将字符串转换为TByteDynArray [英] Converting String to TByteDynArray

问题描述

我在Delphi中有一个 String 对象.我想将其转换为 TByteDynArray .我已经在下面尝试了实现，但是在调试时发现 binaryData 为空，我在做什么错了?

I have a String object in Delphi. I want to convert that to TByteDynArray. I have tried the implementation below.But while debugging I find that binaryData is empty after the assignment.What am I doing wrong?

procedure convertStringToTByteDynArray;
var
  binaryData:TByteDynArray;
  Data: String;

begin
   Data := '8080100B1D472';
  //Copy over string to TByteDynArray
  SetLength(binaryData,Length(Data));
  Move(Data[1],binaryData,Length(Data)); 
end

推荐答案

在Delphi 2007及更早版本中， Char 的大小为1个字节，而在Delphi 2009及更高版本中为2个字节.在后一种情况下，代码会将UTF-16数据放入字节数组，但仅复制一半字符.

The size of Char is 1 byte in Delphi 2007 and earlier, but is 2 bytes in Delphi 2009 and later. In the latter case, the code will put UTF-16 data into the bytearray, but will only copy half of the characters.

您正在犯的核心错误是将 binarydata 本身传递给 Move()会传递变量本身的存储位置，这只是指向其他内存的指针.相反，传递 binarydata [0] 会传递 TByteDynArray 指向的已分配内存的第一个元素的存储位置.那就是您需要通过的内容.

The core mistake you are making is that passing binarydata by itself to Move() passes the memory location of the variable itself, which is just a pointer to other memory. Passing binarydata[0] instead passes the memory location of the first element of the allocated memory that the TByteDynArray is pointing at. That is what you need to pass instead.

我还添加了一个 Length()检查，该检查可以避免在启用范围检查时出现一些错误.

I also added a Length() check that avoids some rangecheck errors when those are enabled.

procedure convertStringToTByteDynArray;
var
  binaryData: TByteDynArray;
  Data: String;
begin
  Data := '8080100B1D472';
  //Copy over string to TByteDynArray
  SetLength(binaryData, Length(Data) * sizeof(Char));
  if Length(Data) > 0 then
    Move(Data[1], binaryData[0], Length(Data) * sizeof(Char)); 
end;

或者:

procedure convertStringToTByteDynArray;
var
  binaryData: TByteDynArray;
  Data: String;
begin
  Data := '8080100B1D472';
  //Copy over string to TByteDynArray
  SetLength(binaryData, Length(Data) * sizeof(Char));
  Move(PChar(Data)^, PByte(binaryData)^, Length(binaryData)); 
end;

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