Simple CSV Library

This is a CSV (delimiter can be changed) parser & writer with a focus on:

1. Simplicity
2. Robustness
3. Performance (to a lesser extent)

Parser

The parser follows RFC 4180, but allows for non-conformant files to be processed.

In order to achieve this robustness, the parser makes the following assumptions:

1. Commas on the end of a line results in a empty string for that column. * 1,2,3, is parsed as ["1","2","3",""]
2. Double quotes in a field that is not enclosed in double quotes are processed as a regular character and are included in the column string. * 1,2",3 is parsed as ["1","2\"","3"]
3. Non-delimiter characters immediately following a quoted field are treated as part of the column data and are appended to the column string. * 1,2,"3"123 is parsed as ["1","2","3123"]
4. An EOF in the middle of a quoted field is parsed as if the field was properly closed. * 1,2,"3*EOF* is parsed as ["1","2","3"]
5. There is no error for empty lines or varying number of columns per line. * An empty line is parsed as [""]
6. Lines are assumed to be UTF8 and are decoded "lossily" via Rust's String::from_utf8_lossy function.
7. The return character \r in unquoted fields is always discarded.

Writer

The writer always produces RFC 4180 compliant output and can write to any object that implements the std::io::Write trait.

Usage

Add to your Cargo.toml:

[dependencies]
simple_csv = "~0.0.8"

Simple CSV Parsing usage

let test_string = "1,2,3\r\n4,5,6".to_string();
let bytes = test_string.into_bytes();
let test_csv_reader = &*bytes;

let mut reader = SimpleCsvReader::new(test_csv_reader);

assert_eq!(reader.next_row().unwrap().unwrap(), &*vec!["1".to_string(),"2".to_string(),"3".to_string()]);
assert_eq!(reader.next_row().unwrap().unwrap(), &*vec!["4".to_string(),"5".to_string(),"6".to_string()]);
assert!(reader.next_row().is_none());

Different Delimiter

let test_string = "1|2|3\r\n4|5|6".to_string();
let bytes = test_string.into_bytes();
let test_csv_reader = &*bytes;
let mut csv_options: SimpleCsvReaderOptions = Default::default();
csv_options.delimiter = '|';
let mut reader = SimpleCsvReader::with_options(test_csv_reader,csv_options);

assert_eq!(reader.next_row().unwrap().unwrap(), &*vec!["1".to_string(),"2".to_string(),"3".to_string()]);
assert_eq!(reader.next_row().unwrap().unwrap(), &*vec!["4".to_string(),"5".to_string(),"6".to_string()]);
assert!(reader.next_row().is_none());

Using a iterator

let test_string = "1,2,3\r\n4,5,6".to_string();
let bytes = test_string.into_bytes();
let test_csv_reader = &*bytes;

let mut reader = SimpleCsvReader::new(test_csv_reader);

for row in reader {
	println!("{}",row);
}

Different Text Enclosing Character

let test_string = "1,#2#,3\r\n#4#,5,6".to_string();
let bytes = test_string.into_bytes();
let test_csv_reader = &*bytes;
let mut csv_options: SimpleCsvReaderOptions = Default::default();
csv_options.text_enclosure = '#';
let mut reader = SimpleCsvReader::with_options(test_csv_reader,csv_options);

assert_eq!(reader.next_row().unwrap().unwrap(), &*vec!["1".to_string(),"2".to_string(),"3".to_string()]);
assert_eq!(reader.next_row().unwrap().unwrap(), &*vec!["4".to_string(),"5".to_string(),"6".to_string()]);
assert!(reader.next_row().is_none());

Simple CSV Writing Usage

let mut vec = Vec::new();
let mut writer = SimpleCsvWriter::new(vec);
let _ = writer.write_all(&vec![
    vec!["1".to_string(),"2".to_string(),"3".to_string()],
    vec!["4".to_string(),"5".to_string(),"6".to_string()]]);
vec = writer.as_inner();

let test_string = "1,2,3\n4,5,6";
assert_eq!(vec, test_string.as_bytes());