#ifndef __FILEINPUTSTREAM_H__#define __FILEINPUTSTREAM_H__ #include <fstream>#include "InputStream.h" class FileInputStream : public InputStream { public:  bool Open (const char* fileName) {    file_.open (fileName, std::ios_base::in | std::ios_base::binary);    return file_.is_open();  }  int read (void* ptr, size_t len) {    if (!file_.good()) {      return -1;    }    file_.read (static_cast<char*> (ptr), len);    return file_.gcount();  } private:  std::ifstream file_;}; #endif //__FILEINPUTSTREAM_H__