/* * Copyright 2015-2017 Leonid Yuriev * and other libmdbx authors: please see AUTHORS file. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted only as authorized by the OpenLDAP * Public License. * * A copy of this license is available in the file LICENSE in the * top-level directory of the distribution or, alternatively, at * . */ #pragma once /* *INDENT-OFF* */ /* clang-format off */ #ifndef MDBX_DEBUG # define MDBX_DEBUG 0 #endif #if MDBX_DEBUG # undef NDEBUG #endif /* Features under development */ #ifndef MDBX_DEVEL # define MDBX_DEVEL 1 #endif /*----------------------------------------------------------------------------*/ /* Should be defined before any includes */ #ifndef _GNU_SOURCE # define _GNU_SOURCE 1 #endif #ifndef _FILE_OFFSET_BITS # define _FILE_OFFSET_BITS 64 #endif #ifdef _MSC_VER # ifndef _CRT_SECURE_NO_WARNINGS # define _CRT_SECURE_NO_WARNINGS # endif #if _MSC_VER > 1800 # pragma warning(disable : 4464) /* relative include path contains '..' */ #endif #pragma warning(disable : 4710) /* 'xyz': function not inlined */ #pragma warning(disable : 4711) /* function 'xyz' selected for automatic inline expansion */ #pragma warning(disable : 4201) /* nonstandard extension used : nameless struct / union */ #pragma warning(disable : 4702) /* unreachable code */ #pragma warning(disable : 4706) /* assignment within conditional expression */ #pragma warning(disable : 4127) /* conditional expression is constant */ #pragma warning(disable : 4324) /* 'xyz': structure was padded due to alignment specifier */ #pragma warning(disable : 4310) /* cast truncates constant value */ #pragma warning(disable : 4820) /* bytes padding added after data member for aligment */ #pragma warning(disable : 4548) /* expression before comma has no effect; expected expression with side - effect */ #endif /* _MSC_VER (warnings) */ #include "./mdbx.h" #include "./defs.h" #if defined(__GNUC__) && !__GNUC_PREREQ(4,2) /* Actualy libmdbx was not tested with compilers older than GCC from RHEL6. * But you could remove this #error and try to continue at your own risk. * In such case please don't rise up an issues related ONLY to old compilers. */ # warning "libmdbx required at least GCC 4.2 compatible C/C++ compiler." #endif #if defined(__GLIBC__) && !__GLIBC_PREREQ(2,12) /* Actualy libmdbx was not tested with something older than glibc 2.12 (from RHEL6). * But you could remove this #error and try to continue at your own risk. * In such case please don't rise up an issues related ONLY to old systems. */ # warning "libmdbx required at least GLIBC 2.12." #endif #ifdef __SANITIZE_THREAD__ # warning "libmdbx don't compatible with ThreadSanitizer, you will get a lot of false-positive issues." #endif /* __SANITIZE_THREAD__ */ #include "./osal.h" /* *INDENT-ON* */ /* clang-format on */ /*----------------------------------------------------------------------------*/ /* Basic constants and types */ /* The minimum number of keys required in a database page. * Setting this to a larger value will place a smaller bound on the * maximum size of a data item. Data items larger than this size will * be pushed into overflow pages instead of being stored directly in * the B-tree node. This value used to default to 4. With a page size * of 4096 bytes that meant that any item larger than 1024 bytes would * go into an overflow page. That also meant that on average 2-3KB of * each overflow page was wasted space. The value cannot be lower than * 2 because then there would no longer be a tree structure. With this * value, items larger than 2KB will go into overflow pages, and on * average only 1KB will be wasted. */ #define MDBX_MINKEYS 2 /* A stamp that identifies a file as an MDBX file. * There's nothing special about this value other than that it is easily * recognizable, and it will reflect any byte order mismatches. */ #define MDBX_MAGIC UINT64_C(/* 56-bit prime */ 0x59659DBDEF4C11) /* The version number for a database's datafile format. */ #define MDBX_DATA_VERSION ((MDBX_DEVEL) ? 255 : 2) /* The version number for a database's lockfile format. */ #define MDBX_LOCK_VERSION ((MDBX_DEVEL) ? 255 : 2) /* handle for the DB used to track free pages. */ #define FREE_DBI 0 /* handle for the default DB. */ #define MAIN_DBI 1 /* Number of DBs in metapage (free and main) - also hardcoded elsewhere */ #define CORE_DBS 2 #define MAX_DBI (INT16_MAX - CORE_DBS) /* Number of meta pages - also hardcoded elsewhere */ #define NUM_METAS 3 /* A page number in the database. * * MDBX uses 32 bit for page numbers. This limits database * size up to 2^44 bytes, in case of 4K pages. */ typedef uint32_t pgno_t; #define PRIaPGNO PRIu32 #define MAX_PAGENO ((pgno_t)UINT64_C(0xffffFFFFffff)) #define MIN_PAGENO NUM_METAS /* A transaction ID. */ typedef uint64_t txnid_t; #define PRIaTXN PRIi64 #if MDBX_DEVEL #define MIN_TXNID (UINT64_MAX - UINT32_MAX) #elif MDBX_DEBUG #define MIN_TXNID UINT64_C(0x100000000) #else #define MIN_TXNID UINT64_C(1) #endif /* MIN_TXNID */ /* Used for offsets within a single page. * Since memory pages are typically 4 or 8KB in size, 12-13 bits, * this is plenty. */ typedef uint16_t indx_t; #define MEGABYTE ((size_t)1 << 20) /*----------------------------------------------------------------------------*/ /* Core structures for database and shared memory (i.e. format definition) */ #pragma pack(push, 1) /* Reader Lock Table * * Readers don't acquire any locks for their data access. Instead, they * simply record their transaction ID in the reader table. The reader * mutex is needed just to find an empty slot in the reader table. The * slot's address is saved in thread-specific data so that subsequent * read transactions started by the same thread need no further locking to * proceed. * * If MDBX_NOTLS is set, the slot address is not saved in thread-specific data. * No reader table is used if the database is on a read-only filesystem. * * Since the database uses multi-version concurrency control, readers don't * actually need any locking. This table is used to keep track of which * readers are using data from which old transactions, so that we'll know * when a particular old transaction is no longer in use. Old transactions * that have discarded any data pages can then have those pages reclaimed * for use by a later write transaction. * * The lock table is constructed such that reader slots are aligned with the * processor's cache line size. Any slot is only ever used by one thread. * This alignment guarantees that there will be no contention or cache * thrashing as threads update their own slot info, and also eliminates * any need for locking when accessing a slot. * * A writer thread will scan every slot in the table to determine the oldest * outstanding reader transaction. Any freed pages older than this will be * reclaimed by the writer. The writer doesn't use any locks when scanning * this table. This means that there's no guarantee that the writer will * see the most up-to-date reader info, but that's not required for correct * operation - all we need is to know the upper bound on the oldest reader, * we don't care at all about the newest reader. So the only consequence of * reading stale information here is that old pages might hang around a * while longer before being reclaimed. That's actually good anyway, because * the longer we delay reclaiming old pages, the more likely it is that a * string of contiguous pages can be found after coalescing old pages from * many old transactions together. */ /* The actual reader record, with cacheline padding. */ typedef struct MDBX_reader { /* Current Transaction ID when this transaction began, or (txnid_t)-1. * Multiple readers that start at the same time will probably have the * same ID here. Again, it's not important to exclude them from * anything; all we need to know is which version of the DB they * started from so we can avoid overwriting any data used in that * particular version. */ volatile txnid_t mr_txnid; /* The information we store in a single slot of the reader table. * In addition to a transaction ID, we also record the process and * thread ID that owns a slot, so that we can detect stale information, * e.g. threads or processes that went away without cleaning up. * * NOTE: We currently don't check for stale records. * We simply re-init the table when we know that we're the only process * opening the lock file. */ /* The process ID of the process owning this reader txn. */ volatile mdbx_pid_t mr_pid; /* The thread ID of the thread owning this txn. */ volatile mdbx_tid_t mr_tid; /* cache line alignment */ uint8_t pad[MDBX_CACHELINE_SIZE - (sizeof(txnid_t) + sizeof(mdbx_pid_t) + sizeof(mdbx_tid_t)) % MDBX_CACHELINE_SIZE]; } __cache_aligned MDBX_reader; /* Information about a single database in the environment. */ typedef struct MDBX_db { uint16_t md_flags; /* see mdbx_dbi_open */ uint16_t md_depth; /* depth of this tree */ uint32_t md_xsize; /* also ksize for LEAF2 pages */ pgno_t md_root; /* the root page of this tree */ pgno_t md_branch_pages; /* number of internal pages */ pgno_t md_leaf_pages; /* number of leaf pages */ pgno_t md_overflow_pages; /* number of overflow pages */ uint64_t md_seq; /* table sequence counter */ uint64_t md_entries; /* number of data items */ uint64_t md_merkle; /* Merkle tree checksum */ } MDBX_db; /* Meta page content. * A meta page is the start point for accessing a database snapshot. * Pages 0-1 are meta pages. Transaction N writes meta page (N % 2). */ typedef struct MDBX_meta { /* Stamp identifying this as an MDBX file. * It must be set to MDBX_MAGIC with MDBX_DATA_VERSION. */ uint64_t mm_magic_and_version; /* txnid that committed this page, the first of a two-phase-update pair */ volatile txnid_t mm_txnid_a; uint16_t mm_extra_flags; /* extra DB flags, zero (nothing) for now */ uint8_t mm_validator_id; /* ID of checksum and page validation method, * zero (nothing) for now */ uint8_t mm_extra_pagehdr; /* extra bytes in the page header, * zero (nothing) for now */ struct { uint16_t grow; /* datafile growth step in pages */ uint16_t shrink; /* datafile shrink threshold in pages */ pgno_t lower; /* minimal size of datafile in pages */ pgno_t upper; /* maximal size of datafile in pages */ pgno_t now; /* current size of datafile in pages */ pgno_t next; /* first unused page in the datafile, * but actually the file may be shorter. */ } mm_geo; MDBX_db mm_dbs[CORE_DBS]; /* first is free space, 2nd is main db */ /* The size of pages used in this DB */ #define mm_psize mm_dbs[FREE_DBI].md_xsize /* Any persistent environment flags, see mdbx_env */ #define mm_flags mm_dbs[FREE_DBI].md_flags mdbx_canary mm_canary; #define MDBX_DATASIGN_NONE 0u #define MDBX_DATASIGN_WEAK 1u #define SIGN_IS_WEAK(sign) ((sign) == MDBX_DATASIGN_WEAK) #define SIGN_IS_STEADY(sign) ((sign) > MDBX_DATASIGN_WEAK) #define META_IS_WEAK(meta) SIGN_IS_WEAK((meta)->mm_datasync_sign) #define META_IS_STEADY(meta) SIGN_IS_STEADY((meta)->mm_datasync_sign) volatile uint64_t mm_datasync_sign; /* txnid that committed this page, the second of a two-phase-update pair */ volatile txnid_t mm_txnid_b; } MDBX_meta; /* Common header for all page types. The page type depends on mp_flags. * * P_BRANCH and P_LEAF pages have unsorted 'MDBX_node's at the end, with * sorted mp_ptrs[] entries referring to them. Exception: P_LEAF2 pages * omit mp_ptrs and pack sorted MDBX_DUPFIXED values after the page header. * * P_OVERFLOW records occupy one or more contiguous pages where only the * first has a page header. They hold the real data of F_BIGDATA nodes. * * P_SUBP sub-pages are small leaf "pages" with duplicate data. * A node with flag F_DUPDATA but not F_SUBDATA contains a sub-page. * (Duplicate data can also go in sub-databases, which use normal pages.) * * P_META pages contain MDBX_meta, the start point of an MDBX snapshot. * * Each non-metapage up to MDBX_meta.mm_last_pg is reachable exactly once * in the snapshot: Either used by a database or listed in a freeDB record. */ typedef struct MDBX_page { union { struct MDBX_page *mp_next; /* for in-memory list of freed pages, * must be first field, see NEXT_LOOSE_PAGE */ uint64_t mp_validator; /* checksum of page content or a txnid during * which the page has been updated */ }; uint16_t mp_leaf2_ksize; /* key size if this is a LEAF2 page */ #define P_BRANCH 0x01 /* branch page */ #define P_LEAF 0x02 /* leaf page */ #define P_OVERFLOW 0x04 /* overflow page */ #define P_META 0x08 /* meta page */ #define P_DIRTY 0x10 /* dirty page, also set for P_SUBP pages */ #define P_LEAF2 0x20 /* for MDBX_DUPFIXED records */ #define P_SUBP 0x40 /* for MDBX_DUPSORT sub-pages */ #define P_LOOSE 0x4000 /* page was dirtied then freed, can be reused */ #define P_KEEP 0x8000 /* leave this page alone during spill */ uint16_t mp_flags; union { struct { indx_t mp_lower; /* lower bound of free space */ indx_t mp_upper; /* upper bound of free space */ }; uint32_t mp_pages; /* number of overflow pages */ }; pgno_t mp_pgno; /* page number */ /* dynamic size */ union { indx_t mp_ptrs[1]; MDBX_meta mp_meta; uint8_t mp_data[1]; }; } MDBX_page; /* Size of the page header, excluding dynamic data at the end */ #define PAGEHDRSZ ((unsigned)offsetof(MDBX_page, mp_data)) /* The maximum size of a database page. * * It is 64K, but value-PAGEHDRSZ must fit in MDBX_page.mp_upper. * * MDBX will use database pages < OS pages if needed. * That causes more I/O in write transactions: The OS must * know (read) the whole page before writing a partial page. * * Note that we don't currently support Huge pages. On Linux, * regular data files cannot use Huge pages, and in general * Huge pages aren't actually pageable. We rely on the OS * demand-pager to read our data and page it out when memory * pressure from other processes is high. So until OSs have * actual paging support for Huge pages, they're not viable. */ #define MAX_PAGESIZE 0x10000u #define MIN_PAGESIZE 512u #define MIN_MAPSIZE (MIN_PAGESIZE * MIN_PAGENO) #if defined(_WIN32) || defined(_WIN64) #define MAX_MAPSIZE32 UINT32_C(0x38000000) #else #define MAX_MAPSIZE32 UINT32_C(0x7ff80000) #endif #define MAX_MAPSIZE64 \ ((sizeof(pgno_t) > 4) ? UINT64_C(0x7fffFFFFfff80000) \ : MAX_PAGENO * (uint64_t)MAX_PAGESIZE) #define MAX_MAPSIZE ((sizeof(size_t) < 8) ? MAX_MAPSIZE32 : MAX_MAPSIZE64) /* The header for the reader table (a memory-mapped lock file). */ typedef struct MDBX_lockinfo { /* Stamp identifying this as an MDBX file. * It must be set to MDBX_MAGIC with with MDBX_LOCK_VERSION. */ uint64_t mti_magic_and_version; /* Format of this lock file. Must be set to MDBX_LOCK_FORMAT. */ uint32_t mti_os_and_format; /* Flags which environment was opened. */ volatile uint32_t mti_envmode; union { #ifdef MDBX_OSAL_LOCK MDBX_OSAL_LOCK mti_wmutex; #endif uint64_t align_wmutex; }; union { /* The number of slots that have been used in the reader table. * This always records the maximum count, it is not decremented * when readers release their slots. */ volatile unsigned __cache_aligned mti_numreaders; uint64_t align_numreaders; }; union { #ifdef MDBX_OSAL_LOCK /* Mutex protecting access to this table. */ MDBX_OSAL_LOCK mti_rmutex; #endif uint64_t align_rmutex; }; union { volatile txnid_t mti_oldest; uint64_t align_oldest; }; union { volatile uint32_t mti_readers_refresh_flag; uint64_t align_reader_finished_flag; }; uint8_t pad_align[MDBX_CACHELINE_SIZE - sizeof(uint64_t) * 7]; MDBX_reader __cache_aligned mti_readers[1]; } MDBX_lockinfo; #ifdef _MSC_VER #pragma pack(pop) #endif /* MSVC: Enable aligment */ #define MDBX_LOCKINFO_WHOLE_SIZE \ ((sizeof(MDBX_lockinfo) + MDBX_CACHELINE_SIZE - 1) & \ ~((size_t)MDBX_CACHELINE_SIZE - 1)) /* Lockfile format signature: version, features and field layout */ #define MDBX_LOCK_FORMAT \ ((MDBX_OSAL_LOCK_SIGN << 16) + \ (uint16_t)(MDBX_LOCKINFO_WHOLE_SIZE + MDBX_CACHELINE_SIZE - 1)) #define MDBX_DATA_MAGIC ((MDBX_MAGIC << 8) + MDBX_DATA_VERSION) #define MDBX_LOCK_MAGIC ((MDBX_MAGIC << 8) + MDBX_LOCK_VERSION) /*----------------------------------------------------------------------------*/ /* Two kind lists of pages (aka PNL) */ /* An PNL is an Page Number List, a sorted array of IDs. The first element of * the array is a counter for how many actual page-numbers are in the list. * PNLs are sorted in descending order, this allow cut off a page with lowest * pgno (at the tail) just truncating the list */ #define MDBX_PNL_ASCENDING 0 typedef pgno_t *MDBX_PNL; #if MDBX_PNL_ASCENDING #define MDBX_PNL_ORDERED(first, last) ((first) < (last)) #define MDBX_PNL_DISORDERED(first, last) ((first) >= (last)) #else #define MDBX_PNL_ORDERED(first, last) ((first) > (last)) #define MDBX_PNL_DISORDERED(first, last) ((first) <= (last)) #endif /* List of txnid, only for MDBX_env.mt_lifo_reclaimed */ typedef txnid_t *MDBX_TXL; /* An ID2 is an ID/pointer pair. */ typedef struct MDBX_ID2 { pgno_t mid; /* The ID */ void *mptr; /* The pointer */ } MDBX_ID2; /* An ID2L is an ID2 List, a sorted array of ID2s. * The first element's mid member is a count of how many actual * elements are in the array. The mptr member of the first element is * unused. The array is sorted in ascending order by mid. */ typedef MDBX_ID2 *MDBX_ID2L; /* PNL sizes - likely should be even bigger * limiting factors: sizeof(pgno_t), thread stack size */ #define MDBX_PNL_LOGN 16 /* DB_SIZE is 2^16, UM_SIZE is 2^17 */ #define MDBX_PNL_DB_SIZE (1 << MDBX_PNL_LOGN) #define MDBX_PNL_UM_SIZE (1 << (MDBX_PNL_LOGN + 1)) #define MDBX_PNL_DB_MAX (MDBX_PNL_DB_SIZE - 1) #define MDBX_PNL_UM_MAX (MDBX_PNL_UM_SIZE - 1) #define MDBX_PNL_SIZEOF(pl) (((pl)[0] + 1) * sizeof(pgno_t)) #define MDBX_PNL_IS_ZERO(pl) ((pl)[0] == 0) #define MDBX_PNL_CPY(dst, src) (memcpy(dst, src, MDBX_PNL_SIZEOF(src))) #define MDBX_PNL_FIRST(pl) ((pl)[1]) #define MDBX_PNL_LAST(pl) ((pl)[(pl)[0]]) /* Current max length of an mdbx_pnl_alloc()ed PNL */ #define MDBX_PNL_ALLOCLEN(pl) ((pl)[-1]) /*----------------------------------------------------------------------------*/ /* Internal structures */ /* Auxiliary DB info. * The information here is mostly static/read-only. There is * only a single copy of this record in the environment. */ typedef struct MDBX_dbx { MDBX_val md_name; /* name of the database */ MDBX_cmp_func *md_cmp; /* function for comparing keys */ MDBX_cmp_func *md_dcmp; /* function for comparing data items */ } MDBX_dbx; /* A database transaction. * Every operation requires a transaction handle. */ struct MDBX_txn { #define MDBX_MT_SIGNATURE UINT32_C(0x93D53A31) size_t mt_signature; MDBX_txn *mt_parent; /* parent of a nested txn */ /* Nested txn under this txn, set together with flag MDBX_TXN_HAS_CHILD */ MDBX_txn *mt_child; pgno_t mt_next_pgno; /* next unallocated page */ pgno_t mt_end_pgno; /* corresponding to the current size of datafile */ /* The ID of this transaction. IDs are integers incrementing from 1. * Only committed write transactions increment the ID. If a transaction * aborts, the ID may be re-used by the next writer. */ txnid_t mt_txnid; MDBX_env *mt_env; /* the DB environment */ /* The list of reclaimed txns from freeDB */ MDBX_TXL mt_lifo_reclaimed; /* The list of pages that became unused during this transaction. */ MDBX_PNL mt_befree_pages; /* The list of loose pages that became unused and may be reused * in this transaction, linked through NEXT_LOOSE_PAGE(page). */ MDBX_page *mt_loose_pages; /* Number of loose pages (mt_loose_pages) */ unsigned mt_loose_count; /* The sorted list of dirty pages we temporarily wrote to disk * because the dirty list was full. page numbers in here are * shifted left by 1, deleted slots have the LSB set. */ MDBX_PNL mt_spill_pages; union { /* For write txns: Modified pages. Sorted when not MDBX_WRITEMAP. */ MDBX_ID2L mt_rw_dirtylist; /* For read txns: This thread/txn's reader table slot, or NULL. */ MDBX_reader *mt_ro_reader; }; /* Array of records for each DB known in the environment. */ MDBX_dbx *mt_dbxs; /* Array of MDBX_db records for each known DB */ MDBX_db *mt_dbs; /* Array of sequence numbers for each DB handle */ unsigned *mt_dbiseqs; /* Transaction DB Flags */ #define DB_DIRTY MDBX_TBL_DIRTY /* DB was written in this txn */ #define DB_STALE MDBX_TBL_STALE /* Named-DB record is older than txnID */ #define DB_NEW MDBX_TBL_NEW /* Named-DB handle opened in this txn */ #define DB_VALID 0x08 /* DB handle is valid, see also MDBX_VALID */ #define DB_USRVALID 0x10 /* As DB_VALID, but not set for FREE_DBI */ #define DB_DUPDATA 0x20 /* DB is MDBX_DUPSORT data */ /* In write txns, array of cursors for each DB */ MDBX_cursor **mt_cursors; /* Array of flags for each DB */ uint8_t *mt_dbflags; /* Number of DB records in use, or 0 when the txn is finished. * This number only ever increments until the txn finishes; we * don't decrement it when individual DB handles are closed. */ MDBX_dbi mt_numdbs; /* Transaction Flags */ /* mdbx_txn_begin() flags */ #define MDBX_TXN_BEGIN_FLAGS \ (MDBX_NOMETASYNC | MDBX_NOSYNC | MDBX_RDONLY | MDBX_TRYTXN) #define MDBX_TXN_NOMETASYNC \ MDBX_NOMETASYNC /* don't sync meta for this txn on commit */ #define MDBX_TXN_NOSYNC MDBX_NOSYNC /* don't sync this txn on commit */ #define MDBX_TXN_RDONLY MDBX_RDONLY /* read-only transaction */ /* internal txn flags */ #define MDBX_TXN_WRITEMAP MDBX_WRITEMAP /* copy of MDBX_env flag in writers */ #define MDBX_TXN_FINISHED 0x01 /* txn is finished or never began */ #define MDBX_TXN_ERROR 0x02 /* txn is unusable after an error */ #define MDBX_TXN_DIRTY 0x04 /* must write, even if dirty list is empty */ #define MDBX_TXN_SPILLS 0x08 /* txn or a parent has spilled pages */ #define MDBX_TXN_HAS_CHILD 0x10 /* txn has an MDBX_txn.mt_child */ /* most operations on the txn are currently illegal */ #define MDBX_TXN_BLOCKED \ (MDBX_TXN_FINISHED | MDBX_TXN_ERROR | MDBX_TXN_HAS_CHILD) unsigned mt_flags; /* dirtylist room: Array size - dirty pages visible to this txn. * Includes ancestor txns' dirty pages not hidden by other txns' * dirty/spilled pages. Thus commit(nested txn) has room to merge * dirtylist into mt_parent after freeing hidden mt_parent pages. */ unsigned mt_dirtyroom; mdbx_tid_t mt_owner; /* thread ID that owns this transaction */ mdbx_canary mt_canary; }; /* Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty. * At 4 keys per node, enough for 2^64 nodes, so there's probably no need to * raise this on a 64 bit machine. */ #define CURSOR_STACK 32 struct MDBX_xcursor; /* Cursors are used for all DB operations. * A cursor holds a path of (page pointer, key index) from the DB * root to a position in the DB, plus other state. MDBX_DUPSORT * cursors include an xcursor to the current data item. Write txns * track their cursors and keep them up to date when data moves. * Exception: An xcursor's pointer to a P_SUBP page can be stale. * (A node with F_DUPDATA but no F_SUBDATA contains a subpage). */ struct MDBX_cursor { #define MDBX_MC_SIGNATURE UINT32_C(0xFE05D5B1) #define MDBX_MC_READY4CLOSE UINT32_C(0x2817A047) #define MDBX_MC_WAIT4EOT UINT32_C(0x90E297A7) uint32_t mc_signature; /* The database handle this cursor operates on */ MDBX_dbi mc_dbi; /* Next cursor on this DB in this txn */ MDBX_cursor *mc_next; /* Backup of the original cursor if this cursor is a shadow */ MDBX_cursor *mc_backup; /* Context used for databases with MDBX_DUPSORT, otherwise NULL */ struct MDBX_xcursor *mc_xcursor; /* The transaction that owns this cursor */ MDBX_txn *mc_txn; /* The database record for this cursor */ MDBX_db *mc_db; /* The database auxiliary record for this cursor */ MDBX_dbx *mc_dbx; /* The mt_dbflag for this database */ uint8_t *mc_dbflag; uint16_t mc_snum; /* number of pushed pages */ uint16_t mc_top; /* index of top page, normally mc_snum-1 */ /* Cursor state flags. */ #define C_INITIALIZED 0x01 /* cursor has been initialized and is valid */ #define C_EOF 0x02 /* No more data */ #define C_SUB 0x04 /* Cursor is a sub-cursor */ #define C_DEL 0x08 /* last op was a cursor_del */ #define C_UNTRACK 0x40 /* Un-track cursor when closing */ #define C_RECLAIMING 0x80 /* FreeDB lookup is prohibited */ unsigned mc_flags; /* see mdbx_cursor */ MDBX_page *mc_pg[CURSOR_STACK]; /* stack of pushed pages */ indx_t mc_ki[CURSOR_STACK]; /* stack of page indices */ }; /* Context for sorted-dup records. * We could have gone to a fully recursive design, with arbitrarily * deep nesting of sub-databases. But for now we only handle these * levels - main DB, optional sub-DB, sorted-duplicate DB. */ typedef struct MDBX_xcursor { /* A sub-cursor for traversing the Dup DB */ MDBX_cursor mx_cursor; /* The database record for this Dup DB */ MDBX_db mx_db; /* The auxiliary DB record for this Dup DB */ MDBX_dbx mx_dbx; /* The mt_dbflag for this Dup DB */ uint8_t mx_dbflag; } MDBX_xcursor; /* Check if there is an inited xcursor, so XCURSOR_REFRESH() is proper */ #define XCURSOR_INITED(mc) \ ((mc)->mc_xcursor && ((mc)->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) /* Update sub-page pointer, if any, in mc->mc_xcursor. * Needed when the node which contains the sub-page may have moved. * Called with mp = mc->mc_pg[mc->mc_top], ki = mc->mc_ki[mc->mc_top]. */ #define XCURSOR_REFRESH(mc, mp, ki) \ do { \ MDBX_page *xr_pg = (mp); \ MDBX_node *xr_node = NODEPTR(xr_pg, ki); \ if ((xr_node->mn_flags & (F_DUPDATA | F_SUBDATA)) == F_DUPDATA) \ (mc)->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(xr_node); \ } while (0) /* State of FreeDB old pages, stored in the MDBX_env */ typedef struct MDBX_pgstate { pgno_t *mf_reclaimed_pglist; /* Reclaimed freeDB pages, or NULL before use */ txnid_t mf_last_reclaimed; /* ID of last used record, or 0 if !mf_reclaimed_pglist */ } MDBX_pgstate; /* The database environment. */ struct MDBX_env { #define MDBX_ME_SIGNATURE UINT32_C(0x9A899641) size_t me_signature; mdbx_mmap_t me_dxb_mmap; /* The main data file */ #define me_map me_dxb_mmap.dxb #define me_fd me_dxb_mmap.fd #define me_mapsize me_dxb_mmap.length mdbx_mmap_t me_lck_mmap; /* The lock file */ #define me_lfd me_lck_mmap.fd #define me_lck me_lck_mmap.lck /* Failed to update the meta page. Probably an I/O error. */ #define MDBX_FATAL_ERROR UINT32_C(0x80000000) /* Additional flag for mdbx_sync_locked() */ #define MDBX_SHRINK_ALLOWED UINT32_C(0x40000000) /* Some fields are initialized. */ #define MDBX_ENV_ACTIVE UINT32_C(0x20000000) /* me_txkey is set */ #define MDBX_ENV_TXKEY UINT32_C(0x10000000) uint32_t me_flags; /* see mdbx_env */ unsigned me_psize; /* DB page size, inited from me_os_psize */ unsigned me_psize2log; /* log2 of DB page size */ unsigned me_os_psize; /* OS page size, from mdbx_syspagesize() */ unsigned me_maxreaders; /* size of the reader table */ /* Max MDBX_lockinfo.mti_numreaders of interest to mdbx_env_close() */ unsigned me_close_readers; mdbx_fastmutex_t me_dbi_lock; MDBX_dbi me_numdbs; /* number of DBs opened */ MDBX_dbi me_maxdbs; /* size of the DB table */ mdbx_pid_t me_pid; /* process ID of this env */ mdbx_thread_key_t me_txkey; /* thread-key for readers */ char *me_path; /* path to the DB files */ void *me_pbuf; /* scratch area for DUPSORT put() */ MDBX_txn *me_txn; /* current write transaction */ MDBX_txn *me_txn0; /* prealloc'd write transaction */ MDBX_dbx *me_dbxs; /* array of static DB info */ uint16_t *me_dbflags; /* array of flags from MDBX_db.md_flags */ unsigned *me_dbiseqs; /* array of dbi sequence numbers */ volatile txnid_t *me_oldest; /* ID of oldest reader last time we looked */ MDBX_pgstate me_pgstate; /* state of old pages from freeDB */ #define me_last_reclaimed me_pgstate.mf_last_reclaimed #define me_reclaimed_pglist me_pgstate.mf_reclaimed_pglist MDBX_page *me_dpages; /* list of malloc'd blocks for re-use */ /* PNL of pages that became unused in a write txn */ MDBX_PNL me_free_pgs; /* ID2L of pages written during a write txn. Length MDBX_PNL_UM_SIZE. */ MDBX_ID2L me_dirtylist; /* Max number of freelist items that can fit in a single overflow page */ unsigned me_maxfree_1pg; /* Max size of a node on a page */ unsigned me_nodemax; unsigned me_maxkey_limit; /* max size of a key */ mdbx_pid_t me_live_reader; /* have liveness lock in reader table */ void *me_userctx; /* User-settable context */ size_t me_sync_pending; /* Total dirty/non-sync'ed bytes * since the last mdbx_env_sync() */ size_t me_sync_threshold; /* Treshold of above to force synchronous flush */ MDBX_oom_func *me_oom_func; /* Callback for kicking laggard readers */ txnid_t me_oldest_stub; #if MDBX_DEBUG MDBX_assert_func *me_assert_func; /* Callback for assertion failures */ #endif #ifdef USE_VALGRIND int me_valgrind_handle; #endif struct { size_t lower; /* minimal size of datafile */ size_t upper; /* maximal size of datafile */ size_t now; /* current size of datafile */ size_t grow; /* step to grow datafile */ size_t shrink; /* threshold to shrink datafile */ } me_dbgeo; /* */ }; /* Nested transaction */ typedef struct MDBX_ntxn { MDBX_txn mnt_txn; /* the transaction */ MDBX_pgstate mnt_pgstate; /* parent transaction's saved freestate */ } MDBX_ntxn; /*----------------------------------------------------------------------------*/ /* Debug and Logging stuff */ extern int mdbx_runtime_flags; extern MDBX_debug_func *mdbx_debug_logger; extern txnid_t mdbx_debug_edge; void mdbx_debug_log(int type, const char *function, int line, const char *fmt, ...) #if defined(__GNUC__) || __has_attribute(format) __attribute__((format(printf, 4, 5))) #endif ; void mdbx_panic(const char *fmt, ...) #if defined(__GNUC__) || __has_attribute(format) __attribute__((format(printf, 1, 2))) #endif ; #if MDBX_DEBUG #define mdbx_assert_enabled() unlikely(mdbx_runtime_flags &MDBX_DBG_ASSERT) #define mdbx_audit_enabled() unlikely(mdbx_runtime_flags &MDBX_DBG_AUDIT) #define mdbx_debug_enabled(type) \ unlikely(mdbx_runtime_flags &(type & (MDBX_DBG_TRACE | MDBX_DBG_EXTRA))) #else #define mdbx_debug_enabled(type) (0) #define mdbx_audit_enabled() (0) #ifndef NDEBUG #define mdbx_assert_enabled() (1) #else #define mdbx_assert_enabled() (0) #endif /* NDEBUG */ #endif /* MDBX_DEBUG */ #define mdbx_print(fmt, ...) \ mdbx_debug_log(MDBX_DBG_PRINT, NULL, 0, fmt, ##__VA_ARGS__) #define mdbx_trace(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE)) \ mdbx_debug_log(MDBX_DBG_TRACE, __FUNCTION__, __LINE__, fmt "\n", \ ##__VA_ARGS__); \ } while (0) #define mdbx_verbose(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE /* FIXME */)) \ mdbx_debug_log(MDBX_DBG_TRACE /* FIXME */, __FUNCTION__, __LINE__, \ fmt "\n", ##__VA_ARGS__); \ } while (0) #define mdbx_info(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE /* FIXME */)) \ mdbx_debug_log(MDBX_DBG_TRACE /* FIXME */, __FUNCTION__, __LINE__, \ fmt "\n", ##__VA_ARGS__); \ } while (0) #define mdbx_notice(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE /* FIXME */)) \ mdbx_debug_log(MDBX_DBG_TRACE /* FIXME */, __FUNCTION__, __LINE__, \ fmt "\n", ##__VA_ARGS__); \ } while (0) #define mdbx_warning(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE /* FIXME */)) \ mdbx_debug_log(MDBX_DBG_TRACE /* FIXME */, __FUNCTION__, __LINE__, \ fmt "\n", ##__VA_ARGS__); \ } while (0) #define mdbx_error(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE /* FIXME */)) \ mdbx_debug_log(MDBX_DBG_TRACE /* FIXME */, __FUNCTION__, __LINE__, \ fmt "\n", ##__VA_ARGS__); \ } while (0) #define mdbx_fatal(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE /* FIXME */)) \ mdbx_debug_log(MDBX_DBG_TRACE /* FIXME */, __FUNCTION__, __LINE__, \ fmt "\n", ##__VA_ARGS__); \ } while (0) #define mdbx_debug(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE)) \ mdbx_debug_log(MDBX_DBG_TRACE, __FUNCTION__, __LINE__, fmt "\n", \ ##__VA_ARGS__); \ } while (0) #define mdbx_debug_print(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_TRACE)) \ mdbx_debug_log(MDBX_DBG_TRACE, NULL, 0, fmt, ##__VA_ARGS__); \ } while (0) #define mdbx_debug_extra(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_EXTRA)) \ mdbx_debug_log(MDBX_DBG_EXTRA, __FUNCTION__, __LINE__, fmt, \ ##__VA_ARGS__); \ } while (0) #define mdbx_debug_extra_print(fmt, ...) \ do { \ if (mdbx_debug_enabled(MDBX_DBG_EXTRA)) \ mdbx_debug_log(MDBX_DBG_EXTRA, NULL, 0, fmt, ##__VA_ARGS__); \ } while (0) #define mdbx_ensure_msg(env, expr, msg) \ do { \ if (unlikely(!(expr))) \ mdbx_assert_fail(env, msg, __FUNCTION__, __LINE__); \ } while (0) #define mdbx_ensure(env, expr) mdbx_ensure_msg(env, expr, #expr) /* assert(3) variant in environment context */ #define mdbx_assert(env, expr) \ do { \ if (mdbx_assert_enabled()) \ mdbx_ensure(env, expr); \ } while (0) /* assert(3) variant in cursor context */ #define mdbx_cassert(mc, expr) mdbx_assert((mc)->mc_txn->mt_env, expr) /* assert(3) variant in transaction context */ #define mdbx_tassert(txn, expr) mdbx_assert((txn)->mt_env, expr) static __inline void mdbx_jitter4testing(bool tiny) { #ifndef NDEBUG if (MDBX_DBG_JITTER & mdbx_runtime_flags) mdbx_osal_jitter(tiny); #else (void)tiny; #endif } /*----------------------------------------------------------------------------*/ /* Internal prototypes and inlines */ int mdbx_reader_check0(MDBX_env *env, int rlocked, int *dead); void mdbx_rthc_dtor(void *rthc); void mdbx_rthc_lock(void); void mdbx_rthc_unlock(void); int mdbx_rthc_alloc(mdbx_thread_key_t *key, MDBX_reader *begin, MDBX_reader *end); void mdbx_rthc_remove(mdbx_thread_key_t key); void mdbx_rthc_cleanup(void); static __inline bool mdbx_is_power2(size_t x) { return (x & (x - 1)) == 0; } static __inline size_t mdbx_roundup2(size_t value, size_t granularity) { assert(mdbx_is_power2(granularity)); return (value + granularity - 1) & ~(granularity - 1); } static __inline unsigned mdbx_log2(size_t value) { assert(mdbx_is_power2(value)); unsigned log = 0; while (value > 1) { log += 1; value >>= 1; } return log; } #define MDBX_IS_ERROR(rc) \ ((rc) != MDBX_RESULT_TRUE && (rc) != MDBX_RESULT_FALSE) /* Internal error codes, not exposed outside libmdbx */ #define MDBX_NO_ROOT (MDBX_LAST_ERRCODE + 10) /* Debuging output value of a cursor DBI: Negative in a sub-cursor. */ #define DDBI(mc) \ (((mc)->mc_flags & C_SUB) ? -(int)(mc)->mc_dbi : (int)(mc)->mc_dbi) /* Key size which fits in a DKBUF. */ #define DKBUF_MAXKEYSIZE 511 /* FIXME */ #if MDBX_DEBUG #define DKBUF char _kbuf[DKBUF_MAXKEYSIZE * 4 + 2] #define DKEY(x) mdbx_dkey(x, _kbuf, DKBUF_MAXKEYSIZE * 2 + 1) #define DVAL(x) \ mdbx_dkey(x, _kbuf + DKBUF_MAXKEYSIZE * 2 + 1, DKBUF_MAXKEYSIZE * 2 + 1) #else #define DKBUF ((void)(0)) #define DKEY(x) ("-") #define DVAL(x) ("-") #endif /* An invalid page number. * Mainly used to denote an empty tree. */ #define P_INVALID (~(pgno_t)0) /* Test if the flags f are set in a flag word w. */ #define F_ISSET(w, f) (((w) & (f)) == (f)) /* Round n up to an even number. */ #define EVEN(n) (((n) + 1U) & -2) /* sign-extending -2 to match n+1U */ /* Default size of memory map. * This is certainly too small for any actual applications. Apps should * always set the size explicitly using mdbx_env_set_mapsize(). */ #define DEFAULT_MAPSIZE 1048576 /* Number of slots in the reader table. * This value was chosen somewhat arbitrarily. The 61 is a prime number, * and such readers plus a couple mutexes fit into single 4KB page. * Applications should set the table size using mdbx_env_set_maxreaders(). */ #define DEFAULT_READERS 61 /* Address of first usable data byte in a page, after the header */ #define PAGEDATA(p) ((void *)((char *)(p) + PAGEHDRSZ)) /* Number of nodes on a page */ #define NUMKEYS(p) ((unsigned)(p)->mp_lower >> 1) /* The amount of space remaining in the page */ #define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower) /* The percentage of space used in the page, in tenths of a percent. */ #define PAGEFILL(env, p) \ (1024UL * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \ ((env)->me_psize - PAGEHDRSZ)) /* The minimum page fill factor, in tenths of a percent. * Pages emptier than this are candidates for merging. */ #define FILL_THRESHOLD 256 /* Test if a page is a leaf page */ #define IS_LEAF(p) F_ISSET((p)->mp_flags, P_LEAF) /* Test if a page is a LEAF2 page */ #define IS_LEAF2(p) F_ISSET((p)->mp_flags, P_LEAF2) /* Test if a page is a branch page */ #define IS_BRANCH(p) F_ISSET((p)->mp_flags, P_BRANCH) /* Test if a page is an overflow page */ #define IS_OVERFLOW(p) unlikely(F_ISSET((p)->mp_flags, P_OVERFLOW)) /* Test if a page is a sub page */ #define IS_SUBP(p) F_ISSET((p)->mp_flags, P_SUBP) /* The number of overflow pages needed to store the given size. */ #define OVPAGES(env, size) (bytes2pgno(env, PAGEHDRSZ - 1 + (size)) + 1) /* Link in MDBX_txn.mt_loose_pages list. * Kept outside the page header, which is needed when reusing the page. */ #define NEXT_LOOSE_PAGE(p) (*(MDBX_page **)((p) + 2)) /* Header for a single key/data pair within a page. * Used in pages of type P_BRANCH and P_LEAF without P_LEAF2. * We guarantee 2-byte alignment for 'MDBX_node's. * * mn_lo and mn_hi are used for data size on leaf nodes, and for child * pgno on branch nodes. On 64 bit platforms, mn_flags is also used * for pgno. (Branch nodes have no flags). Lo and hi are in host byte * order in case some accesses can be optimized to 32-bit word access. * * Leaf node flags describe node contents. F_BIGDATA says the node's * data part is the page number of an overflow page with actual data. * F_DUPDATA and F_SUBDATA can be combined giving duplicate data in * a sub-page/sub-database, and named databases (just F_SUBDATA). */ typedef struct MDBX_node { union { struct { #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ union { struct { uint16_t mn_lo, mn_hi; /* part of data size or pgno */ }; uint32_t mn_dsize; }; uint16_t mn_flags; /* see mdbx_node */ uint16_t mn_ksize; /* key size */ #else uint16_t mn_ksize; /* key size */ uint16_t mn_flags; /* see mdbx_node */ union { struct { uint16_t mn_hi, mn_lo; /* part of data size or pgno */ }; uint32_t mn_dsize; }; #endif }; pgno_t mn_ksize_and_pgno; }; /* mdbx_node Flags */ #define F_BIGDATA 0x01 /* data put on overflow page */ #define F_SUBDATA 0x02 /* data is a sub-database */ #define F_DUPDATA 0x04 /* data has duplicates */ /* valid flags for mdbx_node_add() */ #define NODE_ADD_FLAGS (F_DUPDATA | F_SUBDATA | MDBX_RESERVE | MDBX_APPEND) uint8_t mn_data[1]; /* key and data are appended here */ } MDBX_node; /* Size of the node header, excluding dynamic data at the end */ #define NODESIZE offsetof(MDBX_node, mn_data) /* Bit position of top word in page number, for shifting mn_flags */ #define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0) /* Size of a node in a branch page with a given key. * This is just the node header plus the key, there is no data. */ #define INDXSIZE(k) (NODESIZE + ((k) == NULL ? 0 : (k)->iov_len)) /* Size of a node in a leaf page with a given key and data. * This is node header plus key plus data size. */ #define LEAFSIZE(k, d) (NODESIZE + (k)->iov_len + (d)->iov_len) /* Address of node i in page p */ static __inline MDBX_node *NODEPTR(MDBX_page *p, unsigned i) { assert(NUMKEYS(p) > (unsigned)(i)); return (MDBX_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEHDRSZ); } /* Address of the key for the node */ #define NODEKEY(node) (void *)((node)->mn_data) /* Address of the data for a node */ #define NODEDATA(node) (void *)((char *)(node)->mn_data + (node)->mn_ksize) /* Get the page number pointed to by a branch node */ static __inline pgno_t NODEPGNO(const MDBX_node *node) { pgno_t pgno; if (UNALIGNED_OK) { pgno = node->mn_ksize_and_pgno; if (sizeof(pgno_t) > 4) pgno &= MAX_PAGENO; } else { pgno = node->mn_lo | ((pgno_t)node->mn_hi << 16); if (sizeof(pgno_t) > 4) pgno |= ((uint64_t)node->mn_flags) << 32; } return pgno; } /* Set the page number in a branch node */ static __inline void SETPGNO(MDBX_node *node, pgno_t pgno) { assert(pgno <= MAX_PAGENO); if (UNALIGNED_OK) { if (sizeof(pgno_t) > 4) pgno |= ((uint64_t)node->mn_ksize) << 48; node->mn_ksize_and_pgno = pgno; } else { node->mn_lo = (uint16_t)pgno; node->mn_hi = (uint16_t)(pgno >> 16); if (sizeof(pgno_t) > 4) node->mn_flags = (uint16_t)((uint64_t)pgno >> 32); } } /* Get the size of the data in a leaf node */ static __inline size_t NODEDSZ(const MDBX_node *node) { size_t size; if (UNALIGNED_OK) { size = node->mn_dsize; } else { size = node->mn_lo | ((size_t)node->mn_hi << 16); } return size; } /* Set the size of the data for a leaf node */ static __inline void SETDSZ(MDBX_node *node, size_t size) { assert(size < INT_MAX); if (UNALIGNED_OK) { node->mn_dsize = (uint32_t)size; } else { node->mn_lo = (uint16_t)size; node->mn_hi = (uint16_t)(size >> 16); } } /* The size of a key in a node */ #define NODEKSZ(node) ((node)->mn_ksize) /* The address of a key in a LEAF2 page. * LEAF2 pages are used for MDBX_DUPFIXED sorted-duplicate sub-DBs. * There are no node headers, keys are stored contiguously. */ #define LEAF2KEY(p, i, ks) ((char *)(p) + PAGEHDRSZ + ((i) * (ks))) /* Set the node's key into keyptr, if requested. */ #define MDBX_GET_KEY(node, keyptr) \ do { \ if ((keyptr) != NULL) { \ (keyptr)->iov_len = NODEKSZ(node); \ (keyptr)->iov_base = NODEKEY(node); \ } \ } while (0) /* Set the node's key into key. */ #define MDBX_GET_KEY2(node, key) \ do { \ key.iov_len = NODEKSZ(node); \ key.iov_base = NODEKEY(node); \ } while (0) #define MDBX_VALID 0x8000 /* DB handle is valid, for me_dbflags */ #define PERSISTENT_FLAGS (0xffff & ~(MDBX_VALID)) /* mdbx_dbi_open() flags */ #define VALID_FLAGS \ (MDBX_REVERSEKEY | MDBX_DUPSORT | MDBX_INTEGERKEY | MDBX_DUPFIXED | \ MDBX_INTEGERDUP | MDBX_REVERSEDUP | MDBX_CREATE) /* max number of pages to commit in one writev() call */ #define MDBX_COMMIT_PAGES 64 #if defined(IOV_MAX) && IOV_MAX < MDBX_COMMIT_PAGES /* sysconf(_SC_IOV_MAX) */ #undef MDBX_COMMIT_PAGES #define MDBX_COMMIT_PAGES IOV_MAX #endif /* Check txn and dbi arguments to a function */ #define TXN_DBI_EXIST(txn, dbi, validity) \ ((dbi) < (txn)->mt_numdbs && ((txn)->mt_dbflags[dbi] & (validity))) /* Check for misused dbi handles */ #define TXN_DBI_CHANGED(txn, dbi) \ ((txn)->mt_dbiseqs[dbi] != (txn)->mt_env->me_dbiseqs[dbi]) /* LY: fast enough on most systems * * / * | -1, a < b * cmp2int(a,b) = < 0, a == b * | 1, a > b * \ */ #if 1 #define mdbx_cmp2int(a, b) (((b) > (a)) ? -1 : (a) > (b)) #else #define mdbx_cmp2int(a, b) (((a) > (b)) - ((b) > (a))) #endif static __inline size_t pgno2bytes(const MDBX_env *env, pgno_t pgno) { mdbx_assert(env, (1u << env->me_psize2log) == env->me_psize); return ((size_t)pgno) << env->me_psize2log; } static __inline MDBX_page *pgno2page(const MDBX_env *env, pgno_t pgno) { return (MDBX_page *)(env->me_map + pgno2bytes(env, pgno)); } static __inline pgno_t bytes2pgno(const MDBX_env *env, size_t bytes) { mdbx_assert(env, (env->me_psize >> env->me_psize2log) == 1); return (pgno_t)(bytes >> env->me_psize2log); } static __inline pgno_t pgno_add(pgno_t base, pgno_t augend) { assert(base <= MAX_PAGENO); return (augend < MAX_PAGENO - base) ? base + augend : MAX_PAGENO; } static __inline pgno_t pgno_sub(pgno_t base, pgno_t subtrahend) { assert(base >= MIN_PAGENO); return (subtrahend < base - MIN_PAGENO) ? base - subtrahend : MIN_PAGENO; } static __inline size_t pgno_align2os_bytes(const MDBX_env *env, pgno_t pgno) { return mdbx_roundup2(pgno2bytes(env, pgno), env->me_os_psize); } static __inline pgno_t pgno_align2os_pgno(const MDBX_env *env, pgno_t pgno) { return bytes2pgno(env, pgno_align2os_bytes(env, pgno)); }