Description

Version 1.02 (last update: Nov. 10, 20:00)
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Changes

In the following, the word actor refers to a person who acts regardless of gender.

Summary and Purpose

For this assignment, you will be creating a small database system, consisting of 5 programs. You will use hash tables and binary files to understand how a practical application might be constructed.

You program will make use of a C file of supporting functions called util.c and an accompanying header file called util.h.

Deliverables

You will be submitting:

1) A file called buildidx.c that will be compiled to create a program called buildidx.
2) A file called key2val.c that will be compiled to create a program called key2val.
3) A file called val2key.c that will be compiled to create a program called val2key.
4) A file called actors.c that will be compiled to create a program called actors.
5) A file called bacon1.c that will be compiled to create a program called bacon1. 6) A makefile that contains the instructions to compile your code.

The programs

buildidx
This program will accept 2 command line arguments (you must not read from the standard input, nor prompt the user). If a different number of command line arguments are provided, then your program shall:

fprintf( stderr, “Usage: %s filename.kv capacity “, argv[0] );

The program should open the given file name for reading, along with two other files for reading and writing. All files are binary files.

The other two files will have the same name as the read file, except that instead of extension
“.kv” they will have extensions “.khs” and “.vhs”.

The khs and vhs files will be initialized by calling the write_empty function from util.c with the command line parameter capacity passed as capacity.

Your program should read the contents of the kv file using read_keyval in the util.c file keeping track of the index of the key and value in the kv file (i.e. the first key, value pair red has index 0, the second key, value pair read has index 1, etc.). For each key and value read, your program should compute a hash value using the hashfn in hashfn.c (1 hash value for the key and a different hash value for the value).

It should then try to write_index the value of the index at the location of the key’s hash value within the khs file, and at the location of the value’s hash value within the vhs file. Of course, if the location in the hash file is already occupied (read_index returns an index value that’s not -1), you will have to move to the next location. Naturally, once you hit the end of the file, you will need to start again from the beginning until you have found an empty location.

Make sure to free any memory that you allocated and to close your files when you are done.

Your program should not print anything (other than the error condition, above).

key2val
This program will accept 2 command line arguments (you must not read from the standard input, nor prompt the user). If a different number of command line arguments are provided, then your program shall:

fprintf( stderr, “Usage: %s filename.kv ‘search term’ “, argv[0] );

Otherwise, the first argument should be interpreted as a kv file which can be accessed using the read_key, read_val, and read_keyval function provided in util.c.

The program should open the given file name for reading, along with the corresponding “.khs” file.

This program should perform a search for the search term, beginning at the index computed by the hashfn in hashfn.c. It should use that value as the hash in the read_index function and check the return value of read_key with the value generated by read_index. If the key value retrieved from the kv file matches the search term, then you can use read_value to retrieve the corresponding value from the kv file and print it followed by ‘ ’. You should only print the value retrieved by read_value and the ‘ ’, nothing else.

Of course, if the key value doesn’t match the search term, you must continue through the hash table, looping back to zero when you hit the end of the file, until you have searched the entire table.

If you do not fine the ‘search term’, you will

printf( “NOT FOUND ” );

val2key
This program is the exact analog of key2val, except that you use the vhs file to search for a value and return the corresponding key value. If you do not find the ‘search term’, you will

printf( “NOT FOUND ” );

The Last 20%

actors

bacon1

You can write additional helper functions as necessary to make sure your code is modular, readable, and easy to modify.

Testing

You are responsible for testing your code to make sure that it works as required. The
CourseLink web-site will contain some test programs to get you started. However, we will use a different set of test programs to grade your code, so you need to make sure that your code performs according to the instructions above by writing more test code.

Your assignment will be tested on the standard SoCS Virtualbox VM
(http://socs.uoguelph.ca/SoCSVM.zip) which will be run using the Oracle Virtualbox software (https://www.virtualbox.org/wiki/Downloads). If you are developing in a different environment, you will need to allow yourself enough time to test and debug your code on the target machine. We will NOT test your code on YOUR machine/environment.

Full instructions for using the SoCS Virtualbox VM can be found at:
https://wiki.socs.uoguelph.ca/students/socsvm.

Makefile

You will create a makefile that supports the following targets:

all:

this target should generate the executable files buildidx, key2val, val2key, and optionally actors, and bacon1.
clean:

this target should delete all *.o and executable files.

Each, *.c file should correspond to a rule in the makefile that generates a corresponding *.o file.
Additionally, there should be an individual rule for each executable file.

All compilations and linking must be done with the -Wall -pedantic -std=c99 flags and compile and link without any warnings or errors.

Git

Also, do your own work, do not hire someone to do the work for you.

Grading Rubric
buildidx 8 key2val 2 val2key 2 style 2 makefile 2 actors 2 bacon1 2

Total 20

Ask Questions

The instructions above are intended to be as complete and clear as possible. However, it is YOUR responsibility to resolve any ambiguities or confusion about the instructions by asking questions in class, via the discussion forums, or by e-mailing the course e-mail.