EncdDecd的DecodeBase64是否有限制？

问题描述

您可以传入的Base64字符串的大小是否有限制？

Is there a limit on how large of a Base64 string you can pass in?

我正在使用以下内容，并且在创建图片时丢失了一部分底部的。我看到BufferLen约为44000，但DecodeBase64返回的数组大约为24000。

I'm using the following and when my image gets created it's missing a portion of the bottom. I see that BufferLen is ~44000 and yet DecodeBase64 returns about an array of about 24000 items.

BufferLen := (Length(JVal) * 4) div 3;
SetLength(PtrB, BufferLen);
PtrB := DecodeBase64(AnsiString(JVal));

JStream := TStringStream.Create(PtrB);
Jpeg := TJPEGImage.Create;
Jpeg.LoadFromStream(JStream);
Self.JPG := Jpeg;

推荐答案

Soap中的代码没有大小限制EncdDecd单元，而不是使用 AnsiString 数据类型所施加的单元。

There is no size limitation on the code in the Soap.EncdDecd unit, beyond that imposed by the use of the AnsiString data type.

此程序可以成功编码并然后解码一个100MB的字符串即可证明这一点：

This program which successfully encodes and then decodes a 100MB string demonstrates the point:

{$APPTYPE CONSOLE}

uses
  Soap.EncdDecd;

var
  i: Integer;
  plain, encoded: string;

begin
  SetLength(plain, 100*1024*1024);
  for i := 1 to Length(plain) do
    plain[i] := Chr(32+Random(80));
  encoded := EncodeString(plain);
  if plain=DecodeString(encoded) then
    Writeln('passed')
  else
    Writeln('failed');
  Readln;
end.

您的问题几乎肯定在您的代码中，而不是 EncdDecd 单位。

Your problem almost certainly lies in your code rather than the EncdDecd unit.

您的代码可能会更简单。例如：

You code could be quite a bit simpler. For example:

JStream := TBytesStream.Create(DecodeBase64(JVal));
Jpeg := TJPEGImage.Create;
Jpeg.LoadFromStream(JStream);

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