Subject ot4xb - Build: 1_5_2_54 From Pablo Botella Date Sat, 30 Aug 2008 23:06:44 +0200 Newsgroups ot4xb.snapshots Attachment(s) _ot4xb_.zip, HashTableNotes.txt, TestHash.zip ot4xb - Build: 1_5_2_54 Hash Table Functions: _HDICT_NEW() -> pHt                          -  Create a new hash table and return the handle _HDICT_KEY_COMPARE( key1 , key2 ) -> lEqual  -  Compare 2 keys (num,char or date) and return .T. if are equivalents _HDICT_DESTROY(pHt)                          -  Release memory used to store the hash table. _HDICT_SETPROP(pHt, key , val )              -  Add new entry to the hash table and discard previous if any. _HDICT_GETPROP(pHt,key )                     -  Retrieve a value or NIL if entry not exist. _HDICT_REMOVEPROP(pHt,key)                   -  Remove a entry if exist _HDICT_REMOVEALL(pHt)                        -  Remove all entries _HDICT_COUNT(pHt)                            -  Count existing entries in the hash table // --------------------------------------------------------------------------- _HDICT_ITERATE_STEP(pHt,@pIterator,@item,@key) - Return 1 item at time from the hash table storage pIterator must be passed by reference and must be NIL the first time the function is called item and key params will receive the key and item values for each iteration _HDICT_ITERATE_STEP() will return .T. while not reach the end of storage See the following sample: i := k := v := NIL while _HDICT_ITERATE_STEP( pHt, @i, @v , @k)    ? k ," -> " , v end                                    NOTES: -  pIterator MUST NOT be changed by the application -  Items inside the hash storage are sorted in random order acording with the hash algoritm    so iterate the entire hash table will warrat all items are retrieved but not the order    in wich you retrieve the items    -  Remove items inside the iteration can result into a memory exception -  Add items withing the iteration can produce dupe evaluations // --------------------------------------------------------------------------- _HDICT_ITERATE_CB( pHt , codeblock , @cargo ) - Evaluate a codeblock across all items The codeblock will receive 4 params nItemPosition , cKey , xValue and the provided cargo The codeblock must return .T. to continue or .F. to stop See the following sample: aItems := Array( _HDICT_COUNT( pDict ) , 2 ) cbk    := {|pos,key,val,cargo| cargo[pos][1] := key ,cargo[pos][2] := val, .T. } _HDICT_ITERATE_CB( pDict, cbk , @aItems )   NOTES: -  Items inside the hash storage are sorted in random order acording with the hash algoritm    so iterate the entire hash table will warrat all items are retrieved but not the order    in wich you retrieve the items    -  Remove items inside the iteration can result into a memory exception -  Add items withing the iteration can produce dupe evaluations // --------------------------------------------------------------------------- _HDICT_* functions and multi-thread ========================= _HDICT_* functions and THDict class don't provide builtin multithread serialization But your classes can provide the required multithread suppor in a easy manner just using SYNC methods Example: CLASS Dictionary EXPORTED: VAR ht INLINE METHOD init()           ; ::ht := _HDICT_NEW() ; return Self INLINE SYNC METHOD Destroy()   ; _HDICT_DESTROY(::ht) ;  ::ht := NIL ;  return Self INLINE SYNC METHOD Put(key,val); return _HDICT_SETPROP(::ht,key,val) INLINE SYNC METHOD Get(key)    ; return _HDICT_GETPROP(::ht,key) INLINE SYNC METHOD Del(key)    ; return _HDICT_REMOVEPROP(::ht,key) INLINE SYNC METHOD Zap()       ; return _HDICT_REMOVEALL(::ht) ENDCLASS // ---------------------------------------------------------------------------