Heap Simulator

Compile instruction

make run

OR

python3 hsim.py [-h] [-s <value>] [-w] [-v] [-d] --free-list={implicit or explicit} --fit={first or best} <input file>

Required flags:

--fit= {first/best}
--free-list={implicit/explicit}

Usable optional flags:

-h          prints usage
-v          is for verbose mode
-d          will prevent from creating a `output.txt` file and display on screen
-s <value>  will allow to change the size of initial heap 
-w          writes the verbose commands into a file and stores into the `verbose` folder

output.txt file is creadted on deafult to show the state of the heap.

output.txt will not be created if there is the error on inputfile instruction.

Input File format Requirement

a, 5, 0      // ptr0 = myalloc(5)
f, 0         // myfree(ptr0)
a, 10, 1     // ptr1 = myalloc(10)
r, 20, 1, 2  // ptr2 = myrealloc(ptr1,20)
f, 2         // myfree(ptr2)

Output file format

  0, 0x00000001 // placeholder
  1, 0x00000F98 // header
  2,            // payload
  3,            // payload
  4, 0x00000011 // remaining footer of myalloc(5)
  5, 0x00000F88 // remaining header of free block after myalloc(5)
  6, 0x00000018 // remaining footer of myalloc(10)
  7, 0x00000021 // remaining header of myrealloc(20)
     ......
 10, 0x00000011 // copied payload from word 4 of myrealloc(20)
 11, 0x00000F88 // copied payload from word 5 of myrealloc(20)
     ......
 14, 0x00000021 // remaining footer of myrealloc(20)
 15, 0x00000F60 // remaining header of free block after myrealloc(20)

     ......

998, 0x00000F98 // footer
999, 0x00000001 // placeholder

Test

Few test states are avilable under examples to compare the working program.

Precision of code can be checked by the provided makefiles by using the command.

make -f <test_file> -i

Explicit state of heap will not pass all the test cases

Notes on Explicit first and best fit:

For these conditions fist footer is collased then header is collased and the new pointers will not be assigned until both collasing are checked and/or completed