Reading binary file C++

Question

Please, help me. I can't read binary file. The file's length is 198944, but my code reads 374. I tried to use fread, ifstream, WinAPI ReadFile. This is the function that reads file:

std::string ReadThisFile(std::string aPath) {
   FILE *inputstream = fopen(aPath.c_str(),"rb");
   long size;
   size_t result; 
   fseek(inputstream,0,SEEK_END); 
   size = ftell(inputstream); 
   rewind(inputstream); 
   char *buff = new char [size];
   result = fread (buff,1,size,inputstream); 
   std::string ret=buff; 
   fclose(inputstream); 
   delete[]buff; 
   return ret; 
}

File sample

Any help is needed, thank you!

Answer 1

As long as you're aware of that the std::string that you return contains binary data, replace

std::string ret=buff;

with

std::string ret(buff, size);

Answer 2

You can't put binary data in a string. Remember that a string is terminated by the special character '\\0' which is the same as the value zero. If the binary data contains a zero, that is the same as the end of the string.

You should probably use a std::vector<int8_t> to store binary data.

Answer 3

The problem is here:

std::string ret = buff;

According to this , it:

"Copies the null-terminated character sequence (C-string) pointed by s."

So it stops as soon as a 0x00 character is reached.

If you were to return buff (which is a dangerous practice) or have your function take a char array as an input parameter and merely store it there, it should work. And you may want to return a length indicator, since otherwise C++ will not know how large the array is.