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CS253 HW7: I/O Streams!                

Description                

For this assignment, you will write two classes, IFSerial and OFSerial. They will behave much like ifstream and ofstream, except that they will read & write serialized data.                 

Methods                

Your classes must have the folowing operators & methods:                 

IFSerial:

• ctor that takes a std::string filename
• dtor
• IFSerial >> bool
• IFSerial >> int
• IFSerial >> short
• IFSerial >> long
• IFSerial >> char
• IFSerial >> std::string
• IFSerial.eof()
• IFSerial.fail()
• Evaluation in a boolean context.

OFSerial:

• ctor that takes a std::string filename
• dtor
• OFSerial << bool
• OFSerial << int
• OFSerial << short
• OFSerial << long
• OFSerial << char
• OFSerial << std::string
• OFSerial.fail()
• Evaluation in a boolean context.

The above may be methods, or free functions, as you wish.                 

Const-correctness, both arguments & methods, is your job. For example, it must be possible to call .eof() on a const IFSerial.                 

You may add other functions, methods, or operators, public or private, as you wish.                 

.eof()                

• .eof() will return true if and only if end-of-file has been encountered. It reflects the past; it does not predict the future.

.fail()                

• .fail() will return true if and only if a conversion has failed, or if the given filename can’t be opened in the desired manner.

Boolean context                

• Evaluating an IFSerial or OFSerial in boolean context yields the opposite boolean result than .fail().

FSerial.h                

• The header file FSerial.h will contain class declarations for both IFSerial and OFSerial.
• Include FSerial.h and any necessary code in your hw7.tar.

Errors                

• None of the required methods, functions, or operators should write to cout or cerr, throw anything, or exit.
• Instead, if an error is detected, .fail() should return true.
• Failure is “sticky”. That is, once a stream enters the failure state, it stays in the failure state. Unfortunately, no method is defined to clear the failure state.
• Same for end-of-file.

Test program                

Here is a sample test program:                 

    % cat test.cc
    #include "FSerial.h"
    #include <fstream>
    #include <iostream>
    #include <string>
    #include <cassert>

    using namespace std;

    int main() {
        cout << "Test begins.\n";
        {
            OFSerial out("data");
            out << true;
            out << 'x' << 42;
        }

        IFSerial in("data");
        bool b; char c; int i;
        in >> b >> c;
        in >> i;
        assert(b);
        assert(c == 'x');
        assert(i == 42);
        assert(in);
        assert(!in.fail());
        assert(!in.eof());
        in >> i;
        assert(!in);		// same as in.fail()
        assert(in.fail());	// a conversion (in >> i) failed
        assert(in.eof());	// we hit end-of-file


        // Read the raw datafile
        ifstream raw("data");
        string data;
        while (raw.get(c))
            data += c;
        assert(data == "t" "cx" "i\x10\x2a");   // true, 'x', 42

        // Try writing to a file that can’t be created.
        OFSerial o("/this/does/not/exist");
        assert(!o);
        assert(o.fail());
        o << 2555903;	    // Must not complain, throw, or exit.
        assert(!o);
        assert(o.fail());

        cout << "Test ends.\n";
        return 0;
    }
    % g++ -Wall test.cc hw7.a
    % ./a.out
    Test begins.
    Test ends.

    export STACK_FRAME_LINK_OVERRIDE=ffff-ad921d60486366258809553a3db49a4a

Requirements                

Requirements are not inherited, except as noted below:

• Chaining of << or >> must work in the usual I/O stream manner.
• No global variables.
• Don’t put main in hw7.a.
• You may not use C-style <stdio.h> or <cstdio> facilities, such as printf, scanf, fopen, and getchar.
  • Instead, use C++ facilities such as cout, and ifstream.
• For readability, don’t use ASCII int constants (65) instead of char constants ('A') for printable characters.
• We will compile your code by untarring and typing “make”, which must produce hw7.a.
  • If that generates warnings, you will lose a point.
  • If that generates errors, you will lose all points.

Testing                

• Like HW6, you will have to write a main() function to test your code. Don’t turn it in.
• We will test your program in much the same manner as for HW6.

Tar file                

• The tar file for this assignment must be called: hw7.tar
• It must contain:
  • source files (*.cc)
  • header files (*.h), including FSerial.h
  • Makefile (Makefile, with a capital M)
• The Makefile’s default target must create the library file hw7.a.
• Your Makefile must use at least -Wall when compiling.

How to submit your homework:                

• Use web checkin, or Linux checkin:

    ~cs253/bin/checkin HW7 hw7.tar

How to receive negative points:                

Turn in someone else’s work.                 

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