Homework 2, Note Keeper.

Short Description:

Write a program that shows your ability to use open/read/write/close and lseek.

Goals

When you finish this homework, you should have:

Used the read/write/open/close and lseek functions in a program.

Formal Description

You are to create a program that keeps a series of short log/diary entries. This program must work as follows:

No user interaction, all is accomplished via command line arguments.
- --init
  - This should initialize the notebook file.
  - Notebook files should have space for 10 entries.
  - Any existing data in the file should be removed.
- --note note, -n note
  - add a new entry to the file, the value of the entry is in arg
  - notebook --note "It is a good day to die."
  - If the notebook is out of space, print an error
```
Error: No space left in the notebook.
```
  - If the value of n is invalid, print
```
Error: 11 is an invalid note number.
```
- --print n -p n
  - Print note number n if it exists.
  - notebook --print 3 might print
```
Note 3: It is a good day to fry!.
```
  - If note n does not exist, print
```
Note 3 does not exist!
```
  - If the value of n is invalid, print
```
Error: 11 is an invalid note number.
```
  - Note: Notes are numbered from 1, so humans can use the program.
    - It may be stored at position 0, but it is note number 1.
- --dump, -d
  - Print the contents of the notebook in order
```
 The notebook contains 4 entries
Note 1: It is a good day to die!
Note 2: It is a good day to pry!
Note 3: It is a good day to fry!
Note 4: Hello World!  
```
  - Of there are no entries print
```
The notebook is empty.
```
- --remove n, -r n
  - Remove note n.
  - If note n does not exist, print
```
Note 3 does not exist!
```
  - If the value of n is invalid, print
```
Error: 11 is an invalid note number.
```
- --clear -c
  - Clear all entries in the notebook.
- --help -h
  - Print help on usage.
  - Format up to you.
All file interaction must be done with read, write, open, close, lseek
Output to the screen can be done with whatever mechanism you wish. I used cout.
The notes should be stored in a single file.
- The file should begin with 20 integers indicating the beginning byte and ending byte of each note.
  - These should be set to -1 to indicate no note.
  - When a note is added:
    - Seek to the end of the file to find a place to put the note
    - Record this number in the note's starting position.
    - Write the note at the end of the file
    - Record the ending byte in the note's ending position.
  - When a note is deleted:
    - Change the starting and ending position to be -1
    - Change the data in the note to be 0.
  - These can be stored in any order.
    - Assume the user inserts three messages, deletes the second and inserts a new message.
    - The new message will become message 2
    - But the message will be stored at the end of the message file.
    - And the space the old message 2 was in will be filled with zeros.
    - The message file will become fragmented.
- This is the heart of the assignment, if you don't do this, you will receive no credit.

A NotebookFile file might contain:

80 24 104 24 128 24 152 12 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1It is a good day to die!It is a good day to pry!It is a good day to fry!Hello World! 0 0 0 0 ...

Note:

The values in the file will be in binary, not ascii and decimal
The first three strings are all the same size, the last is shorter.
I put an ! at the end of each string.

The file was produced by the commands:

notebook --note "It is a good day to die!"
notebook --note "It is a good day to pry!"
notebook --note "It is a good day to fry!"
notebook --note "Hello World!"

No message will be longer than 99 characters.
Please call your file NotebookFile
Please call your program notebook
The return value of all system calls should be checked and any error should be reported. The format of errors is up to you, I will not generate any errors on purpose.
For 10 points extra credit you may implement a --compact, -c option that will "clean up" any blank spaces in the file.

For 5 points of extra credit, check the environment variable DEBUG_NOTEBOOK.

If this is set, print debugging messages describing the actions that are occurring in the program.

For example

% notebook --init
   initializing the notebook.
% notebook --note "Hello World!"
   Searching for the first empty position:
      Found it at 0
   Seeking to the end of the file
      Found at position 80
      Writing the message
      Saving 80 and 12 at positions 0 and 4
% notebook  -p 1
      Looking for note 1
         Fond 80 and 12 for note one
Note 1: Hello World!

Make sure you provide a list of collaborators, sources and AI agents used in your comments.

Required Files

A single c/c++ source code file.

Submission

Submit the assignment to the D2L folder Homework 2 by the due date.