我正在尝试将TMemoryStream缓冲区的内容复制到void指针,下面你可以看到不起作用的示例代码 - void buffer为空,但textbox包含有效大小 - 我用winrar大小检查它。以下代码创建了exe文件,但它的大小为0。
void __fastcall TForm1::Button1Click(TObject *Sender)
{
TMemoryStream* ms = new TMemoryStream();
Download->Get("http://rarlab.com/rar/wrar521pl.exe",ms);
this->Edit1->Text = ms->Size;
void* buffer = malloc(ms->Size );
ms->Read(buffer,ms->Size);
FILE* pFile = fopen("test.exe","wb");
fwrite(buffer,4,ms->Size,pFile);
fclose(pFile);
delete ms;
}
另外,我知道我可以轻松地将TMemoryStream缓冲区的内容保存到文件中,但我需要将其内容作为void指针,所以我编写了以下代码来测试它。
答案 0 :(得分:1)
从流中读取的代码几乎正确。在读取之前,您没有将流的Position
属性重置为0,因此您实际上是在流的末尾读取,其中没有要读取的数据。
试试这个:
void __fastcall TForm1::Button1Click(TObject *Sender)
{
TMemoryStream* ms = new TMemoryStream();
try
{
Download->Get("http://rarlab.com/rar/wrar521pl.exe", ms);
ms->Position = 0; // <-- ADD THIS
Edit1->Text = ms->Size;
void* buffer = malloc(ms->Size);
if (buffer)
{
ms->ReadBuffer(buffer, ms->Size);
// ms->SaveToFile("test.exe");
FILE* pFile = fopen("test.exe", "wb");
if (pFile)
{
fwrite(buffer, 1, ms->Size, pFile);
fclose(pFile);
}
free(buffer);
}
}
__finally
{
delete ms;
}
}
或者,只是不分配单独的缓冲区,而是直接使用流的自己的缓冲区:
void __fastcall TForm1::Button1Click(TObject *Sender)
{
TMemoryStream* ms = new TMemoryStream();
try
{
Download->Get("http://rarlab.com/rar/wrar521pl.exe", ms);
Edit1->Text = ms->Size;
void* buffer = ms->Memory;
// ms->SaveToFile("test.exe");
FILE* pFile = fopen("test.exe", "wb");
if (pFile)
{
fwrite(buffer, 1, ms->Size, pFile);
fclose(pFile);
}
}
__finally
{
delete ms;
}
}