delphi的hashmap

delphi的hashmap

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/// 支持D7，更低版本没有测试，支持跨OS   unit hashMap;   interface   uses   SysUtils;   type   PHashData = ^THashData;     THashData = record     KeyS: string;     KeyI: Int64;     Next: PHashData;     Data: Pointer;   end;     THashMap = class   private     FBucketsSize: Cardinal;                  // 桶大小     FBuckets: array of PHashData;    // 桶   public     constructor Create(BucketsSize: Cardinal = 20000);     destructor destroy; override;   public     procedure SetValue(const key: string; val: Pointer); overload;     procedure SetValue(const key: integer; val: Pointer); overload;     function GetValue(const key: string; var val: Pointer): Boolean; overload;     function GetValue(const key: Integer; var val: Pointer): Boolean; overload;   end;   function hashOf(const p: Pointer; l: Integer): Integer; overload;   function hashOf(const s: string): Integer; overload;   implementation   function hashOf(const p: Pointer; l: Integer): Integer; overload; var   ps: PInteger;   lr: Integer; begin   Result := 0;   if l > 0 then   begin     ps := p;     lr := (l and $03);     l := (l and $FFFFFFFC);     while l > 0 do     begin       Result := ((Result shl 5) or (Result shr 27)) xor ps^;       Inc(ps);       Dec(l, 4);     end;     if lr <> 0 then     begin       l := 0;       Move(ps^, l, lr);       Result := ((Result shl 5) or (Result shr 27)) xor l;     end;   end; end;   function hashOf(const s: string): Integer; overload; begin   Result := hashOf(PChar(s), Length(s) * SizeOf(Char)); end;   { THashMap }   constructor THashMap.Create(BucketsSize: Cardinal = 20000); var   i: Integer; begin   FBucketsSize := BucketsSize;   SetLength(FBuckets, FBucketsSize);   for i := 0 to FBucketsSize - 1 do     FBuckets[i] := nil; end;   destructor THashMap.destroy; var   I: Integer;   item, lNext: PHashData; begin   for I := 0 to High(FBuckets) do   begin     lNext := FBuckets[I];     while lNext <> nil do     begin       item := lNext;       lNext := lNext.Next;       Dispose(item);     end;   end;   inherited; end;   function THashMap.GetValue(const key: string; var val: Pointer): Boolean; var   Idx: Cardinal;   Rec: PHashData;   HashV: Cardinal; begin   Result := False;   HashV := Cardinal(hashOf(key));   Idx := HashV mod Cardinal(FBucketsSize);   Rec := FBuckets[Idx];   while Assigned(Rec) do   begin     if Rec.KeyS = key then     begin       val := Rec.Data;       Result := True;       Break;     end;     Rec := Rec.Next;   end; end;   procedure THashMap.SetValue(const key: string; val: Pointer); var   Idx: Integer;   Rec, MatchtedRec: PHashData;   hashVal: Cardinal; begin   hashVal := Cardinal(hashof(key));   Idx := hashVal mod Cardinal(FBucketsSize);   Rec := FBuckets[Idx];   MatchtedRec := nil;   while Assigned(Rec) do   begin     if Rec.KeyS = key then     begin       MatchtedRec := Rec;       Break;     end;     Rec := Rec.Next;   end;   if MatchtedRec <> nil then   begin     MatchtedRec.Data := val;   end   else   begin     New(MatchtedRec);     MatchtedRec.KeyS := key;     MatchtedRec.Data := val;     MatchtedRec.Next := FBuckets[Idx];     FBuckets[Idx] := MatchtedRec;   end; end;   function THashMap.GetValue(const key: Integer; var val: Pointer): Boolean; var   Idx: Cardinal;   Rec: PHashData; begin   Result := False;   Idx := Cardinal(key) mod FBucketsSize;   Rec := FBuckets[Idx];   while Assigned(Rec) do   begin     if Rec.KeyI = key then     begin       val := Rec.Data;       Result := True;       Break;     end;     Rec := Rec.Next;   end; end;   procedure THashMap.SetValue(const key: integer; val: Pointer); var   Idx: Integer;   Rec, MatchtedRec: PHashData; begin   Idx := Cardinal(key) mod Cardinal(FBucketsSize);   Rec := FBuckets[Idx];   MatchtedRec := nil;   while Assigned(Rec) do   begin     if Rec.KeyI = key then     begin       MatchtedRec := Rec;       Break;     end;     Rec := Rec.Next;   end;   if MatchtedRec <> nil then   begin     MatchtedRec.Data := val;   end   else   begin     GetMem(MatchtedRec, SizeOf(THashData));     MatchtedRec.KeyI := key;     MatchtedRec.Data := val;     MatchtedRec.Next := FBuckets[Idx];     FBuckets[Idx] := MatchtedRec;   end; end;   end.