 20-21: Number of items on the page. */
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db_indx_t hf_offset; /* 22-23: High free byte page offset. */
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/*
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* The btree levels are numbered from the leaf to the root, starting
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* with 1, so the leaf is level 1, its parent is level 2, and so on.
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* We maintain this level on all btree pages, but the only place that
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* we actually need it is on the root page. It would not be difficult
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* to hide the byte on the root page once it becomes an internal page,
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* so we could get this byte back if we needed it for something else.
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*/
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#define LEAFLEVEL 1
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#define MAXBTREELEVEL 255
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u_int8_t level; /* 24: Btree tree level. */
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u_int8_t type; /* 25: Page type. */
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db_indx_t inp[1]; /* Variable length index of items. */
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} PAGE;
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/************************************************************************
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QUEUE MAIN PAGE LAYOUT
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************************************************************************/
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typedef struct _qpage {
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DB_LSN lsn; /* 00-07: Log sequence number. */
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db_pgno_t pgno; /* 08-11: Current page number. */
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u_int32_t unused0[3]; /* 12-23: Unused. */
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u_int8_t unused1[1]; /* 24: Unused. */
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u_int8_t type; /* 25: Page type. */
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u_int8_t unused2[2]; /* 26-27: Unused. */
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} QPAGE;
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/* Main page element macros. */
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#define LSN(p) (((PAGE *)p)->lsn)
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#define PGNO(p) (((PAGE *)p)->pgno)
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#define PREV_PGNO(p) (((PAGE *)p)->prev_pgno)
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#define NEXT_PGNO(p) (((PAGE *)p)->next_pgno)
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#define NUM_ENT(p) (((PAGE *)p)->entries)
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#define HOFFSET(p) (((PAGE *)p)->hf_offset)
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#define LEVEL(p) (((PAGE *)p)->level)
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#define TYPE(p) (((PAGE *)p)->type)
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/*
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* !!!
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* The next_pgno and prev_pgno fields are not maintained for btree and recno
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* internal pages. It's a minor performance improvement, and more, it's
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* hard to do when deleting internal pages, and it decreases the chance of
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* deadlock during deletes and splits.
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*
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* !!!
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* The btree/recno access method needs db_recno_t bytes of space on the root
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* page to specify how many records are stored in the tree. (The alternative
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* is to store the number of records in the meta-data page, which will create
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* a second hot spot in trees being actively modified, or recalculate it from
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* the BINTERNAL fields on each access.) Overload the prev_pgno field.
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*/
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#define RE_NREC(p) \
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(TYPE(p) == P_LBTREE ? NUM_ENT(p) / 2 : \
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TYPE(p) == P_LRECNO ? NUM_ENT(p) : PREV_PGNO(p))
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#define RE_NREC_ADJ(p, adj) \
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PREV_PGNO(p) += adj;
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#define RE_NREC_SET(p, num) \
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PREV_PGNO(p) = num;
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/*
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* Initialize a page.
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*
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* !!!
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* Don't modify the page's LSN, code depends on it being unchanged after a
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* P_INIT call.
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*/
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#define P_INIT(pg, pg_size, n, pg_prev, pg_next, btl, pg_type) do { \
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PGNO(pg) = n; \
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PREV_PGNO(pg) = pg_prev; \
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NEXT_PGNO(pg) = pg_next; \
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NUM_ENT(pg) = 0; \
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HOFFSET(pg) = pg_size; \
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LEVEL(pg) = btl; \
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TYPE(pg) = pg_type; \
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} while (0)
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/* Page header length (offset to first index). */
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#define P_OVERHEAD (SSZA(PAGE, inp))
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/* First free byte. */
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#define LOFFSET(pg) (P_OVERHEAD + NUM_ENT(pg) * sizeof(db_indx_t))
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/* Free space on a regular page. */
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#define P_FREESPACE(pg) (HOFFSET(pg) - LOFFSET(pg))
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/* Get a pointer to the bytes at a specific index. */
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#define P_ENTRY(pg, indx) ((u_int8_t *)pg + ((PAGE *)pg)->inp[indx])
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/************************************************************************
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OVERFLOW PAGE LAYOUT
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************************************************************************/
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/*
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* Overflow items are referenced by HOFFPAGE and BOVERFLOW structures, which
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* store a page number (the first page of the overflow item) and a length
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* (the total length of the overflow item). The overflow item consists of
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* some number of overflow pages, linked by the next_pgno field of the page.
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* A next_pgno field of PGNO_INVALID flags the end of the overflow item.
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*
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* Overflow page overloads:
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* The amount of overflow data stored on each page is stored in the
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* hf_offset field.
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*
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* The implementation reference counts overflow items as it's possible
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* for them to be promoted onto btree internal pages. The reference
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* count is stored in the entries field.
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*/
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#define OV_LEN(p) (((PAGE *)p)->hf_offset)
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#define OV_REF(p) (((PAGE *)p)->entries)
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/* Maximum number of bytes that you can put on an overflow page. */
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#define P_MAXSPACE(psize) ((psize) - P_OVERHEAD)
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/* Free space on an overflow page. */
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#define P_OVFLSPACE(psize, pg) (P_MAXSPACE(psize) - HOFFSET(pg))
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/************************************************************************
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HASH PAGE LAYOUT
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************************************************************************/
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/* Each index references a group of bytes on the page. */
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#define H_KEYDATA 1 /* Key/data item. */
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#define H_DUPLICATE 2 /* Duplicate key/data item. */
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#define H_OFFPAGE 3 /* Overflow key/data item. */
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#define H_OFFDUP 4 /* Overflow page of duplicates. */
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/*
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* !!!
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* Items on hash pages are (potentially) unaligned, so we can never cast the
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* (page + offset) pointer to an HKEYDATA, HOFFPAGE or HOFFDUP structure, as
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* we do with B+tree on-page structures. Because we frequently want the type
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* field, it requires no alignment, and it's in the same location in all three
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* structures, there's a pair of macros.
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*/
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#define HPAGE_PTYPE(p) (*(u_int8_t *)p)
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#define HPAGE_TYPE(pg, indx) (*P_ENTRY(pg, indx))
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/*
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* The first and second types are H_KEYDATA and H_DUPLICATE, represented
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* by the HKEYDATA structure:
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*
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* +-----------------------------------+
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* | type | key/data ... |
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* +-----------------------------------+
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*
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* For duplicates, the data field encodes duplicate elements in the data
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* field:
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||
|
|
*
|
||
|
|
* +---------------------------------------------------------------+
|
||
|
|
* | type | len1 | element1 | len1 | len2 | element2 | len2 |
|
||
|
|
* +---------------------------------------------------------------+
|
||
|
|
*
|
||
|
|
* Thus, by keeping track of the offset in the element, we can do both
|
||
|
|
* backward and forward traversal.
|
||
|
|
*/
|
||
|
|
typedef struct _hkeydata {
|
||
|
|
u_int8_t type; /* 00: Page type. */
|
||
|
|
u_int8_t data[1]; /* Variable length key/data item. */
|
||
|
|
} HKEYDATA;
|
||
|
|
#define HKEYDATA_DATA(p) (((u_int8_t *)p) + SSZA(HKEYDATA, data))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The length of any HKEYDATA item. Note that indx is an element index,
|
||
|
|
* not a PAIR index.
|
||
|
|
*/
|
||
|
|
#define LEN_HITEM(pg, pgsize, indx) \
|
||
|
|
(((indx) == 0 ? pgsize : pg->inp[indx - 1]) - pg->inp[indx])
|
||
|
|
|
||
|
|
#define LEN_HKEYDATA(pg, psize, indx) \
|
||
|
|
(((indx) == 0 ? psize : pg->inp[indx - 1]) - \
|
||
|
|
pg->inp[indx] - HKEYDATA_SIZE(0))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Page space required to add a new HKEYDATA item to the page, with and
|
||
|
|
* without the index value.
|
||
|
|
*/
|
||
|
|
#define HKEYDATA_SIZE(len) \
|
||
|
|
((len) + SSZA(HKEYDATA, data))
|
||
|
|
#define HKEYDATA_PSIZE(len) \
|
||
|
|
(HKEYDATA_SIZE(len) + sizeof(db_indx_t))
|
||
|
|
|
||
|
|
/* Put a HKEYDATA item at the location referenced by a page entry. */
|
||
|
|
#define PUT_HKEYDATA(pe, kd, len, type) { \
|
||
|
|
((HKEYDATA *)pe)->type = type; \
|
||
|
|
memcpy((u_int8_t *)pe + sizeof(u_int8_t), kd, len); \
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Macros the describe the page layout in terms of key-data pairs.
|
||
|
|
* The use of "pindex" indicates that the argument is the index
|
||
|
|
* expressed in pairs instead of individual elements.
|
||
|
|
*/
|
||
|
|
#define H_NUMPAIRS(pg) (NUM_ENT(pg) / 2)
|
||
|
|
#define H_KEYINDEX(pindx) (2 * (pindx))
|
||
|
|
#define H_DATAINDEX(pindx) ((2 * (pindx)) + 1)
|
||
|
|
#define H_PAIRKEY(pg, pindx) P_ENTRY(pg, H_KEYINDEX(pindx))
|
||
|
|
#define H_PAIRDATA(pg, pindx) P_ENTRY(pg, H_DATAINDEX(pindx))
|
||
|
|
#define H_PAIRSIZE(pg, psize, pindx) \
|
||
|
|
(LEN_HITEM(pg, psize, H_KEYINDEX(pindx)) + \
|
||
|
|
LEN_HITEM(pg, psize, H_DATAINDEX(pindx)))
|
||
|
|
#define LEN_HDATA(p, psize, pindx) LEN_HKEYDATA(p, psize, H_DATAINDEX(pindx))
|
||
|
|
#define LEN_HKEY(p, psize, pindx) LEN_HKEYDATA(p, psize, H_KEYINDEX(pindx))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The third type is the H_OFFPAGE, represented by the HOFFPAGE structure:
|
||
|
|
*/
|
||
|
|
typedef struct _hoffpage {
|
||
|
|
u_int8_t type; /* 00: Page type and delete flag. */
|
||
|
|
u_int8_t unused[3]; /* 01-03: Padding, unused. */
|
||
|
|
db_pgno_t pgno; /* 04-07: Offpage page number. */
|
||
|
|
u_int32_t tlen; /* 08-11: Total length of item. */
|
||
|
|
} HOFFPAGE;
|
||
|
|
|
||
|
|
#define HOFFPAGE_PGNO(p) (((u_int8_t *)p) + SSZ(HOFFPAGE, pgno))
|
||
|
|
#define HOFFPAGE_TLEN(p) (((u_int8_t *)p) + SSZ(HOFFPAGE, tlen))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Page space required to add a new HOFFPAGE item to the page, with and
|
||
|
|
* without the index value.
|
||
|
|
*/
|
||
|
|
#define HOFFPAGE_SIZE (sizeof(HOFFPAGE))
|
||
|
|
#define HOFFPAGE_PSIZE (HOFFPAGE_SIZE + sizeof(db_indx_t))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The fourth type is H_OFFDUP represented by the HOFFDUP structure:
|
||
|
|
*/
|
||
|
|
typedef struct _hoffdup {
|
||
|
|
u_int8_t type; /* 00: Page type and delete flag. */
|
||
|
|
u_int8_t unused[3]; /* 01-03: Padding, unused. */
|
||
|
|
db_pgno_t pgno; /* 04-07: Offpage page number. */
|
||
|
|
} HOFFDUP;
|
||
|
|
#define HOFFDUP_PGNO(p) (((u_int8_t *)p) + SSZ(HOFFDUP, pgno))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Page space required to add a new HOFFDUP item to the page, with and
|
||
|
|
* without the index value.
|
||
|
|
*/
|
||
|
|
#define HOFFDUP_SIZE (sizeof(HOFFDUP))
|
||
|
|
#define HOFFDUP_PSIZE (HOFFDUP_SIZE + sizeof(db_indx_t))
|
||
|
|
|
||
|
|
/************************************************************************
|
||
|
|
BTREE PAGE LAYOUT
|
||
|
|
************************************************************************/
|
||
|
|
|
||
|
|
/* Each index references a group of bytes on the page. */
|
||
|
|
#define B_KEYDATA 1 /* Key/data item. */
|
||
|
|
#define B_DUPLICATE 2 /* Duplicate key/data item. */
|
||
|
|
#define B_OVERFLOW 3 /* Overflow key/data item. */
|
||
|
|
|
||
|
|
/*
|
||
|
|
* We have to store a deleted entry flag in the page. The reason is complex,
|
||
|
|
* but the simple version is that we can't delete on-page items referenced by
|
||
|
|
* a cursor -- the return order of subsequent insertions might be wrong. The
|
||
|
|
* delete flag is an overload of the top bit of the type byte.
|
||
|
|
*/
|
||
|
|
#define B_DELETE (0x80)
|
||
|
|
#define B_DCLR(t) (t) &= ~B_DELETE
|
||
|
|
#define B_DSET(t) (t) |= B_DELETE
|
||
|
|
#define B_DISSET(t) ((t) & B_DELETE)
|
||
|
|
|
||
|
|
#define B_TYPE(t) ((t) & ~B_DELETE)
|
||
|
|
#define B_TSET(t, type, deleted) { \
|
||
|
|
(t) = (type); \
|
||
|
|
if (deleted) \
|
||
|
|
B_DSET(t); \
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The first type is B_KEYDATA, represented by the BKEYDATA structure:
|
||
|
|
*/
|
||
|
|
typedef struct _bkeydata {
|
||
|
|
db_indx_t len; /* 00-01: Key/data item length. */
|
||
|
|
u_int8_t type; /* 02: Page type AND DELETE FLAG. */
|
||
|
|
u_int8_t data[1]; /* Variable length key/data item. */
|
||
|
|
} BKEYDATA;
|
||
|
|
|
||
|
|
/* Get a BKEYDATA item for a specific index. */
|
||
|
|
#define GET_BKEYDATA(pg, indx) \
|
||
|
|
((BKEYDATA *)P_ENTRY(pg, indx))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Page space required to add a new BKEYDATA item to the page, with and
|
||
|
|
* without the index value.
|
||
|
|
*/
|
||
|
|
#define BKEYDATA_SIZE(len) \
|
||
|
|
ALIGN((len) + SSZA(BKEYDATA, data), 4)
|
||
|
|
#define BKEYDATA_PSIZE(len) \
|
||
|
|
(BKEYDATA_SIZE(len) + sizeof(db_indx_t))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The second and third types are B_DUPLICATE and B_OVERFLOW, represented
|
||
|
|
* by the BOVERFLOW structure.
|
||
|
|
*/
|
||
|
|
typedef struct _boverflow {
|
||
|
|
db_indx_t unused1; /* 00-01: Padding, unused. */
|
||
|
|
u_int8_t type; /* 02: Page type AND DELETE FLAG. */
|
||
|
|
u_int8_t unused2; /* 03: Padding, unused. */
|
||
|
|
db_pgno_t pgno; /* 04-07: Next page number. */
|
||
|
|
u_int32_t tlen; /* 08-11: Total length of item. */
|
||
|
|
} BOVERFLOW;
|
||
|
|
|
||
|
|
/* Get a BOVERFLOW item for a specific index. */
|
||
|
|
#define GET_BOVERFLOW(pg, indx) \
|
||
|
|
((BOVERFLOW *)P_ENTRY(pg, indx))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Page space required to add a new BOVERFLOW item to the page, with and
|
||
|
|
* without the index value.
|
||
|
|
*/
|
||
|
|
#define BOVERFLOW_SIZE \
|
||
|
|
ALIGN(sizeof(BOVERFLOW), 4)
|
||
|
|
#define BOVERFLOW_PSIZE \
|
||
|
|
(BOVERFLOW_SIZE + sizeof(db_indx_t))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Btree leaf and hash page layouts group indices in sets of two, one
|
||
|
|
* for the key and one for the data. Everything else does it in sets
|
||
|
|
* of one to save space. I use the following macros so that it's real
|
||
|
|
* obvious what's going on...
|
||
|
|
*/
|
||
|
|
#define O_INDX 1
|
||
|
|
#define P_INDX 2
|
||
|
|
|
||
|
|
/************************************************************************
|
||
|
|
BTREE INTERNAL PAGE LAYOUT
|
||
|
|
************************************************************************/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Btree internal entry.
|
||
|
|
*/
|
||
|
|
typedef struct _binternal {
|
||
|
|
db_indx_t len; /* 00-01: Key/data item length. */
|
||
|
|
u_int8_t type; /* 02: Page type AND DELETE FLAG. */
|
||
|
|
u_int8_t unused; /* 03: Padding, unused. */
|
||
|
|
db_pgno_t pgno; /* 04-07: Page number of referenced page. */
|
||
|
|
db_recno_t nrecs; /* 08-11: Subtree record count. */
|
||
|
|
u_int8_t data[1]; /* Variable length key item. */
|
||
|
|
} BINTERNAL;
|
||
|
|
|
||
|
|
/* Get a BINTERNAL item for a specific index. */
|
||
|
|
#define GET_BINTERNAL(pg, indx) \
|
||
|
|
((BINTERNAL *)P_ENTRY(pg, indx))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Page space required to add a new BINTERNAL item to the page, with and
|
||
|
|
* without the index value.
|
||
|
|
*/
|
||
|
|
#define BINTERNAL_SIZE(len) \
|
||
|
|
ALIGN((len) + SSZA(BINTERNAL, data), 4)
|
||
|
|
#define BINTERNAL_PSIZE(len) \
|
||
|
|
(BINTERNAL_SIZE(len) + sizeof(db_indx_t))
|
||
|
|
|
||
|
|
/************************************************************************
|
||
|
|
RECNO INTERNAL PAGE LAYOUT
|
||
|
|
************************************************************************/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The recno internal entry.
|
||
|
|
*
|
||
|
|
* XXX
|
||
|
|
* Why not fold this into the db_indx_t structure, it's fixed length?
|
||
|
|
*/
|
||
|
|
typedef struct _rinternal {
|
||
|
|
db_pgno_t pgno; /* 00-03: Page number of referenced page. */
|
||
|
|
db_recno_t nrecs; /* 04-07: Subtree record count. */
|
||
|
|
} RINTERNAL;
|
||
|
|
|
||
|
|
/* Get a RINTERNAL item for a specific index. */
|
||
|
|
#define GET_RINTERNAL(pg, indx) \
|
||
|
|
((RINTERNAL *)P_ENTRY(pg, indx))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Page space required to add a new RINTERNAL item to the page, with and
|
||
|
|
* without the index value.
|
||
|
|
*/
|
||
|
|
#define RINTERNAL_SIZE \
|
||
|
|
ALIGN(sizeof(RINTERNAL), 4)
|
||
|
|
#define RINTERNAL_PSIZE \
|
||
|
|
(RINTERNAL_SIZE + sizeof(db_indx_t))
|
||
|
|
#endif /* _DB_PAGE_H_ */
|