Homework 1 - Extracting Data from a CSV file

This assignment is based on a class of problem solved in enterprise computing; extraction, transformation, and loading. This is often referred to as ETL. The inputs will be data extracted from a leading aviation industry data and consulting firm, GCR. (See GCR.com for additional data.) The data is in a well known format where each data element is separated from the previous and following data elements by using a comma. It should be noted that this method of data manipulation is extremely common. The explicit order of the data fields and the desired outputs are defined in the "Specifications".

1          Objectives
The objectives of this assignment are to demonstrate proficiency in file I/O, data structures, and data transformation using C language resources. Specifically, you will read in data from a text file, use that data to populate a data structure, and print that data to STDOUT by accessing the newly populated structure.

1.1     Extraction

The first part of ETL is extraction. The filename of a text file will be passed to your program via the command line. The data contained in that file is to be read into memory (i.e., extracted). Your program will be compiled and run on Eustis using the following commands:

gcc -o etl hw1etl.c ./etl inputFile

It is entirely possible that the input file either does not exist or is not where it is supposed to be. In such an event, your program should print an error message to STDERR that indicates which file is missing, then your program should exit safely. Use the following format for your error message (fileName should display



the actual name of the missing file):

etl ERROR: File “fileName” not found.

The input file is in CSV (comma separated values) format where each line contains the data for one airport and the fields are as printed below. Note that these fields vary in size and content. Some fields may even be empty. Also note that the data for some of the fields are a melange of types. Specifically, the FAA Site Number and both latitude and longitude contain numbers, punctuation, and text.

For this assignment, treat all input data as character data.



Table 1: Airports Data Fields

Field Title
Description
Size
FAA Site Number
Contains leading digits followed by a decimal point and short text
Leading digits followed by a decimal point and zero to two digits and a letter
Loc ID
The airport’s short name, i.e.

MCO for Orlando
4 characters
Airport Name
The airport’s full name, i.e. Orlando International
≤ 50 characters
Associated City
The nearest city
≤ 50 characters
State
State
2 characters
Region
FAA Region
3 characters
ADO
Airline Dispatch Office
3 characters
Use
Public or Private
2 characters
Latitude
DD-MM-ss.ssssDirection
Degrees, minutes, seconds. Direction is either N,S,E or W.

Treated as a string (for now).
Longitude
See Latitude above.
ditto
Airport Ownership
Public or Private
2 characters
Part 139
FAA Regulation
No data
NPIAS Service Level
National Plan Integrated Airport

Systems Descriptor
≤ 50 characters
NPIAS Hub Type
Intentionally left blank
n/a
Airport Control Tower
Y/N
one character
Fuel
Fuel types available
up to 6 characters
Other Services
Collections of tag indicating INSTRuction, etc.
12 characters
Based Aircraft Total
Number of aircraft (may be

blank)
Integer number
Total Operations
Takeoffs/Landings/etc (may be blank)
Integer number
1.2     Transformation

The second part of ETL is transformation. A list of comma separated values is convenient for text files, but it is far less convenient in memory. Once the data for a single airport has been read into a buffer, you will need to parse the buffer based on the commas between the data fields. The parsed data will then be used to populate a structure of the type struct airPdata (i.e. the data has been transformed from CSV to a data structure). The format of airPdata, shown below, will be defined in airPdata.h. Note that the airPdata structure uses the same names as the input file’s Field Names (See Table 1 on page 2), though not all of the Field Names are used.



typedef struct airPdata{

char *siteNumber; //FAA Site Number char *LocID; //Airport’s ‘‘Short Name’’, \textit{e.g.} MCO char *fieldName; //Airport Name char *city; //Associated City char *state; //State char *latitude; //Latitude char *longitude; //Longitude char controlTower;//Control Tower, this is a single character (Y/N)

} airPdata;



Remember, some of these fields will be of differing lengths for each airport. When you allocate memory structure’s fields, you can assume that no entry will be longer than 50 characters (plus 1 character for the terminating NULL).

1.3     Loading

Finally, the third part of ETL is loading. With the data now in an airPdata structure it can be easily accessed by functions and/or other programs (i.e., loaded). For this assignment, you will use pass the airPdata structure to a function ( PrintData(airPdata airport) ) that will print the data to STDOUT (aka the console). Before calling PrintData for the first time, make sure you print a header line that names each column. Specifically, use the following two lines of code:

printf("%-12s %-11s %-42s %-34s %-3s %-15s %-16s Tower\n",

"FAA Site", "Short Name", "Airport Name", "City", "ST",

"Latitude", "Longitude");

printf("%-12s %-11s %-42s %-34s %-3s %-15s %-16s =====\n",

"========", "==========", "============", "====", "==",

"========", "=========");

The “-” preceding each of the format specifiers left-justifies the printed values, while the numbers indicate the width of the printed field. Your data should be left-justified as well and should use widths that are identical to those in the header line. It is your choice whether you want to populate one airPdata structure and then print it, or to populate an array of airPdata structures and then print each of them. If you choose to populate and print one at a time, be sure to free any allocated memory before reallocating for the same variable. If you choose to read in all of the airports before printing them, you will have an easier time modifying your HW1 code when it comes time for HW3 and will only need to free the memory when you are done. Again, the choice is yours. An example of what the output should look like is shown on the next page.

FAA Site
Short Name Airport Name
City
ST
Latitude                         Longitude                    Tower
========
========== ============
====
==
========                     =========                   =====
03406.20*H
2FD7
AIR ORLANDO
ORLANDO
FL
28-26-08.0210N 081-28-23.2590W N
03406.31*H
3FD5
ARNOLD PALMER HOSPITAL
ORLANDO
FL
28-31-21.0090N 081-22-49.2520W N
03406.36*H
2FL5
BROOKSVILLE INTL AIRWAYS- INC
ORLANDO
FL
28-25-26.0000N 081-27-35.0000W N
03406.24*H
FD99
DR P PHILLIPS HOSPITAL
ORLANDO
FL
28-25-43.0220N 081-28-38.2590W N
03408.*A
ORL
EXECUTIVE
ORLANDO
FL
28-32-43.7000N 081-19-58.5000W Y
03406.11*H
37FA
FLORIDA HOSPITAL
ORLANDO
FL
28-34-32.0020N 081-22-06.2490W N
03406.22*H
FD36
FLORIDA HOSPITAL EAST ORLANDO
ORLANDO
FL
28-32-26.7000N 081-16-51.0000W N
03406.40*H
FL76
HELI-PARTNERS I-DRIVE
ORLANDO
FL
27-23-04.0000N 081-29-07.0000W N
03406.39*H
97FD
HELICOPTERS INTL
ORLANDO
FL
28-27-51.8300N 081-27-35.8800W N
03407.2*A
ISM
KISSIMMEE GATEWAY
ORLANDO
FL
28-17-23.3000N 081-26-13.5000W Y
03406.*C
91FL
LAKE CONWAY NORTH
ORLANDO
FL
28-28-45.0140N 081-22-03.2510W N
03406.33*C
89FL
LAKE HIAWASSEE
ORLANDO
FL
28-31-45.0100N 081-28-51.2600W N
03407.15*A
54FD
LM-ETS
ORLANDO
FL
28-22-03.0000N 081-04-34.0000W N
03407.09*H
82FD
LOCKHEED MARTIN
ORLANDO
FL
28-26-48.4900N 081-27-03.6900W N
03406.18*H
32FL
MEYER
ORLANDO
FL
28-30-05.0120N 081-26-39.2560W N
03408.4*H
27FA
ORANGE COUNTY SHERIFF’S OFFICE
ORLANDO
FL
28-30-27.0110N 081-24-48.2540W N
03407.*A
MCO
ORLANDO INTL
ORLANDO
FL
28-25-45.8000N 081-18-32.4000W Y
03406.21*H
FD28
ORLANDO RGNL MEDICAL CENTER
ORLANDO
FL
28-31-31.0090N 081-22-37.2510W N
03407.1*A
SFB
ORLANDO SANFORD INTL
ORLANDO
FL
28-46-37.1000N 081-14-05.7000W Y
03406.29*H
7FA5
PREMIUM
ORLANDO
FL
28-23-21.0000N 081-29-19.0000W N
03406.113*H 26FA
PRINCETON HOSPITAL
ORLANDO
FL
28-34-06.0040N 081-26-02.2550W N
03406.14*A           01FA
RYBOLT RANCH
ORLANDO
FL
28-35-21.9970N 081-08-39.2290W N
03406.38*C           12FL
TIMBERLACHEN
ORLANDO
FL
28-35-34.0000N 081-24-14.0000W N
03406.34*H           0FL7
WKMG-TV
ORLANDO
FL
28-35-38.7000N 081-25-11.6000W N
03406.3*H            13FD
YELVINGTON
ORLANDO
FL
28-31-07.0090N 081-22-59.2520W N


 
 




2          Required Functions
void printData(airPdata airport);

Description: Prints the data for a given airport, using the same format as the provided header line.

Input: A pointer to an airPdata structure.

Special Cases: If a NULL pointer is passed to this function, print an error message to STDERR and return from the function without printing anything to STDOUT.

Returns: Nothing

3          Testing
There are several possible approaches for parsing the input data. Regardless of the approach you use, make sure to test your code on Eustis even if it works perfectly on your machine . If your code does not compile on Eustis you will receive a 0 for the assignment. There will be four (4) files provided for testing your code, they are as follows.

Table 2: Test Files

Filename
Description
twolines.csv
Two lines of test data, where one line consists of lower case letters, one unique letter per field, the other line will consist of uppercase letters.
orlando5.csv
Five lines of Orlando airport data.
orlando.csv
All 26 of the Orlando airports.
florida.csv
All 877 of Florida’s airports.
The expected output for these test cases will also be provided. To compare your output to the expected output you will first need to redirect STDOUT to a text file. Run your code with the following command (substitute the actual name of the input CSV file):

./etl inputFile output.txt

The run the following command (substitute the actual name of the expected output file):

diff output.txt expectedOutputFile

If there are any differences the relevant lines will be displayed (note that even a single extra space will cause a difference to be detected). If nothing is displayed, then congratulations the outputs match! For each of the four (4) test cases, your code will need to output to STDOUT text that is identical to the corresponding expectedOutputFile. If your code crashes for a particular test case, you will not get credit for that case.