Fixed File Format converter
Your goal is to write a generic tool to convert fixed file format files to a csv file based on a metadata file describing its structure.
Feel free to use your favorite language and libraries if needed (but no proprietary libraries, only open source), fork this project and provide your complete code as a pull request (including source and tests).
Use case
Our fixed file format files can have any number of columns A column can be of 3 formats:
- date (format yyyy-mm-dd)
- numeric (decimal separator '.' ; no thousands separator ; can be negative)
- string
The structure of the file is described in a metadata file in csv format with a line for each column defining:
- column name
- column length
- column type
You should transform the file to a csv file (separator ',' and row separator CRLF)
The dates have to be reformatted to dd/mm/yyyy
The trailing spaces of string columns must be trimmed
The csv file must include a first line with the columns names
Example
Data file:
1970-01-01John Smith 81.5
1975-01-31Jane Doe 61.1
1988-11-28Bob Big 102.4
Metadata file:
Birth date,10,date
First name,15,string
Last name,15,string
Weight,5,numeric
Output file:
Birth date,First name,Last name,Weight
01/01/1970,John,Smith,81.5
31/01/1975,Jane,Doe,61.1
28/11/1988,Bob,Big,102.4
Extra requirements
- files are encoded in UTF-8 and may contain special characters
- strings columns may contain separator characters like ',' and then the whole string needs to be escaped with " (double quotes). Only CR or LF are forbidden
- in case the format of the file is not correct, the program should fail but say explicitly why
- a fixed format file may be very big (several GB)