用ifstream读取.exe文件的二进制文件 [英] reading .exe file with ifstream by binary

问题描述

正如标题所说，我试图以二进制方式使用ifstream读取.exe文件。但它总是会遗漏一些字节，因此新复制的.exe文件不合法。我试着评论f_write语句，问题仍然存在。



代码如下所示。

as the title said, I tried to read a .exe file using ifstream in binary way. but it always miss some bytes, so the newly copied .exe file is not legal. I tried to comment the f_write statement, the problem still there.

code looks like following.

int main(int argc, char *argv[])
{
        if (argc != 3)
        {
                cerr << "Error! \n filecopy.exe srcfilename destfilename" << endl;
                return 0;
        }
        
        ifstream f_read (argv[1],ios::binary | ios::in);
    	ofstream f_write(argv[2],ios::binary | ios::out);

        char i;

        if (f_read == NULL)
        {
          return 0;
        }
                
        while (f_read >> i)
        {
           f_write << i;
        }

        f_read.close();
        f_write.close();

        return 0; 
}

任何提示都将受到欢迎。

Any tips will be appreciate.

推荐答案

当您读入字节时，iostream对象可能会跳过换行符（ascii 10或0x0a）。在复制之前尝试插入以下行：

Probably the newline characters (ascii 10 or 0x0a) are skipped by the iostream object when you are reading in the bytes. Try inserting the following line before doing the copy:

f_read.unsetf(ios::skipws);

编辑：逐字节复制文件无效。读取整个文件然后将其写入一个大块也是一个坏主意，因为在这种情况下你将无法复制大文件。最好的是黄金中间方式，使用缓冲区（很少，可能是4-16千字节）作为读取/写入数据有效的单位。

copying a file byte-by-byte is not effective. Reading in the whole file and then writing it out in one big piece is also a bad idea as in that case you wouldn't be able to copy huge files. The best is the golden middle way, using a buffer (few, maybe 4-16 kilobytes) as a unit for reading/writing data to be effective.

@pasztoripisti非常感谢。它有效。

@pasztoripisti thanks very much. it works.

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