Random Bytes added to an end of a buffer - c++

Question

I was making a re-creation of some System.IO functions from that class.
When I setup a buffer and allocate n number of bytes it'll read bytes to that and then add random bytes to the end of that buffer.
For example:
My Main:
int main(int argc, char *args[])
{
SetConsoleTitle(TEXT("Stream Test."));
cout<<"Press any Key to begin reading.";
cin.get();
const char* data = File::ReadAllBytes(args[1]);
Stream* stream = new Stream(data);
char* magic = new char[8];
stream->Read(magic, 0, 8);
magic[8] = '\0';
cout<<magic<<endl<<endl;
delete[]data;
cout<<"Press any key to quit.";
cin.get();
return 0;
}
and here is my System::IO namespace + stream class:
namespace System
{
namespace IO
{
class File
{
public:
static char* ReadAllBytes(const char *name)
{
ifstream fl(name, ifstream::in|ifstream::binary);
fl.seekg( 0, ifstream::end );
size_t len = fl.tellg();
char* ret = new char[len+1];
ret[len] = '\0';
fl.seekg(0);
fl.read(ret, len);
fl.close();
return ret;
}
//not sure of this use yet.
static size_t fileSize(const char* filename)
{
ifstream in(filename, ifstream::in | ifstream::binary);
in.seekg(0, ifstream::end);
return in.tellg();
}
};
class Stream
{
public:
const char *_buffer;
__int64 _origin;
__int64 _position;
__int64 _length;
__int64 _capacity;
bool _expandable;
bool _writable;
bool _exposable;
bool _isOpen;
static const int MemStreamMaxLength = 2147483647;
Stream()
{
InitializeInstanceFields();
}
Stream(const char *buffer)
{
_buffer = buffer;
_length = strlen(_buffer);
_capacity = _length;
_position = 0;
_origin = 0;
_expandable = false;
_writable = true;
_exposable = true;
_isOpen = true;
}
int ReadByte()
{
if (_position >= _length)
return -1;
return _buffer[_position++];
}
void Read(char* &buffer, int offset, int length)
{
if((_position + offset + length) <= _length)
{
memcpy( buffer, _buffer + (_position + offset), length );
_position += length;
}
}
private:
void InitializeInstanceFields()
{
_origin = 0;
_position = 0;
_length = 0;
_capacity = 0;
_expandable = false;
_writable = false;
_exposable = false;
_isOpen = false;
}
};
}
}
This is what ends up happening:
Can anyone explain why this happens, how I can fix, or anything else? I'm new to C++ so any explanations would help. Also please don't criticize my scripting, I know it may be bad, outdated, deprecated, etc. but I'm open to learning and any helping advice goes for the better. :)

Answer 1

You can only use operator << (char *) on C-style strings, not arbitrary arrays of characters. How would you expect it to know how many characters to output?

Answer 2

I would guess the file was not opened correctly and thus the magic buffer is not set at all which leaves it with initialized junk data:
If the constructor is not successful in opening the file, the object
is still created although no file is associated to the stream buffer
and the stream's failbit is set (which can be checked with inherited
member fail).
http://www.cplusplus.com/reference/fstream/ifstream/ifstream/
Try adding more error checking along the way (using cout), especially when opening and reading the buffer. Perhaps set the magic buffer to zero or something recognizable that is overwritten when successful.