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pub(crate) fn is_valid_file_extension(file_type: &str) -> bool {
// println!("Validating file type: {file_type}");
let file_type_length = file_type.len();
// println!("file type length: {file_type_length}");
if file_type_length < 1 {
return false;
}
let first_char = &file_type[0..1];
let first_char_is_s = first_char == "s";
if !first_char_is_s {
return false;
}
let last_char = &file_type[file_type_length - 1..file_type_length];
let last_char_is_p = last_char == "p";
if !last_char_is_p {
return false;
}
let middle_chars = &file_type[1..file_type_length - 1];
// must have at least one character in the middle
// these are the number of ports, which must be defined
if middle_chars.is_empty() {
return false;
}
let middle_chars_are_digits = middle_chars.chars().all(|c| c.is_ascii_digit());
// must be digits in the middle
if !middle_chars_are_digits {
return false;
}
// cannot start with 0
if middle_chars.starts_with('0') {
return false;
}
// println!("middle chars: {middle_chars}");
let middle_chars_as_int = middle_chars
.parse::<i32>()
.expect("Failed to parse middle chars as int {middle_chars}");
middle_chars_as_int >= 1
}
#[cfg(test)]
mod tests {
#[test]
fn is_valid_file_extension_single_port() {
assert!(super::is_valid_file_extension("s1p"));
}
#[test]
fn is_valid_file_extension_expected_two_port() {
assert!(super::is_valid_file_extension("s2p"));
}
#[test]
fn is_valid_file_extension_expected_three_port() {
assert!(super::is_valid_file_extension("s3p"));
}
#[test]
fn is_valid_file_extension_expected_four_port() {
assert!(super::is_valid_file_extension("s4p"));
}
#[test]
fn is_valid_file_extension_large_values() {
assert!(super::is_valid_file_extension("s10p"));
assert!(super::is_valid_file_extension("s217p"));
}
#[test]
fn is_valid_file_extension_zeros() {
assert!(!super::is_valid_file_extension("s0p"));
assert!(!super::is_valid_file_extension("s01p"));
}
#[test]
fn is_valid_file_extension_other_extensions() {
assert!(!super::is_valid_file_extension("txt"));
assert!(!super::is_valid_file_extension("sxp"));
assert!(!super::is_valid_file_extension("s2x"));
assert!(!super::is_valid_file_extension("x2p"));
assert!(!super::is_valid_file_extension("2p"));
assert!(!super::is_valid_file_extension("s2"));
assert!(!super::is_valid_file_extension("sp"));
assert!(!super::is_valid_file_extension("s"));
assert!(!super::is_valid_file_extension("1p"));
}
#[test]
fn is_valid_file_extension_no_extension() {
assert!(!super::is_valid_file_extension(""));
}
}