--- /dev/null
+// btree version threadskv4b sched_yield version
+// with reworked bt_deletekey code,
+// phase-fair reader writer lock,
+// librarian page split code,
+// and duplicate key management
+
+// 08 SEP 2014
+
+// author: karl malbrain, malbrain@cal.berkeley.edu
+
+/*
+This work, including the source code, documentation
+and related data, is placed into the public domain.
+
+The orginal author is Karl Malbrain.
+
+THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY
+OF ANY KIND, NOT EVEN THE IMPLIED WARRANTY OF
+MERCHANTABILITY. THE AUTHOR OF THIS SOFTWARE,
+ASSUMES _NO_ RESPONSIBILITY FOR ANY CONSEQUENCE
+RESULTING FROM THE USE, MODIFICATION, OR
+REDISTRIBUTION OF THIS SOFTWARE.
+*/
+
+// Please see the project home page for documentation
+// code.google.com/p/high-concurrency-btree
+
+#define _FILE_OFFSET_BITS 64
+#define _LARGEFILE64_SOURCE
+
+#ifdef linux
+#define _GNU_SOURCE
+#endif
+
+#ifdef unix
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/time.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <pthread.h>
+#else
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <fcntl.h>
+#include <process.h>
+#include <intrin.h>
+#endif
+
+#include <memory.h>
+#include <string.h>
+#include <stddef.h>
+
+typedef unsigned long long uid;
+
+#ifndef unix
+typedef unsigned long long off64_t;
+typedef unsigned short ushort;
+typedef unsigned int uint;
+#endif
+
+#define BT_latchtable 128 // number of latch manager slots
+
+#define BT_ro 0x6f72 // ro
+#define BT_rw 0x7772 // rw
+
+#define BT_maxbits 24 // maximum page size in bits
+#define BT_minbits 9 // minimum page size in bits
+#define BT_minpage (1 << BT_minbits) // minimum page size
+#define BT_maxpage (1 << BT_maxbits) // maximum page size
+
+/*
+There are five lock types for each node in three independent sets:
+1. (set 1) AccessIntent: Sharable. Going to Read the node. Incompatible with NodeDelete.
+2. (set 1) NodeDelete: Exclusive. About to release the node. Incompatible with AccessIntent.
+3. (set 2) ReadLock: Sharable. Read the node. Incompatible with WriteLock.
+4. (set 2) WriteLock: Exclusive. Modify the node. Incompatible with ReadLock and other WriteLocks.
+5. (set 3) ParentModification: Exclusive. Change the node's parent keys. Incompatible with another ParentModification.
+*/
+
+typedef enum{
+ BtLockAccess,
+ BtLockDelete,
+ BtLockRead,
+ BtLockWrite,
+ BtLockParent
+} BtLock;
+
+// definition for phase-fair reader/writer lock implementation
+
+typedef struct {
+ ushort rin[1];
+ ushort rout[1];
+ ushort ticket[1];
+ ushort serving[1];
+} RWLock;
+
+#define PHID 0x1
+#define PRES 0x2
+#define MASK 0x3
+#define RINC 0x4
+
+// definition for spin latch implementation
+
+// exclusive is set for write access
+// share is count of read accessors
+// grant write lock when share == 0
+
+volatile typedef struct {
+ ushort exclusive:1;
+ ushort pending:1;
+ ushort share:14;
+} BtSpinLatch;
+
+#define XCL 1
+#define PEND 2
+#define BOTH 3
+#define SHARE 4
+
+// hash table entries
+
+typedef struct {
+ BtSpinLatch latch[1];
+ volatile ushort slot; // Latch table entry at head of chain
+} BtHashEntry;
+
+// latch manager table structure
+
+typedef struct {
+ RWLock readwr[1]; // read/write page lock
+ RWLock access[1]; // Access Intent/Page delete
+ RWLock parent[1]; // Posting of fence key in parent
+ BtSpinLatch busy[1]; // slot is being moved between chains
+ volatile ushort next; // next entry in hash table chain
+ volatile ushort prev; // prev entry in hash table chain
+ volatile ushort pin; // number of outstanding locks
+ volatile ushort hash; // hash slot entry is under
+ volatile uid page_no; // latch set page number
+} BtLatchSet;
+
+// Define the length of the page and key pointers
+
+#define BtId 6
+
+// Page key slot definition.
+
+// Keys are marked dead, but remain on the page until
+// it cleanup is called. The fence key (highest key) for
+// a leaf page is always present, even after cleanup.
+
+// Slot types
+
+// In addition to the Unique keys that occupy slots
+// there are Librarian and Duplicate key
+// slots occupying the key slot array.
+
+// The Librarian slots are dead keys that
+// serve as filler, available to add new Unique
+// or Dup slots that are inserted into the B-tree.
+
+// The Duplicate slots have had their key bytes extended
+// by 6 bytes to contain a binary duplicate key uniqueifier.
+
+typedef enum {
+ Unique,
+ Librarian,
+ Duplicate
+} BtSlotType;
+
+typedef struct {
+ uint off:BT_maxbits; // page offset for key start
+ uint type:3; // type of slot
+ uint dead:1; // set for deleted slot
+} BtSlot;
+
+// The key structure occupies space at the upper end of
+// each page. It's a length byte followed by the key
+// bytes.
+
+typedef struct {
+ unsigned char len;
+ unsigned char key[1];
+} *BtKey;
+
+// the value structure also occupies space at the upper
+// end of the page. Each key is immediately followed by a value.
+
+typedef struct {
+ unsigned char len;
+ unsigned char value[1];
+} *BtVal;
+
+// The first part of an index page.
+// It is immediately followed
+// by the BtSlot array of keys.
+
+// note that this structure size
+// must be a multiple of 8 bytes
+// in order to place dups correctly.
+
+typedef struct BtPage_ {
+ uint cnt; // count of keys in page
+ uint act; // count of active keys
+ uint min; // next key offset
+ uint garbage; // page garbage in bytes
+ unsigned char bits:7; // page size in bits
+ unsigned char free:1; // page is on free chain
+ unsigned char lvl:7; // level of page
+ unsigned char kill:1; // page is being deleted
+ unsigned char right[BtId]; // page number to right
+} *BtPage;
+
+// The memory mapping pool table buffer manager entry
+
+typedef struct {
+ uid basepage; // mapped base page number
+ char *map; // mapped memory pointer
+ ushort slot; // slot index in this array
+ ushort pin; // mapped page pin counter
+ void *hashprev; // previous pool entry for the same hash idx
+ void *hashnext; // next pool entry for the same hash idx
+#ifndef unix
+ HANDLE hmap; // Windows memory mapping handle
+#endif
+} BtPool;
+
+#define CLOCK_bit 0x8000 // bit in pool->pin
+
+// The loadpage interface object
+
+typedef struct {
+ uid page_no; // current page number
+ BtPage page; // current page pointer
+ BtPool *pool; // current page pool
+ BtLatchSet *latch; // current page latch set
+} BtPageSet;
+
+// structure for latch manager on ALLOC_page
+
+typedef struct {
+ struct BtPage_ alloc[1]; // next page_no in right ptr
+ unsigned long long dups[1]; // global duplicate key uniqueifier
+ unsigned char chain[BtId]; // head of free page_nos chain
+ BtSpinLatch lock[1]; // allocation area lite latch
+ ushort latchdeployed; // highest number of latch entries deployed
+ ushort nlatchpage; // number of latch pages at BT_latch
+ ushort latchtotal; // number of page latch entries
+ ushort latchhash; // number of latch hash table slots
+ ushort latchvictim; // next latch entry to examine
+ BtHashEntry table[0]; // the hash table
+} BtLatchMgr;
+
+// The object structure for Btree access
+
+typedef struct {
+ uint page_size; // page size
+ uint page_bits; // page size in bits
+ uint seg_bits; // seg size in pages in bits
+ uint mode; // read-write mode
+#ifdef unix
+ int idx;
+#else
+ HANDLE idx;
+#endif
+ ushort poolcnt; // highest page pool node in use
+ ushort poolmax; // highest page pool node allocated
+ ushort poolmask; // total number of pages in mmap segment - 1
+ ushort hashsize; // size of Hash Table for pool entries
+ volatile uint evicted; // last evicted hash table slot
+ ushort *hash; // pool index for hash entries
+ BtSpinLatch *latch; // latches for hash table slots
+ BtLatchMgr *latchmgr; // mapped latch page from allocation page
+ BtLatchSet *latchsets; // mapped latch set from latch pages
+ BtPool *pool; // memory pool page segments
+#ifndef unix
+ HANDLE halloc; // allocation and latch table handle
+#endif
+} BtMgr;
+
+typedef struct {
+ BtMgr *mgr; // buffer manager for thread
+ BtPage cursor; // cached frame for start/next (never mapped)
+ BtPage frame; // spare frame for the page split (never mapped)
+ uid cursor_page; // current cursor page number
+ unsigned char *mem; // frame, cursor, page memory buffer
+ unsigned char key[256]; // last found complete key
+ int found; // last delete or insert was found
+ int err; // last error
+} BtDb;
+
+typedef enum {
+ BTERR_ok = 0,
+ BTERR_struct,
+ BTERR_ovflw,
+ BTERR_lock,
+ BTERR_map,
+ BTERR_wrt,
+ BTERR_hash
+} BTERR;
+
+// B-Tree functions
+extern void bt_close (BtDb *bt);
+extern BtDb *bt_open (BtMgr *mgr);
+extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, void *value, uint vallen, uint update);
+extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl);
+extern int bt_findkey (BtDb *bt, unsigned char *key, uint keylen, unsigned char *value, uint valmax);
+extern BtKey bt_foundkey (BtDb *bt);
+extern uint bt_startkey (BtDb *bt, unsigned char *key, uint len);
+extern uint bt_nextkey (BtDb *bt, uint slot);
+
+// manager functions
+extern BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolsize, uint segsize, uint hashsize);
+void bt_mgrclose (BtMgr *mgr);
+
+// Helper functions to return slot values
+// from the cursor page.
+
+extern BtKey bt_key (BtDb *bt, uint slot);
+extern BtVal bt_val (BtDb *bt, uint slot);
+
+// BTree page number constants
+#define ALLOC_page 0 // allocation & latch manager hash table
+#define ROOT_page 1 // root of the btree
+#define LEAF_page 2 // first page of leaves
+#define LATCH_page 3 // pages for latch manager
+
+// Number of levels to create in a new BTree
+
+#define MIN_lvl 2
+
+// The page is allocated from low and hi ends.
+// The key slots are allocated from the bottom,
+// while the text and value of the key
+// are allocated from the top. When the two
+// areas meet, the page is split into two.
+
+// A key consists of a length byte, two bytes of
+// index number (0 - 65534), and up to 253 bytes
+// of key value.
+
+// Associated with each key is a value byte string
+// containing any value desired.
+
+// The b-tree root is always located at page 1.
+// The first leaf page of level zero is always
+// located on page 2.
+
+// The b-tree pages are linked with next
+// pointers to facilitate enumerators,
+// and provide for concurrency.
+
+// When to root page fills, it is split in two and
+// the tree height is raised by a new root at page
+// one with two keys.
+
+// Deleted keys are marked with a dead bit until
+// page cleanup. The fence key for a leaf node is
+// always present
+
+// Groups of pages called segments from the btree are optionally
+// cached with a memory mapped pool. A hash table is used to keep
+// track of the cached segments. This behaviour is controlled
+// by the cache block size parameter to bt_open.
+
+// To achieve maximum concurrency one page is locked at a time
+// as the tree is traversed to find leaf key in question. The right
+// page numbers are used in cases where the page is being split,
+// or consolidated.
+
+// Page 0 is dedicated to lock for new page extensions,
+// and chains empty pages together for reuse. It also
+// contains the latch manager hash table.
+
+// The ParentModification lock on a node is obtained to serialize posting
+// or changing the fence key for a node.
+
+// Empty pages are chained together through the ALLOC page and reused.
+
+// Access macros to address slot and key values from the page
+// Page slots use 1 based indexing.
+
+#define slotptr(page, slot) (((BtSlot *)(page+1)) + (slot-1))
+#define keyptr(page, slot) ((BtKey)((unsigned char*)(page) + slotptr(page, slot)->off))
+#define valptr(page, slot) ((BtVal)(keyptr(page,slot)->key + keyptr(page,slot)->len))
+
+void bt_putid(unsigned char *dest, uid id)
+{
+int i = BtId;
+
+ while( i-- )
+ dest[i] = (unsigned char)id, id >>= 8;
+}
+
+uid bt_getid(unsigned char *src)
+{
+uid id = 0;
+int i;
+
+ for( i = 0; i < BtId; i++ )
+ id <<= 8, id |= *src++;
+
+ return id;
+}
+
+uid bt_newdup (BtDb *bt)
+{
+#ifdef unix
+ return __sync_fetch_and_add (bt->mgr->latchmgr->dups, 1) + 1;
+#else
+ return _InterlockedIncrement64(bt->mgr->latchmgr->dups, 1);
+#endif
+}
+
+// Phase-Fair reader/writer lock implementation
+
+void WriteLock (RWLock *lock)
+{
+ushort w, r, tix;
+
+#ifdef unix
+ tix = __sync_fetch_and_add (lock->ticket, 1);
+#else
+ tix = _InterlockedExchangeAdd16 (lock->ticket, 1);
+#endif
+ // wait for our ticket to come up
+
+ while( tix != lock->serving[0] )
+#ifdef unix
+ sched_yield();
+#else
+ SwitchToThread ();
+#endif
+
+ w = PRES | (tix & PHID);
+#ifdef unix
+ r = __sync_fetch_and_add (lock->rin, w);
+#else
+ r = _InterlockedExchangeAdd16 (lock->rin, w);
+#endif
+ while( r != *lock->rout )
+#ifdef unix
+ sched_yield();
+#else
+ SwitchToThread();
+#endif
+}
+
+void WriteRelease (RWLock *lock)
+{
+#ifdef unix
+ __sync_fetch_and_and (lock->rin, ~MASK);
+#else
+ _InterlockedAnd16 (lock->rin, ~MASK);
+#endif
+ lock->serving[0]++;
+}
+
+void ReadLock (RWLock *lock)
+{
+ushort w;
+#ifdef unix
+ w = __sync_fetch_and_add (lock->rin, RINC) & MASK;
+#else
+ w = _InterlockedExchangeAdd16 (lock->rin, RINC) & MASK;
+#endif
+ if( w )
+ while( w == (*lock->rin & MASK) )
+#ifdef unix
+ sched_yield ();
+#else
+ SwitchToThread ();
+#endif
+}
+
+void ReadRelease (RWLock *lock)
+{
+#ifdef unix
+ __sync_fetch_and_add (lock->rout, RINC);
+#else
+ _InterlockedExchangeAdd16 (lock->rout, RINC);
+#endif
+}
+
+// Spin Latch Manager
+
+// wait until write lock mode is clear
+// and add 1 to the share count
+
+void bt_spinreadlock(BtSpinLatch *latch)
+{
+ushort prev;
+
+ do {
+#ifdef unix
+ prev = __sync_fetch_and_add ((ushort *)latch, SHARE);
+#else
+ prev = _InterlockedExchangeAdd16((ushort *)latch, SHARE);
+#endif
+ // see if exclusive request is granted or pending
+
+ if( !(prev & BOTH) )
+ return;
+#ifdef unix
+ prev = __sync_fetch_and_add ((ushort *)latch, -SHARE);
+#else
+ prev = _InterlockedExchangeAdd16((ushort *)latch, -SHARE);
+#endif
+#ifdef unix
+ } while( sched_yield(), 1 );
+#else
+ } while( SwitchToThread(), 1 );
+#endif
+}
+
+// wait for other read and write latches to relinquish
+
+void bt_spinwritelock(BtSpinLatch *latch)
+{
+ushort prev;
+
+ do {
+#ifdef unix
+ prev = __sync_fetch_and_or((ushort *)latch, PEND | XCL);
+#else
+ prev = _InterlockedOr16((ushort *)latch, PEND | XCL);
+#endif
+ if( !(prev & XCL) )
+ if( !(prev & ~BOTH) )
+ return;
+ else
+#ifdef unix
+ __sync_fetch_and_and ((ushort *)latch, ~XCL);
+#else
+ _InterlockedAnd16((ushort *)latch, ~XCL);
+#endif
+#ifdef unix
+ } while( sched_yield(), 1 );
+#else
+ } while( SwitchToThread(), 1 );
+#endif
+}
+
+// try to obtain write lock
+
+// return 1 if obtained,
+// 0 otherwise
+
+int bt_spinwritetry(BtSpinLatch *latch)
+{
+ushort prev;
+
+#ifdef unix
+ prev = __sync_fetch_and_or((ushort *)latch, XCL);
+#else
+ prev = _InterlockedOr16((ushort *)latch, XCL);
+#endif
+ // take write access if all bits are clear
+
+ if( !(prev & XCL) )
+ if( !(prev & ~BOTH) )
+ return 1;
+ else
+#ifdef unix
+ __sync_fetch_and_and ((ushort *)latch, ~XCL);
+#else
+ _InterlockedAnd16((ushort *)latch, ~XCL);
+#endif
+ return 0;
+}
+
+// clear write mode
+
+void bt_spinreleasewrite(BtSpinLatch *latch)
+{
+#ifdef unix
+ __sync_fetch_and_and((ushort *)latch, ~BOTH);
+#else
+ _InterlockedAnd16((ushort *)latch, ~BOTH);
+#endif
+}
+
+// decrement reader count
+
+void bt_spinreleaseread(BtSpinLatch *latch)
+{
+#ifdef unix
+ __sync_fetch_and_add((ushort *)latch, -SHARE);
+#else
+ _InterlockedExchangeAdd16((ushort *)latch, -SHARE);
+#endif
+}
+
+// link latch table entry into latch hash table
+
+void bt_latchlink (BtDb *bt, ushort hashidx, ushort victim, uid page_no)
+{
+BtLatchSet *set = bt->mgr->latchsets + victim;
+
+ if( set->next = bt->mgr->latchmgr->table[hashidx].slot )
+ bt->mgr->latchsets[set->next].prev = victim;
+
+ bt->mgr->latchmgr->table[hashidx].slot = victim;
+ set->page_no = page_no;
+ set->hash = hashidx;
+ set->prev = 0;
+}
+
+// release latch pin
+
+void bt_unpinlatch (BtLatchSet *set)
+{
+#ifdef unix
+ __sync_fetch_and_add(&set->pin, -1);
+#else
+ _InterlockedDecrement16 (&set->pin);
+#endif
+}
+
+// find existing latchset or inspire new one
+// return with latchset pinned
+
+BtLatchSet *bt_pinlatch (BtDb *bt, uid page_no)
+{
+ushort hashidx = page_no % bt->mgr->latchmgr->latchhash;
+ushort slot, avail = 0, victim, idx;
+BtLatchSet *set;
+
+ // obtain read lock on hash table entry
+
+ bt_spinreadlock(bt->mgr->latchmgr->table[hashidx].latch);
+
+ if( slot = bt->mgr->latchmgr->table[hashidx].slot ) do
+ {
+ set = bt->mgr->latchsets + slot;
+ if( page_no == set->page_no )
+ break;
+ } while( slot = set->next );
+
+ if( slot ) {
+#ifdef unix
+ __sync_fetch_and_add(&set->pin, 1);
+#else
+ _InterlockedIncrement16 (&set->pin);
+#endif
+ }
+
+ bt_spinreleaseread (bt->mgr->latchmgr->table[hashidx].latch);
+
+ if( slot )
+ return set;
+
+ // try again, this time with write lock
+
+ bt_spinwritelock(bt->mgr->latchmgr->table[hashidx].latch);
+
+ if( slot = bt->mgr->latchmgr->table[hashidx].slot ) do
+ {
+ set = bt->mgr->latchsets + slot;
+ if( page_no == set->page_no )
+ break;
+ if( !set->pin && !avail )
+ avail = slot;
+ } while( slot = set->next );
+
+ // found our entry, or take over an unpinned one
+
+ if( slot || (slot = avail) ) {
+ set = bt->mgr->latchsets + slot;
+#ifdef unix
+ __sync_fetch_and_add(&set->pin, 1);
+#else
+ _InterlockedIncrement16 (&set->pin);
+#endif
+ set->page_no = page_no;
+ bt_spinreleasewrite(bt->mgr->latchmgr->table[hashidx].latch);
+ return set;
+ }
+
+ // see if there are any unused entries
+#ifdef unix
+ victim = __sync_fetch_and_add (&bt->mgr->latchmgr->latchdeployed, 1) + 1;
+#else
+ victim = _InterlockedIncrement16 (&bt->mgr->latchmgr->latchdeployed);
+#endif
+
+ if( victim < bt->mgr->latchmgr->latchtotal ) {
+ set = bt->mgr->latchsets + victim;
+#ifdef unix
+ __sync_fetch_and_add(&set->pin, 1);
+#else
+ _InterlockedIncrement16 (&set->pin);
+#endif
+ bt_latchlink (bt, hashidx, victim, page_no);
+ bt_spinreleasewrite (bt->mgr->latchmgr->table[hashidx].latch);
+ return set;
+ }
+
+#ifdef unix
+ victim = __sync_fetch_and_add (&bt->mgr->latchmgr->latchdeployed, -1);
+#else
+ victim = _InterlockedDecrement16 (&bt->mgr->latchmgr->latchdeployed);
+#endif
+ // find and reuse previous lock entry
+
+ while( 1 ) {
+#ifdef unix
+ victim = __sync_fetch_and_add(&bt->mgr->latchmgr->latchvictim, 1);
+#else
+ victim = _InterlockedIncrement16 (&bt->mgr->latchmgr->latchvictim) - 1;
+#endif
+ // we don't use slot zero
+
+ if( victim %= bt->mgr->latchmgr->latchtotal )
+ set = bt->mgr->latchsets + victim;
+ else
+ continue;
+
+ // take control of our slot
+ // from other threads
+
+ if( set->pin || !bt_spinwritetry (set->busy) )
+ continue;
+
+ idx = set->hash;
+
+ // try to get write lock on hash chain
+ // skip entry if not obtained
+ // or has outstanding locks
+
+ if( !bt_spinwritetry (bt->mgr->latchmgr->table[idx].latch) ) {
+ bt_spinreleasewrite (set->busy);
+ continue;
+ }
+
+ if( set->pin ) {
+ bt_spinreleasewrite (set->busy);
+ bt_spinreleasewrite (bt->mgr->latchmgr->table[idx].latch);
+ continue;
+ }
+
+ // unlink our available victim from its hash chain
+
+ if( set->prev )
+ bt->mgr->latchsets[set->prev].next = set->next;
+ else
+ bt->mgr->latchmgr->table[idx].slot = set->next;
+
+ if( set->next )
+ bt->mgr->latchsets[set->next].prev = set->prev;
+
+ bt_spinreleasewrite (bt->mgr->latchmgr->table[idx].latch);
+#ifdef unix
+ __sync_fetch_and_add(&set->pin, 1);
+#else
+ _InterlockedIncrement16 (&set->pin);
+#endif
+ bt_latchlink (bt, hashidx, victim, page_no);
+ bt_spinreleasewrite (bt->mgr->latchmgr->table[hashidx].latch);
+ bt_spinreleasewrite (set->busy);
+ return set;
+ }
+}
+
+void bt_mgrclose (BtMgr *mgr)
+{
+BtPool *pool;
+uint slot;
+
+ // release mapped pages
+ // note that slot zero is never used
+
+ for( slot = 1; slot < mgr->poolmax; slot++ ) {
+ pool = mgr->pool + slot;
+ if( pool->slot )
+#ifdef unix
+ munmap (pool->map, (uid)(mgr->poolmask+1) << mgr->page_bits);
+#else
+ {
+ FlushViewOfFile(pool->map, 0);
+ UnmapViewOfFile(pool->map);
+ CloseHandle(pool->hmap);
+ }
+#endif
+ }
+
+#ifdef unix
+ munmap (mgr->latchsets, mgr->latchmgr->nlatchpage * mgr->page_size);
+ munmap (mgr->latchmgr, 2 * mgr->page_size);
+#else
+ FlushViewOfFile(mgr->latchmgr, 0);
+ UnmapViewOfFile(mgr->latchmgr);
+ CloseHandle(mgr->halloc);
+#endif
+#ifdef unix
+ close (mgr->idx);
+ free (mgr->pool);
+ free (mgr->hash);
+ free ((void *)mgr->latch);
+ free (mgr);
+#else
+ FlushFileBuffers(mgr->idx);
+ CloseHandle(mgr->idx);
+ GlobalFree (mgr->pool);
+ GlobalFree (mgr->hash);
+ GlobalFree ((void *)mgr->latch);
+ GlobalFree (mgr);
+#endif
+}
+
+// close and release memory
+
+void bt_close (BtDb *bt)
+{
+#ifdef unix
+ if( bt->mem )
+ free (bt->mem);
+#else
+ if( bt->mem)
+ VirtualFree (bt->mem, 0, MEM_RELEASE);
+#endif
+ free (bt);
+}
+
+// open/create new btree buffer manager
+
+// call with file_name, BT_openmode, bits in page size (e.g. 16),
+// size of mapped page pool (e.g. 8192)
+
+BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolmax, uint segsize, uint hashsize)
+{
+uint lvl, attr, cacheblk, last, slot, idx;
+uint nlatchpage, latchhash;
+unsigned char value[BtId];
+BtLatchMgr *latchmgr;
+off64_t size;
+uint amt[1];
+BtMgr* mgr;
+BtKey key;
+BtVal val;
+int flag;
+
+#ifndef unix
+SYSTEM_INFO sysinfo[1];
+#endif
+
+ // determine sanity of page size and buffer pool
+
+ if( bits > BT_maxbits )
+ bits = BT_maxbits;
+ else if( bits < BT_minbits )
+ bits = BT_minbits;
+
+ if( !poolmax )
+ return NULL; // must have buffer pool
+
+#ifdef unix
+ mgr = calloc (1, sizeof(BtMgr));
+
+ mgr->idx = open ((char*)name, O_RDWR | O_CREAT, 0666);
+
+ if( mgr->idx == -1 )
+ return free(mgr), NULL;
+
+ cacheblk = 4096; // minimum mmap segment size for unix
+
+#else
+ mgr = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, sizeof(BtMgr));
+ attr = FILE_ATTRIBUTE_NORMAL;
+ mgr->idx = CreateFile(name, GENERIC_READ| GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, attr, NULL);
+
+ if( mgr->idx == INVALID_HANDLE_VALUE )
+ return GlobalFree(mgr), NULL;
+
+ // normalize cacheblk to multiple of sysinfo->dwAllocationGranularity
+ GetSystemInfo(sysinfo);
+ cacheblk = sysinfo->dwAllocationGranularity;
+#endif
+
+#ifdef unix
+ latchmgr = malloc (BT_maxpage);
+ *amt = 0;
+
+ // read minimum page size to get root info
+
+ if( size = lseek (mgr->idx, 0L, 2) ) {
+ if( pread(mgr->idx, latchmgr, BT_minpage, 0) == BT_minpage )
+ bits = latchmgr->alloc->bits;
+ else
+ return free(mgr), free(latchmgr), NULL;
+ } else if( mode == BT_ro )
+ return free(latchmgr), bt_mgrclose (mgr), NULL;
+#else
+ latchmgr = VirtualAlloc(NULL, BT_maxpage, MEM_COMMIT, PAGE_READWRITE);
+ size = GetFileSize(mgr->idx, amt);
+
+ if( size || *amt ) {
+ if( !ReadFile(mgr->idx, (char *)latchmgr, BT_minpage, amt, NULL) )
+ return bt_mgrclose (mgr), NULL;
+ bits = latchmgr->alloc->bits;
+ } else if( mode == BT_ro )
+ return bt_mgrclose (mgr), NULL;
+#endif
+
+ mgr->page_size = 1 << bits;
+ mgr->page_bits = bits;
+
+ mgr->poolmax = poolmax;
+ mgr->mode = mode;
+
+ if( cacheblk < mgr->page_size )
+ cacheblk = mgr->page_size;
+
+ // mask for partial memmaps
+
+ mgr->poolmask = (cacheblk >> bits) - 1;
+
+ // see if requested size of pages per memmap is greater
+
+ if( (1 << segsize) > mgr->poolmask )
+ mgr->poolmask = (1 << segsize) - 1;
+
+ mgr->seg_bits = 0;
+
+ while( (1 << mgr->seg_bits) <= mgr->poolmask )
+ mgr->seg_bits++;
+
+ mgr->hashsize = hashsize;
+
+#ifdef unix
+ mgr->pool = calloc (poolmax, sizeof(BtPool));
+ mgr->hash = calloc (hashsize, sizeof(ushort));
+ mgr->latch = calloc (hashsize, sizeof(BtSpinLatch));
+#else
+ mgr->pool = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, poolmax * sizeof(BtPool));
+ mgr->hash = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, hashsize * sizeof(ushort));
+ mgr->latch = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, hashsize * sizeof(BtSpinLatch));
+#endif
+
+ if( size || *amt )
+ goto mgrlatch;
+
+ // initialize an empty b-tree with latch page, root page, page of leaves
+ // and page(s) of latches
+
+ memset (latchmgr, 0, 1 << bits);
+ nlatchpage = BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1;
+ bt_putid(latchmgr->alloc->right, MIN_lvl+1+nlatchpage);
+ latchmgr->alloc->bits = mgr->page_bits;
+
+ latchmgr->nlatchpage = nlatchpage;
+ latchmgr->latchtotal = nlatchpage * (mgr->page_size / sizeof(BtLatchSet));
+
+ // initialize latch manager
+
+ latchhash = (mgr->page_size - sizeof(BtLatchMgr)) / sizeof(BtHashEntry);
+
+ // size of hash table = total number of latchsets
+
+ if( latchhash > latchmgr->latchtotal )
+ latchhash = latchmgr->latchtotal;
+
+ latchmgr->latchhash = latchhash;
+
+#ifdef unix
+ if( write (mgr->idx, latchmgr, mgr->page_size) < mgr->page_size )
+ return bt_mgrclose (mgr), NULL;
+#else
+ if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) )
+ return bt_mgrclose (mgr), NULL;
+
+ if( *amt < mgr->page_size )
+ return bt_mgrclose (mgr), NULL;
+#endif
+
+ memset (latchmgr, 0, 1 << bits);
+ latchmgr->alloc->bits = mgr->page_bits;
+
+ for( lvl=MIN_lvl; lvl--; ) {
+ slotptr(latchmgr->alloc, 1)->off = mgr->page_size - 3 - (lvl ? BtId + 1: 1);
+ key = keyptr(latchmgr->alloc, 1);
+ key->len = 2; // create stopper key
+ key->key[0] = 0xff;
+ key->key[1] = 0xff;
+
+ bt_putid(value, MIN_lvl - lvl + 1);
+ val = valptr(latchmgr->alloc, 1);
+ val->len = lvl ? BtId : 0;
+ memcpy (val->value, value, val->len);
+
+ latchmgr->alloc->min = slotptr(latchmgr->alloc, 1)->off;
+ latchmgr->alloc->lvl = lvl;
+ latchmgr->alloc->cnt = 1;
+ latchmgr->alloc->act = 1;
+#ifdef unix
+ if( write (mgr->idx, latchmgr, mgr->page_size) < mgr->page_size )
+ return bt_mgrclose (mgr), NULL;
+#else
+ if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) )
+ return bt_mgrclose (mgr), NULL;
+
+ if( *amt < mgr->page_size )
+ return bt_mgrclose (mgr), NULL;
+#endif
+ }
+
+ // clear out latch manager locks
+ // and rest of pages to round out segment
+
+ memset(latchmgr, 0, mgr->page_size);
+ last = MIN_lvl + 1;
+
+ while( last <= ((MIN_lvl + 1 + nlatchpage) | mgr->poolmask) ) {
+#ifdef unix
+ pwrite(mgr->idx, latchmgr, mgr->page_size, last << mgr->page_bits);
+#else
+ SetFilePointer (mgr->idx, last << mgr->page_bits, NULL, FILE_BEGIN);
+ if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) )
+ return bt_mgrclose (mgr), NULL;
+ if( *amt < mgr->page_size )
+ return bt_mgrclose (mgr), NULL;
+#endif
+ last++;
+ }
+
+mgrlatch:
+#ifdef unix
+ // mlock the root page and the latchmgr page
+
+ flag = PROT_READ | PROT_WRITE;
+ mgr->latchmgr = mmap (0, 2 * mgr->page_size, flag, MAP_SHARED, mgr->idx, ALLOC_page * mgr->page_size);
+ if( mgr->latchmgr == MAP_FAILED )
+ return bt_mgrclose (mgr), NULL;
+ mlock (mgr->latchmgr, 2 * mgr->page_size);
+
+ mgr->latchsets = (BtLatchSet *)mmap (0, mgr->latchmgr->nlatchpage * mgr->page_size, flag, MAP_SHARED, mgr->idx, LATCH_page * mgr->page_size);
+ if( mgr->latchsets == MAP_FAILED )
+ return bt_mgrclose (mgr), NULL;
+ mlock (mgr->latchsets, mgr->latchmgr->nlatchpage * mgr->page_size);
+#else
+ flag = PAGE_READWRITE;
+ mgr->halloc = CreateFileMapping(mgr->idx, NULL, flag, 0, (BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1 + LATCH_page) * mgr->page_size, NULL);
+ if( !mgr->halloc )
+ return bt_mgrclose (mgr), NULL;
+
+ flag = FILE_MAP_WRITE;
+ mgr->latchmgr = MapViewOfFile(mgr->halloc, flag, 0, 0, (BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1 + LATCH_page) * mgr->page_size);
+ if( !mgr->latchmgr )
+ return GetLastError(), bt_mgrclose (mgr), NULL;
+
+ mgr->latchsets = (void *)((char *)mgr->latchmgr + LATCH_page * mgr->page_size);
+#endif
+
+#ifdef unix
+ free (latchmgr);
+#else
+ VirtualFree (latchmgr, 0, MEM_RELEASE);
+#endif
+ return mgr;
+}
+
+// open BTree access method
+// based on buffer manager
+
+BtDb *bt_open (BtMgr *mgr)
+{
+BtDb *bt = malloc (sizeof(*bt));
+
+ memset (bt, 0, sizeof(*bt));
+ bt->mgr = mgr;
+#ifdef unix
+ bt->mem = malloc (2 *mgr->page_size);
+#else
+ bt->mem = VirtualAlloc(NULL, 2 * mgr->page_size, MEM_COMMIT, PAGE_READWRITE);
+#endif
+ bt->frame = (BtPage)bt->mem;
+ bt->cursor = (BtPage)(bt->mem + 1 * mgr->page_size);
+ return bt;
+}
+
+// compare two keys, returning > 0, = 0, or < 0
+// as the comparison value
+
+int keycmp (BtKey key1, unsigned char *key2, uint len2)
+{
+uint len1 = key1->len;
+int ans;
+
+ if( ans = memcmp (key1->key, key2, len1 > len2 ? len2 : len1) )
+ return ans;
+
+ if( len1 > len2 )
+ return 1;
+ if( len1 < len2 )
+ return -1;
+
+ return 0;
+}
+
+// Buffer Pool mgr
+
+// find segment in pool
+// must be called with hashslot idx locked
+// return NULL if not there
+// otherwise return node
+
+BtPool *bt_findpool(BtDb *bt, uid page_no, uint idx)
+{
+BtPool *pool;
+uint slot;
+
+ // compute start of hash chain in pool
+
+ if( slot = bt->mgr->hash[idx] )
+ pool = bt->mgr->pool + slot;
+ else
+ return NULL;
+
+ page_no &= ~bt->mgr->poolmask;
+
+ while( pool->basepage != page_no )
+ if( pool = pool->hashnext )
+ continue;
+ else
+ return NULL;
+
+ return pool;
+}
+
+// add segment to hash table
+
+void bt_linkhash(BtDb *bt, BtPool *pool, uid page_no, int idx)
+{
+BtPool *node;
+uint slot;
+
+ pool->hashprev = pool->hashnext = NULL;
+ pool->basepage = page_no & ~bt->mgr->poolmask;
+ pool->pin = CLOCK_bit + 1;
+
+ if( slot = bt->mgr->hash[idx] ) {
+ node = bt->mgr->pool + slot;
+ pool->hashnext = node;
+ node->hashprev = pool;
+ }
+
+ bt->mgr->hash[idx] = pool->slot;
+}
+
+// map new buffer pool segment to virtual memory
+
+BTERR bt_mapsegment(BtDb *bt, BtPool *pool, uid page_no)
+{
+off64_t off = (page_no & ~bt->mgr->poolmask) << bt->mgr->page_bits;
+off64_t limit = off + ((bt->mgr->poolmask+1) << bt->mgr->page_bits);
+int flag;
+
+#ifdef unix
+ flag = PROT_READ | ( bt->mgr->mode == BT_ro ? 0 : PROT_WRITE );
+ pool->map = mmap (0, (uid)(bt->mgr->poolmask+1) << bt->mgr->page_bits, flag, MAP_SHARED, bt->mgr->idx, off);
+ if( pool->map == MAP_FAILED )
+ return bt->err = BTERR_map;
+
+#else
+ flag = ( bt->mgr->mode == BT_ro ? PAGE_READONLY : PAGE_READWRITE );
+ pool->hmap = CreateFileMapping(bt->mgr->idx, NULL, flag, (DWORD)(limit >> 32), (DWORD)limit, NULL);
+ if( !pool->hmap )
+ return bt->err = BTERR_map;
+
+ flag = ( bt->mgr->mode == BT_ro ? FILE_MAP_READ : FILE_MAP_WRITE );
+ pool->map = MapViewOfFile(pool->hmap, flag, (DWORD)(off >> 32), (DWORD)off, (uid)(bt->mgr->poolmask+1) << bt->mgr->page_bits);
+ if( !pool->map )
+ return bt->err = BTERR_map;
+#endif
+ return bt->err = 0;
+}
+
+// calculate page within pool
+
+BtPage bt_page (BtDb *bt, BtPool *pool, uid page_no)
+{
+uint subpage = (uint)(page_no & bt->mgr->poolmask); // page within mapping
+BtPage page;
+
+ page = (BtPage)(pool->map + (subpage << bt->mgr->page_bits));
+// madvise (page, bt->mgr->page_size, MADV_WILLNEED);
+ return page;
+}
+
+// release pool pin
+
+void bt_unpinpool (BtPool *pool)
+{
+#ifdef unix
+ __sync_fetch_and_add(&pool->pin, -1);
+#else
+ _InterlockedDecrement16 (&pool->pin);
+#endif
+}
+
+// find or place requested page in segment-pool
+// return pool table entry, incrementing pin
+
+BtPool *bt_pinpool(BtDb *bt, uid page_no)
+{
+uint slot, hashidx, idx, victim;
+BtPool *pool, *node, *next;
+
+ // lock hash table chain
+
+ hashidx = (uint)(page_no >> bt->mgr->seg_bits) % bt->mgr->hashsize;
+ bt_spinwritelock (&bt->mgr->latch[hashidx]);
+
+ // look up in hash table
+
+ if( pool = bt_findpool(bt, page_no, hashidx) ) {
+#ifdef unix
+ __sync_fetch_and_or(&pool->pin, CLOCK_bit);
+ __sync_fetch_and_add(&pool->pin, 1);
+#else
+ _InterlockedOr16 (&pool->pin, CLOCK_bit);
+ _InterlockedIncrement16 (&pool->pin);
+#endif
+ bt_spinreleasewrite (&bt->mgr->latch[hashidx]);
+ return pool;
+ }
+
+ // allocate a new pool node
+ // and add to hash table
+
+#ifdef unix
+ slot = __sync_fetch_and_add(&bt->mgr->poolcnt, 1);
+#else
+ slot = _InterlockedIncrement16 (&bt->mgr->poolcnt) - 1;
+#endif
+
+ if( ++slot < bt->mgr->poolmax ) {
+ pool = bt->mgr->pool + slot;
+ pool->slot = slot;
+
+ if( bt_mapsegment(bt, pool, page_no) )
+ return NULL;
+
+ bt_linkhash(bt, pool, page_no, hashidx);
+ bt_spinreleasewrite (&bt->mgr->latch[hashidx]);
+ return pool;
+ }
+
+ // pool table is full
+ // find best pool entry to evict
+
+#ifdef unix
+ __sync_fetch_and_add(&bt->mgr->poolcnt, -1);
+#else
+ _InterlockedDecrement16 (&bt->mgr->poolcnt);
+#endif
+
+ while( 1 ) {
+#ifdef unix
+ victim = __sync_fetch_and_add(&bt->mgr->evicted, 1);
+#else
+ victim = _InterlockedIncrement (&bt->mgr->evicted) - 1;
+#endif
+ victim %= bt->mgr->poolmax;
+ pool = bt->mgr->pool + victim;
+ idx = (uint)(pool->basepage >> bt->mgr->seg_bits) % bt->mgr->hashsize;
+
+ if( !victim )
+ continue;
+
+ // try to get write lock
+ // skip entry if not obtained
+
+ if( !bt_spinwritetry (&bt->mgr->latch[idx]) )
+ continue;
+
+ // skip this entry if
+ // page is pinned
+ // or clock bit is set
+
+ if( pool->pin ) {
+#ifdef unix
+ __sync_fetch_and_and(&pool->pin, ~CLOCK_bit);
+#else
+ _InterlockedAnd16 (&pool->pin, ~CLOCK_bit);
+#endif
+ bt_spinreleasewrite (&bt->mgr->latch[idx]);
+ continue;
+ }
+
+ // unlink victim pool node from hash table
+
+ if( node = pool->hashprev )
+ node->hashnext = pool->hashnext;
+ else if( node = pool->hashnext )
+ bt->mgr->hash[idx] = node->slot;
+ else
+ bt->mgr->hash[idx] = 0;
+
+ if( node = pool->hashnext )
+ node->hashprev = pool->hashprev;
+
+ bt_spinreleasewrite (&bt->mgr->latch[idx]);
+
+ // remove old file mapping
+#ifdef unix
+ munmap (pool->map, (uid)(bt->mgr->poolmask+1) << bt->mgr->page_bits);
+#else
+// FlushViewOfFile(pool->map, 0);
+ UnmapViewOfFile(pool->map);
+ CloseHandle(pool->hmap);
+#endif
+ pool->map = NULL;
+
+ // create new pool mapping
+ // and link into hash table
+
+ if( bt_mapsegment(bt, pool, page_no) )
+ return NULL;
+
+ bt_linkhash(bt, pool, page_no, hashidx);
+ bt_spinreleasewrite (&bt->mgr->latch[hashidx]);
+ return pool;
+ }
+}
+
+// place write, read, or parent lock on requested page_no.
+
+void bt_lockpage(BtLock mode, BtLatchSet *set)
+{
+ switch( mode ) {
+ case BtLockRead:
+ ReadLock (set->readwr);
+ break;
+ case BtLockWrite:
+ WriteLock (set->readwr);
+ break;
+ case BtLockAccess:
+ ReadLock (set->access);
+ break;
+ case BtLockDelete:
+ WriteLock (set->access);
+ break;
+ case BtLockParent:
+ WriteLock (set->parent);
+ break;
+ }
+}
+
+// remove write, read, or parent lock on requested page
+
+void bt_unlockpage(BtLock mode, BtLatchSet *set)
+{
+ switch( mode ) {
+ case BtLockRead:
+ ReadRelease (set->readwr);
+ break;
+ case BtLockWrite:
+ WriteRelease (set->readwr);
+ break;
+ case BtLockAccess:
+ ReadRelease (set->access);
+ break;
+ case BtLockDelete:
+ WriteRelease (set->access);
+ break;
+ case BtLockParent:
+ WriteRelease (set->parent);
+ break;
+ }
+}
+
+// allocate a new page and write page into it
+
+uid bt_newpage(BtDb *bt, BtPage page)
+{
+BtPageSet set[1];
+uid new_page;
+int blk;
+
+ // lock allocation page
+
+ bt_spinwritelock(bt->mgr->latchmgr->lock);
+
+ // use empty chain first
+ // else allocate empty page
+
+ if( new_page = bt_getid(bt->mgr->latchmgr->chain) ) {
+ if( set->pool = bt_pinpool (bt, new_page) )
+ set->page = bt_page (bt, set->pool, new_page);
+ else
+ return 0;
+
+ bt_putid(bt->mgr->latchmgr->chain, bt_getid(set->page->right));
+ bt_unpinpool (set->pool);
+ } else {
+ new_page = bt_getid(bt->mgr->latchmgr->alloc->right);
+ bt_putid(bt->mgr->latchmgr->alloc->right, new_page+1);
+#ifdef unix
+ // if writing first page of pool block, set file length thru last page
+
+ if( (new_page & bt->mgr->poolmask) == 0 )
+ ftruncate (bt->mgr->idx, (new_page + bt->mgr->poolmask + 1) << bt->mgr->page_bits);
+#endif
+ }
+#ifdef unix
+ // unlock allocation latch
+
+ bt_spinreleasewrite(bt->mgr->latchmgr->lock);
+#endif
+
+ // bring new page into pool and copy page.
+ // this will extend the file into the new pages on WIN32.
+
+ if( set->pool = bt_pinpool (bt, new_page) )
+ set->page = bt_page (bt, set->pool, new_page);
+ else
+ return 0;
+
+ memcpy(set->page, page, bt->mgr->page_size);
+ bt_unpinpool (set->pool);
+
+#ifndef unix
+ // unlock allocation latch
+
+ bt_spinreleasewrite(bt->mgr->latchmgr->lock);
+#endif
+ return new_page;
+}
+
+// find slot in page for given key at a given level
+
+int bt_findslot (BtPageSet *set, unsigned char *key, uint len)
+{
+uint diff, higher = set->page->cnt, low = 1, slot;
+uint good = 0;
+
+ // make stopper key an infinite fence value
+
+ if( bt_getid (set->page->right) )
+ higher++;
+ else
+ good++;
+
+ // low is the lowest candidate.
+ // loop ends when they meet
+
+ // higher is already
+ // tested as .ge. the passed key.
+
+ while( diff = higher - low ) {
+ slot = low + ( diff >> 1 );
+ if( keycmp (keyptr(set->page, slot), key, len) < 0 )
+ low = slot + 1;
+ else
+ higher = slot, good++;
+ }
+
+ // return zero if key is on right link page
+
+ return good ? higher : 0;
+}
+
+// find and load page at given level for given key
+// leave page rd or wr locked as requested
+
+int bt_loadpage (BtDb *bt, BtPageSet *set, unsigned char *key, uint len, uint lvl, BtLock lock)
+{
+uid page_no = ROOT_page, prevpage = 0;
+uint drill = 0xff, slot;
+BtLatchSet *prevlatch;
+uint mode, prevmode;
+BtPool *prevpool;
+
+ // start at root of btree and drill down
+
+ do {
+ // determine lock mode of drill level
+ mode = (drill == lvl) ? lock : BtLockRead;
+
+ set->latch = bt_pinlatch (bt, page_no);
+ set->page_no = page_no;
+
+ // pin page contents
+
+ if( set->pool = bt_pinpool (bt, page_no) )
+ set->page = bt_page (bt, set->pool, page_no);
+ else
+ return 0;
+
+ // obtain access lock using lock chaining with Access mode
+
+ if( page_no > ROOT_page )
+ bt_lockpage(BtLockAccess, set->latch);
+
+ // release & unpin parent page
+
+ if( prevpage ) {
+ bt_unlockpage(prevmode, prevlatch);
+ bt_unpinlatch (prevlatch);
+ bt_unpinpool (prevpool);
+ prevpage = 0;
+ }
+
+ // obtain read lock using lock chaining
+
+ bt_lockpage(mode, set->latch);
+
+ if( set->page->free )
+ return bt->err = BTERR_struct, 0;
+
+ if( page_no > ROOT_page )
+ bt_unlockpage(BtLockAccess, set->latch);
+
+ // re-read and re-lock root after determining actual level of root
+
+ if( set->page->lvl != drill) {
+ if( set->page_no != ROOT_page )
+ return bt->err = BTERR_struct, 0;
+
+ drill = set->page->lvl;
+
+ if( lock != BtLockRead && drill == lvl ) {
+ bt_unlockpage(mode, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ continue;
+ }
+ }
+
+ prevpage = set->page_no;
+ prevlatch = set->latch;
+ prevpool = set->pool;
+ prevmode = mode;
+
+ // find key on page at this level
+ // and descend to requested level
+
+ if( set->page->kill )
+ goto slideright;
+
+ if( slot = bt_findslot (set, key, len) ) {
+ if( drill == lvl )
+ return slot;
+
+ while( slotptr(set->page, slot)->dead )
+ if( slot++ < set->page->cnt )
+ continue;
+ else
+ goto slideright;
+
+ page_no = bt_getid(valptr(set->page, slot)->value);
+ drill--;
+ continue;
+ }
+
+ // or slide right into next page
+
+slideright:
+ page_no = bt_getid(set->page->right);
+
+ } while( page_no );
+
+ // return error on end of right chain
+
+ bt->err = BTERR_struct;
+ return 0; // return error
+}
+
+// return page to free list
+// page must be delete & write locked
+
+void bt_freepage (BtDb *bt, BtPageSet *set)
+{
+ // lock allocation page
+
+ bt_spinwritelock (bt->mgr->latchmgr->lock);
+
+ // store chain
+ memcpy(set->page->right, bt->mgr->latchmgr->chain, BtId);
+ bt_putid(bt->mgr->latchmgr->chain, set->page_no);
+ set->page->free = 1;
+
+ // unlock released page
+
+ bt_unlockpage (BtLockDelete, set->latch);
+ bt_unlockpage (BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+
+ // unlock allocation page
+
+ bt_spinreleasewrite (bt->mgr->latchmgr->lock);
+}
+
+// a fence key was deleted from a page
+// push new fence value upwards
+
+BTERR bt_fixfence (BtDb *bt, BtPageSet *set, uint lvl)
+{
+unsigned char leftkey[256], rightkey[256];
+unsigned char value[BtId];
+BtKey ptr;
+
+ // remove the old fence value
+
+ ptr = keyptr(set->page, set->page->cnt);
+ memcpy (rightkey, ptr, ptr->len + 1);
+ memset (slotptr(set->page, set->page->cnt--), 0, sizeof(BtSlot));
+
+ // cache new fence value
+
+ ptr = keyptr(set->page, set->page->cnt);
+ memcpy (leftkey, ptr, ptr->len + 1);
+
+ bt_lockpage (BtLockParent, set->latch);
+ bt_unlockpage (BtLockWrite, set->latch);
+
+ // insert new (now smaller) fence key
+
+ bt_putid (value, set->page_no);
+
+ if( bt_insertkey (bt, leftkey+1, *leftkey, lvl+1, value, BtId, 1) )
+ return bt->err;
+
+ // now delete old fence key
+
+ if( bt_deletekey (bt, rightkey+1, *rightkey, lvl+1) )
+ return bt->err;
+
+ bt_unlockpage (BtLockParent, set->latch);
+ bt_unpinlatch(set->latch);
+ bt_unpinpool (set->pool);
+ return 0;
+}
+
+// root has a single child
+// collapse a level from the tree
+
+BTERR bt_collapseroot (BtDb *bt, BtPageSet *root)
+{
+BtPageSet child[1];
+uint idx;
+
+ // find the child entry and promote as new root contents
+
+ do {
+ for( idx = 0; idx++ < root->page->cnt; )
+ if( !slotptr(root->page, idx)->dead )
+ break;
+
+ child->page_no = bt_getid (valptr(root->page, idx)->value);
+
+ child->latch = bt_pinlatch (bt, child->page_no);
+ bt_lockpage (BtLockDelete, child->latch);
+ bt_lockpage (BtLockWrite, child->latch);
+
+ if( child->pool = bt_pinpool (bt, child->page_no) )
+ child->page = bt_page (bt, child->pool, child->page_no);
+ else
+ return bt->err;
+
+ memcpy (root->page, child->page, bt->mgr->page_size);
+ bt_freepage (bt, child);
+
+ } while( root->page->lvl > 1 && root->page->act == 1 );
+
+ bt_unlockpage (BtLockWrite, root->latch);
+ bt_unpinlatch (root->latch);
+ bt_unpinpool (root->pool);
+ return 0;
+}
+
+// find and delete key on page by marking delete flag bit
+// if page becomes empty, delete it from the btree
+
+BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl)
+{
+unsigned char lowerfence[256], higherfence[256];
+uint slot, idx, found, fence;
+BtPageSet set[1], right[1];
+unsigned char value[BtId];
+BtKey ptr, tst;
+BtVal val;
+
+ if( slot = bt_loadpage (bt, set, key, len, lvl, BtLockWrite) )
+ ptr = keyptr(set->page, slot);
+ else
+ return bt->err;
+
+ // if librarian slot, advance to real slot
+
+ if( slotptr(set->page, slot)->type == Librarian )
+ ptr = keyptr(set->page, ++slot);
+
+ fence = slot == set->page->cnt;
+
+ // if key is found delete it, otherwise ignore request
+
+ if( found = !keycmp (ptr, key, len) )
+ if( found = slotptr(set->page, slot)->dead == 0 ) {
+ val = valptr(set->page,slot);
+ slotptr(set->page, slot)->dead = 1;
+ set->page->garbage += ptr->len + val->len + 2;
+ set->page->act--;
+
+ // collapse empty slots beneath our fence
+
+ while( idx = set->page->cnt - 1 )
+ if( slotptr(set->page, idx)->dead ) {
+ *slotptr(set->page, idx) = *slotptr(set->page, idx + 1);
+ memset (slotptr(set->page, set->page->cnt--), 0, sizeof(BtSlot));
+ } else
+ break;
+ }
+
+ // did we delete a fence key in an upper level?
+
+ if( found && lvl && fence && set->page->act )
+ if( bt_fixfence (bt, set, lvl) )
+ return bt->err;
+ else
+ return bt->found = found, 0;
+
+ // do we need to collapse root?
+
+ if( lvl > 1 && set->page_no == ROOT_page && set->page->act == 1 )
+ if( bt_collapseroot (bt, set) )
+ return bt->err;
+ else
+ return bt->found = found, 0;
+
+ // return if page is not empty
+
+ if( set->page->act ) {
+ bt_unlockpage(BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ return bt->found = found, 0;
+ }
+
+ // cache copy of fence key
+ // to post in parent
+
+ ptr = keyptr(set->page, set->page->cnt);
+ memcpy (lowerfence, ptr, ptr->len + 1);
+
+ // obtain lock on right page
+
+ right->page_no = bt_getid(set->page->right);
+ right->latch = bt_pinlatch (bt, right->page_no);
+ bt_lockpage (BtLockWrite, right->latch);
+
+ // pin page contents
+
+ if( right->pool = bt_pinpool (bt, right->page_no) )
+ right->page = bt_page (bt, right->pool, right->page_no);
+ else
+ return 0;
+
+ if( right->page->kill )
+ return bt->err = BTERR_struct;
+
+ // pull contents of right peer into our empty page
+
+ memcpy (set->page, right->page, bt->mgr->page_size);
+
+ // cache copy of key to update
+
+ ptr = keyptr(right->page, right->page->cnt);
+ memcpy (higherfence, ptr, ptr->len + 1);
+
+ // mark right page deleted and point it to left page
+ // until we can post parent updates
+
+ bt_putid (right->page->right, set->page_no);
+ right->page->kill = 1;
+
+ bt_lockpage (BtLockParent, right->latch);
+ bt_unlockpage (BtLockWrite, right->latch);
+
+ bt_lockpage (BtLockParent, set->latch);
+ bt_unlockpage (BtLockWrite, set->latch);
+
+ // redirect higher key directly to our new node contents
+
+ bt_putid (value, set->page_no);
+
+ if( bt_insertkey (bt, higherfence+1, *higherfence, lvl+1, value, BtId, 1) )
+ return bt->err;
+
+ // delete old lower key to our node
+
+ if( bt_deletekey (bt, lowerfence+1, *lowerfence, lvl+1) )
+ return bt->err;
+
+ // obtain delete and write locks to right node
+
+ bt_unlockpage (BtLockParent, right->latch);
+ bt_lockpage (BtLockDelete, right->latch);
+ bt_lockpage (BtLockWrite, right->latch);
+ bt_freepage (bt, right);
+
+ bt_unlockpage (BtLockParent, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ bt->found = found;
+ return 0;
+}
+
+BtKey bt_foundkey (BtDb *bt)
+{
+ return (BtKey)(bt->key);
+}
+
+// advance to next slot
+
+uint bt_findnext (BtDb *bt, BtPageSet *set, uint slot)
+{
+BtLatchSet *prevlatch;
+BtPool *prevpool;
+uid page_no;
+
+ if( slot < set->page->cnt )
+ return slot + 1;
+
+ prevlatch = set->latch;
+ prevpool = set->pool;
+
+ if( page_no = bt_getid(set->page->right) )
+ set->latch = bt_pinlatch (bt, page_no);
+ else
+ return bt->err = BTERR_struct, 0;
+
+ // pin page contents
+
+ if( set->pool = bt_pinpool (bt, page_no) )
+ set->page = bt_page (bt, set->pool, page_no);
+ else
+ return 0;
+
+ // obtain access lock using lock chaining with Access mode
+
+ bt_lockpage(BtLockAccess, set->latch);
+
+ bt_unlockpage(BtLockRead, prevlatch);
+ bt_unpinlatch (prevlatch);
+ bt_unpinpool (prevpool);
+
+ bt_lockpage(BtLockRead, set->latch);
+ bt_unlockpage(BtLockAccess, set->latch);
+
+ set->page_no = page_no;
+ return 1;
+}
+
+// find unique key or first duplicate key in
+// leaf level and return number of value bytes
+// or (-1) if not found. Setup key for bt_foundkey
+
+int bt_findkey (BtDb *bt, unsigned char *key, uint keylen, unsigned char *value, uint valmax)
+{
+BtPageSet set[1];
+uint len, slot;
+int ret = -1;
+BtKey ptr;
+BtVal val;
+
+ if( slot = bt_loadpage (bt, set, key, keylen, 0, BtLockRead) )
+ do {
+ ptr = keyptr(set->page, slot);
+
+ // skip librarian slot place holder
+
+ if( slotptr(set->page, slot)->type == Librarian )
+ ptr = keyptr(set->page, ++slot);
+
+ if( slotptr(set->page, slot)->dead )
+ continue;
+
+ // return actual key found
+
+ memcpy (bt->key, ptr, ptr->len + 1);
+ len = ptr->len;
+
+ if( slotptr(set->page, slot)->type == Duplicate )
+ len -= BtId;
+
+ // if key exists, return >= 0 value bytes copied
+ // otherwise return (-1)
+
+ if( keylen == len )
+ if( !memcmp (ptr->key, key, len) ) {
+ val = valptr (set->page,slot);
+ if( valmax > val->len )
+ valmax = val->len;
+ memcpy (value, val->value, valmax);
+ ret = valmax;
+ }
+
+ break;
+
+ } while( slot = bt_findnext (bt, set, slot) );
+
+ bt_unlockpage (BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ return ret;
+}
+
+// check page for space available,
+// clean if necessary and return
+// 0 - page needs splitting
+// >0 new slot value
+
+uint bt_cleanpage(BtDb *bt, BtPage page, uint keylen, uint slot, uint vallen)
+{
+uint nxt = bt->mgr->page_size;
+uint cnt = 0, idx = 0;
+uint max = page->cnt;
+uint newslot = max;
+BtKey key;
+BtVal val;
+
+ if( page->min >= (max+2) * sizeof(BtSlot) + sizeof(*page) + keylen + 1 + vallen + 1)
+ return slot;
+
+ // skip cleanup and proceed to split
+ // if there's not enough garbage
+ // to bother with.
+
+ if( page->garbage < nxt / 5 )
+ return 0;
+
+ memcpy (bt->frame, page, bt->mgr->page_size);
+
+ // skip page info and set rest of page to zero
+
+ memset (page+1, 0, bt->mgr->page_size - sizeof(*page));
+ page->garbage = 0;
+ page->act = 0;
+
+ // clean up page first by
+ // removing deleted keys
+
+ while( cnt++ < max ) {
+ if( cnt == slot )
+ newslot = idx + 2;
+ if( cnt < max && slotptr(bt->frame,cnt)->dead )
+ continue;
+
+ // copy the value across
+
+ val = valptr(bt->frame, cnt);
+ nxt -= val->len + 1;
+ ((unsigned char *)page)[nxt] = val->len;
+ memcpy ((unsigned char *)page + nxt + 1, val->value, val->len);
+
+ // copy the key across
+
+ key = keyptr(bt->frame, cnt);
+ nxt -= key->len + 1;
+ memcpy ((unsigned char *)page + nxt, key, key->len + 1);
+
+ // make a librarian slot
+
+ if( idx ) {
+ slotptr(page, ++idx)->off = nxt;
+ slotptr(page, idx)->type = Librarian;
+ slotptr(page, idx)->dead = 1;
+ }
+
+ // set up the slot
+
+ slotptr(page, ++idx)->off = nxt;
+ slotptr(page, idx)->type = slotptr(bt->frame, cnt)->type;
+
+ if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) )
+ page->act++;
+ }
+
+ page->min = nxt;
+ page->cnt = idx;
+
+ // see if page has enough space now, or does it need splitting?
+
+ if( page->min >= (idx+2) * sizeof(BtSlot) + sizeof(*page) + keylen + 1 + vallen + 1 )
+ return newslot;
+
+ return 0;
+}
+
+// split the root and raise the height of the btree
+
+BTERR bt_splitroot(BtDb *bt, BtPageSet *root, unsigned char *leftkey, uid page_no2)
+{
+uint nxt = bt->mgr->page_size;
+unsigned char value[BtId];
+uid left;
+
+ // Obtain an empty page to use, and copy the current
+ // root contents into it, e.g. lower keys
+
+ if( !(left = bt_newpage(bt, root->page)) )
+ return bt->err;
+
+ // preserve the page info at the bottom
+ // of higher keys and set rest to zero
+
+ memset(root->page+1, 0, bt->mgr->page_size - sizeof(*root->page));
+
+ // insert lower keys page fence key on newroot page as first key
+
+ nxt -= BtId + 1;
+ bt_putid (value, left);
+ ((unsigned char *)root->page)[nxt] = BtId;
+ memcpy ((unsigned char *)root->page + nxt + 1, value, BtId);
+
+ nxt -= *leftkey + 1;
+ memcpy ((unsigned char *)root->page + nxt, leftkey, *leftkey + 1);
+ slotptr(root->page, 1)->off = nxt;
+
+ // insert stopper key on newroot page
+ // and increase the root height
+
+ nxt -= 3 + BtId + 1;
+ ((unsigned char *)root->page)[nxt] = 2;
+ ((unsigned char *)root->page)[nxt+1] = 0xff;
+ ((unsigned char *)root->page)[nxt+2] = 0xff;
+
+ bt_putid (value, page_no2);
+ ((unsigned char *)root->page)[nxt+3] = BtId;
+ memcpy ((unsigned char *)root->page + nxt + 4, value, BtId);
+ slotptr(root->page, 2)->off = nxt;
+
+ bt_putid(root->page->right, 0);
+ root->page->min = nxt; // reset lowest used offset and key count
+ root->page->cnt = 2;
+ root->page->act = 2;
+ root->page->lvl++;
+
+ // release and unpin root
+
+ bt_unlockpage(BtLockWrite, root->latch);
+ bt_unpinlatch (root->latch);
+ bt_unpinpool (root->pool);
+ return 0;
+}
+
+// split already locked full node
+// return unlocked.
+
+BTERR bt_splitpage (BtDb *bt, BtPageSet *set)
+{
+uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size;
+unsigned char fencekey[256], rightkey[256];
+unsigned char value[BtId];
+uint lvl = set->page->lvl;
+BtPageSet right[1];
+uint prev;
+BtKey key;
+BtVal val;
+
+ // split higher half of keys to bt->frame
+
+ memset (bt->frame, 0, bt->mgr->page_size);
+ max = set->page->cnt;
+ cnt = max / 2;
+ idx = 0;
+
+ while( cnt++ < max ) {
+ if( slotptr(set->page, cnt)->dead && cnt < max )
+ continue;
+ val = valptr(set->page, cnt);
+ nxt -= val->len + 1;
+ ((unsigned char *)bt->frame)[nxt] = val->len;
+ memcpy ((unsigned char *)bt->frame + nxt + 1, val->value, val->len);
+
+ key = keyptr(set->page, cnt);
+ nxt -= key->len + 1;
+ memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1);
+
+ // add librarian slot
+
+ if( idx ) {
+ slotptr(bt->frame, ++idx)->off = nxt;
+ slotptr(bt->frame, idx)->type = Librarian;
+ slotptr(bt->frame, idx)->dead = 1;
+ }
+
+ // add actual slot
+
+ slotptr(bt->frame, ++idx)->off = nxt;
+ slotptr(bt->frame, idx)->type = slotptr(set->page, cnt)->type;
+
+ if( !(slotptr(bt->frame, idx)->dead = slotptr(set->page, cnt)->dead) )
+ bt->frame->act++;
+ }
+
+ // remember existing fence key for new page to the right
+
+ memcpy (rightkey, key, key->len + 1);
+
+ bt->frame->bits = bt->mgr->page_bits;
+ bt->frame->min = nxt;
+ bt->frame->cnt = idx;
+ bt->frame->lvl = lvl;
+
+ // link right node
+
+ if( set->page_no > ROOT_page )
+ memcpy (bt->frame->right, set->page->right, BtId);
+
+ // get new free page and write higher keys to it.
+
+ if( !(right->page_no = bt_newpage(bt, bt->frame)) )
+ return bt->err;
+
+ // update lower keys to continue in old page
+
+ memcpy (bt->frame, set->page, bt->mgr->page_size);
+ memset (set->page+1, 0, bt->mgr->page_size - sizeof(*set->page));
+ nxt = bt->mgr->page_size;
+ set->page->garbage = 0;
+ set->page->act = 0;
+ max /= 2;
+ cnt = 0;
+ idx = 0;
+
+ if( slotptr(bt->frame, max)->type == Librarian )
+ max--;
+
+ // assemble page of smaller keys
+
+ while( cnt++ < max ) {
+ if( slotptr(bt->frame, cnt)->dead )
+ continue;
+ val = valptr(bt->frame, cnt);
+ nxt -= val->len + 1;
+ ((unsigned char *)set->page)[nxt] = val->len;
+ memcpy ((unsigned char *)set->page + nxt + 1, val->value, val->len);
+
+ key = keyptr(bt->frame, cnt);
+ nxt -= key->len + 1;
+ memcpy ((unsigned char *)set->page + nxt, key, key->len + 1);
+
+ // add librarian slot
+
+ if( idx ) {
+ slotptr(set->page, ++idx)->off = nxt;
+ slotptr(set->page, idx)->type = Librarian;
+ slotptr(set->page, idx)->dead = 1;
+ }
+
+ // add actual slot
+
+ slotptr(set->page, ++idx)->off = nxt;
+ slotptr(set->page, idx)->type = slotptr(bt->frame, cnt)->type;
+ set->page->act++;
+ }
+
+ // remember fence key for smaller page
+
+ memcpy(fencekey, key, key->len + 1);
+
+ bt_putid(set->page->right, right->page_no);
+ set->page->min = nxt;
+ set->page->cnt = idx;
+
+ // if current page is the root page, split it
+
+ if( set->page_no == ROOT_page )
+ return bt_splitroot (bt, set, fencekey, right->page_no);
+
+ // insert new fences in their parent pages
+
+ right->latch = bt_pinlatch (bt, right->page_no);
+ bt_lockpage (BtLockParent, right->latch);
+
+ bt_lockpage (BtLockParent, set->latch);
+ bt_unlockpage (BtLockWrite, set->latch);
+
+ // insert new fence for reformulated left block of smaller keys
+
+ bt_putid (value, set->page_no);
+
+ if( bt_insertkey (bt, fencekey+1, *fencekey, lvl+1, value, BtId, 1) )
+ return bt->err;
+
+ // switch fence for right block of larger keys to new right page
+
+ bt_putid (value, right->page_no);
+
+ if( bt_insertkey (bt, rightkey+1, *rightkey, lvl+1, value, BtId, 1) )
+ return bt->err;
+
+ bt_unlockpage (BtLockParent, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+
+ bt_unlockpage (BtLockParent, right->latch);
+ bt_unpinlatch (right->latch);
+ return 0;
+}
+
+// install new key and value onto page
+// page must already be checked for
+// adequate space
+
+BTERR bt_insertslot (BtDb *bt, BtPageSet *set, uint slot, unsigned char *key,uint keylen, unsigned char *value, uint vallen, uint type)
+{
+uint idx, librarian;
+BtSlot *node;
+
+ // if found slot > desired slot and previous slot
+ // is a librarian slot, use it
+
+ if( slot > 1 )
+ if( slotptr(set->page, slot-1)->type == Librarian )
+ slot--;
+
+ // copy value onto page
+
+ set->page->min -= vallen + 1; // reset lowest used offset
+ ((unsigned char *)set->page)[set->page->min] = vallen;
+ memcpy ((unsigned char *)set->page + set->page->min +1, value, vallen );
+
+ // copy key onto page
+
+ set->page->min -= keylen + 1; // reset lowest used offset
+ ((unsigned char *)set->page)[set->page->min] = keylen;
+ memcpy ((unsigned char *)set->page + set->page->min +1, key, keylen );
+
+ // find first empty slot
+
+ for( idx = slot; idx < set->page->cnt; idx++ )
+ if( slotptr(set->page, idx)->dead )
+ break;
+
+ // now insert key into array before slot
+
+ if( idx == set->page->cnt )
+ idx += 2, set->page->cnt += 2, librarian = 2;
+ else
+ librarian = 1;
+
+ set->page->act++;
+
+ while( idx > slot + librarian - 1 )
+ *slotptr(set->page, idx) = *slotptr(set->page, idx - librarian), idx--;
+
+ // add librarian slot
+
+ if( librarian > 1 ) {
+ node = slotptr(set->page, slot++);
+ node->off = set->page->min;
+ node->type = Librarian;
+ node->dead = 1;
+ }
+
+ // fill in new slot
+
+ node = slotptr(set->page, slot);
+ node->off = set->page->min;
+ node->type = type;
+ node->dead = 0;
+
+ bt_unlockpage (BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ return 0;
+}
+
+// Insert new key into the btree at given level.
+// either add a new key or update/add an existing one
+
+BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint keylen, uint lvl, void *value, uint vallen, uint unique)
+{
+unsigned char newkey[256];
+uint slot, idx, len;
+BtPageSet set[1];
+uid sequence;
+BtKey ptr;
+BtVal val;
+uint type;
+
+ // set up the key we're working on
+
+ memcpy (newkey + 1, key, keylen);
+ newkey[0] = keylen;
+
+ // is this a non-unique index value?
+
+ if( unique )
+ type = Unique;
+ else {
+ type = Duplicate;
+ sequence = bt_newdup (bt);
+ bt_putid (newkey + *newkey + 1, sequence);
+ *newkey += BtId;
+ }
+
+ while( 1 ) { // find the page and slot for the current key
+ if( slot = bt_loadpage (bt, set, newkey + 1, *newkey, lvl, BtLockWrite) )
+ ptr = keyptr(set->page, slot);
+ else {
+ if( !bt->err )
+ bt->err = BTERR_ovflw;
+ return bt->err;
+ }
+
+ // if librarian slot == found slot, advance to real slot
+
+ if( slotptr(set->page, slot)->type == Librarian )
+ if( !keycmp (ptr, key, keylen) )
+ ptr = keyptr(set->page, ++slot);
+
+ len = ptr->len;
+
+ if( slotptr(set->page, slot)->type == Duplicate )
+ len -= BtId;
+
+ // if inserting a duplicate key or unique key
+ // check for adequate space on the page
+ // and insert the new key before slot.
+
+ if( unique && (len != *newkey || memcmp (ptr->key, newkey+1, *newkey)) || !unique ) {
+ if( !(slot = bt_cleanpage (bt, set->page, *newkey, slot, vallen)) )
+ if( bt_splitpage (bt, set) )
+ return bt->err;
+ else
+ continue;
+
+ return bt_insertslot (bt, set, slot, newkey + 1, *newkey, value, vallen, type);
+ }
+
+ // if key already exists, update value and return
+
+ if( val = valptr(set->page, slot), val->len >= vallen ) {
+ if( slotptr(set->page, slot)->dead )
+ set->page->act++;
+ set->page->garbage += val->len - vallen;
+ slotptr(set->page, slot)->dead = 0;
+ val->len = vallen;
+ memcpy (val->value, value, vallen);
+ bt_unlockpage(BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ return 0;
+ }
+
+ // new update value doesn't fit in existing value area
+
+ if( !slotptr(set->page, slot)->dead )
+ set->page->garbage += val->len + ptr->len + 2;
+ else {
+ slotptr(set->page, slot)->dead = 0;
+ set->page->act++;
+ }
+
+ if( !(slot = bt_cleanpage (bt, set->page, keylen, slot, vallen)) )
+ if( bt_splitpage (bt, set) )
+ return bt->err;
+ else
+ continue;
+
+ set->page->min -= vallen + 1;
+ ((unsigned char *)set->page)[set->page->min] = vallen;
+ memcpy ((unsigned char *)set->page + set->page->min +1, value, vallen);
+
+ set->page->min -= keylen + 1;
+ ((unsigned char *)set->page)[set->page->min] = keylen;
+ memcpy ((unsigned char *)set->page + set->page->min +1, key, keylen);
+
+ slotptr(set->page, slot)->off = set->page->min;
+ bt_unlockpage(BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ return 0;
+ }
+ return 0;
+}
+
+// return next slot for cursor page
+// or slide cursor right into next page
+
+uint bt_nextkey (BtDb *bt, uint slot)
+{
+BtPageSet set[1];
+uid right;
+
+ do {
+ right = bt_getid(bt->cursor->right);
+
+ while( slot++ < bt->cursor->cnt )
+ if( slotptr(bt->cursor,slot)->dead )
+ continue;
+ else if( right || (slot < bt->cursor->cnt) ) // skip infinite stopper
+ return slot;
+ else
+ break;
+
+ if( !right )
+ break;
+
+ bt->cursor_page = right;
+
+ if( set->pool = bt_pinpool (bt, right) )
+ set->page = bt_page (bt, set->pool, right);
+ else
+ return 0;
+
+ set->latch = bt_pinlatch (bt, right);
+ bt_lockpage(BtLockRead, set->latch);
+
+ memcpy (bt->cursor, set->page, bt->mgr->page_size);
+
+ bt_unlockpage(BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ slot = 0;
+
+ } while( 1 );
+
+ return bt->err = 0;
+}
+
+// cache page of keys into cursor and return starting slot for given key
+
+uint bt_startkey (BtDb *bt, unsigned char *key, uint len)
+{
+BtPageSet set[1];
+uint slot;
+
+ // cache page for retrieval
+
+ if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) )
+ memcpy (bt->cursor, set->page, bt->mgr->page_size);
+ else
+ return 0;
+
+ bt->cursor_page = set->page_no;
+
+ bt_unlockpage(BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ return slot;
+}
+
+BtKey bt_key(BtDb *bt, uint slot)
+{
+ return keyptr(bt->cursor, slot);
+}
+
+BtVal bt_val(BtDb *bt, uint slot)
+{
+ return valptr(bt->cursor,slot);
+}
+
+#ifdef STANDALONE
+
+#ifndef unix
+double getCpuTime(int type)
+{
+FILETIME crtime[1];
+FILETIME xittime[1];
+FILETIME systime[1];
+FILETIME usrtime[1];
+SYSTEMTIME timeconv[1];
+double ans = 0;
+
+ memset (timeconv, 0, sizeof(SYSTEMTIME));
+
+ switch( type ) {
+ case 0:
+ GetSystemTimeAsFileTime (xittime);
+ FileTimeToSystemTime (xittime, timeconv);
+ ans = (double)timeconv->wDayOfWeek * 3600 * 24;
+ break;
+ case 1:
+ GetProcessTimes (GetCurrentProcess(), crtime, xittime, systime, usrtime);
+ FileTimeToSystemTime (usrtime, timeconv);
+ break;
+ case 2:
+ GetProcessTimes (GetCurrentProcess(), crtime, xittime, systime, usrtime);
+ FileTimeToSystemTime (systime, timeconv);
+ break;
+ }
+
+ ans += (double)timeconv->wHour * 3600;
+ ans += (double)timeconv->wMinute * 60;
+ ans += (double)timeconv->wSecond;
+ ans += (double)timeconv->wMilliseconds / 1000;
+ return ans;
+}
+#else
+#include <time.h>
+#include <sys/resource.h>
+
+double getCpuTime(int type)
+{
+struct rusage used[1];
+struct timeval tv[1];
+
+ switch( type ) {
+ case 0:
+ gettimeofday(tv, NULL);
+ return (double)tv->tv_sec + (double)tv->tv_usec / 1000000;
+
+ case 1:
+ getrusage(RUSAGE_SELF, used);
+ return (double)used->ru_utime.tv_sec + (double)used->ru_utime.tv_usec / 1000000;
+
+ case 2:
+ getrusage(RUSAGE_SELF, used);
+ return (double)used->ru_stime.tv_sec + (double)used->ru_stime.tv_usec / 1000000;
+ }
+
+ return 0;
+}
+#endif
+
+uint bt_latchaudit (BtDb *bt)
+{
+ushort idx, hashidx;
+uid next, page_no;
+BtLatchSet *latch;
+uint cnt = 0;
+BtKey ptr;
+
+#ifdef unix
+ posix_fadvise( bt->mgr->idx, 0, 0, POSIX_FADV_SEQUENTIAL);
+#endif
+ if( *(ushort *)(bt->mgr->latchmgr->lock) )
+ fprintf(stderr, "Alloc page locked\n");
+ *(ushort *)(bt->mgr->latchmgr->lock) = 0;
+
+ for( idx = 1; idx <= bt->mgr->latchmgr->latchdeployed; idx++ ) {
+ latch = bt->mgr->latchsets + idx;
+ if( *latch->readwr->rin & MASK )
+ fprintf(stderr, "latchset %d rwlocked for page %.8x\n", idx, latch->page_no);
+ memset ((ushort *)latch->readwr, 0, sizeof(RWLock));
+
+ if( *latch->access->rin & MASK )
+ fprintf(stderr, "latchset %d accesslocked for page %.8x\n", idx, latch->page_no);
+ memset ((ushort *)latch->access, 0, sizeof(RWLock));
+
+ if( *latch->parent->rin & MASK )
+ fprintf(stderr, "latchset %d parentlocked for page %.8x\n", idx, latch->page_no);
+ memset ((ushort *)latch->parent, 0, sizeof(RWLock));
+
+ if( latch->pin ) {
+ fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, latch->page_no);
+ latch->pin = 0;
+ }
+ }
+
+ for( hashidx = 0; hashidx < bt->mgr->latchmgr->latchhash; hashidx++ ) {
+ if( *(ushort *)(bt->mgr->latchmgr->table[hashidx].latch) )
+ fprintf(stderr, "hash entry %d locked\n", hashidx);
+
+ *(ushort *)(bt->mgr->latchmgr->table[hashidx].latch) = 0;
+
+ if( idx = bt->mgr->latchmgr->table[hashidx].slot ) do {
+ latch = bt->mgr->latchsets + idx;
+ if( *(ushort *)latch->busy )
+ fprintf(stderr, "latchset %d busylocked for page %.8x\n", idx, latch->page_no);
+ *(ushort *)latch->busy = 0;
+ if( latch->pin )
+ fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, latch->page_no);
+ } while( idx = latch->next );
+ }
+
+ next = bt->mgr->latchmgr->nlatchpage + LATCH_page;
+ page_no = LEAF_page;
+
+ while( page_no < bt_getid(bt->mgr->latchmgr->alloc->right) ) {
+ off64_t off = page_no << bt->mgr->page_bits;
+#ifdef unix
+ pread (bt->mgr->idx, bt->frame, bt->mgr->page_size, off);
+#else
+ DWORD amt[1];
+
+ SetFilePointer (bt->mgr->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
+
+ if( !ReadFile(bt->mgr->idx, bt->frame, bt->mgr->page_size, amt, NULL))
+ fprintf(stderr, "page %.8x unable to read\n", page_no);
+
+ if( *amt < bt->mgr->page_size )
+ fprintf(stderr, "page %.8x unable to read\n", page_no);
+#endif
+ if( !bt->frame->free ) {
+ for( idx = 0; idx++ < bt->frame->cnt - 1; ) {
+ ptr = keyptr(bt->frame, idx+1);
+ if( keycmp (keyptr(bt->frame, idx), ptr->key, ptr->len) >= 0 )
+ fprintf(stderr, "page %.8x idx %.2x out of order\n", page_no, idx);
+ }
+ if( !bt->frame->lvl )
+ cnt += bt->frame->act;
+ }
+ if( page_no > LEAF_page )
+ next = page_no + 1;
+ page_no = next;
+ }
+ return cnt - 1;
+}
+
+typedef struct {
+ char idx;
+ char *type;
+ char *infile;
+ BtMgr *mgr;
+ int num;
+} ThreadArg;
+
+// standalone program to index file of keys
+// then list them onto std-out
+
+#ifdef unix
+void *index_file (void *arg)
+#else
+uint __stdcall index_file (void *arg)
+#endif
+{
+int line = 0, found = 0, cnt = 0;
+uid next, page_no = LEAF_page; // start on first page of leaves
+unsigned char key[256];
+ThreadArg *args = arg;
+int ch, len = 0, slot;
+BtPageSet set[1];
+BtKey ptr;
+BtDb *bt;
+FILE *in;
+
+ bt = bt_open (args->mgr);
+
+ switch(args->type[0] | 0x20)
+ {
+ case 'a':
+ fprintf(stderr, "started latch mgr audit\n");
+ cnt = bt_latchaudit (bt);
+ fprintf(stderr, "finished latch mgr audit, found %d keys\n", cnt);
+ break;
+
+ case 'p':
+ fprintf(stderr, "started pennysort for %s\n", args->infile);
+ if( in = fopen (args->infile, "rb") )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ line++;
+
+ if( bt_insertkey (bt, key, 10, 0, key + 10, len - 10, 0) )
+ fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
+ len = 0;
+ }
+ else if( len < 255 )
+ key[len++] = ch;
+ fprintf(stderr, "finished %s for %d keys\n", args->infile, line);
+ break;
+
+ case 'w':
+ fprintf(stderr, "started indexing for %s\n", args->infile);
+ if( in = fopen (args->infile, "rb") )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ line++;
+
+ if( args->num == 1 )
+ sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9;
+
+ else if( args->num )
+ sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
+
+ if( bt_insertkey (bt, key, len, 0, NULL, 0, 0) )
+ fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
+ len = 0;
+ }
+ else if( len < 255 )
+ key[len++] = ch;
+ fprintf(stderr, "finished %s for %d keys\n", args->infile, line);
+ break;
+
+ case 'd':
+ fprintf(stderr, "started deleting keys for %s\n", args->infile);
+ if( in = fopen (args->infile, "rb") )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ line++;
+ if( args->num == 1 )
+ sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9;
+
+ else if( args->num )
+ sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
+
+ if( bt_findkey (bt, key, len, NULL, 0) < 0 )
+ fprintf(stderr, "Cannot find key for Line: %d\n", line), exit(0);
+ ptr = (BtKey)(bt->key);
+
+ if( bt_deletekey (bt, ptr->key, ptr->len, 0) )
+ fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
+ found += bt->found;
+ len = 0;
+ }
+ else if( len < 255 )
+ key[len++] = ch;
+ fprintf(stderr, "finished %s for %d keys, %d found\n", args->infile, line, found);
+ break;
+
+ case 'f':
+ fprintf(stderr, "started finding keys for %s\n", args->infile);
+ if( in = fopen (args->infile, "rb") )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ line++;
+ if( args->num == 1 )
+ sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9;
+
+ else if( args->num )
+ sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
+
+ if( bt_findkey (bt, key, len, NULL, 0) == 0 )
+ found++;
+ else if( bt->err )
+ fprintf(stderr, "Error %d Syserr %d Line: %d\n", bt->err, errno, line), exit(0);
+ len = 0;
+ }
+ else if( len < 255 )
+ key[len++] = ch;
+ fprintf(stderr, "finished %s for %d keys, found %d\n", args->infile, line, found);
+ break;
+
+ case 's':
+ fprintf(stderr, "started scanning\n");
+ do {
+ if( set->pool = bt_pinpool (bt, page_no) )
+ set->page = bt_page (bt, set->pool, page_no);
+ else
+ break;
+ set->latch = bt_pinlatch (bt, page_no);
+ bt_lockpage (BtLockRead, set->latch);
+ next = bt_getid (set->page->right);
+
+ for( slot = 0; slot++ < set->page->cnt; )
+ if( next || slot < set->page->cnt )
+ if( !slotptr(set->page, slot)->dead ) {
+ ptr = keyptr(set->page, slot);
+ len = ptr->len;
+
+ if( slotptr(set->page, slot)->type == Duplicate )
+ len -= BtId;
+
+ fwrite (ptr->key, len, 1, stdout);
+ fputc ('\n', stdout);
+ cnt++;
+ }
+
+ bt_unlockpage (BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+ bt_unpinpool (set->pool);
+ } while( page_no = next );
+
+ fprintf(stderr, " Total keys read %d\n", cnt);
+ break;
+
+ case 'c':
+#ifdef unix
+ posix_fadvise( bt->mgr->idx, 0, 0, POSIX_FADV_SEQUENTIAL);
+#endif
+ fprintf(stderr, "started counting\n");
+ next = bt->mgr->latchmgr->nlatchpage + LATCH_page;
+ page_no = LEAF_page;
+
+ while( page_no < bt_getid(bt->mgr->latchmgr->alloc->right) ) {
+ uid off = page_no << bt->mgr->page_bits;
+#ifdef unix
+ pread (bt->mgr->idx, bt->frame, bt->mgr->page_size, off);
+#else
+ DWORD amt[1];
+
+ SetFilePointer (bt->mgr->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
+
+ if( !ReadFile(bt->mgr->idx, bt->frame, bt->mgr->page_size, amt, NULL))
+ return bt->err = BTERR_map;
+
+ if( *amt < bt->mgr->page_size )
+ return bt->err = BTERR_map;
+#endif
+ if( !bt->frame->free && !bt->frame->lvl )
+ cnt += bt->frame->act;
+ if( page_no > LEAF_page )
+ next = page_no + 1;
+ page_no = next;
+ }
+
+ cnt--; // remove stopper key
+ fprintf(stderr, " Total keys read %d\n", cnt);
+ break;
+ }
+
+ bt_close (bt);
+#ifdef unix
+ return NULL;
+#else
+ return 0;
+#endif
+}
+
+typedef struct timeval timer;
+
+int main (int argc, char **argv)
+{
+int idx, cnt, len, slot, err;
+int segsize, bits = 16;
+double start, stop;
+#ifdef unix
+pthread_t *threads;
+#else
+HANDLE *threads;
+#endif
+ThreadArg *args;
+uint poolsize = 0;
+float elapsed;
+int num = 0;
+char key[1];
+BtMgr *mgr;
+BtKey ptr;
+BtDb *bt;
+
+ if( argc < 3 ) {
+ fprintf (stderr, "Usage: %s idx_file Read/Write/Scan/Delete/Find [page_bits mapped_segments seg_bits line_numbers src_file1 src_file2 ... ]\n", argv[0]);
+ fprintf (stderr, " where page_bits is the page size in bits\n");
+ fprintf (stderr, " mapped_segments is the number of mmap segments in buffer pool\n");
+ fprintf (stderr, " seg_bits is the size of individual segments in buffer pool in pages in bits\n");
+ fprintf (stderr, " line_numbers = 1 to append line numbers to keys\n");
+ fprintf (stderr, " src_file1 thru src_filen are files of keys separated by newline\n");
+ exit(0);
+ }
+
+ start = getCpuTime(0);
+
+ if( argc > 3 )
+ bits = atoi(argv[3]);
+
+ if( argc > 4 )
+ poolsize = atoi(argv[4]);
+
+ if( !poolsize )
+ fprintf (stderr, "Warning: no mapped_pool\n");
+
+ if( poolsize > 65535 )
+ fprintf (stderr, "Warning: mapped_pool > 65535 segments\n");
+
+ if( argc > 5 )
+ segsize = atoi(argv[5]);
+ else
+ segsize = 4; // 16 pages per mmap segment
+
+ if( argc > 6 )
+ num = atoi(argv[6]);
+
+ cnt = argc - 7;
+#ifdef unix
+ threads = malloc (cnt * sizeof(pthread_t));
+#else
+ threads = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, cnt * sizeof(HANDLE));
+#endif
+ args = malloc (cnt * sizeof(ThreadArg));
+
+ mgr = bt_mgr ((argv[1]), BT_rw, bits, poolsize, segsize, poolsize / 8);
+
+ if( !mgr ) {
+ fprintf(stderr, "Index Open Error %s\n", argv[1]);
+ exit (1);
+ }
+
+ // fire off threads
+
+ for( idx = 0; idx < cnt; idx++ ) {
+ args[idx].infile = argv[idx + 7];
+ args[idx].type = argv[2];
+ args[idx].mgr = mgr;
+ args[idx].num = num;
+ args[idx].idx = idx;
+#ifdef unix
+ if( err = pthread_create (threads + idx, NULL, index_file, args + idx) )
+ fprintf(stderr, "Error creating thread %d\n", err);
+#else
+ threads[idx] = (HANDLE)_beginthreadex(NULL, 65536, index_file, args + idx, 0, NULL);
+#endif
+ }
+
+ // wait for termination
+
+#ifdef unix
+ for( idx = 0; idx < cnt; idx++ )
+ pthread_join (threads[idx], NULL);
+#else
+ WaitForMultipleObjects (cnt, threads, TRUE, INFINITE);
+
+ for( idx = 0; idx < cnt; idx++ )
+ CloseHandle(threads[idx]);
+
+#endif
+ elapsed = getCpuTime(0) - start;
+ fprintf(stderr, " real %dm%.3fs\n", (int)(elapsed/60), elapsed - (int)(elapsed/60)*60);
+ elapsed = getCpuTime(1);
+ fprintf(stderr, " user %dm%.3fs\n", (int)(elapsed/60), elapsed - (int)(elapsed/60)*60);
+ elapsed = getCpuTime(2);
+ fprintf(stderr, " sys %dm%.3fs\n", (int)(elapsed/60), elapsed - (int)(elapsed/60)*60);
+
+ bt_mgrclose (mgr);
+}
+
+#endif //STANDALONE
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