--- /dev/null
+// btree version threadskv9 sched_yield version
+// with reworked bt_deletekey code,
+// phase-fair reader writer lock,
+// librarian page split code,
+// duplicate key management
+// bi-directional cursors
+// traditional buffer pool manager
+// ACID batched key-value updates
+// and redo log for failure recovery
+
+// 01 OCT 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;
+typedef unsigned long long logseqno;
+
+#ifndef unix
+typedef unsigned long long off64_t;
+typedef unsigned short ushort;
+typedef unsigned int uint;
+#endif
+
+#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
+
+// BTree page number constants
+#define ALLOC_page 0 // allocation page
+#define ROOT_page 1 // root of the btree
+#define LEAF_page 2 // first page of leaves
+#define REDO_page 3 // first page of redo buffer
+
+// Number of levels to create in a new BTree
+
+#define MIN_lvl 2
+
+/*
+There are six lock types for each node in four 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.
+6. (set 4) AtomicModification: Exclusive. Atomic Update including node is underway. Incompatible with another AtomicModification.
+*/
+
+typedef enum{
+ BtLockAccess = 1,
+ BtLockDelete = 2,
+ BtLockRead = 4,
+ BtLockWrite = 8,
+ BtLockParent = 16,
+ BtLockAtomic = 32
+} BtLock;
+
+// definition for phase-fair reader/writer lock implementation
+
+typedef struct {
+ volatile ushort rin[1];
+ volatile ushort rout[1];
+ volatile ushort ticket[1];
+ volatile ushort serving[1];
+ ushort tid;
+ ushort dup;
+} RWLock;
+
+// write only queue lock
+
+typedef struct {
+ volatile ushort ticket[1];
+ volatile ushort serving[1];
+ ushort tid;
+ ushort dup;
+} WOLock;
+
+#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 {
+ volatile uint slot; // Latch table entry at head of chain
+ BtSpinLatch latch[1];
+} BtHashEntry;
+
+// latch manager table structure
+
+typedef struct {
+ uid page_no; // latch set page number
+ RWLock readwr[1]; // read/write page lock
+ RWLock access[1]; // Access Intent/Page delete
+ WOLock parent[1]; // Posting of fence key in parent
+ WOLock atomic[1]; // Atomic update in progress
+ uint split; // right split page atomic insert
+ uint entry; // entry slot in latch table
+ uint next; // next entry in hash table chain
+ uint prev; // prev entry in hash table chain
+ volatile ushort pin; // number of outstanding threads
+ ushort dirty:1; // page in cache is dirty
+} BtLatchSet;
+
+// Define the length of the page record numbers
+
+#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,
+ Delete,
+ Update
+} 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; // this can be changed to a ushort or uint
+ unsigned char key[0];
+} 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; // this can be changed to a ushort or uint
+ unsigned char value[0];
+} BtVal;
+
+#define BT_maxkey 255 // maximum number of bytes in a key
+#define BT_keyarray (BT_maxkey + sizeof(BtKey))
+
+// 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
+ unsigned char left[BtId]; // page number to left
+ unsigned char filler[2]; // padding to multiple of 8
+ logseqno lsn; // last LogSeqNo applied to page
+} *BtPage;
+
+// The loadpage interface object
+
+typedef struct {
+ BtPage page; // current page pointer
+ 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
+} BtPageZero;
+
+// The object structure for Btree access
+
+typedef struct {
+ uint page_size; // page size
+ uint page_bits; // page size in bits
+#ifdef unix
+ int idx;
+#else
+ HANDLE idx;
+#endif
+ BtPageZero *pagezero; // mapped allocation page
+ BtHashEntry *hashtable; // the buffer pool hash table entries
+ BtLatchSet *latchsets; // mapped latch set from buffer pool
+ unsigned char *pagepool; // mapped to the buffer pool pages
+ unsigned char *redobuff; // mapped recovery buffer pointer
+ logseqno flushlsn; // first lsn flushed w/msync
+ BtSpinLatch redo[1]; // redo area lite latch
+ BtSpinLatch lock[1]; // allocation area lite latch
+ ushort thread_no[1]; // next thread number
+ uint latchdeployed; // highest number of latch entries deployed
+ uint nlatchpage; // number of latch pages at BT_latch
+ uint latchtotal; // number of page latch entries
+ uint latchhash; // number of latch hash table slots
+ uint latchvictim; // next latch entry to examine
+ uint redopages; // size of recovery buff in pages
+ uint redoend; // eof/end element in recovery buff
+#ifndef unix
+ HANDLE halloc; // allocation handle
+ HANDLE hpool; // buffer pool 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[BT_keyarray]; // last found complete key
+ int found; // last delete or insert was found
+ int err; // last error
+ int reads, writes; // number of reads and writes from the btree
+ ushort thread_no; // thread number
+} BtDb;
+
+// Catastrophic errors
+
+typedef enum {
+ BTERR_ok = 0,
+ BTERR_struct,
+ BTERR_ovflw,
+ BTERR_lock,
+ BTERR_map,
+ BTERR_read,
+ BTERR_wrt,
+ BTERR_atomic,
+ BTERR_recovery
+} BTERR;
+
+#define CLOCK_bit 0x8000
+
+// recovery manager entry types
+
+typedef enum {
+ BTRM_eof = 0, // rest of buffer is emtpy
+ BTRM_add, // add a unique key-value to btree
+ BTRM_dup, // add a duplicate key-value to btree
+ BTRM_del, // delete a key-value from btree
+ BTRM_upd, // update a key with a new value
+ BTRM_new, // allocate a new empty page
+ BTRM_old, // reuse an old empty page
+ BTRM_end = 255 // circular buffer inter-gap
+} BTRM;
+
+// recovery manager entry
+// structure followed by BtKey & BtVal
+
+typedef struct {
+ logseqno lsn; // log sequence number for entry
+ uint len; // length of entry
+ unsigned char type; // type of entry
+ unsigned char lvl; // level of btree entry pertains to
+} BtLogHdr;
+
+// B-Tree functions
+
+extern void bt_close (BtDb *bt);
+extern BtDb *bt_open (BtMgr *mgr);
+extern void bt_flushlsn (BtDb *bt);
+extern void bt_lockpage(BtDb *bt, BtLock mode, BtLatchSet *latch);
+extern void bt_unlockpage(BtDb *bt, BtLock mode, BtLatchSet *latch);
+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 bits, uint poolsize, uint rmpages);
+extern void bt_mgrclose (BtMgr *mgr);
+extern logseqno bt_newredo (BtDb *bt, BTRM type, int lvl, BtKey *key, BtVal *val);
+
+// 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);
+
+// 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 - 65535), 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
+
+// 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->pagezero->dups, 1) + 1;
+#else
+ return _InterlockedIncrement64(bt->mgr->pagezero->dups, 1);
+#endif
+}
+
+// Write-Only Queue Lock
+
+void WriteOLock (WOLock *lock, ushort tid)
+{
+ushort tix;
+
+ if( lock->tid == tid ) {
+ lock->dup++;
+ return;
+ }
+#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
+ lock->tid = tid;
+}
+
+void WriteORelease (WOLock *lock)
+{
+ if( lock->dup ) {
+ lock->dup--;
+ return;
+ }
+
+ lock->tid = 0;
+ lock->serving[0]++;
+}
+
+// Phase-Fair reader/writer lock implementation
+
+void WriteLock (RWLock *lock, ushort tid)
+{
+ushort w, r, tix;
+
+ if( lock->tid == tid ) {
+ lock->dup++;
+ return;
+ }
+#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
+ lock->tid = tid;
+}
+
+void WriteRelease (RWLock *lock)
+{
+ if( lock->dup ) {
+ lock->dup--;
+ return;
+ }
+
+ lock->tid = 0;
+#ifdef unix
+ __sync_fetch_and_and (lock->rin, ~MASK);
+#else
+ _InterlockedAnd16 (lock->rin, ~MASK);
+#endif
+ lock->serving[0]++;
+}
+
+void ReadLock (RWLock *lock, ushort tid)
+{
+ushort w;
+ if( lock->tid == tid ) {
+ lock->dup++;
+ return;
+ }
+#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)
+{
+ if( lock->dup ) {
+ lock->dup--;
+ return;
+ }
+
+#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
+}
+
+// recovery manager -- dump current recovery buff & flush
+
+BTERR bt_dumpredo (BtDb *bt)
+{
+BtLogHdr *eof;
+
+ eof = (BtLogHdr *)(bt->mgr->redobuff + bt->mgr->redoend);
+ memset (eof, 0, sizeof(BtLogHdr));
+
+ pwrite (bt->mgr->idx, bt->mgr->redobuff, bt->mgr->redoend + sizeof(BtLogHdr), REDO_page << bt->mgr->page_bits);
+
+ // flush pages written at beginning of this redo buffer
+ // along with the redo buffer out to disk
+
+ fdatasync (bt->mgr->idx);
+
+ bt->mgr->flushlsn = bt->mgr->pagezero->alloc->lsn;
+ bt->mgr->redoend = 0;
+ return 0;
+}
+
+// recovery manager -- append new entry to recovery log
+// flush to disk when it overflows.
+
+logseqno bt_newredo (BtDb *bt, BTRM type, int lvl, BtKey *key, BtVal *val)
+{
+uint size = bt->mgr->page_size * bt->mgr->redopages - sizeof(BtLogHdr);
+uint amt = sizeof(BtLogHdr);
+BtLogHdr *hdr, *eof;
+uint flush;
+
+ bt_spinwritelock (bt->mgr->redo);
+
+ if( key )
+ amt += key->len + val->len + sizeof(BtKey) + sizeof(BtVal);
+
+ // see if new entry fits in buffer
+ // flush and reset if it doesn't
+
+ if( flush = amt > size - bt->mgr->redoend )
+ if( bt_dumpredo (bt) )
+ return 0;
+
+ // fill in new entry & either eof or end block
+
+ hdr = (BtLogHdr *)(bt->mgr->redobuff + bt->mgr->redoend);
+
+ hdr->len = amt;
+ hdr->type = type;
+ hdr->lvl = lvl;
+ hdr->lsn = ++bt->mgr->pagezero->alloc->lsn;
+
+ bt->mgr->redoend += amt;
+
+ eof = (BtLogHdr *)(bt->mgr->redobuff + bt->mgr->redoend);
+ memset (eof, 0, sizeof(BtLogHdr));
+
+ // fill in key and value
+
+ if( key ) {
+ memcpy ((unsigned char *)(hdr + 1), key, key->len + sizeof(BtKey));
+ memcpy ((unsigned char *)(hdr + 1) + key->len + sizeof(BtKey), val, val->len + sizeof(BtVal));
+ }
+
+ bt_spinreleasewrite(bt->mgr->redo);
+
+ if( flush )
+ bt_flushlsn (bt);
+
+ return hdr->lsn;
+}
+
+// read page into buffer pool from permanent location in Btree file
+
+BTERR bt_readpage (BtMgr *mgr, BtPage page, uid page_no)
+{
+off64_t off = page_no << mgr->page_bits;
+
+#ifdef unix
+ if( pread (mgr->idx, page, mgr->page_size, page_no << mgr->page_bits) < mgr->page_size ) {
+ fprintf (stderr, "Unable to read page %.8x errno = %d\n", page_no, errno);
+ return BTERR_read;
+ }
+#else
+OVERLAPPED ovl[1];
+uint amt[1];
+
+ memset (ovl, 0, sizeof(OVERLAPPED));
+ ovl->Offset = off;
+ ovl->OffsetHigh = off >> 32;
+
+ if( !ReadFile(mgr->idx, page, mgr->page_size, amt, ovl)) {
+ fprintf (stderr, "Unable to read page %.8x GetLastError = %d\n", page_no, GetLastError());
+ return BTERR_read;
+ }
+ if( *amt < mgr->page_size ) {
+ fprintf (stderr, "Unable to read page %.8x GetLastError = %d\n", page_no, GetLastError());
+ return BTERR_read;
+ }
+#endif
+ return 0;
+}
+
+// write page to permanent location in Btree file
+// clear the dirty bit
+
+BTERR bt_writepage (BtMgr *mgr, BtPage page, uid page_no)
+{
+off64_t off = page_no << mgr->page_bits;
+
+#ifdef unix
+ if( pwrite(mgr->idx, page, mgr->page_size, off) < mgr->page_size )
+ return BTERR_wrt;
+#else
+OVERLAPPED ovl[1];
+uint amt[1];
+
+ memset (ovl, 0, sizeof(OVERLAPPED));
+ ovl->Offset = off;
+ ovl->OffsetHigh = off >> 32;
+
+ if( !WriteFile(mgr->idx, page, mgr->page_size, amt, ovl) )
+ return BTERR_wrt;
+
+ if( *amt < mgr->page_size )
+ return BTERR_wrt;
+#endif
+ return 0;
+}
+
+// link latch table entry into head of latch hash table
+
+BTERR bt_latchlink (BtDb *bt, uint hashidx, uint slot, uid page_no, uint loadit)
+{
+BtPage page = (BtPage)(((uid)slot << bt->mgr->page_bits) + bt->mgr->pagepool);
+BtLatchSet *latch = bt->mgr->latchsets + slot;
+
+ if( latch->next = bt->mgr->hashtable[hashidx].slot )
+ bt->mgr->latchsets[latch->next].prev = slot;
+
+ bt->mgr->hashtable[hashidx].slot = slot;
+ latch->page_no = page_no;
+ latch->entry = slot;
+ latch->split = 0;
+ latch->prev = 0;
+ latch->pin = 1;
+
+ if( loadit )
+ if( bt->err = bt_readpage (bt->mgr, page, page_no) )
+ return bt->err;
+ else
+ bt->reads++;
+
+ return bt->err = 0;
+}
+
+// set CLOCK bit in latch
+// decrement pin count
+
+void bt_unpinlatch (BtLatchSet *latch)
+{
+#ifdef unix
+ if( ~latch->pin & CLOCK_bit )
+ __sync_fetch_and_or(&latch->pin, CLOCK_bit);
+ __sync_fetch_and_add(&latch->pin, -1);
+#else
+ if( ~latch->pin & CLOCK_bit )
+ _InterlockedOr16 (&latch->pin, CLOCK_bit);
+ _InterlockedDecrement16 (&latch->pin);
+#endif
+}
+
+// return the btree cached page address
+// if page is dirty and has not yet been
+// flushed to disk for the current redo
+// recovery buffer, write it out.
+
+BtPage bt_mappage (BtDb *bt, BtLatchSet *latch)
+{
+BtPage page = (BtPage)(((uid)latch->entry << bt->mgr->page_bits) + bt->mgr->pagepool);
+
+ if( latch->dirty )
+ if( page->lsn < bt->mgr->flushlsn )
+ if( bt->err = bt_writepage (bt->mgr, page, latch->page_no) )
+ return NULL;
+ else
+ latch->dirty = 0, bt->writes++;
+
+ return page;
+}
+
+// find existing latchset or inspire new one
+// return with latchset pinned
+
+BtLatchSet *bt_pinlatch (BtDb *bt, uid page_no, uint loadit)
+{
+uint hashidx = page_no % bt->mgr->latchhash;
+BtLatchSet *latch;
+uint attempts = 0;
+uint slot, idx;
+uint lvl, cnt;
+off64_t off;
+uint amt[1];
+BtPage page;
+
+ // try to find our entry
+
+ bt_spinwritelock(bt->mgr->hashtable[hashidx].latch);
+
+ if( slot = bt->mgr->hashtable[hashidx].slot ) do
+ {
+ latch = bt->mgr->latchsets + slot;
+ if( page_no == latch->page_no )
+ break;
+ } while( slot = latch->next );
+
+ // found our entry
+ // increment clock
+
+ if( slot ) {
+ latch = bt->mgr->latchsets + slot;
+#ifdef unix
+ __sync_fetch_and_add(&latch->pin, 1);
+#else
+ _InterlockedIncrement16 (&latch->pin);
+#endif
+ bt_spinreleasewrite(bt->mgr->hashtable[hashidx].latch);
+ return latch;
+ }
+
+ // see if there are any unused pool entries
+#ifdef unix
+ slot = __sync_fetch_and_add (&bt->mgr->latchdeployed, 1) + 1;
+#else
+ slot = _InterlockedIncrement (&bt->mgr->latchdeployed);
+#endif
+
+ if( slot < bt->mgr->latchtotal ) {
+ latch = bt->mgr->latchsets + slot;
+ if( bt_latchlink (bt, hashidx, slot, page_no, loadit) )
+ return NULL;
+ bt_spinreleasewrite (bt->mgr->hashtable[hashidx].latch);
+ return latch;
+ }
+
+#ifdef unix
+ __sync_fetch_and_add (&bt->mgr->latchdeployed, -1);
+#else
+ _InterlockedDecrement (&bt->mgr->latchdeployed);
+#endif
+ // find and reuse previous entry on victim
+
+ while( 1 ) {
+#ifdef unix
+ slot = __sync_fetch_and_add(&bt->mgr->latchvictim, 1);
+#else
+ slot = _InterlockedIncrement (&bt->mgr->latchvictim) - 1;
+#endif
+ // try to get write lock on hash chain
+ // skip entry if not obtained
+ // or has outstanding pins
+
+ slot %= bt->mgr->latchtotal;
+
+ if( !slot )
+ continue;
+
+ // only go around two times before
+ // flushing redo recovery buffer,
+ // and the buffer pool.
+
+ if( bt->mgr->redopages )
+ if( attempts++ > 2 * bt->mgr->latchtotal ) {
+ if( bt_dumpredo (bt) )
+ return NULL;
+ bt_flushlsn (bt);
+ attempts = 0;
+ }
+
+ latch = bt->mgr->latchsets + slot;
+ idx = latch->page_no % bt->mgr->latchhash;
+
+ // see we are on same chain as hashidx
+
+ if( idx == hashidx )
+ continue;
+
+ if( !bt_spinwritetry (bt->mgr->hashtable[idx].latch) )
+ continue;
+
+ // skip this slot if it is pinned
+ // or the CLOCK bit is set
+
+ if( latch->pin ) {
+ if( latch->pin & CLOCK_bit ) {
+#ifdef unix
+ __sync_fetch_and_and(&latch->pin, ~CLOCK_bit);
+#else
+ _InterlockedAnd16 (&latch->pin, ~CLOCK_bit);
+#endif
+ }
+ bt_spinreleasewrite (bt->mgr->hashtable[idx].latch);
+ continue;
+ }
+
+ page = (BtPage)(((uid)slot << bt->mgr->page_bits) + bt->mgr->pagepool);
+
+ // if dirty page has lsn >= last redo recovery buffer
+ // then hold page in the buffer pool until redo
+ // recovery buffer is written to disk.
+
+ if( latch->dirty )
+ if( page->lsn >= bt->mgr->flushlsn ) {
+ bt_spinreleasewrite (bt->mgr->hashtable[idx].latch);
+ continue;
+ }
+
+ // update permanent page area in btree from buffer pool
+ // no read-lock is required since page is not pinned.
+
+ if( latch->dirty )
+ if( bt->err = bt_writepage (bt->mgr, page, latch->page_no) )
+ return NULL;
+ else
+ latch->dirty = 0, bt->writes++;
+
+ // unlink our available slot from its hash chain
+
+ if( latch->prev )
+ bt->mgr->latchsets[latch->prev].next = latch->next;
+ else
+ bt->mgr->hashtable[idx].slot = latch->next;
+
+ if( latch->next )
+ bt->mgr->latchsets[latch->next].prev = latch->prev;
+
+ bt_spinreleasewrite (bt->mgr->hashtable[idx].latch);
+
+ if( bt_latchlink (bt, hashidx, slot, page_no, loadit) )
+ return NULL;
+
+ bt_spinreleasewrite (bt->mgr->hashtable[hashidx].latch);
+ return latch;
+ }
+}
+
+// flush pages
+
+void bt_flushlsn (BtDb *bt)
+{
+BtLatchSet *latch;
+uint hashidx;
+uint num = 0;
+BtPage page;
+uint slot;
+
+ // flush dirty pool pages to the btree that were
+ // dirty before the start of this redo recovery buffer
+
+ for( slot = 1; slot <= bt->mgr->latchdeployed; slot++ ) {
+ page = (BtPage)(((uid)slot << bt->mgr->page_bits) + bt->mgr->pagepool);
+ latch = bt->mgr->latchsets + slot;
+// hashidx = latch->page_no % bt->mgr->latchhash;
+
+// if( !bt_spinwritetry (bt->mgr->hashtable[hashidx].latch) )
+// continue;
+
+ if( latch->dirty ) {
+ bt_lockpage(bt, BtLockRead, latch);
+ bt_writepage(bt->mgr, page, latch->page_no);
+ latch->dirty = 0, bt->writes++;
+ bt_unlockpage(bt, BtLockRead, latch);
+ }
+
+// bt_spinreleasewrite (bt->mgr->hashtable[hashidx].latch);
+ }
+}
+
+void bt_mgrclose (BtMgr *mgr)
+{
+BtLatchSet *latch;
+BtLogHdr *eof;
+uint num = 0;
+BtPage page;
+uint slot;
+
+ // flush recovery buffer to disk
+
+ if( mgr->redoend ) {
+ eof = (BtLogHdr *)(mgr->redobuff + mgr->redoend);
+ memset (eof, 0, sizeof(BtLogHdr));
+
+ pwrite (mgr->idx, mgr->redobuff, mgr->redoend + sizeof(BtLogHdr), REDO_page << mgr->page_bits);
+ }
+
+ // flush dirty pool pages to the btree
+
+ for( slot = 1; slot <= mgr->latchdeployed; slot++ ) {
+ page = (BtPage)(((uid)slot << mgr->page_bits) + mgr->pagepool);
+ latch = mgr->latchsets + slot;
+
+ if( latch->dirty ) {
+ bt_writepage(mgr, page, latch->page_no);
+ latch->dirty = 0, num++;
+ }
+ }
+
+ fprintf(stderr, "%d buffer pool pages flushed\n", num);
+
+#ifdef unix
+ munmap (mgr->hashtable, (uid)mgr->nlatchpage << mgr->page_bits);
+ munmap (mgr->pagezero, mgr->page_size);
+#else
+ FlushViewOfFile(mgr->pagezero, 0);
+ UnmapViewOfFile(mgr->pagezero);
+ UnmapViewOfFile(mgr->hashtable);
+ CloseHandle(mgr->halloc);
+ CloseHandle(mgr->hpool);
+#endif
+#ifdef unix
+ free (mgr->redobuff);
+ close (mgr->idx);
+ free (mgr);
+#else
+ VirtualFree (mgr->redobuff, 0, MEM_RELEASE);
+ FlushFileBuffers(mgr->idx);
+ CloseHandle(mgr->idx);
+ 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 page pool (e.g. 262144)
+
+BtMgr *bt_mgr (char *name, uint bits, uint nodemax, uint redopages)
+{
+uint lvl, attr, last, slot, idx;
+uint nlatchpage, latchhash;
+unsigned char value[BtId];
+int flag, initit = 0;
+BtPageZero *pagezero;
+off64_t size;
+uint amt[1];
+BtMgr* mgr;
+BtKey* key;
+BtVal *val;
+
+ // determine sanity of page size and buffer pool
+
+ if( bits > BT_maxbits )
+ bits = BT_maxbits;
+ else if( bits < BT_minbits )
+ bits = BT_minbits;
+
+ if( nodemax < 16 ) {
+ fprintf(stderr, "Buffer pool too small: %d\n", nodemax);
+ return NULL;
+ }
+
+#ifdef unix
+ mgr = calloc (1, sizeof(BtMgr));
+
+ mgr->idx = open ((char*)name, O_RDWR | O_CREAT, 0666);
+
+ if( mgr->idx == -1 ) {
+ fprintf (stderr, "Unable to open btree file\n");
+ return free(mgr), NULL;
+ }
+#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;
+#endif
+
+#ifdef unix
+ pagezero = valloc (BT_maxpage);
+ *amt = 0;
+
+ // read minimum page size to get root info
+ // to support raw disk partition files
+ // check if bits == 0 on the disk.
+
+ if( size = lseek (mgr->idx, 0L, 2) )
+ if( pread(mgr->idx, pagezero, BT_minpage, 0) == BT_minpage )
+ if( pagezero->alloc->bits )
+ bits = pagezero->alloc->bits;
+ else
+ initit = 1;
+ else
+ return free(mgr), free(pagezero), NULL;
+ else
+ initit = 1;
+#else
+ pagezero = VirtualAlloc(NULL, BT_maxpage, MEM_COMMIT, PAGE_READWRITE);
+ size = GetFileSize(mgr->idx, amt);
+
+ if( size || *amt ) {
+ if( !ReadFile(mgr->idx, (char *)pagezero, BT_minpage, amt, NULL) )
+ return bt_mgrclose (mgr), NULL;
+ bits = pagezero->alloc->bits;
+ } else
+ initit = 1;
+#endif
+
+ mgr->page_size = 1 << bits;
+ mgr->page_bits = bits;
+
+ // calculate number of latch hash table entries
+
+ mgr->nlatchpage = (nodemax/16 * sizeof(BtHashEntry) + mgr->page_size - 1) / mgr->page_size;
+ mgr->latchhash = ((uid)mgr->nlatchpage << mgr->page_bits) / sizeof(BtHashEntry);
+
+ mgr->nlatchpage += nodemax; // size of the buffer pool in pages
+ mgr->nlatchpage += (sizeof(BtLatchSet) * nodemax + mgr->page_size - 1)/mgr->page_size;
+ mgr->latchtotal = nodemax;
+
+ if( !initit )
+ goto mgrlatch;
+
+ // initialize an empty b-tree with latch page, root page, page of leaves
+ // and page(s) of latches and page pool cache
+
+ memset (pagezero, 0, 1 << bits);
+ pagezero->alloc->bits = mgr->page_bits;
+ bt_putid(pagezero->alloc->right, redopages + MIN_lvl+1);
+
+ // initialize left-most LEAF page in
+ // alloc->left.
+
+ bt_putid (pagezero->alloc->left, LEAF_page);
+
+ if( bt_writepage (mgr, pagezero->alloc, 0) ) {
+ fprintf (stderr, "Unable to create btree page zero\n");
+ return bt_mgrclose (mgr), NULL;
+ }
+
+ memset (pagezero, 0, 1 << bits);
+ pagezero->alloc->bits = mgr->page_bits;
+
+ for( lvl=MIN_lvl; lvl--; ) {
+ slotptr(pagezero->alloc, 1)->off = mgr->page_size - 3 - (lvl ? BtId + sizeof(BtVal): sizeof(BtVal));
+ key = keyptr(pagezero->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(pagezero->alloc, 1);
+ val->len = lvl ? BtId : 0;
+ memcpy (val->value, value, val->len);
+
+ pagezero->alloc->min = slotptr(pagezero->alloc, 1)->off;
+ pagezero->alloc->lvl = lvl;
+ pagezero->alloc->cnt = 1;
+ pagezero->alloc->act = 1;
+
+ if( bt_writepage (mgr, pagezero->alloc, MIN_lvl - lvl) ) {
+ fprintf (stderr, "Unable to create btree page zero\n");
+ return bt_mgrclose (mgr), NULL;
+ }
+ }
+
+mgrlatch:
+#ifdef unix
+ free (pagezero);
+#else
+ VirtualFree (pagezero, 0, MEM_RELEASE);
+#endif
+#ifdef unix
+ // mlock the pagezero page
+
+ flag = PROT_READ | PROT_WRITE;
+ mgr->pagezero = mmap (0, mgr->page_size, flag, MAP_SHARED, mgr->idx, ALLOC_page << mgr->page_bits);
+ if( mgr->pagezero == MAP_FAILED ) {
+ fprintf (stderr, "Unable to mmap btree page zero, error = %d\n", errno);
+ return bt_mgrclose (mgr), NULL;
+ }
+ mlock (mgr->pagezero, mgr->page_size);
+
+ mgr->hashtable = (void *)mmap (0, (uid)mgr->nlatchpage << mgr->page_bits, flag, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+ if( mgr->hashtable == MAP_FAILED ) {
+ fprintf (stderr, "Unable to mmap anonymous buffer pool pages, error = %d\n", errno);
+ return bt_mgrclose (mgr), NULL;
+ }
+ if( mgr->redopages = redopages )
+ mgr->redobuff = valloc (redopages * mgr->page_size);
+#else
+ flag = PAGE_READWRITE;
+ mgr->halloc = CreateFileMapping(mgr->idx, NULL, flag, 0, mgr->page_size, NULL);
+ if( !mgr->halloc ) {
+ fprintf (stderr, "Unable to create page zero memory mapping, error = %d\n", GetLastError());
+ return bt_mgrclose (mgr), NULL;
+ }
+
+ flag = FILE_MAP_WRITE;
+ mgr->pagezero = MapViewOfFile(mgr->halloc, flag, 0, 0, mgr->page_size);
+ if( !mgr->pagezero ) {
+ fprintf (stderr, "Unable to map page zero, error = %d\n", GetLastError());
+ return bt_mgrclose (mgr), NULL;
+ }
+
+ flag = PAGE_READWRITE;
+ size = (uid)mgr->nlatchpage << mgr->page_bits;
+ mgr->hpool = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, flag, size >> 32, size, NULL);
+ if( !mgr->hpool ) {
+ fprintf (stderr, "Unable to create buffer pool memory mapping, error = %d\n", GetLastError());
+ return bt_mgrclose (mgr), NULL;
+ }
+
+ flag = FILE_MAP_WRITE;
+ mgr->hashtable = MapViewOfFile(mgr->pool, flag, 0, 0, size);
+ if( !mgr->hashtable ) {
+ fprintf (stderr, "Unable to map buffer pool, error = %d\n", GetLastError());
+ return bt_mgrclose (mgr), NULL;
+ }
+ if( mgr->redopages = redopages )
+ mgr->redobuff = VirtualAlloc (NULL, redopages * mgr->page_size | MEM_COMMIT, PAGE_READWRITE);
+#endif
+
+ mgr->pagepool = (unsigned char *)mgr->hashtable + ((uid)(mgr->nlatchpage - mgr->latchtotal) << mgr->page_bits);
+ mgr->latchsets = (BtLatchSet *)(mgr->pagepool - (uid)mgr->latchtotal * sizeof(BtLatchSet));
+
+ 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 = valloc (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);
+#ifdef unix
+ bt->thread_no = __sync_fetch_and_add (mgr->thread_no, 1) + 1;
+#else
+ bt->thread_no = _InterlockedIncrement16(mgr->thread_no, 1);
+#endif
+ return bt;
+}
+
+// compare two keys, return > 0, = 0, or < 0
+// =0: keys are same
+// -1: key2 > key1
+// +1: key2 < key1
+// 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;
+}
+
+// place write, read, or parent lock on requested page_no.
+
+void bt_lockpage(BtDb *bt, BtLock mode, BtLatchSet *latch)
+{
+ switch( mode ) {
+ case BtLockRead:
+ ReadLock (latch->readwr, bt->thread_no);
+ break;
+ case BtLockWrite:
+ WriteLock (latch->readwr, bt->thread_no);
+ break;
+ case BtLockAccess:
+ ReadLock (latch->access, bt->thread_no);
+ break;
+ case BtLockDelete:
+ WriteLock (latch->access, bt->thread_no);
+ break;
+ case BtLockParent:
+ WriteOLock (latch->parent, bt->thread_no);
+ break;
+ case BtLockAtomic:
+ WriteOLock (latch->atomic, bt->thread_no);
+ break;
+ case BtLockAtomic | BtLockRead:
+ WriteOLock (latch->atomic, bt->thread_no);
+ ReadLock (latch->readwr, bt->thread_no);
+ break;
+ }
+}
+
+// remove write, read, or parent lock on requested page
+
+void bt_unlockpage(BtDb *bt, BtLock mode, BtLatchSet *latch)
+{
+ switch( mode ) {
+ case BtLockRead:
+ ReadRelease (latch->readwr);
+ break;
+ case BtLockWrite:
+ WriteRelease (latch->readwr);
+ break;
+ case BtLockAccess:
+ ReadRelease (latch->access);
+ break;
+ case BtLockDelete:
+ WriteRelease (latch->access);
+ break;
+ case BtLockParent:
+ WriteORelease (latch->parent);
+ break;
+ case BtLockAtomic:
+ WriteORelease (latch->atomic);
+ break;
+ case BtLockAtomic | BtLockRead:
+ WriteORelease (latch->atomic);
+ ReadRelease (latch->readwr);
+ break;
+ }
+}
+
+// allocate a new page
+// return with page latched, but unlocked.
+
+int bt_newpage(BtDb *bt, BtPageSet *set, BtPage contents)
+{
+uid page_no;
+int blk;
+
+ // lock allocation page
+
+ bt_spinwritelock(bt->mgr->lock);
+
+ // use empty chain first
+ // else allocate empty page
+
+ if( page_no = bt_getid(bt->mgr->pagezero->chain) ) {
+ if( set->latch = bt_pinlatch (bt, page_no, 1) )
+ set->page = bt_mappage (bt, set->latch);
+ else
+ return bt->err = BTERR_struct, -1;
+
+ bt_putid(bt->mgr->pagezero->chain, bt_getid(set->page->right));
+ bt_spinreleasewrite(bt->mgr->lock);
+
+ memcpy (set->page, contents, bt->mgr->page_size);
+ set->latch->dirty = 1;
+ return 0;
+ }
+
+ page_no = bt_getid(bt->mgr->pagezero->alloc->right);
+ bt_putid(bt->mgr->pagezero->alloc->right, page_no+1);
+
+ // unlock allocation latch
+
+ bt_spinreleasewrite(bt->mgr->lock);
+
+ // don't load cache from btree page
+
+ if( set->latch = bt_pinlatch (bt, page_no, 0) )
+ set->page = bt_mappage (bt, set->latch);
+ else
+ return bt->err = BTERR_struct;
+
+ memcpy (set->page, contents, bt->mgr->page_size);
+ set->latch->dirty = 1;
+ return 0;
+}
+
+// find slot in page for given key at a given level
+
+int bt_findslot (BtPage page, unsigned char *key, uint len)
+{
+uint diff, higher = page->cnt, low = 1, slot;
+uint good = 0;
+
+ // make stopper key an infinite fence value
+
+ if( bt_getid (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(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;
+
+ // start at root of btree and drill down
+
+ do {
+ // determine lock mode of drill level
+ mode = (drill == lvl) ? lock : BtLockRead;
+
+ if( !(set->latch = bt_pinlatch (bt, page_no, 1)) )
+ return 0;
+
+ // obtain access lock using lock chaining with Access mode
+
+ if( page_no > ROOT_page )
+ bt_lockpage(bt, BtLockAccess, set->latch);
+
+ set->page = bt_mappage (bt, set->latch);
+
+ // release & unpin parent or left sibling page
+
+ if( prevpage ) {
+ bt_unlockpage(bt, prevmode, prevlatch);
+ bt_unpinlatch (prevlatch);
+ prevpage = 0;
+ }
+
+ // obtain mode lock using lock chaining through AccessLock
+
+ bt_lockpage(bt, mode, set->latch);
+
+ if( set->page->free )
+ return bt->err = BTERR_struct, 0;
+
+ if( page_no > ROOT_page )
+ bt_unlockpage(bt, BtLockAccess, set->latch);
+
+ // re-read and re-lock root after determining actual level of root
+
+ if( set->page->lvl != drill) {
+ if( set->latch->page_no != ROOT_page )
+ return bt->err = BTERR_struct, 0;
+
+ drill = set->page->lvl;
+
+ if( lock != BtLockRead && drill == lvl ) {
+ bt_unlockpage(bt, mode, set->latch);
+ bt_unpinlatch (set->latch);
+ continue;
+ }
+ }
+
+ prevpage = set->latch->page_no;
+ prevlatch = set->latch;
+ prevmode = mode;
+
+ // find key on page at this level
+ // and descend to requested level
+
+ if( !set->page->kill )
+ if( slot = bt_findslot (set->page, key, len) ) {
+ if( drill == lvl )
+ return slot;
+
+ // find next non-dead slot -- the fence key if nothing else
+
+ while( slotptr(set->page, slot)->dead )
+ if( slot++ < set->page->cnt )
+ continue;
+ else
+ return bt->err = BTERR_struct, 0;
+
+ page_no = bt_getid(valptr(set->page, slot)->value);
+ drill--;
+ continue;
+ }
+
+ // or slide right into next page
+
+ 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->lock);
+
+ // store chain
+
+ memcpy(set->page->right, bt->mgr->pagezero->chain, BtId);
+ bt_putid(bt->mgr->pagezero->chain, set->latch->page_no);
+ set->latch->dirty = 1;
+ set->page->free = 1;
+
+ // unlock released page
+
+ bt_unlockpage (bt, BtLockDelete, set->latch);
+ bt_unlockpage (bt, BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+
+ // unlock allocation page
+
+ bt_spinreleasewrite (bt->mgr->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[BT_keyarray], rightkey[BT_keyarray];
+unsigned char value[BtId];
+BtKey* ptr;
+uint idx;
+
+ // remove the old fence value
+
+ ptr = keyptr(set->page, set->page->cnt);
+ memcpy (rightkey, ptr, ptr->len + sizeof(BtKey));
+ memset (slotptr(set->page, set->page->cnt--), 0, sizeof(BtSlot));
+ set->latch->dirty = 1;
+
+ // cache new fence value
+
+ ptr = keyptr(set->page, set->page->cnt);
+ memcpy (leftkey, ptr, ptr->len + sizeof(BtKey));
+
+ bt_lockpage (bt, BtLockParent, set->latch);
+ bt_unlockpage (bt, BtLockWrite, set->latch);
+
+ // insert new (now smaller) fence key
+
+ bt_putid (value, set->latch->page_no);
+ ptr = (BtKey*)leftkey;
+
+ if( bt_insertkey (bt, ptr->key, ptr->len, lvl+1, value, BtId, 1) )
+ return bt->err;
+
+ // now delete old fence key
+
+ ptr = (BtKey*)rightkey;
+
+ if( bt_deletekey (bt, ptr->key, ptr->len, lvl+1) )
+ return bt->err;
+
+ bt_unlockpage (bt, BtLockParent, set->latch);
+ bt_unpinlatch(set->latch);
+ return 0;
+}
+
+// root has a single child
+// collapse a level from the tree
+
+BTERR bt_collapseroot (BtDb *bt, BtPageSet *root)
+{
+BtPageSet child[1];
+uid page_no;
+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;
+
+ page_no = bt_getid (valptr(root->page, idx)->value);
+
+ if( child->latch = bt_pinlatch (bt, page_no, 1) )
+ child->page = bt_mappage (bt, child->latch);
+ else
+ return bt->err;
+
+ bt_lockpage (bt, BtLockDelete, child->latch);
+ bt_lockpage (bt, BtLockWrite, child->latch);
+
+ memcpy (root->page, child->page, bt->mgr->page_size);
+ root->latch->dirty = 1;
+
+ bt_freepage (bt, child);
+
+ } while( root->page->lvl > 1 && root->page->act == 1 );
+
+ bt_unlockpage (bt, BtLockWrite, root->latch);
+ bt_unpinlatch (root->latch);
+ return 0;
+}
+
+// delete a page and manage keys
+// call with page writelocked
+// returns with page unpinned
+
+BTERR bt_deletepage (BtDb *bt, BtPageSet *set)
+{
+unsigned char lowerfence[BT_keyarray], higherfence[BT_keyarray];
+unsigned char value[BtId];
+uint lvl = set->page->lvl;
+BtPageSet right[1];
+uid page_no;
+BtKey *ptr;
+
+ // cache copy of fence key
+ // to post in parent
+
+ ptr = keyptr(set->page, set->page->cnt);
+ memcpy (lowerfence, ptr, ptr->len + sizeof(BtKey));
+
+ // obtain lock on right page
+
+ page_no = bt_getid(set->page->right);
+
+ if( right->latch = bt_pinlatch (bt, page_no, 1) )
+ right->page = bt_mappage (bt, right->latch);
+ else
+ return 0;
+
+ bt_lockpage (bt, BtLockWrite, right->latch);
+
+ // cache copy of key to update
+
+ ptr = keyptr(right->page, right->page->cnt);
+ memcpy (higherfence, ptr, ptr->len + sizeof(BtKey));
+
+ 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);
+ set->latch->dirty = 1;
+
+ // mark right page deleted and point it to left page
+ // until we can post parent updates that remove access
+ // to the deleted page.
+
+ bt_putid (right->page->right, set->latch->page_no);
+ right->latch->dirty = 1;
+ right->page->kill = 1;
+
+ bt_lockpage (bt, BtLockParent, right->latch);
+ bt_unlockpage (bt, BtLockWrite, right->latch);
+
+ bt_lockpage (bt, BtLockParent, set->latch);
+ bt_unlockpage (bt, BtLockWrite, set->latch);
+
+ // redirect higher key directly to our new node contents
+
+ bt_putid (value, set->latch->page_no);
+ ptr = (BtKey*)higherfence;
+
+ if( bt_insertkey (bt, ptr->key, ptr->len, lvl+1, value, BtId, 1) )
+ return bt->err;
+
+ // delete old lower key to our node
+
+ ptr = (BtKey*)lowerfence;
+
+ if( bt_deletekey (bt, ptr->key, ptr->len, lvl+1) )
+ return bt->err;
+
+ // obtain delete and write locks to right node
+
+ bt_unlockpage (bt, BtLockParent, right->latch);
+ bt_lockpage (bt, BtLockDelete, right->latch);
+ bt_lockpage (bt, BtLockWrite, right->latch);
+ bt_freepage (bt, right);
+
+ bt_unlockpage (bt, BtLockParent, set->latch);
+ bt_unpinlatch (set->latch);
+ 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)
+{
+uint slot, idx, found, fence;
+BtPageSet set[1];
+BtKey *ptr;
+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 + sizeof(BtKey) + sizeof(BtVal);
+ set->page->act--;
+
+ // collapse empty slots beneath the 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 && set->page->act && fence )
+ if( bt_fixfence (bt, set, lvl) )
+ return bt->err;
+ else
+ return 0;
+
+ // do we need to collapse root?
+
+ if( lvl > 1 && set->latch->page_no == ROOT_page && set->page->act == 1 )
+ if( bt_collapseroot (bt, set) )
+ return bt->err;
+ else
+ return 0;
+
+ // delete empty page
+
+ if( !set->page->act )
+ return bt_deletepage (bt, set);
+
+ set->latch->dirty = 1;
+ bt_unlockpage(bt, BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ 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;
+uid page_no;
+
+ if( slot < set->page->cnt )
+ return slot + 1;
+
+ prevlatch = set->latch;
+
+ if( page_no = bt_getid(set->page->right) )
+ if( set->latch = bt_pinlatch (bt, page_no, 1) )
+ set->page = bt_mappage (bt, set->latch);
+ else
+ return 0;
+ else
+ return bt->err = BTERR_struct, 0;
+
+ // obtain access lock using lock chaining with Access mode
+
+ bt_lockpage(bt, BtLockAccess, set->latch);
+
+ bt_unlockpage(bt, BtLockRead, prevlatch);
+ bt_unpinlatch (prevlatch);
+
+ bt_lockpage(bt, BtLockRead, set->latch);
+ bt_unlockpage(bt, BtLockAccess, set->latch);
+ 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);
+
+ // return actual key found
+
+ memcpy (bt->key, ptr, ptr->len + sizeof(BtKey));
+ len = ptr->len;
+
+ if( slotptr(set->page, slot)->type == Duplicate )
+ len -= BtId;
+
+ // not there if we reach the stopper key
+
+ if( slot == set->page->cnt )
+ if( !bt_getid (set->page->right) )
+ break;
+
+ // if key exists, return >= 0 value bytes copied
+ // otherwise return (-1)
+
+ if( slotptr(set->page, slot)->dead )
+ continue;
+
+ 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 (bt, BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+ 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, BtPageSet *set, uint keylen, uint slot, uint vallen)
+{
+uint nxt = bt->mgr->page_size;
+BtPage page = set->page;
+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 + sizeof(BtKey) + vallen + sizeof(BtVal))
+ 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));
+ set->latch->dirty = 1;
+ 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 || bt->frame->lvl )
+ if( slotptr(bt->frame,cnt)->dead )
+ continue;
+
+ // copy the value across
+
+ val = valptr(bt->frame, cnt);
+ nxt -= val->len + sizeof(BtVal);
+ memcpy ((unsigned char *)page + nxt, val, val->len + sizeof(BtVal));
+
+ // copy the key across
+
+ key = keyptr(bt->frame, cnt);
+ nxt -= key->len + sizeof(BtKey);
+ memcpy ((unsigned char *)page + nxt, key, key->len + sizeof(BtKey));
+
+ // make a librarian slot
+
+ 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 + sizeof(BtKey) + vallen + sizeof(BtVal) )
+ return newslot;
+
+ return 0;
+}
+
+// split the root and raise the height of the btree
+
+BTERR bt_splitroot(BtDb *bt, BtPageSet *root, BtLatchSet *right)
+{
+unsigned char leftkey[BT_keyarray];
+uint nxt = bt->mgr->page_size;
+unsigned char value[BtId];
+BtPageSet left[1];
+uid left_page_no;
+BtKey *ptr;
+BtVal *val;
+
+ // save left page fence key for new root
+
+ ptr = keyptr(root->page, root->page->cnt);
+ memcpy (leftkey, ptr, ptr->len + sizeof(BtKey));
+
+ // Obtain an empty page to use, and copy the current
+ // root contents into it, e.g. lower keys
+
+ if( bt_newpage(bt, left, root->page) )
+ return bt->err;
+
+ left_page_no = left->latch->page_no;
+ bt_unpinlatch (left->latch);
+
+ // 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 stopper key at top of newroot page
+ // and increase the root height
+
+ nxt -= BtId + sizeof(BtVal);
+ bt_putid (value, right->page_no);
+ val = (BtVal *)((unsigned char *)root->page + nxt);
+ memcpy (val->value, value, BtId);
+ val->len = BtId;
+
+ nxt -= 2 + sizeof(BtKey);
+ slotptr(root->page, 2)->off = nxt;
+ ptr = (BtKey *)((unsigned char *)root->page + nxt);
+ ptr->len = 2;
+ ptr->key[0] = 0xff;
+ ptr->key[1] = 0xff;
+
+ // insert lower keys page fence key on newroot page as first key
+
+ nxt -= BtId + sizeof(BtVal);
+ bt_putid (value, left_page_no);
+ val = (BtVal *)((unsigned char *)root->page + nxt);
+ memcpy (val->value, value, BtId);
+ val->len = BtId;
+
+ ptr = (BtKey *)leftkey;
+ nxt -= ptr->len + sizeof(BtKey);
+ slotptr(root->page, 1)->off = nxt;
+ memcpy ((unsigned char *)root->page + nxt, leftkey, ptr->len + sizeof(BtKey));
+
+ 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 pages
+
+ bt_unlockpage(bt, BtLockWrite, root->latch);
+ bt_unpinlatch (root->latch);
+
+ bt_unpinlatch (right);
+ return 0;
+}
+
+// split already locked full node
+// leave it locked.
+// return pool entry for new right
+// page, unlocked
+
+uint bt_splitpage (BtDb *bt, BtPageSet *set)
+{
+uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size;
+uint lvl = set->page->lvl;
+BtPageSet right[1];
+BtKey *key, *ptr;
+BtVal *val, *src;
+uid right2;
+uint prev;
+
+ // 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( cnt < max || set->page->lvl )
+ if( slotptr(set->page, cnt)->dead )
+ continue;
+
+ src = valptr(set->page, cnt);
+ nxt -= src->len + sizeof(BtVal);
+ memcpy ((unsigned char *)bt->frame + nxt, src, src->len + sizeof(BtVal));
+
+ key = keyptr(set->page, cnt);
+ nxt -= key->len + sizeof(BtKey);
+ ptr = (BtKey*)((unsigned char *)bt->frame + nxt);
+ memcpy (ptr, key, key->len + sizeof(BtKey));
+
+ // add librarian slot
+
+ 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++;
+ }
+
+ bt->frame->bits = bt->mgr->page_bits;
+ bt->frame->min = nxt;
+ bt->frame->cnt = idx;
+ bt->frame->lvl = lvl;
+
+ // link right node
+
+ if( set->latch->page_no > ROOT_page )
+ bt_putid (bt->frame->right, bt_getid (set->page->right));
+
+ // get new free page and write higher keys to it.
+
+ if( bt_newpage(bt, right, bt->frame) )
+ return 0;
+
+ memcpy (bt->frame, set->page, bt->mgr->page_size);
+ memset (set->page+1, 0, bt->mgr->page_size - sizeof(*set->page));
+ set->latch->dirty = 1;
+
+ 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 + sizeof(BtVal);
+ memcpy ((unsigned char *)set->page + nxt, val, val->len + sizeof(BtVal));
+
+ key = keyptr(bt->frame, cnt);
+ nxt -= key->len + sizeof(BtKey);
+ memcpy ((unsigned char *)set->page + nxt, key, key->len + sizeof(BtKey));
+
+ // add librarian slot
+
+ 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++;
+ }
+
+ bt_putid(set->page->right, right->latch->page_no);
+ set->page->min = nxt;
+ set->page->cnt = idx;
+
+ return right->latch->entry;
+}
+
+// fix keys for newly split page
+// call with page locked, return
+// unlocked
+
+BTERR bt_splitkeys (BtDb *bt, BtPageSet *set, BtLatchSet *right)
+{
+unsigned char leftkey[BT_keyarray], rightkey[BT_keyarray];
+unsigned char value[BtId];
+uint lvl = set->page->lvl;
+BtPage page;
+BtKey *ptr;
+
+ // if current page is the root page, split it
+
+ if( set->latch->page_no == ROOT_page )
+ return bt_splitroot (bt, set, right);
+
+ ptr = keyptr(set->page, set->page->cnt);
+ memcpy (leftkey, ptr, ptr->len + sizeof(BtKey));
+
+ page = bt_mappage (bt, right);
+
+ ptr = keyptr(page, page->cnt);
+ memcpy (rightkey, ptr, ptr->len + sizeof(BtKey));
+
+ // insert new fences in their parent pages
+
+ bt_lockpage (bt, BtLockParent, right);
+
+ bt_lockpage (bt, BtLockParent, set->latch);
+ bt_unlockpage (bt, BtLockWrite, set->latch);
+
+ // insert new fence for reformulated left block of smaller keys
+
+ bt_putid (value, set->latch->page_no);
+ ptr = (BtKey *)leftkey;
+
+ if( bt_insertkey (bt, ptr->key, ptr->len, 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);
+ ptr = (BtKey *)rightkey;
+
+ if( bt_insertkey (bt, ptr->key, ptr->len, lvl+1, value, BtId, 1) )
+ return bt->err;
+
+ bt_unlockpage (bt, BtLockParent, set->latch);
+ bt_unpinlatch (set->latch);
+
+ bt_unlockpage (bt, BtLockParent, right);
+ bt_unpinlatch (right);
+ 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 release)
+{
+uint idx, librarian;
+BtSlot *node;
+BtKey *ptr;
+BtVal *val;
+
+ // 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 + sizeof(BtVal);
+ val = (BtVal*)((unsigned char *)set->page + set->page->min);
+ memcpy (val->value, value, vallen);
+ val->len = vallen;
+
+ // copy key onto page
+
+ set->page->min -= keylen + sizeof(BtKey);
+ ptr = (BtKey*)((unsigned char *)set->page + set->page->min);
+ memcpy (ptr->key, key, keylen);
+ ptr->len = 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->latch->dirty = 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;
+
+ if( release ) {
+ bt_unlockpage (bt, BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ }
+
+ 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[BT_keyarray];
+uint slot, idx, len, entry;
+BtPageSet set[1];
+BtKey *ptr, *ins;
+uid sequence;
+BtVal *val;
+uint type;
+
+ // set up the key we're working on
+
+ ins = (BtKey*)newkey;
+ memcpy (ins->key, key, keylen);
+ ins->len = keylen;
+
+ // is this a non-unique index value?
+
+ if( unique )
+ type = Unique;
+ else {
+ type = Duplicate;
+ sequence = bt_newdup (bt);
+ bt_putid (ins->key + ins->len + sizeof(BtKey), sequence);
+ ins->len += BtId;
+ }
+
+ while( 1 ) { // find the page and slot for the current key
+ if( slot = bt_loadpage (bt, set, ins->key, ins->len, 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 != ins->len || memcmp (ptr->key, ins->key, ins->len)) || !unique ) {
+ if( !(slot = bt_cleanpage (bt, set, ins->len, slot, vallen)) )
+ if( !(entry = bt_splitpage (bt, set)) )
+ return bt->err;
+ else if( bt_splitkeys (bt, set, bt->mgr->latchsets + entry) )
+ return bt->err;
+ else
+ continue;
+
+ return bt_insertslot (bt, set, slot, ins->key, ins->len, value, vallen, type, 1);
+ }
+
+ // if key already exists, update value and return
+
+ val = valptr(set->page, slot);
+
+ if( val->len >= vallen ) {
+ if( slotptr(set->page, slot)->dead )
+ set->page->act++;
+ set->page->garbage += val->len - vallen;
+ set->latch->dirty = 1;
+ slotptr(set->page, slot)->dead = 0;
+ val->len = vallen;
+ memcpy (val->value, value, vallen);
+ bt_unlockpage(bt, BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ 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 + sizeof(BtKey) + sizeof(BtVal);
+ else {
+ slotptr(set->page, slot)->dead = 0;
+ set->page->act++;
+ }
+
+ if( !(slot = bt_cleanpage (bt, set, keylen, slot, vallen)) )
+ if( !(entry = bt_splitpage (bt, set)) )
+ return bt->err;
+ else if( bt_splitkeys (bt, set, bt->mgr->latchsets + entry) )
+ return bt->err;
+ else
+ continue;
+
+ set->page->min -= vallen + sizeof(BtVal);
+ val = (BtVal*)((unsigned char *)set->page + set->page->min);
+ memcpy (val->value, value, vallen);
+ val->len = vallen;
+
+ set->latch->dirty = 1;
+ set->page->min -= keylen + sizeof(BtKey);
+ ptr = (BtKey*)((unsigned char *)set->page + set->page->min);
+ memcpy (ptr->key, key, keylen);
+ ptr->len = keylen;
+
+ slotptr(set->page, slot)->off = set->page->min;
+ bt_unlockpage(bt, BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ return 0;
+ }
+ return 0;
+}
+
+typedef struct {
+ logseqno lsn; // redo log sequence number
+ uint entry; // latch table entry number
+ uint slot:31; // page slot number
+ uint reuse:1; // reused previous page
+} AtomicTxn;
+
+typedef struct {
+ uid page_no; // page number for split leaf
+ void *next; // next key to insert
+ uint entry:29; // latch table entry number
+ uint type:2; // 0 == insert, 1 == delete, 2 == free
+ uint nounlock:1; // don't unlock ParentModification
+ unsigned char leafkey[BT_keyarray];
+} AtomicKey;
+
+// determine actual page where key is located
+// return slot number
+
+uint bt_atomicpage (BtDb *bt, BtPage source, AtomicTxn *locks, uint src, BtPageSet *set)
+{
+BtKey *key = keyptr(source,src);
+uint slot = locks[src].slot;
+uint entry;
+
+ if( src > 1 && locks[src].reuse )
+ entry = locks[src-1].entry, slot = 0;
+ else
+ entry = locks[src].entry;
+
+ if( slot ) {
+ set->latch = bt->mgr->latchsets + entry;
+ set->page = bt_mappage (bt, set->latch);
+ return slot;
+ }
+
+ // is locks->reuse set? or was slot zeroed?
+ // if so, find where our key is located
+ // on current page or pages split on
+ // same page txn operations.
+
+ do {
+ set->latch = bt->mgr->latchsets + entry;
+ set->page = bt_mappage (bt, set->latch);
+
+ if( slot = bt_findslot(set->page, key->key, key->len) ) {
+ if( slotptr(set->page, slot)->type == Librarian )
+ slot++;
+ if( locks[src].reuse )
+ locks[src].entry = entry;
+ return slot;
+ }
+ } while( entry = set->latch->split );
+
+ bt->err = BTERR_atomic;
+ return 0;
+}
+
+BTERR bt_atomicinsert (BtDb *bt, BtPage source, AtomicTxn *locks, uint src)
+{
+BtKey *key = keyptr(source, src);
+BtVal *val = valptr(source, src);
+BtLatchSet *latch;
+BtPageSet set[1];
+uint entry, slot;
+
+ while( slot = bt_atomicpage (bt, source, locks, src, set) ) {
+ if( slot = bt_cleanpage(bt, set, key->len, slot, val->len) ) {
+ if( bt_insertslot (bt, set, slot, key->key, key->len, val->value, val->len, slotptr(source,src)->type, 0) )
+ return bt->err;
+ set->page->lsn = locks[src].lsn;
+ return 0;
+ }
+
+ if( entry = bt_splitpage (bt, set) )
+ latch = bt->mgr->latchsets + entry;
+ else
+ return bt->err;
+
+ // splice right page into split chain
+ // and WriteLock it.
+
+ bt_lockpage(bt, BtLockWrite, latch);
+ latch->split = set->latch->split;
+ set->latch->split = entry;
+ locks[src].slot = 0;
+ }
+
+ return bt->err = BTERR_atomic;
+}
+
+BTERR bt_atomicdelete (BtDb *bt, BtPage source, AtomicTxn *locks, uint src)
+{
+BtKey *key = keyptr(source, src);
+uint idx, entry, slot;
+BtPageSet set[1];
+BtKey *ptr;
+BtVal *val;
+
+ if( slot = bt_atomicpage (bt, source, locks, src, set) )
+ ptr = keyptr(set->page, slot);
+ else
+ return bt->err = BTERR_struct;
+
+ if( !keycmp (ptr, key->key, key->len) )
+ if( !slotptr(set->page, slot)->dead )
+ slotptr(set->page, slot)->dead = 1;
+ else
+ return 0;
+ else
+ return 0;
+
+ val = valptr(set->page, slot);
+ set->page->garbage += ptr->len + val->len + sizeof(BtKey) + sizeof(BtVal);
+ set->page->lsn = locks[src].lsn;
+ set->latch->dirty = 1;
+ set->page->act--;
+ bt->found++;
+ return 0;
+}
+
+// delete an empty master page for a transaction
+
+// note that the far right page never empties because
+// it always contains (at least) the infinite stopper key
+// and that all pages that don't contain any keys are
+// deleted, or are being held under Atomic lock.
+
+BTERR bt_atomicfree (BtDb *bt, BtPageSet *prev)
+{
+BtPageSet right[1], temp[1];
+unsigned char value[BtId];
+uid right_page_no;
+BtKey *ptr;
+
+ bt_lockpage(bt, BtLockWrite, prev->latch);
+
+ // grab the right sibling
+
+ if( right->latch = bt_pinlatch(bt, bt_getid (prev->page->right), 1) )
+ right->page = bt_mappage (bt, right->latch);
+ else
+ return bt->err;
+
+ bt_lockpage(bt, BtLockAtomic, right->latch);
+ bt_lockpage(bt, BtLockWrite, right->latch);
+
+ // and pull contents over empty page
+ // while preserving master's left link
+
+ memcpy (right->page->left, prev->page->left, BtId);
+ memcpy (prev->page, right->page, bt->mgr->page_size);
+
+ // forward seekers to old right sibling
+ // to new page location in set
+
+ bt_putid (right->page->right, prev->latch->page_no);
+ right->latch->dirty = 1;
+ right->page->kill = 1;
+
+ // remove pointer to right page for searchers by
+ // changing right fence key to point to the master page
+
+ ptr = keyptr(right->page,right->page->cnt);
+ bt_putid (value, prev->latch->page_no);
+
+ if( bt_insertkey (bt, ptr->key, ptr->len, 1, value, BtId, 1) )
+ return bt->err;
+
+ // now that master page is in good shape we can
+ // remove its locks.
+
+ bt_unlockpage (bt, BtLockAtomic, prev->latch);
+ bt_unlockpage (bt, BtLockWrite, prev->latch);
+
+ // fix master's right sibling's left pointer
+ // to remove scanner's poiner to the right page
+
+ if( right_page_no = bt_getid (prev->page->right) ) {
+ if( temp->latch = bt_pinlatch (bt, right_page_no, 1) )
+ temp->page = bt_mappage (bt, temp->latch);
+
+ bt_lockpage (bt, BtLockWrite, temp->latch);
+ bt_putid (temp->page->left, prev->latch->page_no);
+ temp->latch->dirty = 1;
+
+ bt_unlockpage (bt, BtLockWrite, temp->latch);
+ bt_unpinlatch (temp->latch);
+ } else { // master is now the far right page
+ bt_spinwritelock (bt->mgr->lock);
+ bt_putid (bt->mgr->pagezero->alloc->left, prev->latch->page_no);
+ bt_spinreleasewrite(bt->mgr->lock);
+ }
+
+ // now that there are no pointers to the right page
+ // we can delete it after the last read access occurs
+
+ bt_unlockpage (bt, BtLockWrite, right->latch);
+ bt_unlockpage (bt, BtLockAtomic, right->latch);
+ bt_lockpage (bt, BtLockDelete, right->latch);
+ bt_lockpage (bt, BtLockWrite, right->latch);
+ bt_freepage (bt, right);
+ return 0;
+}
+
+// atomic modification of a batch of keys.
+
+// return -1 if BTERR is set
+// otherwise return slot number
+// causing the key constraint violation
+// or zero on successful completion.
+
+int bt_atomictxn (BtDb *bt, BtPage source)
+{
+uint src, idx, slot, samepage, entry;
+AtomicKey *head, *tail, *leaf;
+BtPageSet set[1], prev[1];
+unsigned char value[BtId];
+BtKey *key, *ptr, *key2;
+BtLatchSet *latch;
+AtomicTxn *locks;
+int result = 0;
+BtSlot temp[1];
+BtPage page;
+BtVal *val;
+uid right;
+int type;
+
+ locks = calloc (source->cnt + 1, sizeof(AtomicTxn));
+ head = NULL;
+ tail = NULL;
+
+ // stable sort the list of keys into order to
+ // prevent deadlocks between threads.
+
+ for( src = 1; src++ < source->cnt; ) {
+ *temp = *slotptr(source,src);
+ key = keyptr (source,src);
+
+ for( idx = src; --idx; ) {
+ key2 = keyptr (source,idx);
+ if( keycmp (key, key2->key, key2->len) < 0 ) {
+ *slotptr(source,idx+1) = *slotptr(source,idx);
+ *slotptr(source,idx) = *temp;
+ } else
+ break;
+ }
+ }
+
+ // Load the leaf page for each key
+ // group same page references with reuse bit
+ // and determine any constraint violations
+
+ for( src = 0; src++ < source->cnt; ) {
+ key = keyptr(source, src);
+ slot = 0;
+
+ // first determine if this modification falls
+ // on the same page as the previous modification
+ // note that the far right leaf page is a special case
+
+ if( samepage = src > 1 )
+ if( samepage = !bt_getid(set->page->right) || keycmp (keyptr(set->page, set->page->cnt), key->key, key->len) >= 0 )
+ slot = bt_findslot(set->page, key->key, key->len);
+ else
+ bt_unlockpage(bt, BtLockRead, set->latch);
+
+ if( !slot )
+ if( slot = bt_loadpage(bt, set, key->key, key->len, 0, BtLockRead | BtLockAtomic) )
+ set->latch->split = 0;
+ else
+ goto atomicerr;
+
+ if( slotptr(set->page, slot)->type == Librarian )
+ ptr = keyptr(set->page, ++slot);
+ else
+ ptr = keyptr(set->page, slot);
+
+ if( !samepage ) {
+ locks[src].entry = set->latch->entry;
+ locks[src].slot = slot;
+ locks[src].reuse = 0;
+ } else {
+ locks[src].entry = 0;
+ locks[src].slot = 0;
+ locks[src].reuse = 1;
+ }
+
+ switch( slotptr(source, src)->type ) {
+ case Duplicate:
+ case Unique:
+ if( !slotptr(set->page, slot)->dead )
+ if( slot < set->page->cnt || bt_getid (set->page->right) )
+ if( !keycmp (ptr, key->key, key->len) ) {
+
+ // return constraint violation if key already exists
+
+ bt_unlockpage(bt, BtLockRead, set->latch);
+ result = src;
+
+ while( src ) {
+ if( locks[src].entry ) {
+ set->latch = bt->mgr->latchsets + locks[src].entry;
+ bt_unlockpage(bt, BtLockAtomic, set->latch);
+ bt_unpinlatch (set->latch);
+ }
+ src--;
+ }
+ free (locks);
+ return result;
+ }
+ break;
+ }
+ }
+
+ // unlock last loadpage lock
+
+ if( source->cnt )
+ bt_unlockpage(bt, BtLockRead, set->latch);
+
+ // and add entries to redo log
+
+ for( src = 0; src++ < source->cnt; ) {
+ key = keyptr(source, src);
+ val = valptr(source, src);
+ switch( slotptr(source, src)->type ) {
+ case Unique:
+ type = BTRM_add;
+ break;
+ case Duplicate:
+ type = BTRM_dup;
+ break;
+ case Delete:
+ type = BTRM_del;
+ break;
+ case Update:
+ type = BTRM_upd;
+ break;
+ }
+
+ if( locks[src].lsn = bt_newredo (bt, type, 0, key, val) )
+ continue;
+
+ goto atomicerr;
+ }
+
+ // obtain write lock for each master page
+
+ for( src = 0; src++ < source->cnt; ) {
+ if( locks[src].reuse )
+ continue;
+ else
+ bt_lockpage(bt, BtLockWrite, bt->mgr->latchsets + locks[src].entry);
+ }
+
+ // insert or delete each key
+ // process any splits or merges
+ // release Write & Atomic latches
+ // set ParentModifications and build
+ // queue of keys to insert for split pages
+ // or delete for deleted pages.
+
+ // run through txn list backwards
+
+ samepage = source->cnt + 1;
+
+ for( src = source->cnt; src; src-- ) {
+ if( locks[src].reuse )
+ continue;
+
+ // perform the txn operations
+ // from smaller to larger on
+ // the same page
+
+ for( idx = src; idx < samepage; idx++ )
+ switch( slotptr(source,idx)->type ) {
+ case Delete:
+ if( bt_atomicdelete (bt, source, locks, idx) )
+ goto atomicerr;
+ break;
+
+ case Duplicate:
+ case Unique:
+ if( bt_atomicinsert (bt, source, locks, idx) )
+ goto atomicerr;
+ break;
+ }
+
+ // after the same page operations have finished,
+ // process master page for splits or deletion.
+
+ latch = prev->latch = bt->mgr->latchsets + locks[src].entry;
+ prev->page = bt_mappage (bt, prev->latch);
+ samepage = src;
+
+ // pick-up all splits from master page
+ // each one is already WriteLocked.
+
+ entry = prev->latch->split;
+
+ while( entry ) {
+ set->latch = bt->mgr->latchsets + entry;
+ set->page = bt_mappage (bt, set->latch);
+ entry = set->latch->split;
+
+ // delete empty master page by undoing its split
+ // (this is potentially another empty page)
+ // note that there are no new left pointers yet
+
+ if( !prev->page->act ) {
+ memcpy (set->page->left, prev->page->left, BtId);
+ memcpy (prev->page, set->page, bt->mgr->page_size);
+ bt_lockpage (bt, BtLockDelete, set->latch);
+ bt_freepage (bt, set);
+
+ prev->latch->split = set->latch->split;
+ prev->latch->dirty = 1;
+ continue;
+ }
+
+ // remove empty page from the split chain
+ // and return it to the free list.
+
+ if( !set->page->act ) {
+ memcpy (prev->page->right, set->page->right, BtId);
+ prev->latch->split = set->latch->split;
+ bt_lockpage (bt, BtLockDelete, set->latch);
+ bt_freepage (bt, set);
+ continue;
+ }
+
+ // schedule prev fence key update
+
+ ptr = keyptr(prev->page,prev->page->cnt);
+ leaf = calloc (sizeof(AtomicKey), 1);
+
+ memcpy (leaf->leafkey, ptr, ptr->len + sizeof(BtKey));
+ leaf->page_no = prev->latch->page_no;
+ leaf->entry = prev->latch->entry;
+ leaf->type = 0;
+
+ if( tail )
+ tail->next = leaf;
+ else
+ head = leaf;
+
+ tail = leaf;
+
+ // splice in the left link into the split page
+
+ bt_putid (set->page->left, prev->latch->page_no);
+ bt_lockpage(bt, BtLockParent, prev->latch);
+ bt_unlockpage(bt, BtLockWrite, prev->latch);
+ *prev = *set;
+ }
+
+ // update left pointer in next right page from last split page
+ // (if all splits were reversed, latch->split == 0)
+
+ if( latch->split ) {
+ // fix left pointer in master's original (now split)
+ // far right sibling or set rightmost page in page zero
+
+ if( right = bt_getid (prev->page->right) ) {
+ if( set->latch = bt_pinlatch (bt, right, 1) )
+ set->page = bt_mappage (bt, set->latch);
+ else
+ goto atomicerr;
+
+ bt_lockpage (bt, BtLockWrite, set->latch);
+ bt_putid (set->page->left, prev->latch->page_no);
+ set->latch->dirty = 1;
+ bt_unlockpage (bt, BtLockWrite, set->latch);
+ bt_unpinlatch (set->latch);
+ } else { // prev is rightmost page
+ bt_spinwritelock (bt->mgr->lock);
+ bt_putid (bt->mgr->pagezero->alloc->left, prev->latch->page_no);
+ bt_spinreleasewrite(bt->mgr->lock);
+ }
+
+ // Process last page split in chain
+
+ ptr = keyptr(prev->page,prev->page->cnt);
+ leaf = calloc (sizeof(AtomicKey), 1);
+
+ memcpy (leaf->leafkey, ptr, ptr->len + sizeof(BtKey));
+ leaf->page_no = prev->latch->page_no;
+ leaf->entry = prev->latch->entry;
+ leaf->type = 0;
+
+ if( tail )
+ tail->next = leaf;
+ else
+ head = leaf;
+
+ tail = leaf;
+
+ bt_lockpage(bt, BtLockParent, prev->latch);
+ bt_unlockpage(bt, BtLockWrite, prev->latch);
+
+ // remove atomic lock on master page
+
+ bt_unlockpage(bt, BtLockAtomic, latch);
+ continue;
+ }
+
+ // finished if prev page occupied (either master or final split)
+
+ if( prev->page->act ) {
+ bt_unlockpage(bt, BtLockWrite, latch);
+ bt_unlockpage(bt, BtLockAtomic, latch);
+ bt_unpinlatch(latch);
+ continue;
+ }
+
+ // any and all splits were reversed, and the
+ // master page located in prev is empty, delete it
+ // by pulling over master's right sibling.
+
+ // Remove empty master's fence key
+
+ ptr = keyptr(prev->page,prev->page->cnt);
+
+ if( bt_deletekey (bt, ptr->key, ptr->len, 1) )
+ goto atomicerr;
+
+ // perform the remainder of the delete
+ // from the FIFO queue
+
+ leaf = calloc (sizeof(AtomicKey), 1);
+
+ memcpy (leaf->leafkey, ptr, ptr->len + sizeof(BtKey));
+ leaf->page_no = prev->latch->page_no;
+ leaf->entry = prev->latch->entry;
+ leaf->nounlock = 1;
+ leaf->type = 2;
+
+ if( tail )
+ tail->next = leaf;
+ else
+ head = leaf;
+
+ tail = leaf;
+
+ // leave atomic lock in place until
+ // deletion completes in next phase.
+
+ bt_unlockpage(bt, BtLockWrite, prev->latch);
+ }
+
+ // add & delete keys for any pages split or merged during transaction
+
+ if( leaf = head )
+ do {
+ set->latch = bt->mgr->latchsets + leaf->entry;
+ set->page = bt_mappage (bt, set->latch);
+
+ bt_putid (value, leaf->page_no);
+ ptr = (BtKey *)leaf->leafkey;
+
+ switch( leaf->type ) {
+ case 0: // insert key
+ if( bt_insertkey (bt, ptr->key, ptr->len, 1, value, BtId, 1) )
+ goto atomicerr;
+
+ break;
+
+ case 1: // delete key
+ if( bt_deletekey (bt, ptr->key, ptr->len, 1) )
+ goto atomicerr;
+
+ break;
+
+ case 2: // free page
+ if( bt_atomicfree (bt, set) )
+ goto atomicerr;
+
+ break;
+ }
+
+ if( !leaf->nounlock )
+ bt_unlockpage (bt, BtLockParent, set->latch);
+
+ bt_unpinlatch (set->latch);
+ tail = leaf->next;
+ free (leaf);
+ } while( leaf = tail );
+
+ // return success
+
+ free (locks);
+ return 0;
+atomicerr:
+ return -1;
+}
+
+// set cursor to highest slot on highest page
+
+uint bt_lastkey (BtDb *bt)
+{
+uid page_no = bt_getid (bt->mgr->pagezero->alloc->left);
+BtPageSet set[1];
+
+ if( set->latch = bt_pinlatch (bt, page_no, 1) )
+ set->page = bt_mappage (bt, set->latch);
+ else
+ return 0;
+
+ bt_lockpage(bt, BtLockRead, set->latch);
+ memcpy (bt->cursor, set->page, bt->mgr->page_size);
+ bt_unlockpage(bt, BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+
+ bt->cursor_page = page_no;
+ return bt->cursor->cnt;
+}
+
+// return previous slot on cursor page
+
+uint bt_prevkey (BtDb *bt, uint slot)
+{
+uid ourright, next, us = bt->cursor_page;
+BtPageSet set[1];
+
+ if( --slot )
+ return slot;
+
+ ourright = bt_getid(bt->cursor->right);
+
+goleft:
+ if( !(next = bt_getid(bt->cursor->left)) )
+ return 0;
+
+findourself:
+ bt->cursor_page = next;
+
+ if( set->latch = bt_pinlatch (bt, next, 1) )
+ set->page = bt_mappage (bt, set->latch);
+ else
+ return 0;
+
+ bt_lockpage(bt, BtLockRead, set->latch);
+ memcpy (bt->cursor, set->page, bt->mgr->page_size);
+ bt_unlockpage(bt, BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+
+ next = bt_getid (bt->cursor->right);
+
+ if( bt->cursor->kill )
+ goto findourself;
+
+ if( next != us )
+ if( next == ourright )
+ goto goleft;
+ else
+ goto findourself;
+
+ return bt->cursor->cnt;
+}
+
+// return next slot on 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->latch = bt_pinlatch (bt, right, 1) )
+ set->page = bt_mappage (bt, set->latch);
+ else
+ return 0;
+
+ bt_lockpage(bt, BtLockRead, set->latch);
+
+ memcpy (bt->cursor, set->page, bt->mgr->page_size);
+
+ bt_unlockpage(bt, BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+ 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->latch->page_no;
+
+ bt_unlockpage(bt, BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+ 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
+
+void bt_poolaudit (BtMgr *mgr)
+{
+BtLatchSet *latch;
+uint slot = 0;
+
+ while( slot++ < mgr->latchdeployed ) {
+ latch = mgr->latchsets + slot;
+
+ if( *latch->readwr->rin & MASK )
+ fprintf(stderr, "latchset %d rwlocked for page %.8x\n", slot, latch->page_no);
+ memset ((ushort *)latch->readwr, 0, sizeof(RWLock));
+
+ if( *latch->access->rin & MASK )
+ fprintf(stderr, "latchset %d accesslocked for page %.8x\n", slot, latch->page_no);
+ memset ((ushort *)latch->access, 0, sizeof(RWLock));
+
+ if( *latch->parent->ticket != *latch->parent->serving )
+ fprintf(stderr, "latchset %d parentlocked for page %.8x\n", slot, latch->page_no);
+ memset ((ushort *)latch->parent, 0, sizeof(RWLock));
+
+ if( latch->pin & ~CLOCK_bit ) {
+ fprintf(stderr, "latchset %d pinned for page %.8x\n", slot, latch->page_no);
+ latch->pin = 0;
+ }
+ }
+}
+
+uint bt_latchaudit (BtDb *bt)
+{
+ushort idx, hashidx;
+uid next, page_no;
+BtLatchSet *latch;
+uint cnt = 0;
+BtKey *ptr;
+
+ if( *(ushort *)(bt->mgr->lock) )
+ fprintf(stderr, "Alloc page locked\n");
+ *(ushort *)(bt->mgr->lock) = 0;
+
+ for( idx = 1; idx <= bt->mgr->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->ticket != *latch->parent->serving )
+ 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->latchhash; hashidx++ ) {
+ if( *(ushort *)(bt->mgr->hashtable[hashidx].latch) )
+ fprintf(stderr, "hash entry %d locked\n", hashidx);
+
+ *(ushort *)(bt->mgr->hashtable[hashidx].latch) = 0;
+
+ if( idx = bt->mgr->hashtable[hashidx].slot ) do {
+ latch = bt->mgr->latchsets + idx;
+ if( latch->pin )
+ fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, latch->page_no);
+ } while( idx = latch->next );
+ }
+
+ page_no = LEAF_page;
+
+ while( page_no < bt_getid(bt->mgr->pagezero->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;
+ page_no++;
+ }
+
+ cnt--; // remove stopper key
+ fprintf(stderr, " Total keys read %d\n", cnt);
+
+ bt_close (bt);
+ return 0;
+}
+
+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, idx;
+uid next, page_no = LEAF_page; // start on first page of leaves
+int ch, len = 0, slot, type = 0;
+unsigned char key[BT_maxkey];
+unsigned char txn[65536];
+ThreadArg *args = arg;
+BtPageSet set[1];
+uint nxt = 65536;
+BtPage page;
+BtKey *ptr;
+BtVal *val;
+BtDb *bt;
+FILE *in;
+
+ bt = bt_open (args->mgr);
+ page = (BtPage)txn;
+
+ if( args->idx < strlen (args->type) )
+ ch = args->type[args->idx];
+ else
+ ch = args->type[strlen(args->type) - 1];
+
+ switch(ch | 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 'd':
+ type = Delete;
+
+ case 'p':
+ if( !type )
+ type = Unique;
+
+ if( args->num )
+ if( type == Delete )
+ fprintf(stderr, "started TXN pennysort delete for %s\n", args->infile);
+ else
+ fprintf(stderr, "started TXN pennysort insert for %s\n", args->infile);
+ else
+ if( type == Delete )
+ fprintf(stderr, "started pennysort delete for %s\n", args->infile);
+ else
+ fprintf(stderr, "started pennysort insert for %s\n", args->infile);
+
+ if( in = fopen (args->infile, "rb") )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ line++;
+
+ if( !args->num ) {
+ if( bt_insertkey (bt, key, 10, 0, key + 10, len - 10, 1) )
+ fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
+ len = 0;
+ continue;
+ }
+
+ nxt -= len - 10;
+ memcpy (txn + nxt, key + 10, len - 10);
+ nxt -= 1;
+ txn[nxt] = len - 10;
+ nxt -= 10;
+ memcpy (txn + nxt, key, 10);
+ nxt -= 1;
+ txn[nxt] = 10;
+ slotptr(page,++cnt)->off = nxt;
+ slotptr(page,cnt)->type = type;
+ len = 0;
+
+ if( cnt < args->num )
+ continue;
+
+ page->cnt = cnt;
+ page->act = cnt;
+ page->min = nxt;
+
+ if( bt_atomictxn (bt, page) )
+ fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
+ nxt = sizeof(txn);
+ cnt = 0;
+
+ }
+ else if( len < BT_maxkey )
+ key[len++] = ch;
+ fprintf(stderr, "finished %s for %d keys: %d reads %d writes %d found\n", args->infile, line, bt->reads, bt->writes, bt->found);
+ break;
+
+ case 'w':
+ fprintf(stderr, "started indexing for %s\n", args->infile);
+ if( in = fopen (args->infile, "r") )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ line++;
+
+ if( bt_insertkey (bt, key, len, 0, NULL, 0, 1) )
+ fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
+ len = 0;
+ }
+ else if( len < BT_maxkey )
+ key[len++] = ch;
+ fprintf(stderr, "finished %s for %d keys: %d reads %d writes\n", args->infile, line, bt->reads, bt->writes);
+ 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( 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 < BT_maxkey )
+ key[len++] = ch;
+ fprintf(stderr, "finished %s for %d keys, found %d: %d reads %d writes\n", args->infile, line, found, bt->reads, bt->writes);
+ break;
+
+ case 's':
+ fprintf(stderr, "started scanning\n");
+ do {
+ if( set->latch = bt_pinlatch (bt, page_no, 1) )
+ set->page = bt_mappage (bt, set->latch);
+ else
+ fprintf(stderr, "unable to obtain latch"), exit(1);
+ bt_lockpage (bt, 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);
+ val = valptr(set->page, slot);
+ fwrite (val->value, val->len, 1, stdout);
+ fputc ('\n', stdout);
+ cnt++;
+ }
+
+ bt_unlockpage (bt, BtLockRead, set->latch);
+ bt_unpinlatch (set->latch);
+ } while( page_no = next );
+
+ fprintf(stderr, " Total keys read %d: %d reads, %d writes\n", cnt, bt->reads, bt->writes);
+ break;
+
+ case 'r':
+ fprintf(stderr, "started reverse scan\n");
+ if( slot = bt_lastkey (bt) )
+ while( slot = bt_prevkey (bt, slot) ) {
+ if( slotptr(bt->cursor, slot)->dead )
+ continue;
+
+ ptr = keyptr(bt->cursor, slot);
+ len = ptr->len;
+
+ if( slotptr(bt->cursor, slot)->type == Duplicate )
+ len -= BtId;
+
+ fwrite (ptr->key, len, 1, stdout);
+ val = valptr(bt->cursor, slot);
+ fwrite (val->value, val->len, 1, stdout);
+ fputc ('\n', stdout);
+ cnt++;
+ }
+
+ fprintf(stderr, " Total keys read %d: %d reads, %d writes\n", cnt, bt->reads, bt->writes);
+ break;
+
+ case 'c':
+#ifdef unix
+ posix_fadvise( bt->mgr->idx, 0, 0, POSIX_FADV_SEQUENTIAL);
+#endif
+ fprintf(stderr, "started counting\n");
+ page_no = LEAF_page;
+
+ while( page_no < bt_getid(bt->mgr->pagezero->alloc->right) ) {
+ if( bt_readpage (bt->mgr, bt->frame, page_no) )
+ break;
+
+ if( !bt->frame->free && !bt->frame->lvl )
+ cnt += bt->frame->act;
+
+ bt->reads++;
+ page_no++;
+ }
+
+ cnt--; // remove stopper key
+ fprintf(stderr, " Total keys counted %d: %d reads, %d writes\n", cnt, bt->reads, bt->writes);
+ 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;
+uint recovery = 0;
+float elapsed;
+int num = 0;
+char key[1];
+BtMgr *mgr;
+BtKey *ptr;
+BtDb *bt;
+
+ if( argc < 3 ) {
+ fprintf (stderr, "Usage: %s idx_file cmds [page_bits buffer_pool_size txn_size recovery_pages src_file1 src_file2 ... ]\n", argv[0]);
+ fprintf (stderr, " where idx_file is the name of the btree file\n");
+ fprintf (stderr, " cmds is a string of (c)ount/(r)ev scan/(w)rite/(s)can/(d)elete/(f)ind/(p)ennysort, with one character command for each input src_file. Commands with no input file need a placeholder.\n");
+ fprintf (stderr, " page_bits is the page size in bits\n");
+ fprintf (stderr, " buffer_pool_size is the number of pages in buffer pool\n");
+ fprintf (stderr, " txn_size = n to block transactions into n units, or zero for no transactions\n");
+ fprintf (stderr, " recovery_pages = n to implement recovery buffer with n pages, or zero for no recovery buffer\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( argc > 5 )
+ num = atoi(argv[5]);
+
+ if( argc > 6 )
+ recovery = 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]), bits, poolsize, recovery);
+
+ 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
+ bt_poolaudit(mgr);
+ bt_mgrclose (mgr);
+
+ 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);
+}
+
+#endif //STANDALONE
projects / btree / commitdiff