/*
**?This?file?implements?a?external?（disk-based）?database?using?BTrees.
**?For?a?detailed?discussion?of?BTrees?refer?to
**
**?????Donald?E.?Knuth?THE?ART?OF?COMPUTER?PROGRAMMING?Volume?3:
**?????“Sorting?And?Searching“?pages?473-480.?Addison-Wesley
**?????Publishing?Company?Reading?Massachusetts.
**
**?The?basic?idea?is?that?each?page?of?the?file?contains?N?database
**?entries?and?N+1?pointers?to?subpages.
**
**???----------------------------------------------------------------
**???|??Ptr（0）?|?Key（0）?|?Ptr（1）?|?Key（1）?|?...?|?Key（N）?|?Ptr（N+1）?|
**???----------------------------------------------------------------
**
**?All?of?the?keys?on?the?page?that?Ptr（0）?points?to?have?values?less
**?than?Key（0）.??All?of?the?keys?on?page?Ptr（1）?and?its?subpages?have
**?values?greater?than?Key（0）?and?less?than?Key（1）.??All?of?the?keys
**?on?Ptr（N+1）?and?its?subpages?have?values?greater?than?Key（N）.??And
**?so?forth.
**
**?Finding?a?particular?key?requires?reading?O（log（M））?pages?from?the?
**?disk?where?M?is?the?number?of?entries?in?the?tree.
**
**?In?this?implementation?a?single?file?can?hold?one?or?more?separate?
**?BTrees.??Each?BTree?is?identified?by?the?index?of?its?root?page.??The
**?key?and?data?for?any?entry?are?combined?to?form?the?“payload“.??Up?to
**?MX_LOCAL_PAYLOAD?bytes?of?payload?can?be?carried?directly?on?the
**?database?page.??If?the?payload?is?larger?than?MX_LOCAL_PAYLOAD?bytes
**?then?surplus?bytes?are?stored?on?overflow?pages.??The?payload?for?an
**?entry?and?the?preceding?pointer?are?combined?to?form?a?“Cell“.??Each?
**?page?has?a?small?header?which?contains?the?Ptr（N+1）?pointer.
**
**?The?first?page?of?the?file?contains?a?magic?string?used?to?verify?that
**?the?file?really?is?a?valid?BTree?database?a?pointer?to?a?list?of?unused
**?pages?in?the?file?and?some?meta?information.??The?root?of?the?first
**?BTree?begins?on?page?2?of?the?file.??（Pages?are?numbered?beginning?with
**?1?not?0.）??Thus?a?minimum?database?contains?2?pages.
*/
#include?“eDbInit.h“

/*?Forward?declarations?*/
static?BtOps?eDbBtreeOps;
static?BtCursorOps?eDbBtreeCursorOps;

/*
**?Macros?used?for?byteswapping.??B?is?a?pointer?to?the?Btree
**?structure.??This?is?needed?to?access?the?Btree.needSwab?boolean
**?in?order?to?tell?if?byte?swapping?is?needed?or?not.
**?X?is?an?unsigned?integer.??SWAB16?byte?swaps?a?16-bit?integer.
**?SWAB32?byteswaps?a?32-bit?integer.
*/
#define?SWAB16（BX）???（（B）->needSwab??swab16（（u16）X）?:?（（u16）X））
#define?SWAB32（BX）???（（B）->needSwab??swab32（X）?:?（X））
#define?SWAB_ADD（BXA）?\
???if（（B）->needSwab）{?X=swab32（swab32（X）+A）;?}else{?X?+=?（A）;?}

/*
**?The?following?global?variable?-?available?only?if?eDb_TEST?is
**?defined?-?is?used?to?determine?whether?new?databases?are?created?in
**?native?byte?order?or?in?non-native?byte?order.??Non-native?byte?order
**?databases?are?created?for?testing?purposes?only.??Under?normal?operation
**?only?native?byte-order?databases?should?be?

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

????...D..R?????????0??2004-07-22?19:39??lemon

?????文件???????8755??2004-07-09?09:55??lemon\parse.y

?????文件???????3387??2004-03-30?18:05??lemon\lemon.dsp

?????文件??????99328??2004-06-24?09:43??lemon\lemon.ncb

?????文件???????1331??2004-06-24?09:43??lemon\lemon.plg

?????文件????????533??2004-03-30?18:08??lemon\lemon.dsw

?????文件??????63206??2004-07-09?09:55??lemon\parse.out

?????文件???????2622??2004-07-07?14:08??lemon\parse.h

?????文件??????15725??2004-06-22?16:08??lemon\eDbPparse.y

?????文件??????36619??2004-07-09?09:55??lemon\parse.c

?????文件?????128467??2004-06-24?09:43??lemon\lemon.c

?????文件??????53760??2004-06-24?09:43??lemon\lemon.opt

?????文件??????12344??2004-06-24?09:44??lemon\lempar.c

????...D..R?????????0??2004-07-22?19:39??lemon\Release

????...D..R?????????0??2004-07-22?19:39??lemon\Debug

????...D..R?????????0??2004-07-19?16:55??test

?????文件?????102400??2004-07-22?11:38??test\eDb.exe

?????文件??????36864??2004-07-11?15:17??test\t.exe

?????目錄??????????0??2005-05-12?19:06??uCOSeDb

?????文件??????12325??2005-04-14?11:50??uCOSeDb\eDb.apj

?????目錄??????????0??2005-05-12?19:06??uCOSeDb\Release

?????目錄??????????0??2005-05-12?19:06??uCOSeDb\srcv

?????文件??????28672??2004-09-16?14:37??uCOSeDb\srcv\edb.IMB

?????文件????????608??2004-09-16?14:37??uCOSeDb\srcv\edb.IMD

?????文件??????98304??2004-09-16?14:37??uCOSeDb\srcv\edb.IAB

?????文件???????1288??2004-09-16?14:37??uCOSeDb\srcv\edb.IAD

?????文件??????11432??2004-09-16?14:37??uCOSeDb\srcv\edb.PR

?????文件?????227552??2004-09-16?14:37??uCOSeDb\srcv\edb.PS

?????文件????????140??2004-09-16?14:37??uCOSeDb\srcv\edb.PFI

?????文件????????776??2004-09-16?14:37??uCOSeDb\srcv\edb.PO

............此處省略196個文件信息