+// btree version 2u
+// with combined latch & pool manager
+// 26 FEB 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 <time.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <errno.h>
+#else
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <fcntl.h>
+#endif
+
+#include <memory.h>
+#include <string.h>
+
+typedef unsigned long long uid;
+
+#ifndef unix
+typedef unsigned long long off64_t;
+typedef unsigned short ushort;
+typedef unsigned int uint;
+#endif
+
+#define BT_ro 0x6f72 // ro
+#define BT_rw 0x7772 // rw
+#define BT_fl 0x6c66 // fl
+
+#define BT_maxbits 15 // maximum page size in bits
+#define BT_minbits 12 // minimum page size in bits
+#define BT_minpage (1 << BT_minbits) // minimum page size
+#define BT_maxpage (1 << BT_maxbits) // maximum page size
+
+/*
+There are five lock types for each node in three independent sets:
+1. (set 1) AccessIntent: Sharable. Going to Read the node. Incompatible with NodeDelete.
+2. (set 1) NodeDelete: Exclusive. About to release the node. Incompatible with AccessIntent.
+3. (set 2) ReadLock: Sharable. Read the node. Incompatible with WriteLock.
+4. (set 2) WriteLock: Exclusive. Modify the node. Incompatible with ReadLock and other WriteLocks.
+5. (set 3) ParentModification: Exclusive. Change the node's parent keys. Incompatible with another ParentModification.
+*/
+
+typedef enum{
+ BtLockAccess,
+ BtLockDelete,
+ BtLockRead,
+ BtLockWrite,
+ BtLockParent
+}BtLock;
+
+// definition for latch implementation
+
+// exclusive is set for write access
+// share is count of read accessors
+// grant write lock when share == 0
+
+volatile typedef struct {
+ unsigned char mutex[1];
+ unsigned char exclusive:1;
+ unsigned char pending:1;
+ ushort share;
+} BtSpinLatch;
+
+// Define the length of the page and key pointers
+
+#define BtId 6
+
+// Page key slot definition.
+
+// If BT_maxbits is 15 or less, you can save 2 bytes
+// for each key stored by making the first two uints
+// into ushorts. You can also save 4 bytes by removing
+// the tod field from the key.
+
+// Keys are marked dead, but remain on the page until
+// cleanup is called. The fence key (highest key) for
+// the page is always present, even if dead.
+
+typedef struct {
+#ifdef USETOD
+ uint tod; // time-stamp for key
+#endif
+ ushort off:BT_maxbits; // page offset for key start
+ ushort dead:1; // set for deleted key
+ unsigned char id[BtId]; // id associated with key
+} BtSlot;
+
+// The key structure occupies space at the upper end of
+// each page. It's a length byte followed by the value
+// bytes.
+
+typedef struct {
+ unsigned char len;
+ unsigned char key[0];
+} *BtKey;
+
+// The first part of an index page.
+// It is immediately followed
+// by the BtSlot array of keys.
+
+typedef struct BtPage_ {
+ uint cnt; // count of keys in page
+ uint act; // count of active keys
+ uint min; // next key offset
+ unsigned char bits:7; // page size in bits
+ unsigned char free:1; // page is on free list
+ unsigned char lvl:6; // level of page
+ unsigned char kill:1; // page is being deleted
+ unsigned char dirty:1; // page is dirty
+ unsigned char right[BtId]; // page number to right
+} *BtPage;
+
+typedef struct {
+ struct BtPage_ alloc[2]; // next & free page_nos in right ptr
+ BtSpinLatch lock[1]; // allocation area lite latch
+ 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
+} BtLatchMgr;
+
+// latch hash table entries
+
+typedef struct {
+ volatile uint slot; // Latch table entry at head of collision chain
+ BtSpinLatch latch[1]; // lock for the collision chain
+} BtHashEntry;
+
+// latch manager table structure
+
+typedef struct {
+ BtSpinLatch readwr[1]; // read/write page lock
+ BtSpinLatch access[1]; // Access Intent/Page delete
+ BtSpinLatch parent[1]; // Posting of fence key in parent
+ BtSpinLatch busy[1]; // slot is being moved between chains
+ volatile uint next; // next entry in hash table chain
+ volatile uint prev; // prev entry in hash table chain
+ volatile uint hash; // hash slot entry is under
+ volatile ushort dirty; // page is dirty in cache
+ volatile ushort pin; // number of outstanding pins
+ volatile uid page_no; // latch set page number on disk
+} BtLatchSet;
+
+// The object structure for Btree access
+
+typedef struct _BtDb {
+ uint page_size; // each page size
+ uint page_bits; // each page size in bits
+ uid page_no; // current page number
+ uid cursor_page; // current cursor page number
+ int err;
+ uint mode; // read-write mode
+ BtPage alloc; // frame buffer for alloc page ( page 0 )
+ BtPage cursor; // cached frame for start/next (never mapped)
+ BtPage frame; // spare frame for the page split (never mapped)
+ BtPage zero; // zeroes frame buffer (never mapped)
+ BtPage page; // current page
+ BtLatchSet *latch; // current page latch
+ BtLatchMgr *latchmgr; // mapped latch page from allocation page
+ BtLatchSet *latchsets; // mapped latch set from latch pages
+ unsigned char *latchpool; // cached page pool set
+ BtHashEntry *table; // the hash table
+#ifdef unix
+ int idx;
+#else
+ HANDLE idx;
+ HANDLE halloc; // allocation and latch table handle
+#endif
+ unsigned char *mem; // frame, cursor, page memory buffer
+ uint found; // last deletekey found key
+} BtDb;
+
+typedef enum {
+BTERR_ok = 0,
+BTERR_notfound,
+BTERR_struct,
+BTERR_ovflw,
+BTERR_read,
+BTERR_lock,
+BTERR_hash,
+BTERR_kill,
+BTERR_map,
+BTERR_wrt,
+BTERR_eof
+} BTERR;
+
+// B-Tree functions
+extern void bt_close (BtDb *bt);
+extern BtDb *bt_open (char *name, uint mode, uint bits, uint cacheblk);
+extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod);
+extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl);
+extern uid bt_findkey (BtDb *bt, unsigned char *key, uint len);
+extern uint bt_startkey (BtDb *bt, unsigned char *key, uint len);
+extern uint bt_nextkey (BtDb *bt, uint slot);
+
+// internal functions
+BTERR bt_update (BtDb *bt, BtPage page, BtLatchSet *latch);
+BtPage bt_mappage (BtDb *bt, BtLatchSet *latch);
+// Helper functions to return slot values
+
+extern BtKey bt_key (BtDb *bt, uint slot);
+extern uid bt_uid (BtDb *bt, uint slot);
+#ifdef USETOD
+extern uint bt_tod (BtDb *bt, uint slot);
+#endif
+
+// BTree page number constants
+#define ALLOC_page 0
+#define ROOT_page 1
+#define LEAF_page 2
+#define LATCH_page 3
+
+// Number of levels to create in a new BTree
+
+#define MIN_lvl 2
+
+// The page is allocated from low and hi ends.
+// The key offsets and row-id's are allocated
+// from the bottom, while the text of the key
+// is allocated from the top. When the two
+// areas meet, the page is split into two.
+
+// A key consists of a length byte, two bytes of
+// index number (0 - 65534), and up to 253 bytes
+// of key value. Duplicate keys are discarded.
+// Associated with each key is a 48 bit row-id.
+
+// 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 right
+// 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 node is always
+// present, even after deletion and cleanup.
+
+// Deleted leaf pages are reclaimed on a free list.
+// The upper levels of the btree are fixed on creation.
+
+// 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 (ALLOC page) is dedicated to lock for new page extensions,
+// and chains empty leaf pages together for reuse.
+
+// Parent locks are obtained to prevent resplitting or deleting a node
+// before its fence is posted into its upper level.
+
+// A special open mode of BT_fl is provided to safely access files on
+// WIN32 networks. WIN32 network operations should not use memory mapping.
+// This WIN32 mode sets FILE_FLAG_NOBUFFERING and FILE_FLAG_WRITETHROUGH
+// to prevent local caching of network file contents.
+
+// 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))
+
+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;
+}
+
+BTERR bt_abort (BtDb *bt, BtPage page, uid page_no, BTERR err)
+{
+BtKey ptr;
+
+ fprintf(stderr, "\n Btree2 abort, error %d on page %.8x\n", err, page_no);
+ fprintf(stderr, "level=%d kill=%d free=%d cnt=%x act=%x\n", page->lvl, page->kill, page->free, page->cnt, page->act);
+ ptr = keyptr(page, page->cnt);
+ fprintf(stderr, "fence='%.*s'\n", ptr->len, ptr->key);
+ fprintf(stderr, "right=%.8x\n", bt_getid(page->right));
+ return bt->err = err;
+}
+
+// Latch Manager
+
+// wait until write lock mode is clear
+// and add 1 to the share count
+
+void bt_spinreadlock(BtSpinLatch *latch)
+{
+ushort prev;
+
+ do {
+ // obtain latch mutex
+#ifdef unix
+ if( __sync_lock_test_and_set(latch->mutex, 1) )
+ continue;
+#else
+ if( _InterlockedExchange8(latch->mutex, 1) )
+ continue;
+#endif
+ // see if exclusive request is granted or pending
+
+ if( prev = !(latch->exclusive | latch->pending) )
+ latch->share++;
+
+#ifdef unix
+ *latch->mutex = 0;
+#else
+ _InterlockedExchange8(latch->mutex, 0);
+#endif
+
+ if( prev )
+ return;
+
+#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)
+{
+uint prev;
+
+ do {
+#ifdef unix
+ if( __sync_lock_test_and_set(latch->mutex, 1) )
+ continue;
+#else
+ if( _InterlockedExchange8(latch->mutex, 1) )
+ continue;
+#endif
+ if( prev = !(latch->share | latch->exclusive) )
+ latch->exclusive = 1, latch->pending = 0;
+ else
+ latch->pending = 1;
+#ifdef unix
+ *latch->mutex = 0;
+#else
+ _InterlockedExchange8(latch->mutex, 0);
+#endif
+ if( prev )
+ return;
+#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)
+{
+uint prev;
+
+#ifdef unix
+ if( __sync_lock_test_and_set(latch->mutex, 1) )
+ return 0;
+#else
+ if( _InterlockedExchange8(latch->mutex, 1) )
+ return 0;
+#endif
+ // take write access if all bits are clear
+
+ if( prev = !(latch->exclusive | latch->share) )
+ latch->exclusive = 1;
+
+#ifdef unix
+ *latch->mutex = 0;
+#else
+ _InterlockedExchange8(latch->mutex, 0);
+#endif
+ return prev;
+}
+
+// clear write mode
+
+void bt_spinreleasewrite(BtSpinLatch *latch)
+{
+#ifdef unix
+ while( __sync_lock_test_and_set(latch->mutex, 1) )
+ sched_yield();
+#else
+ while( _InterlockedExchange8(latch->mutex, 1) )
+ SwitchToThread();
+#endif
+ latch->exclusive = 0;
+#ifdef unix
+ *latch->mutex = 0;
+#else
+ _InterlockedExchange8(latch->mutex, 0);
+#endif
+}
+
+// decrement reader count
+
+void bt_spinreleaseread(BtSpinLatch *latch)
+{
+#ifdef unix
+ while( __sync_lock_test_and_set(latch->mutex, 1) )
+ sched_yield();
+#else
+ while( _InterlockedExchange8(latch->mutex, 1) )
+ SwitchToThread();
+#endif
+ latch->share--;
+#ifdef unix
+ *latch->mutex = 0;
+#else
+ _InterlockedExchange8(latch->mutex, 0);
+#endif
+}
+
+// link latch table entry into head of latch hash table
+
+BTERR bt_latchlink (BtDb *bt, uint hashidx, uint victim, uid page_no)
+{
+BtPage page = (BtPage)(victim * bt->page_size + bt->latchpool);
+BtLatchSet *latch = bt->latchsets + victim;
+off64_t off = page_no << bt->page_bits;
+uint amt[1];
+
+ if( latch->next = bt->table[hashidx].slot )
+ bt->latchsets[latch->next].prev = victim;
+
+ bt->table[hashidx].slot = victim;
+ latch->page_no = page_no;
+ latch->hash = hashidx;
+ latch->dirty = 0;
+ latch->prev = 0;
+#ifdef unix
+ if( pread (bt->idx, page, bt->page_size, page_no << bt->page_bits) )
+ return bt->err = BTERR_read;
+#else
+ SetFilePointer (bt->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
+ if( !ReadFile(bt->idx, page, bt->page_size, amt, NULL))
+ return bt->err = BTERR_read;
+ if( *amt < bt->page_size )
+ return bt->err = BTERR_read;
+#endif
+ return 0;
+}
+
+// release latch pin
+
+void bt_unpinlatch (BtLatchSet *latch)
+{
+#ifdef unix
+ __sync_fetch_and_add(&latch->pin, -1);
+#else
+ _InterlockedDecrement16 (&latch->pin);
+#endif
+}
+
+// find existing latchset or inspire new one
+// return with latchset pinned
+
+BtLatchSet *bt_pinlatch (BtDb *bt, uid page_no)
+{
+uint hashidx = page_no % bt->latchmgr->latchhash;
+uint slot, victim, idx;
+BtLatchSet *latch;
+off64_t off;
+uint amt[1];
+BtPage page;
+
+ // try to find unpinned entry
+
+ bt_spinwritelock(bt->table[hashidx].latch);
+
+ if( slot = bt->table[hashidx].slot ) do
+ {
+ latch = bt->latchsets + slot;
+ if( page_no == latch->page_no )
+ break;
+ } while( slot = latch->next );
+
+ // found our entry
+
+ if( slot ) {
+ latch = bt->latchsets + slot;
+#ifdef unix
+ __sync_fetch_and_add(&latch->pin, 1);
+#else
+ _InterlockedIncrement16 (&latch->pin);
+#endif
+ bt_spinreleasewrite(bt->table[hashidx].latch);
+ return latch;
+ }
+
+ // see if there are any unused entries
+#ifdef unix
+ victim = __sync_fetch_and_add (&bt->latchmgr->latchdeployed, 1) + 1;
+#else
+ victim = _InterlockedIncrement (&bt->latchmgr->latchdeployed);
+#endif
+
+ if( victim < bt->latchmgr->latchtotal ) {
+ latch = bt->latchsets + victim;
+#ifdef unix
+ __sync_fetch_and_add(&latch->pin, 1);
+#else
+ _InterlockedIncrement16 (&latch->pin);
+#endif
+ bt_latchlink (bt, hashidx, victim, page_no);
+ bt_spinreleasewrite (bt->table[hashidx].latch);
+ return latch;
+ }
+
+#ifdef unix
+ victim = __sync_fetch_and_add (&bt->latchmgr->latchdeployed, -1);
+#else
+ victim = _InterlockedDecrement (&bt->latchmgr->latchdeployed);
+#endif
+ // find and reuse previous lock entry
+
+ while( 1 ) {
+#ifdef unix
+ victim = __sync_fetch_and_add(&bt->latchmgr->latchvictim, 1);
+#else
+ victim = _InterlockedIncrement (&bt->latchmgr->latchvictim) - 1;
+#endif
+ // we don't use slot zero
+
+ if( victim %= bt->latchmgr->latchtotal )
+ latch = bt->latchsets + victim;
+ else
+ continue;
+
+ // take control of our slot
+ // from other threads
+
+ if( latch->pin || !bt_spinwritetry (latch->busy) )
+ continue;
+
+ idx = latch->hash;
+
+ // try to get write lock on hash chain
+ // skip entry if not obtained
+ // or has outstanding locks
+
+ if( !bt_spinwritetry (bt->table[idx].latch) ) {
+ bt_spinreleasewrite (latch->busy);
+ continue;
+ }
+
+ if( latch->pin ) {
+ bt_spinreleasewrite (latch->busy);
+ bt_spinreleasewrite (bt->table[idx].latch);
+ continue;
+ }
+
+ // update permanent page area in btree
+
+ page = (BtPage)(victim * bt->page_size + bt->latchpool);
+ off = latch->page_no << bt->page_bits;
+#ifdef unix
+ if( latch->dirty )
+ if( pwrite(bt->idx, page, bt->page_size, off) < bt->page_size )
+ return bt->err = BTERR_wrt, NULL;
+#else
+ if( latch->dirty ) {
+ SetFilePointer (bt->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
+
+ if( !WriteFile(bt->idx, page, bt->page_size, amt, NULL) )
+ return bt->err = BTERR_wrt, NULL;
+
+ if( *amt < bt->page_size )
+ return bt->err = BTERR_wrt, NULL;
+ }
+#endif
+ // unlink our available victim from its hash chain
+
+ if( latch->prev )
+ bt->latchsets[latch->prev].next = latch->next;
+ else
+ bt->table[idx].slot = latch->next;
+
+ if( latch->next )
+ bt->latchsets[latch->next].prev = latch->prev;
+
+ bt_spinreleasewrite (bt->table[idx].latch);
+#ifdef unix
+ __sync_fetch_and_add(&latch->pin, 1);
+#else
+ _InterlockedIncrement16 (&latch->pin);
+#endif
+ bt_latchlink (bt, hashidx, victim, page_no);
+ bt_spinreleasewrite (bt->table[hashidx].latch);
+ bt_spinreleasewrite (latch->busy);
+ return latch;
+ }
+}
+
+// close and release memory
+
+void bt_close (BtDb *bt)
+{
+#ifdef unix
+ munmap (bt->table, bt->latchmgr->nlatchpage * bt->page_size);
+ munmap (bt->latchmgr, bt->page_size);
+#else
+ FlushViewOfFile(bt->latchmgr, 0);
+ UnmapViewOfFile(bt->latchmgr);
+ CloseHandle(bt->halloc);
+#endif
+#ifdef unix
+ if( bt->mem )
+ free (bt->mem);
+ close (bt->idx);
+ free (bt);
+#else
+ if( bt->mem)
+ VirtualFree (bt->mem, 0, MEM_RELEASE);
+ FlushFileBuffers(bt->idx);
+ CloseHandle(bt->idx);
+ GlobalFree (bt);
+#endif
+}
+// open/create new btree
+
+// call with file_name, BT_openmode, bits in page size (e.g. 16),
+// size of mapped page pool (e.g. 8192)
+
+BtDb *bt_open (char *name, uint mode, uint bits, uint nodemax)
+{
+uint lvl, attr, last, slot, idx;
+uint nlatchpage, latchhash;
+BtLatchMgr *latchmgr;
+off64_t size, off;
+uint amt[1];
+BtKey key;
+BtDb* bt;
+int flag;
+
+#ifndef unix
+OVERLAPPED ovl[1];
+#else
+struct flock lock[1];
+#endif
+
+ // determine sanity of page size and buffer pool
+
+ if( bits > BT_maxbits )
+ bits = BT_maxbits;
+ else if( bits < BT_minbits )
+ bits = BT_minbits;
+
+#ifdef unix
+ bt = calloc (1, sizeof(BtDb));
+
+ bt->idx = open ((char*)name, O_RDWR | O_CREAT, 0666);
+
+ if( bt->idx == -1 )
+ return free(bt), NULL;
+#else
+ bt = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, sizeof(BtDb));
+ attr = FILE_ATTRIBUTE_NORMAL;
+ bt->idx = CreateFile(name, GENERIC_READ| GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, attr, NULL);
+
+ if( bt->idx == INVALID_HANDLE_VALUE )
+ return GlobalFree(bt), NULL;
+#endif
+#ifdef unix
+ memset (lock, 0, sizeof(lock));
+
+ lock->l_type = F_WRLCK;
+ lock->l_len = sizeof(struct BtPage_);
+ lock->l_whence = 0;
+
+ if( fcntl (bt->idx, F_SETLKW, lock) < 0 )
+ return bt_close (bt), NULL;
+#else
+ memset (ovl, 0, sizeof(ovl));
+ len = sizeof(struct BtPage_);
+
+ // use large offsets to
+ // simulate advisory locking
+
+ ovl->OffsetHigh |= 0x80000000;
+
+ if( LockFileEx (bt->idx, LOCKFILE_EXCLUSIVE_LOCK, 0, len, 0L, ovl) )
+ return bt_close (bt), NULL;
+#endif
+
+#ifdef unix
+ latchmgr = malloc (BT_maxpage);
+ *amt = 0;
+
+ // read minimum page size to get root info
+
+ if( size = lseek (bt->idx, 0L, 2) ) {
+ if( pread(bt->idx, latchmgr, BT_minpage, 0) == BT_minpage )
+ bits = latchmgr->alloc->bits;
+ else
+ return free(bt), free(latchmgr), NULL;
+ } else if( mode == BT_ro )
+ return free(latchmgr), bt_close (bt), NULL;
+#else
+ latchmgr = VirtualAlloc(NULL, BT_maxpage, MEM_COMMIT, PAGE_READWRITE);
+ size = GetFileSize(bt->idx, amt);
+
+ if( size || *amt ) {
+ if( !ReadFile(bt->idx, (char *)latchmgr, BT_minpage, amt, NULL) )
+ return bt_close (bt), NULL;
+ bits = latchmgr->alloc->bits;
+ } else if( mode == BT_ro )
+ return bt_close (bt), NULL;
+#endif
+
+ bt->page_size = 1 << bits;
+ bt->page_bits = bits;
+
+ bt->mode = mode;
+
+ if( size || *amt )
+ goto btlatch;
+
+ // initialize an empty b-tree with latch page, root page, page of leaves
+ // and page(s) of latches and page pool cache
+
+ memset (latchmgr, 0, 1 << bits);
+ latchmgr->alloc->bits = bt->page_bits;
+
+ // calculate number of latch hash table entries
+
+ nlatchpage = (nodemax/8 * sizeof(BtHashEntry) + bt->page_size - 1) / bt->page_size;
+ latchhash = nlatchpage * bt->page_size / sizeof(BtHashEntry);
+
+ nlatchpage += nodemax; // size of the buffer pool in pages
+ nlatchpage += (sizeof(BtLatchSet) * nodemax + bt->page_size - 1)/bt->page_size;
+
+ bt_putid(latchmgr->alloc->right, MIN_lvl+1+nlatchpage);
+ latchmgr->nlatchpage = nlatchpage;
+ latchmgr->latchtotal = nodemax;
+ latchmgr->latchhash = latchhash;
+#ifdef unix
+ if( write (bt->idx, latchmgr, bt->page_size) < bt->page_size )
+ return bt_close (bt), NULL;
+#else
+ if( !WriteFile (bt->idx, (char *)latchmgr, bt->page_size, amt, NULL) )
+ return bt_close (bt), NULL;
+
+ if( *amt < bt->page_size )
+ return bt_close (bt), NULL;
+#endif
+ memset (latchmgr, 0, 1 << bits);
+ latchmgr->alloc->bits = bt->page_bits;
+
+ for( lvl=MIN_lvl; lvl--; ) {
+ slotptr(latchmgr->alloc, 1)->off = bt->page_size - 3;
+ bt_putid(slotptr(latchmgr->alloc, 1)->id, lvl ? MIN_lvl - lvl + 1 : 0); // next(lower) page number
+ key = keyptr(latchmgr->alloc, 1);
+ key->len = 2; // create stopper key
+ key->key[0] = 0xff;
+ key->key[1] = 0xff;
+ latchmgr->alloc->min = bt->page_size - 3;
+ latchmgr->alloc->lvl = lvl;
+ latchmgr->alloc->cnt = 1;
+ latchmgr->alloc->act = 1;
+#ifdef unix
+ if( write (bt->idx, latchmgr, bt->page_size) < bt->page_size )
+ return bt_close (bt), NULL;
+#else
+ if( !WriteFile (bt->idx, (char *)latchmgr, bt->page_size, amt, NULL) )
+ return bt_close (bt), NULL;
+
+ if( *amt < bt->page_size )
+ return bt_close (bt), NULL;
+#endif
+ }
+
+ // clear out latch manager pages
+
+ memset(latchmgr, 0, bt->page_size);
+ last = MIN_lvl + 1;
+
+ while( last < ((MIN_lvl + 1 + nlatchpage) ) ) {
+ off = (uid)last << bt->page_bits;
+#ifdef unix
+ pwrite(bt->idx, latchmgr, bt->page_size, off);
+#else
+ SetFilePointer (bt->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
+ if( !WriteFile (bt->idx, (char *)latchmgr, bt->page_size, amt, NULL) )
+ return bt_close (bt), NULL;
+ if( *amt < bt->page_size )
+ return bt_close (bt), NULL;
+#endif
+ last++;
+ }
+
+btlatch:
+#ifdef unix
+ lock->l_type = F_UNLCK;
+ if( fcntl (bt->idx, F_SETLK, lock) < 0 )
+ return bt_close (bt), NULL;
+#else
+ if( !UnlockFileEx (bt->idx, 0, sizeof(struct BtPage_), 0, ovl) )
+ return bt_close (bt), NULL;
+#endif
+#ifdef unix
+ flag = PROT_READ | PROT_WRITE;
+ bt->latchmgr = mmap (0, bt->page_size, flag, MAP_SHARED, bt->idx, ALLOC_page * bt->page_size);
+ if( bt->latchmgr == MAP_FAILED )
+ return bt_close (bt), NULL;
+ bt->table = (void *)mmap (0, bt->latchmgr->nlatchpage * bt->page_size, flag, MAP_SHARED, bt->idx, LATCH_page * bt->page_size);
+ if( bt->table == MAP_FAILED )
+ return bt_close (bt), NULL;
+#else
+ flag = PAGE_READWRITE;
+ bt->halloc = CreateFileMapping(bt->idx, NULL, flag, 0, (bt->latchmgr->nlatchpage + LATCH_page) * bt->page_size, NULL);
+ if( !bt->halloc )
+ return bt_close (bt), NULL;
+
+ flag = FILE_MAP_WRITE;
+ bt->latchmgr = MapViewOfFile(bt->halloc, flag, 0, 0, (bt->latchmgr->nlatchpage + LATCH_page) * bt->page_size);
+ if( !bt->latchmgr )
+ return GetLastError(), bt_close (bt), NULL;
+
+ bt->table = (void *)((char *)bt->latchmgr + LATCH_page * bt->page_size);
+#endif
+ bt->latchpool = (unsigned char *)bt->table + (bt->latchmgr->nlatchpage - bt->latchmgr->latchtotal) * bt->page_size;
+ bt->latchsets = (BtLatchSet *)(bt->latchpool - bt->latchmgr->latchtotal * sizeof(BtLatchSet));
+
+#ifdef unix
+ free (latchmgr);
+#else
+ VirtualFree (latchmgr, 0, MEM_RELEASE);
+#endif
+
+#ifdef unix
+ bt->mem = malloc (3 * bt->page_size);
+#else
+ bt->mem = VirtualAlloc(NULL, 3 * bt->page_size, MEM_COMMIT, PAGE_READWRITE);
+#endif
+ bt->frame = (BtPage)bt->mem;
+ bt->cursor = (BtPage)(bt->mem + bt->page_size);
+ bt->zero = (BtPage)(bt->mem + 2 * bt->page_size);
+
+ memset (bt->zero, 0, bt->page_size);
+ return bt;
+}
+
+// place write, read, or parent lock on requested page_no.
+
+void bt_lockpage(BtLock mode, BtLatchSet *latch)
+{
+ switch( mode ) {
+ case BtLockRead:
+ bt_spinreadlock (latch->readwr);
+ break;
+ case BtLockWrite:
+ bt_spinwritelock (latch->readwr);
+ break;
+ case BtLockAccess:
+ bt_spinreadlock (latch->access);
+ break;
+ case BtLockDelete:
+ bt_spinwritelock (latch->access);
+ break;
+ case BtLockParent:
+ bt_spinwritelock (latch->parent);
+ break;
+ }
+}
+
+// remove write, read, or parent lock on requested page
+
+void bt_unlockpage(BtLock mode, BtLatchSet *latch)
+{
+ switch( mode ) {
+ case BtLockRead:
+ bt_spinreleaseread (latch->readwr);
+ break;
+ case BtLockWrite:
+ bt_spinreleasewrite (latch->readwr);
+ break;
+ case BtLockAccess:
+ bt_spinreleaseread (latch->access);
+ break;
+ case BtLockDelete:
+ bt_spinreleasewrite (latch->access);
+ break;
+ case BtLockParent:
+ bt_spinreleasewrite (latch->parent);
+ break;
+ }
+}
+
+// allocate a new page and write page into it
+
+uid bt_newpage(BtDb *bt, BtPage page)
+{
+BtLatchSet *latch;
+uid new_page;
+BtPage temp;
+off64_t off;
+uint amt[1];
+int reuse;
+
+ // lock allocation page
+
+ bt_spinwritelock(bt->latchmgr->lock);
+
+ // use empty chain first
+ // else allocate empty page
+
+ if( new_page = bt_getid(bt->latchmgr->alloc[1].right) ) {
+ latch = bt_pinlatch (bt, new_page);
+ temp = bt_mappage (bt, latch);
+
+ bt_putid(bt->latchmgr->alloc[1].right, bt_getid(temp->right));
+ bt_spinreleasewrite(bt->latchmgr->lock);
+ memcpy (temp, page, bt->page_size);
+
+ if( bt_update (bt, temp, latch) )
+ return 0;
+
+ bt_unpinlatch (latch);
+ } else {
+ new_page = bt_getid(bt->latchmgr->alloc->right);
+ bt_putid(bt->latchmgr->alloc->right, new_page+1);
+ bt_spinreleasewrite(bt->latchmgr->lock);
+ off = new_page << bt->page_bits;
+#ifdef unix
+ if( pwrite(bt->idx, page, bt->page_size, off) < bt->page_size )
+ return bt->err = BTERR_wrt, 0;
+#else
+ SetFilePointer (bt->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
+
+ if( !WriteFile(bt->idx, page, bt->page_size, amt, NULL) )
+ return bt->err = BTERR_wrt, 0;
+
+ if( *amt < bt->page_size )
+ return bt->err = BTERR_wrt, 0;
+#endif
+ }
+
+ return new_page;
+}
+
+// compare two keys, returning > 0, = 0, or < 0
+// as the comparison value
+
+int keycmp (BtKey key1, unsigned char *key2, uint len2)
+{
+uint len1 = key1->len;
+int ans;
+
+ if( ans = memcmp (key1->key, key2, len1 > len2 ? len2 : len1) )
+ return ans;
+
+ if( len1 > len2 )
+ return 1;
+ if( len1 < len2 )
+ return -1;
+
+ return 0;
+}
+
+// Update current page of btree by
+// flushing mapped area to disk backing of cache pool.
+
+BTERR bt_update (BtDb *bt, BtPage page, BtLatchSet *latch)
+{
+#ifdef unix
+ msync (page, bt->page_size, MS_ASYNC);
+#else
+ FlushViewOfFile (page, bt->page_size);
+#endif
+ latch->dirty = 1;
+ return 0;
+}
+
+// map the btree cached page onto current page
+
+BtPage bt_mappage (BtDb *bt, BtLatchSet *latch)
+{
+ return (BtPage)((latch - bt->latchsets) * bt->page_size + bt->latchpool);
+}
+
+// deallocate a deleted page
+// place on free chain out of allocator page
+// call with page latched for Writing and Deleting
+
+BTERR bt_freepage(BtDb *bt, uid page_no, BtLatchSet *latch)
+{
+BtPage page = bt_mappage (bt, latch);
+
+ // lock allocation page
+
+ bt_spinwritelock (bt->latchmgr->lock);
+
+ // store chain in second right
+ bt_putid(page->right, bt_getid(bt->latchmgr->alloc[1].right));
+ bt_putid(bt->latchmgr->alloc[1].right, page_no);
+ page->free = 1;
+
+ if( bt_update(bt, page, latch) )
+ return bt->err;
+
+ // unlock released page
+
+ bt_unlockpage (BtLockDelete, latch);
+ bt_unlockpage (BtLockWrite, latch);
+ bt_unpinlatch (latch);
+
+ // unlock allocation page
+
+ bt_spinreleasewrite (bt->latchmgr->lock);
+ return 0;
+}
+
+// find slot in page for given key at a given level
+
+int bt_findslot (BtDb *bt, unsigned char *key, uint len)
+{
+uint diff, higher = bt->page->cnt, low = 1, slot;
+uint good = 0;
+
+ // make stopper key an infinite fence value
+
+ if( bt_getid (bt->page->right) )
+ higher++;
+ else
+ good++;
+
+ // low is the lowest candidate, higher is already
+ // tested as .ge. the given key, loop ends when they meet
+
+ while( diff = higher - low ) {
+ slot = low + ( diff >> 1 );
+ if( keycmp (keyptr(bt->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, unsigned char *key, uint len, uint lvl, uint 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 = (lock == BtLockWrite) && (drill == lvl) ? BtLockWrite : BtLockRead;
+
+ bt->latch = bt_pinlatch(bt, page_no);
+ bt->page_no = page_no;
+
+ // obtain access lock using lock chaining
+
+ if( page_no > ROOT_page )
+ bt_lockpage(BtLockAccess, bt->latch);
+
+ if( prevpage ) {
+ bt_unlockpage(prevmode, prevlatch);
+ bt_unpinlatch(prevlatch);
+ prevpage = 0;
+ }
+
+ // obtain read lock using lock chaining
+
+ bt_lockpage(mode, bt->latch);
+
+ if( page_no > ROOT_page )
+ bt_unlockpage(BtLockAccess, bt->latch);
+
+ // map/obtain page contents
+
+ bt->page = bt_mappage (bt, bt->latch);
+
+ // re-read and re-lock root after determining actual level of root
+
+ if( bt->page->lvl != drill) {
+ if( bt->page_no != ROOT_page )
+ return bt->err = BTERR_struct, 0;
+
+ drill = bt->page->lvl;
+
+ if( lock != BtLockRead && drill == lvl ) {
+ bt_unlockpage(mode, bt->latch);
+ bt_unpinlatch(bt->latch);
+ continue;
+ }
+ }
+
+ prevpage = bt->page_no;
+ prevlatch = bt->latch;
+ prevmode = mode;
+
+ // find key on page at this level
+ // and descend to requested level
+
+ if( !bt->page->kill )
+ if( slot = bt_findslot (bt, key, len) ) {
+ if( drill == lvl )
+ return slot;
+
+ while( slotptr(bt->page, slot)->dead )
+ if( slot++ < bt->page->cnt )
+ continue;
+ else
+ goto slideright;
+
+ page_no = bt_getid(slotptr(bt->page, slot)->id);
+ drill--;
+ continue;
+ }
+
+ // or slide right into next page
+
+slideright:
+ page_no = bt_getid(bt->page->right);
+
+ } while( page_no );
+
+ // return error on end of right chain
+
+ bt->err = BTERR_eof;
+ return 0; // return error
+}
+
+// a fence key was deleted from a page
+// push new fence value upwards
+
+BTERR bt_fixfence (BtDb *bt, uid page_no, uint lvl)
+{
+unsigned char leftkey[256], rightkey[256];
+BtLatchSet *latch = bt->latch;
+BtKey ptr;
+
+ // remove deleted key, the old fence value
+
+ ptr = keyptr(bt->page, bt->page->cnt);
+ memcpy(rightkey, ptr, ptr->len + 1);
+
+ memset (slotptr(bt->page, bt->page->cnt--), 0, sizeof(BtSlot));
+ bt->page->dirty = 1;
+
+ ptr = keyptr(bt->page, bt->page->cnt);
+ memcpy(leftkey, ptr, ptr->len + 1);
+
+ if( bt_update (bt, bt->page, latch) )
+ return bt->err;
+
+ bt_lockpage (BtLockParent, latch);
+ bt_unlockpage (BtLockWrite, latch);
+
+ // insert new (now smaller) fence key
+
+ if( bt_insertkey (bt, leftkey+1, *leftkey, lvl + 1, page_no, time(NULL)) )
+ return bt->err;
+
+ // remove old (larger) fence key
+
+ if( bt_deletekey (bt, rightkey+1, *rightkey, lvl + 1) )
+ return bt->err;
+
+ bt_unlockpage (BtLockParent, latch);
+ bt_unpinlatch (latch);
+ return 0;
+}
+
+// root has a single child
+// collapse a level from the btree
+// call with root locked in bt->page
+
+BTERR bt_collapseroot (BtDb *bt, BtPage root)
+{
+BtLatchSet *latch;
+BtPage temp;
+uid child;
+uint idx;
+
+ // find the child entry
+ // and promote to new root
+
+ do {
+ for( idx = 0; idx++ < root->cnt; )
+ if( !slotptr(root, idx)->dead )
+ break;
+
+ child = bt_getid (slotptr(root, idx)->id);
+ latch = bt_pinlatch (bt, child);
+
+ bt_lockpage (BtLockDelete, latch);
+ bt_lockpage (BtLockWrite, latch);
+
+ temp = bt_mappage (bt, latch);
+ memcpy (root, temp, bt->page_size);
+
+ if( bt_update (bt, root, bt->latch) )
+ return bt->err;
+
+ if( bt_freepage (bt, child, latch) )
+ return bt->err;
+
+ } while( root->lvl > 1 && root->act == 1 );
+
+ bt_unlockpage (BtLockWrite, bt->latch);
+ bt_unpinlatch (bt->latch);
+ return 0;
+}
+
+// find and delete key on page by marking delete flag bit
+// when page becomes empty, delete it
+
+BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl)
+{
+unsigned char lowerkey[256], higherkey[256];
+uint slot, dirty = 0, idx, fence, found;
+BtLatchSet *latch, *rlatch;
+uid page_no, right;
+BtPage temp;
+BtKey ptr;
+
+ if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
+ ptr = keyptr(bt->page, slot);
+ else
+ return bt->err;
+
+ // are we deleting a fence slot?
+
+ fence = slot == bt->page->cnt;
+
+ // if key is found delete it, otherwise ignore request
+
+ if( found = !keycmp (ptr, key, len) )
+ if( found = slotptr(bt->page, slot)->dead == 0 ) {
+ dirty = slotptr(bt->page,slot)->dead = 1;
+ bt->page->dirty = 1;
+ bt->page->act--;
+
+ // collapse empty slots
+
+ while( idx = bt->page->cnt - 1 )
+ if( slotptr(bt->page, idx)->dead ) {
+ *slotptr(bt->page, idx) = *slotptr(bt->page, idx + 1);
+ memset (slotptr(bt->page, bt->page->cnt--), 0, sizeof(BtSlot));
+ } else
+ break;
+ }
+
+ right = bt_getid(bt->page->right);
+ page_no = bt->page_no;
+ latch = bt->latch;
+
+ if( !dirty ) {
+ if( lvl )
+ return bt_abort (bt, bt->page, page_no, BTERR_notfound);
+ bt_unlockpage(BtLockWrite, latch);
+ bt_unpinlatch (latch);
+ return bt->found = found, 0;
+ }
+
+ // did we delete a fence key in an upper level?
+
+ if( lvl && bt->page->act && fence )
+ if( bt_fixfence (bt, page_no, lvl) )
+ return bt->err;
+ else
+ return bt->found = found, 0;
+
+ // is this a collapsed root?
+
+ if( lvl > 1 && page_no == ROOT_page && bt->page->act == 1 )
+ if( bt_collapseroot (bt, bt->page) )
+ return bt->err;
+ else
+ return bt->found = found, 0;
+
+ // return if page is not empty
+
+ if( bt->page->act ) {
+ if( bt_update(bt, bt->page, latch) )
+ return bt->err;
+ bt_unlockpage(BtLockWrite, latch);
+ bt_unpinlatch (latch);
+ return bt->found = found, 0;
+ }
+
+ // cache copy of fence key
+ // in order to find parent
+
+ ptr = keyptr(bt->page, bt->page->cnt);
+ memcpy(lowerkey, ptr, ptr->len + 1);
+
+ // obtain lock on right page
+
+ rlatch = bt_pinlatch (bt, right);
+ bt_lockpage(BtLockWrite, rlatch);
+
+ temp = bt_mappage (bt, rlatch);
+
+ if( temp->kill ) {
+ bt_abort(bt, temp, right, 0);
+ return bt_abort(bt, bt->page, bt->page_no, BTERR_kill);
+ }
+
+ // pull contents of next page into current empty page
+
+ memcpy (bt->page, temp, bt->page_size);
+
+ // cache copy of key to update
+
+ ptr = keyptr(temp, temp->cnt);
+ memcpy(higherkey, ptr, ptr->len + 1);
+
+ // Mark right page as deleted and point it to left page
+ // until we can post updates at higher level.
+
+ bt_putid(temp->right, page_no);
+ temp->kill = 1;
+
+ if( bt_update(bt, bt->page, latch) )
+ return bt->err;
+
+ if( bt_update(bt, temp, rlatch) )
+ return bt->err;
+
+ bt_lockpage(BtLockParent, latch);
+ bt_unlockpage(BtLockWrite, latch);
+
+ bt_lockpage(BtLockParent, rlatch);
+ bt_unlockpage(BtLockWrite, rlatch);
+
+ // redirect higher key directly to consolidated node
+
+ if( bt_insertkey (bt, higherkey+1, *higherkey, lvl+1, page_no, time(NULL)) )
+ return bt->err;
+
+ // delete old lower key to consolidated node
+
+ if( bt_deletekey (bt, lowerkey + 1, *lowerkey, lvl + 1) )
+ return bt->err;
+
+ // obtain write & delete lock on deleted node
+ // add right block to free chain
+
+ bt_lockpage(BtLockDelete, rlatch);
+ bt_lockpage(BtLockWrite, rlatch);
+ bt_unlockpage(BtLockParent, rlatch);
+
+ if( bt_freepage (bt, right, rlatch) )
+ return bt->err;
+
+ bt_unlockpage(BtLockParent, latch);
+ bt_unpinlatch(latch);
+ return 0;
+}
+
+// find key in leaf level and return row-id
+
+uid bt_findkey (BtDb *bt, unsigned char *key, uint len)
+{
+uint slot;
+BtKey ptr;
+uid id;
+
+ if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) )
+ ptr = keyptr(bt->page, slot);
+ else
+ return 0;
+
+ // if key exists, return row-id
+ // otherwise return 0
+
+ if( ptr->len == len && !memcmp (ptr->key, key, len) )
+ id = bt_getid(slotptr(bt->page,slot)->id);
+ else
+ id = 0;
+
+ bt_unlockpage (BtLockRead, bt->latch);
+ bt_unpinlatch (bt->latch);
+ return id;
+}
+
+// check page for space available,
+// clean if necessary and return
+// 0 - page needs splitting
+// >0 - go ahead with new slot
+
+uint bt_cleanpage(BtDb *bt, uint amt, uint slot)
+{
+uint nxt = bt->page_size;
+BtPage page = bt->page;
+uint cnt = 0, idx = 0;
+uint max = page->cnt;
+uint newslot = slot;
+BtKey key;
+int ret;
+
+ if( page->min >= (max+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
+ return slot;
+
+ // skip cleanup if nothing to reclaim
+
+ if( !page->dirty )
+ return 0;
+
+ memcpy (bt->frame, page, bt->page_size);
+
+ // skip page info and set rest of page to zero
+
+ memset (page+1, 0, bt->page_size - sizeof(*page));
+ page->act = 0;
+
+ while( cnt++ < max ) {
+ if( cnt == slot )
+ newslot = idx + 1;
+ // always leave fence key in list
+ if( cnt < max && slotptr(bt->frame,cnt)->dead )
+ continue;
+
+ // copy key
+ key = keyptr(bt->frame, cnt);
+ nxt -= key->len + 1;
+ memcpy ((unsigned char *)page + nxt, key, key->len + 1);
+
+ // copy slot
+ memcpy(slotptr(page, ++idx)->id, slotptr(bt->frame, cnt)->id, BtId);
+ if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) )
+ page->act++;
+#ifdef USETOD
+ slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod;
+#endif
+ slotptr(page, idx)->off = nxt;
+ }
+
+ page->min = nxt;
+ page->cnt = idx;
+
+ if( page->min >= (max+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
+ return newslot;
+
+ return 0;
+}
+
+// split the root and raise the height of the btree
+
+BTERR bt_splitroot(BtDb *bt, unsigned char *leftkey, uid page_no2)
+{
+uint nxt = bt->page_size;
+BtPage root = bt->page;
+uid right;
+
+ // Obtain an empty page to use, and copy the current
+ // root contents into it
+
+ if( !(right = bt_newpage(bt, root)) )
+ return bt->err;
+
+ // preserve the page info at the bottom
+ // and set rest to zero
+
+ memset(root+1, 0, bt->page_size - sizeof(*root));
+
+ // insert first key on newroot page
+
+ nxt -= *leftkey + 1;
+ memcpy ((unsigned char *)root + nxt, leftkey, *leftkey + 1);
+ bt_putid(slotptr(root, 1)->id, right);
+ slotptr(root, 1)->off = nxt;
+
+ // insert second key on newroot page
+ // and increase the root height
+
+ nxt -= 3;
+ ((unsigned char *)root)[nxt] = 2;
+ ((unsigned char *)root)[nxt+1] = 0xff;
+ ((unsigned char *)root)[nxt+2] = 0xff;
+ bt_putid(slotptr(root, 2)->id, page_no2);
+ slotptr(root, 2)->off = nxt;
+
+ bt_putid(root->right, 0);
+ root->min = nxt; // reset lowest used offset and key count
+ root->cnt = 2;
+ root->act = 2;
+ root->lvl++;
+
+ // update and release root (bt->page)
+
+ if( bt_update(bt, root, bt->latch) )
+ return bt->err;
+
+ bt_unlockpage(BtLockWrite, bt->latch);
+ bt_unpinlatch(bt->latch);
+ return 0;
+}
+
+// split already locked full node
+// return unlocked.
+
+BTERR bt_splitpage (BtDb *bt)
+{
+uint cnt = 0, idx = 0, max, nxt = bt->page_size;
+unsigned char fencekey[256], rightkey[256];
+uid page_no = bt->page_no, right;
+BtLatchSet *latch, *rlatch;
+BtPage page = bt->page;
+uint lvl = page->lvl;
+BtKey key;
+
+ latch = bt->latch;
+
+ // split higher half of keys to bt->frame
+ // the last key (fence key) might be dead
+
+ memset (bt->frame, 0, bt->page_size);
+ max = page->cnt;
+ cnt = max / 2;
+ idx = 0;
+
+ while( cnt++ < max ) {
+ key = keyptr(page, cnt);
+ nxt -= key->len + 1;
+ memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1);
+ memcpy(slotptr(bt->frame,++idx)->id, slotptr(page,cnt)->id, BtId);
+ if( !(slotptr(bt->frame, idx)->dead = slotptr(page, cnt)->dead) )
+ bt->frame->act++;
+#ifdef USETOD
+ slotptr(bt->frame, idx)->tod = slotptr(page, cnt)->tod;
+#endif
+ slotptr(bt->frame, idx)->off = nxt;
+ }
+
+ // remember fence key for new right page
+
+ memcpy (rightkey, key, key->len + 1);
+
+ bt->frame->bits = bt->page_bits;
+ bt->frame->min = nxt;
+ bt->frame->cnt = idx;
+ bt->frame->lvl = lvl;
+
+ // link right node
+
+ if( page_no > ROOT_page )
+ memcpy (bt->frame->right, page->right, BtId);
+
+ // get new free page and write frame to it.
+
+ if( !(right = bt_newpage(bt, bt->frame)) )
+ return bt->err;
+
+ // update lower keys to continue in old page
+
+ memcpy (bt->frame, page, bt->page_size);
+ memset (page+1, 0, bt->page_size - sizeof(*page));
+ nxt = bt->page_size;
+ page->dirty = 0;
+ page->act = 0;
+ cnt = 0;
+ idx = 0;
+
+ // assemble page of smaller keys
+ // (they're all active keys)
+
+ while( cnt++ < max / 2 ) {
+ key = keyptr(bt->frame, cnt);
+ nxt -= key->len + 1;
+ memcpy ((unsigned char *)page + nxt, key, key->len + 1);
+ memcpy(slotptr(page,++idx)->id, slotptr(bt->frame,cnt)->id, BtId);
+#ifdef USETOD
+ slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod;
+#endif
+ slotptr(page, idx)->off = nxt;
+ page->act++;
+ }
+
+ // remember fence key for smaller page
+
+ memcpy (fencekey, key, key->len + 1);
+
+ bt_putid(page->right, right);
+ page->min = nxt;
+ page->cnt = idx;
+
+ // if current page is the root page, split it
+
+ if( page_no == ROOT_page )
+ return bt_splitroot (bt, fencekey, right);
+
+ // lock right page
+
+ rlatch = bt_pinlatch (bt, right);
+ bt_lockpage (BtLockParent, rlatch);
+
+ // update left (containing) node
+
+ if( bt_update(bt, page, latch) )
+ return bt->err;
+
+ bt_lockpage (BtLockParent, latch);
+ bt_unlockpage (BtLockWrite, latch);
+
+ // insert new fence for reformulated left block
+
+ if( bt_insertkey (bt, fencekey+1, *fencekey, lvl+1, page_no, time(NULL)) )
+ return bt->err;
+
+ // switch fence for right block of larger keys to new right page
+
+ if( bt_insertkey (bt, rightkey+1, *rightkey, lvl+1, right, time(NULL)) )
+ return bt->err;
+
+ bt_unlockpage (BtLockParent, latch);
+ bt_unlockpage (BtLockParent, rlatch);
+
+ bt_unpinlatch (rlatch);
+ bt_unpinlatch (latch);
+ return 0;
+}
+
+// Insert new key into the btree at requested level.
+// Pages are unlocked at exit.
+
+BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod)
+{
+uint slot, idx;
+BtPage page;
+BtKey ptr;
+
+ while( 1 ) {
+ if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
+ ptr = keyptr(bt->page, slot);
+ else
+ {
+ if( !bt->err )
+ bt->err = BTERR_ovflw;
+ return bt->err;
+ }
+
+ // if key already exists, update id and return
+
+ page = bt->page;
+
+ if( !keycmp (ptr, key, len) ) {
+ if( slotptr(page, slot)->dead )
+ page->act++;
+ slotptr(page, slot)->dead = 0;
+#ifdef USETOD
+ slotptr(page, slot)->tod = tod;
+#endif
+ bt_putid(slotptr(page,slot)->id, id);
+ if( bt_update(bt, bt->page, bt->latch) )
+ return bt->err;
+ bt_unlockpage(BtLockWrite, bt->latch);
+ bt_unpinlatch (bt->latch);
+ return 0;
+ }
+
+ // check if page has enough space
+
+ if( slot = bt_cleanpage (bt, len, slot) )
+ break;
+
+ if( bt_splitpage (bt) )
+ return bt->err;
+ }
+
+ // calculate next available slot and copy key into page
+
+ page->min -= len + 1; // reset lowest used offset
+ ((unsigned char *)page)[page->min] = len;
+ memcpy ((unsigned char *)page + page->min +1, key, len );
+
+ for( idx = slot; idx < page->cnt; idx++ )
+ if( slotptr(page, idx)->dead )
+ break;
+
+ // now insert key into array before slot
+ // preserving the fence slot
+
+ if( idx == page->cnt )
+ idx++, page->cnt++;
+
+ page->act++;
+
+ while( idx > slot )
+ *slotptr(page, idx) = *slotptr(page, idx -1), idx--;
+
+ bt_putid(slotptr(page,slot)->id, id);
+ slotptr(page, slot)->off = page->min;
+#ifdef USETOD
+ slotptr(page, slot)->tod = tod;
+#endif
+ slotptr(page, slot)->dead = 0;
+
+ if( bt_update(bt, bt->page, bt->latch) )
+ return bt->err;
+
+ bt_unlockpage(BtLockWrite, bt->latch);
+ bt_unpinlatch(bt->latch);
+ return 0;
+}
+
+// cache page of keys into cursor and return starting slot for given key
+
+uint bt_startkey (BtDb *bt, unsigned char *key, uint len)
+{
+uint slot;
+
+ // cache page for retrieval
+
+ if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) )
+ memcpy (bt->cursor, bt->page, bt->page_size);
+ else
+ return 0;
+
+ bt_unlockpage(BtLockRead, bt->latch);
+ bt->cursor_page = bt->page_no;
+ bt_unpinlatch (bt->latch);
+ return slot;
+}
+
+// return next slot for cursor page
+// or slide cursor right into next page
+
+uint bt_nextkey (BtDb *bt, uint slot)
+{
+BtLatchSet *latch;
+off64_t 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))
+ return slot;
+ else
+ break;
+
+ if( !right )
+ break;
+
+ bt->cursor_page = right;
+ latch = bt_pinlatch (bt, right);
+ bt_lockpage(BtLockRead, latch);
+
+ bt->page = bt_mappage (bt, latch);
+ memcpy (bt->cursor, bt->page, bt->page_size);
+ bt_unlockpage(BtLockRead, latch);
+ bt_unpinlatch (latch);
+ slot = 0;
+ } while( 1 );
+
+ return bt->err = 0;
+}
+
+BtKey bt_key(BtDb *bt, uint slot)
+{
+ return keyptr(bt->cursor, slot);
+}
+
+uid bt_uid(BtDb *bt, uint slot)
+{
+ return bt_getid(slotptr(bt->cursor,slot)->id);
+}
+
+#ifdef USETOD
+uint bt_tod(BtDb *bt, uint slot)
+{
+ return slotptr(bt->cursor,slot)->tod;
+}
+#endif
+
+#ifdef STANDALONE
+
+uint bt_audit (BtDb *bt)
+{
+uint idx, hashidx;
+uid next, page_no;
+BtLatchSet *latch;
+uint cnt = 0;
+BtPage page;
+off64_t off;
+uint amt[1];
+BtKey ptr;
+
+#ifdef unix
+ if( *(ushort *)(bt->latchmgr->lock) )
+ fprintf(stderr, "Alloc page locked\n");
+ *(ushort *)(bt->latchmgr->lock) = 0;
+
+ for( idx = 1; idx <= bt->latchmgr->latchdeployed; idx++ ) {
+ latch = bt->latchsets + idx;
+ if( *(ushort *)latch->readwr )
+ fprintf(stderr, "latchset %d rwlocked for page %.8x\n", idx, latch->page_no);
+ *(ushort *)latch->readwr = 0;
+
+ if( *(ushort *)latch->access )
+ fprintf(stderr, "latchset %d accesslocked for page %.8x\n", idx, latch->page_no);
+ *(ushort *)latch->access = 0;
+
+ if( *(ushort *)latch->parent )
+ fprintf(stderr, "latchset %d parentlocked for page %.8x\n", idx, latch->page_no);
+ *(ushort *)latch->parent = 0;
+
+ if( latch->pin ) {
+ fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, latch->page_no);
+ latch->pin = 0;
+ }
+ page = (BtPage)(idx * bt->page_size + bt->latchpool);
+ off = latch->page_no << bt->page_bits;
+#ifdef unix
+ if( latch->dirty )
+ if( pwrite(bt->idx, page, bt->page_size, off) < bt->page_size )
+ fprintf(stderr, "Page %.8x Write Error\n", latch->page_no);
+#else
+ if( latch->dirty ) {
+ SetFilePointer (bt->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
+
+ if( !WriteFile(bt->idx, page, bt->page_size, amt, NULL) )
+ fprintf(stderr, "Page %.8x Write Error\n", latch->page_no);
+
+ if( *amt < bt->page_size )
+ fprintf(stderr, "Page %.8x Write Error\n", latch->page_no);
+ }
+#endif
+ latch->dirty = 0;
+ }
+
+ for( hashidx = 0; hashidx < bt->latchmgr->latchhash; hashidx++ ) {
+ if( *(ushort *)(bt->table[hashidx].latch) )
+ fprintf(stderr, "hash entry %d locked\n", hashidx);
+
+ *(ushort *)(bt->table[hashidx].latch) = 0;
+
+ if( idx = bt->table[hashidx].slot ) do {
+ latch = bt->latchsets + idx;
+ if( *(ushort *)latch->busy )
+ fprintf(stderr, "latchset %d busylocked for page %.8x\n", idx, latch->page_no);
+ *(ushort *)latch->busy = 0;
+ if( latch->hash != hashidx )
+ fprintf(stderr, "latchset %d wrong hashidx\n", idx);
+ if( latch->pin )
+ fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, latch->page_no);
+ } while( idx = latch->next );
+ }
+
+ next = bt->latchmgr->nlatchpage + LATCH_page;
+ page_no = LEAF_page;
+
+ while( page_no < bt_getid(bt->latchmgr->alloc->right) ) {
+ pread (bt->idx, bt->frame, bt->page_size, page_no << bt->page_bits);
+ if( !bt->frame->free ) {
+ for( idx = 0; idx++ < bt->frame->cnt - 1; ) {
+ ptr = keyptr(bt->frame, idx+1);
+ if( keycmp (keyptr(bt->frame, idx), ptr->key, ptr->len) >= 0 )
+ fprintf(stderr, "page %.8x idx %.2x out of order\n", page_no, idx);
+ }
+ if( !bt->frame->lvl )
+ cnt += bt->frame->act;
+ }
+
+ if( page_no > LEAF_page )
+ next = page_no + 1;
+ page_no = next;
+ }
+ return cnt - 1;
+#else
+ return 0;
+#endif
+}
+
+#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
+
+// standalone program to index file of keys
+// then list them onto std-out
+
+int main (int argc, char **argv)
+{
+uint slot, line = 0, off = 0, found = 0;
+int ch, cnt = 0, bits = 12, idx;
+unsigned char key[256];
+double done, start;
+uid next, page_no;
+float elapsed;
+time_t tod[1];
+uint scan = 0;
+uint len = 0;
+uint map = 0;
+BtKey ptr;
+BtDb *bt;
+FILE *in;
+
+ if( argc < 4 ) {
+ fprintf (stderr, "Usage: %s idx_file src_file Read/Write/Scan/Delete/Find/Count [page_bits mapped_pool_pages start_line_number]\n", argv[0]);
+ fprintf (stderr, " page_bits: size of btree page in bits\n");
+ fprintf (stderr, " mapped_pool_pages: number of pages in buffer pool\n");
+ exit(0);
+ }
+
+ start = getCpuTime(0);
+ time(tod);
+
+ if( argc > 4 )
+ bits = atoi(argv[4]);
+
+ if( argc > 5 )
+ map = atoi(argv[5]);
+
+ if( argc > 6 )
+ off = atoi(argv[6]);
+
+ bt = bt_open ((argv[1]), BT_rw, bits, map);
+
+ if( !bt ) {
+ fprintf(stderr, "Index Open Error %s\n", argv[1]);
+ exit (1);
+ }
+
+ switch(argv[3][0]| 0x20)
+ {
+ case 'a':
+ fprintf(stderr, "started audit for %s\n", argv[2]);
+ cnt = bt_audit (bt);
+ fprintf(stderr, "finished audit for %s, %d keys\n", argv[2], cnt);
+ break;
+
+ case 'w':
+ fprintf(stderr, "started indexing for %s\n", argv[2]);
+ if( argc > 2 && (in = fopen (argv[2], "rb")) )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ if( off )
+ sprintf((char *)key+len, "%.9d", line + off), len += 9;
+
+ if( bt_insertkey (bt, key, len, 0, ++line, *tod) )
+ fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
+ len = 0;
+ }
+ else if( len < 245 )
+ key[len++] = ch;
+ fprintf(stderr, "finished adding keys for %s, %d \n", argv[2], line);
+ break;
+
+ case 'd':
+ fprintf(stderr, "started deleting keys for %s\n", argv[2]);
+ if( argc > 2 && (in = fopen (argv[2], "rb")) )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ if( off )
+ sprintf((char *)key+len, "%.9d", line + off), len += 9;
+ line++;
+ if( bt_deletekey (bt, key, len, 0) )
+ fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
+ len = 0;
+ }
+ else if( len < 245 )
+ key[len++] = ch;
+ fprintf(stderr, "finished deleting keys for %s, %d \n", argv[2], line);
+ break;
+
+ case 'f':
+ fprintf(stderr, "started finding keys for %s\n", argv[2]);
+ if( argc > 2 && (in = fopen (argv[2], "rb")) )
+ while( ch = getc(in), ch != EOF )
+ if( ch == '\n' )
+ {
+ if( off )
+ sprintf((char *)key+len, "%.9d", line + off), len += 9;
+ line++;
+ if( bt_findkey (bt, key, len) )
+ 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 < 245 )
+ key[len++] = ch;
+ fprintf(stderr, "finished search of %d keys for %s, found %d\n", line, argv[2], found);
+ break;
+
+ case 's':
+ scan++;
+
+ case 'c':
+ fprintf(stderr, "started counting\n");
+ cnt = 0;
+
+ next = bt->latchmgr->nlatchpage + LATCH_page;
+ page_no = LEAF_page;
+
+ while( page_no < bt_getid(bt->latchmgr->alloc->right) ) {
+ uid off = page_no << bt->page_bits;
+#ifdef unix
+ pread (bt->idx, bt->frame, bt->page_size, off);
+#else
+ DWORD amt[1];
+
+ SetFilePointer (bt->idx, (long)off, NULL, FILE_BEGIN);
+
+ if( !ReadFile(bt->idx, bt->frame, bt->page_size, amt, NULL))
+ fprintf (stderr, "unable to read page %.8x", page_no);
+
+ if( *amt < bt->page_size )
+ fprintf (stderr, "unable to read page %.8x", page_no);
+#endif
+ if( !bt->frame->free && !bt->frame->lvl )
+ cnt += bt->frame->act;
+ if( page_no > LEAF_page )
+ next = page_no + 1;
+ page_no = next;
+ }
+
+ cnt--; // remove stopper key
+ fprintf(stderr, " Total keys read %d\n", cnt);
+ break;
+ }
+
+ done = getCpuTime(0);
+ elapsed = (float)(done - 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);
+ return 0;
+}
+
+#endif //STANDALONE
projects / btree / commitdiff