CODEWITHSUNDEEP
c++imagefile
Pavol modrý
Pavol modrý

Reputation: 43

Reading images from file - C++

I have problem reading image from file, but when there is raw text it works properly. I read, that any file can be read in binary mode, but my output is just this: \FF\D8\FF\E0 and then it stops. It stops at this character so I am not sure whether it just can't resolve that character or what. Does anyone know what is wrong? Thanks in advance.

Here's my code

char* obsah;  
std::string sprava;
std::ifstream is (file.c_str(), std::ifstream::binary);
    if(is){
        is.seekg (0, is.end);
        int length = is.tellg();
        is.seekg (0, is.beg);
        obsah = new char [length];
        is.read(obsah,length);
        sprava = prepinac+"\r\n"+file+"\r\n\r"+obsah;
    }
    else exit(EXIT_FAILURE);

Upvotes: 2

Views: 262

Answers (1)

Christophe
Christophe

Reputation: 73366

sprava is a string. As you use + to concatenate its components, it manages char* obsah as a null terminated c-string. So everything after the first null char will not be copied into sprava.

Edit:

You can have binary data including '\0' in strings (see here). However you need to be very careful in this approach,because whenever you'd convert your string into char* pointer that is processed like a null terminated c-string, a part of the string might be ignored. And if you use your string in I/O it might also give weird results.

If you want to proceed however, you could use std::copy() and a back inserter; 

sprava = prepinac+"\r\n"+file+"\r\n\r"; 
  copy(obsah, obsah+length, back_inserter<string>(sprava));

Here an online demo

Upvotes: 2

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