unit dbisamtbutf8;

interface

uses System.Classes, System.Variants, Data.DB, dbisamtb;

type

TUTF8StringField = class(TStringField) 
private
  FAutoUtf8Conversion:     Boolean;
protected
  function                 GetAsString: string; override;
  function                 GetAsVariant: Variant; override;
  procedure                SetAsString(const Value: string); override;
public
  constructor              Create(AOwner: TComponent); override;
published
  property                 AutoUtf8Conversion: Boolean read FAutoUtf8Conversion write FAutoUtf8Conversion;
end;

TUTF8DBISAMTable = class(TDBISAMTable) 
private
  FAutoUTF8Conversion:     Boolean;
  procedure                SetAutoUTF8Conversion(const NewValue:Boolean);
public
  constructor              Create(AOwner: TComponent); override;
  procedure                Open; overload;
  function                 GetFieldClass(FieldType: TFieldType): TFieldClass; override;
published
  property                 AutoUTF8Conversion:Boolean read FAutoUTF8Conversion write SetAutoUTF8Conversion;
end;

implementation

constructor TUTF8StringField.Create(AOwner: TComponent);
begin
  FAutoUtf8Conversion:=false;
  inherited Create(AOwner);
end;

function TUTF8StringField.GetAsString: string;
begin
  if FAutoUtf8Conversion then
    Result:=UTF8ToString(GetAsAnsiString)
  else
    Result:=inherited GetAsString;
end;

function TUTF8StringField.GetAsVariant: Variant;
begin
  if FAutoUtf8Conversion then
    Result:=UTF8ToString(AnsiString(inherited GetAsVariant))
  else
    Result:=inherited GetAsVariant;
end;

procedure TUTF8StringField.SetAsString(const Value: string);
begin
  if FAutoUtf8Conversion then
    inherited SetAsAnsiString(UTF8Encode(Value))
  else
    Inherited SetAsString(Value);
end;

{ TUTF8DBISAMTable }
constructor TUTF8DBISAMTable.Create(AOwner: TComponent);
begin
  FAutoUTF8Conversion:=false;
  inherited Create(AOwner);
end;

function TUTF8DBISAMTable.GetFieldClass(FieldType: TFieldType): TFieldClass;
begin
  if FieldType=ftString then
    Result:=TUTF8StringField
  else
    Result:=inherited GetFieldClass(FieldType);
end;

procedure TUTF8DBISAMTable.SetAutoUTF8Conversion(const NewValue: Boolean);
var
  i:Integer;
begin
  for i := 0 to Fields.Count-1 do
    begin
    if Fields.Fields[i] is TUTF8StringField then
      TUTF8StringField(Fields.Fields[i]).AutoUtf8Conversion:=NewValue;
    end;
  FAutoUTF8Conversion:=NewValue;
end;

procedure TUTF8DBISAMTable.Open;
begin
  inherited Open;
  SetAutoUTF8Conversion(FAutoUTF8Conversion);
end;

end.