CS 280 - Programming Assignment #1

Information

• Handout
• Interface: HTML Text
• Sample driver program: HTML Text
• Random number generator
  • Interface: HTML Text
  • Implementation: HTML Text
• Sample command lines for compiling: (The first two compilers will be used for grading.)
  • GNU g++:

    g++ -o gnu driver-sample.cpp ObjectAllocator.cpp PRNG.cpp -O -Werror -Wall -Wextra -Wconversion -std=c++11 -pedantic
    

    Running under Valgrind in Linux and Mac OS X:

    valgrind -q --leak-check=full --show-reachable=yes --tool=memcheck ./gnu 
    

  • Clang:

    clang++ -o clan driver-sample.cpp ObjectAllocator.cpp PRNG.cpp -Werror -O -Wall -Wextra -Wconversion -std=c++11 -pedantic
    

    Note that building Clang under Windows may fail to link properly. The code will compile (if you didn't have any errors), but will fail to link properly. This means that no executable will be created, or if one is created, it may fail to execute. You don't have to worry about that at this time. Just add the -c option to the command line to compile only.
  • Microsoft: (Not required for grading)

    cl -Fems driver-sample.cpp ObjectAllocator.cpp PRNG.cpp /EHsc /Oy- /Ob0 /MT /Zi /D_CRT_SECURE_NO_DEPRECATE
    

    To check your program for memory leaks and hidden bugs with Dr. Memory, you must make sure that these options are specified with the 32-bit version of Microsoft's compiler (reference):

    /Zi /MT /EHsc /Oy- /Ob0 
    

    Then running it like this:

    drmemory -batch -brief -- ms.exe
    

    If your program is clean, you should see all zeros for the output:

    ~~Dr.M~~
    ~~Dr.M~~ NO ERRORS FOUND:
    ~~Dr.M~~       0 unique,     0 total unaddressable access(es)
    ~~Dr.M~~       0 unique,     0 total uninitialized access(es)
    ~~Dr.M~~       0 unique,     0 total invalid heap argument(s)
    ~~Dr.M~~       0 unique,     0 total GDI usage error(s)
    ~~Dr.M~~       0 unique,     0 total handle leak(s)
    ~~Dr.M~~       0 unique,     0 total warning(s)
    ~~Dr.M~~       0 unique,     0 total,      0 byte(s) of leak(s)
    ~~Dr.M~~       0 unique,     0 total,      0 byte(s) of possible leak(s)
    

    If any errors are found, Dr. Memory will show them and tell you the filenames and line numbers in the call stack:

    ~~Dr.M~~
    ~~Dr.M~~ Error #1: UNADDRESSABLE ACCESS: writing 4 byte(s)
    ~~Dr.M~~ # 0 replace_memset                      [d:\drmemory_package\drmemory\replace.c:182]
    ~~Dr.M~~ # 1 ObjectAllocator::Free               [objectallocator.cpp:247]
    ~~Dr.M~~ # 2 DoEmployees                         [driver.cpp:1206]
    ~~Dr.M~~ # 3 ExecuteTest                         [driver.cpp:2245]
    ~~Dr.M~~ # 4 main                                [driver.cpp:2304]
    ~~Dr.M~~ Note: refers to 0 byte(s) beyond last valid byte in prior malloc
    ~~Dr.M~~
    ~~Dr.M~~ Error #2: UNADDRESSABLE ACCESS: writing 4 byte(s)
    ~~Dr.M~~ # 0 ObjectAllocator::push_front               [objectallocator.cpp:617]
    ~~Dr.M~~ # 1 ObjectAllocator::Free                     [objectallocator.cpp:251]
    ~~Dr.M~~ # 2 DoEmployees                               [driver.cpp:1206]
    ~~Dr.M~~ # 3 ExecuteTest                               [driver.cpp:2245]
    ~~Dr.M~~ # 4 main                                      [driver.cpp:2304]
    ~~Dr.M~~ Note: refers to 0 byte(s) beyond last valid byte in prior malloc
    ~~Dr.M~~ WARNING: application exited with abnormal code 0xffffffff  
    

• Output:
• 64-bit (LP64): Generic (no addresses)  
• Output with extra credit:
• 64-bit (LP64): Generic (no addresses)  
• Diagrams to help you understand the situation.
• FAQ for this assignment.

Other Criteria

• You must use new and delete to allocate/deallocate the pages.
• Do not use std::nothrow with new. (If you don't know what that is, you're probably not going to use it.)
• You must catch the exception (std::bad_alloc) that is thrown from new.
• You can't use any STL code in your implementation (with the exception of std::string for exception messages).
• You can't change the public interface at all.
• Given this struct:

  struct Student
  {
    int Age;   
    float GPA; 
    long Year; 
    long ID;   
  };
  

  sizeof(Student) returns:

   LLP64: 16
    LP64: 24
  

• DO NOT assume that pointers, integers, and long integers are the same size. Doing so may cause the compiler to emit warnings and can also lead to your program crashing. See this for a quick refresher.
• Adjusting for Microsoft's odd compiler:

  struct Student
  {
    int Age;   
    float GPA; 
    long long Year; // Compensate for Microsoft's compiler
    long long ID;   // Compensate for Microsoft's compiler   
  };
  

  sizeof(Student) now returns:

   LLP64: 24
    LP64: 24
  

Exception Handling Examples

Please note that these are examples! Your code will probably be different.

  // Make sure this object hasn't been freed yet
if (is_on_freelist(anObject))
  throw OAException(OAException::E_MULTIPLE_FREE, "FreeObject: Object has already been freed.");


  // If new throws an exception, catch it, and throw our own type of exception
char *newpage;
try
{
  newpage = new char[PageSize_];
}
catch (std::bad_alloc &)
{
  throw OAException(OAException::E_NO_MEMORY, "allocate_new_page: No system memory available.");
}
if ( /* Object is on a valid page boundary */ )
  // put it on the free list
else
  throw OAException(OAException::E_BAD_BOUNDARY, "validate_object: Object not on a boundary.");