delphi - 使用delphi 2007对base64进行编码和解码base64

Question

我必须在旧的 Delphi 2007 上将字节数组编码为 Base64 字符串(并解码该字符串)。 我该怎么办？

更多信息:

我尝试过突触(如此处建议的 Binary to Base64 (Delphi) )。

Answer 1

Indy 随 Delphi 一起提供，并具有用于处理 base64 的 TIdEncoderMIME 和 TIdDecoderMIME 类。例如:

uses
  ..., IdCoder, IdCoderMIME;

var
  Bytes: TIdBytes;
  Base64String: String;
begin
  //...
  Bytes := ...; // array of bytes
  //...
  Base64String := TIdEncoderMIME.EncodeBytes(Bytes);
  //...
  Bytes := TIdDecoderMIME.DecodeBytes(Base64String);
  //...
end;

还有用于编码/解码 String 和 TStream 数据的方法。

更新:或者，如果您的版本没有上面显示的 class 方法:

// TBytesStream was added in D2009, so define it manually for D2007

uses
  ..., IdCoder, IdCoderMIME
  {$IF RTLVersion < 20)
  , RTLConsts
  {$IFEND}
  ;

{$IF RTLVersion < 20)
type
  TBytesStream = class(TMemoryStream)
  private
    FBytes: TBytes;
  protected
    function Realloc(var NewCapacity: Longint): Pointer; override;
  public
    constructor Create(const ABytes: TBytes); overload;
    property Bytes: TBytes read FBytes;
  end;

constructor TBytesStream.Create(const ABytes: TBytes);
begin
  inherited Create;
  FBytes := ABytes;
  SetPointer(Pointer(FBytes), Length(FBytes));
  FCapacity := FSize;
end;

const
  MemoryDelta = $2000; // Must be a power of 2

function TBytesStream.Realloc(var NewCapacity: Integer): Pointer;
begin
  if (NewCapacity > 0) and (NewCapacity <> FSize) then
    NewCapacity := (NewCapacity + (MemoryDelta - 1)) and not (MemoryDelta - 1);
  Result := Pointer(FBytes);
  if NewCapacity <> FCapacity then
  begin
    SetLength(FBytes, NewCapacity);
    Result := Pointer(FBytes);
    if NewCapacity = 0 then
      Exit;
    if Result = nil then raise EStreamError.CreateRes(@SMemoryStreamError);
  end;
end;
{$IFEND}

var
  Bytes: TBytes;
  BStrm: TBytesStream;
  Encoder: TIdEncoderMIME;
  Decoder: TIdDecoderMIME;
  Base64String: String;
begin
  //...
  Bytes := ...; // array of bytes
  //...
  BStrm := TBytesStream.Create(Bytes);
  try
    Encoder := TIdEncoderMIME.Create;
    try
      Base64String := Encoder.Encode(BStrm);
    finally
      Encoder.Free;
    end;
  finally
    BStrm.Free;
  end;
  //...
  BStrm := TBytesStream.Create;
  try
    Decoder := TIdDecoderMIME.Create;
    try
      Decoder.DecodeBegin(BStrm);
      Decoder.Decode(Base64String);
      Decoder.DecodeEnd;
    finally
      Decoder.Free;
    end;
    Bytes := BStrm.Bytes;
  finally
    BStrm.Free;
  end;
  //...
end;