unit HashTableGen;
{$I SynEdit.inc}
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ComCtrls;
type
TFrmHashTableGen = class(TForm)
LabelParams: TLabel;
LabelD: TLabel;
LabelC: TLabel;
LabelM: TLabel;
Label1: TLabel;
Label2: TLabel;
LabelPercentage: TLabel;
ProgressBar1: TProgressBar;
EditD: TMemo;
EditC: TMemo;
EditM: TMemo;
ButtonFindHash: TButton;
procedure ButtonFindHashClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure FormShow(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
private
FKeyList: TList;
public
procedure AssignKeyWords(KeyList: TList; CaseSensitive: Boolean);
function GetHashKeyFunctionSource(ClassName: string): string;
function GetKeyWordConstantsSource(CaseSensitive: Boolean): string;
function KeyIndicesCount: Integer;
end;
const
MaxTableSize = 100000;
type
THashKeyList = class
private
FMaxHashKey: Integer;
FHashKeys: array[0..MaxTableSize - 1] of Boolean;
public
function Add(HashKey: Integer): Boolean;
procedure Clear;
end;
var
FrmHashTableGen: TFrmHashTableGen;
implementation
{$R *.dfm}
uses
StrUtils,
SynGenUnit,
SynUnicode;
{$I primenumbers.inc}
var
m: Cardinal;
FinalC, FinalD, FinalM: Cardinal;
searching: Boolean;
KeyWords: array of string;
HashKeyList: THashKeyList;
{$Q-}
function HashKey(const S: string; c, d: Cardinal): Cardinal;
var
i: Integer;
begin
Result := 0;
for i := 1 to Length(S) do
Result := Result * c + Ord(S[i]) * d;
Result := Result mod m;
end;
{$Q+}
{$Q-}
function FinalHashKey(const S: string): Cardinal;
var
i: Integer;
begin
Result := 0;
for i := 1 to Length(S) do
Result := Result * FinalC + Ord(S[i]) * FinalD;
Result := Result mod FinalM;
end;
{$Q+}
procedure WordWrapAtCol80(Words, Result: TStrings; Indentation: Integer);
var
WrappedLines: TStringList;
i: Integer;
Line: string;
begin
WrappedLines := TStringList.Create;
try
i := 0;
while i < Words.Count do
begin
Line := StringOfChar(' ', Indentation);
while (i < Words.Count) and (Length(Line) + Length(Words[i]) <= 80) do
begin
Line := Line + Words[i] + ' ';
inc(i);
end;
WrappedLines.Add(Line);
end;
Result.Assign(WrappedLines);
finally
WrappedLines.Free;
end;
end;
{ TFrmHashTableGen }
procedure TFrmHashTableGen.FormCreate(Sender: TObject);
begin
HashKeyList := THashKeyList.Create;
ProgressBar1.Max := 1000;
end;
procedure TFrmHashTableGen.FormDestroy(Sender: TObject);
begin
HashKeyList.Free;
end;
procedure TFrmHashTableGen.AssignKeyWords(KeyList: TList; CaseSensitive: Boolean);
var
i: Integer;
KeyWordsList: TStringList;
begin
FKeyList := nil;
SetLength(KeyWords, 0);
HashKeyList.Clear;
KeyWordsList := TStringList.Create;
try
KeyWordsList.Sorted := True;
KeyWordsList.Duplicates := dupIgnore;
for i := 0 to KeyList.Count - 1 do
KeyWordsList.Add(TLexKeys(KeyList[i]).KeyName);
SetLength(KeyWords, KeyWordsList.Count);
if CaseSensitive then
for i := 0 to KeyWordsList.Count - 1 do
KeyWords[i] := KeyWordsList[i]
else
for i := 0 to KeyWordsList.Count - 1 do
KeyWords[i] := SysUtils.AnsiLowerCase(KeyWordsList[i]);
FKeyList := KeyList;
finally
KeyWordsList.Free;
end;
end;
procedure TFrmHashTableGen.FormShow(Sender: TObject);
begin
m := 0;
FinalC := 0;
FinalD := 0;
FinalM := 0;
ProgressBar1.Position := 0;
EditD.Lines.Text := '0';
EditC.Lines.Text := '0';
EditM.Lines.Text := '0';
LabelPercentage.Caption := '0%';
ButtonFindHash.SetFocus;
ButtonFindHash.Caption := 'Find Hash Params';
end;
procedure TFrmHashTableGen.FormClose(Sender: TObject;
var Action: TCloseAction);
var
i: Integer;
begin
if Assigned(FKeyList) then
begin
for i := 0 to FKeyList.Count - 1 do
with TLexKeys(FKeyList[i]) do
begin
Key := FinalHashKey(SysUtils.AnsiLowerCase(KeyName));
end;
end;
end;
procedure TFrmHashTableGen.ButtonFindHashClick(Sender: TObject);
var
i, j, c, d: Integer;
collided: Boolean;
Key, smallestM: Cardinal;
procedure SearchStop;
begin
ButtonFindHash.Caption := 'Find Hash Params';
searching := False;
Close;
if FinalM = 0 then
raise Exception.Create('Cannot build the hashtable as no working hash parameters were found');
end;
begin
collided := False;
if searching then
begin
SearchStop;
Exit;
end
else
begin
ProgressBar1.Position := 0;
LabelPercentage.Caption := '0%';
Application.ProcessMessages;
if Length(KeyWords) = 0 then exit;
searching := True;
ButtonFindHash.Caption := 'Stop Search';
end;
smallestM := MaxTableSize + 1;
for d := 1 to 1000 do
begin
for c := 1 to 1000 do
for j := 0 to High(PrimeNumbers) do
begin
m := PrimeNumbers[j];
if m >= smallestM then
begin
m := smallestM;
Break;
end;
for i := Low(KeyWords) to High(KeyWords) do
begin
Key := HashKey(KeyWords[i], c, d);
collided := HashKeyList.Add(Key);
if collided then
begin
HashKeyList.Clear;
break;
end;
end;
if not collided then
begin
smallestM := m;
EditD.Lines.Text := IntToStr(d);
EditC.Lines.Text := IntToStr(c);
EditM.Lines.Text := IntToStr(m);
FinalD := d;
FinalC := c;
FinalM := m;
if m = Cardinal(Length(KeyWords)) then
begin
ProgressBar1.Position := ProgressBar1.Max;
LabelPercentage.Caption := '100%';
SearchStop;
Exit;
end;
break; // all the following solutions will only have a bigger array
end;
Application.ProcessMessages;
if not searching then
begin
SearchStop;
Exit;
end;
end;
ProgressBar1.Position := d;
LabelPercentage.Caption := FloatToStr(d / 10) + '%';
Application.ProcessMessages;
end;
SearchStop;
end;
function TFrmHashTableGen.GetHashKeyFunctionSource(ClassName: string): string;
begin
Result := '{$Q-}'#13#10;
Result := Result + Format('function %s.HashKey(Str: PWideChar): Cardinal;', [ClassName]) + #13#10;
Result := Result + 'begin'#13#10;
Result := Result + ' Result := 0;'#13#10;
Result := Result + ' while IsIdentChar(Str^) do'#13#10;
Result := Result + ' begin'#13#10;
if (FinalC = 1) and (FinalD = 1) then
Result := Result + ' Result := Result + Ord(Str^);'#13#10
else if FinalC = 1 then
Result := Result + Format(' Result := Result + Ord(Str^) * %d;', [FinalD]) + #13#10
else if FinalD = 1 then
Result := Result + Format(' Result := Result * %d + Ord(Str^);', [FinalC]) + #13#10
else
Result := Result + Format(' Result := Result * %d + Ord(Str^) * %d;', [FinalC, FinalD]) + #13#10;
Result := Result + ' inc(Str);'#13#10;
Result := Result + ' end;'#13#10;
Result := Result + ' Result := Result mod ' + IntToStr(FinalM) + ';'#13#10;
Result := Result + ' fStringLen := Str - fToIdent;'#13#10;
Result := Result + 'end;'#13#10;
Result := Result + '{$Q+}'#13#10;
end;
{$IFNDEF SYN_COMPILER_6_UP}
function DupeString(const AText: string; ACount: Integer): string;
var
P: PChar;
C: Integer;
begin
C := Length(AText);
SetLength(Result, C * ACount);
P := Pointer(Result);
if P = nil then Exit;
while ACount > 0 do
begin
Move(Pointer(AText)^, P^, C);
Inc(P, C);
Dec(ACount);
end;
end;
{$ENDIF}
function TFrmHashTableGen.GetKeyWordConstantsSource(CaseSensitive: Boolean): string;
var
i: Integer;
sl: TStringList;
LastItem: string;
begin
// write KeyWords
if not CaseSensitive then
Result := Result + ' // as this language is case-insensitive keywords *must* be in lowercase'#13#10;
Result := Result + Format(' KeyWords: array[0..%d] of string = (', [High(KeyWords)]) + #13#10;
sl := TStringList.Create;
try
for i := Low(KeyWords) to High(KeyWords) do
sl.Add(#39 + KeyWords[i] + #39 + ',');
if sl.Count > 0 then
begin
// remove comma from last line
LastItem := sl[sl.Count - 1];
Delete(LastItem, Length(LastItem), 1);
sl[sl.Count - 1] := LastItem;
WordWrapAtCol80(sl, sl, 4);
Result := Result + sl.Text;
end;
finally
sl.Free;
end;
Result := Result + ' );'#13#10;
Result := Result + #13#10;
// write KeyIndices
Result := Result + Format(' KeyIndices: array[0..%d] of Integer = (', [FinalM - 1]) + #13#10;
sl := TStringList.Create;
try
sl.Text := DupeString('-1,'#13#10, FinalM);
for i := Low(KeyWords) to High(KeyWords) do
sl[FinalHashKey(KeyWords[i])] := IntToStr(i) + ',';
if sl.Count > 0 then
begin
// remove comma from last line
LastItem := Trim(sl[sl.Count - 1]);
Delete(LastItem, Length(LastItem), 1);
sl[sl.Count - 1] := LastItem;
WordWrapAtCol80(sl, sl, 4);
Result := Result + sl.Text;
end;
finally
sl.Free;
end;
Result := Result + ' );'#13#10;
end;
function TFrmHashTableGen.KeyIndicesCount: Integer;
begin
Result := FinalM;
end;
{ THashKeyList }
function THashKeyList.Add(HashKey: Integer): Boolean;
begin
if HashKey > FMaxHashKey then
FMaxHashKey := HashKey;
Result := FHashKeys[HashKey];
FHashKeys[HashKey] := True;
end;
procedure THashKeyList.Clear;
begin
FillChar(FHashKeys, FMaxHashKey + 1, 0);
FMaxHashKey := 0;
end;
end.
