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Fix detection of short name collisions for very short names

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This commit is contained in:
Rafał Harabień 2018-05-31 00:11:18 +02:00
parent 0b22cfa0b3
commit b53882a2ad
1 changed files with 52 additions and 15 deletions
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67
src/dir.rs
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@ -657,19 +657,24 @@ impl ShortNameGenerator {
} }
fn add_existing(&mut self, short_name: &[u8; 11]) { fn add_existing(&mut self, short_name: &[u8; 11]) {
// check for exact match collision
if short_name == &self.short_name { if short_name == &self.short_name {
self.exact_match = true; self.exact_match = true;
} }
let num_suffix = if short_name[6] as char == '~' { (short_name[7] as char).to_digit(10) } else { None }; // check for long prefix form collision (TEXTFI~1.TXT)
let prefix_len = cmp::min(self.basename_len, 6) as usize;
let num_suffix = if short_name[prefix_len] as char == '~' { (short_name[prefix_len+1] as char).to_digit(10) } else { None };
let ext_matches = short_name[8..] == self.short_name[8..]; let ext_matches = short_name[8..] == self.short_name[8..];
if short_name[..6] == self.short_name[..6] && num_suffix.is_some() && ext_matches { if short_name[..prefix_len] == self.short_name[..prefix_len] && num_suffix.is_some() && ext_matches {
// prefix6-number form (TEXTFI~1.TXT)
let num = num_suffix.unwrap(); // SAFE let num = num_suffix.unwrap(); // SAFE
self.long_prefix_bitmap |= 1 << num; self.long_prefix_bitmap |= 1 << num;
} }
if short_name[..2] == self.short_name[..2] && num_suffix.is_some() && ext_matches {
// prefix2-chsum-number form (TE021F~1.TXT) // check for short prefix + checksum form collision (TE021F~1.TXT)
let chksum_res = str::from_utf8(&short_name[2..6]).map(|s| u16::from_str_radix(s, 16)); let prefix_len = cmp::min(self.basename_len, 2) as usize;
let num_suffix = if short_name[prefix_len+4] as char == '~' { (short_name[prefix_len+4+1] as char).to_digit(10) } else { None };
if short_name[..prefix_len] == self.short_name[..prefix_len] && num_suffix.is_some() && ext_matches {
let chksum_res = str::from_utf8(&short_name[prefix_len..prefix_len+4]).map(|s| u16::from_str_radix(s, 16));
if chksum_res == Ok(Ok(self.chksum)) { if chksum_res == Ok(Ok(self.chksum)) {
let num = num_suffix.unwrap(); // SAFE let num = num_suffix.unwrap(); // SAFE
self.prefix_chksum_bitmap |= 1 << num; self.prefix_chksum_bitmap |= 1 << num;
@ -759,19 +764,51 @@ mod tests {
} }
#[test] #[test]
fn test_generate_short_name_collisions() { fn test_generate_short_name_collisions_long() {
let mut buf = [0u8; 11]; let mut buf: [u8; 11];
let mut gen = ShortNameGenerator::new("TextFile.Mine.txt"); let mut gen = ShortNameGenerator::new("TextFile.Mine.txt");
assert_eq!(&gen.generate().unwrap(), "TEXTFI~1TXT".as_bytes()); buf = gen.generate().unwrap();
buf.copy_from_slice("TEXTFI~1TXT".as_bytes()); assert_eq!(&buf, "TEXTFI~1TXT".as_bytes());
gen.add_existing(&buf); gen.add_existing(&buf);
assert_eq!(&gen.generate().unwrap(), "TEXTFI~2TXT".as_bytes()); buf = gen.generate().unwrap();
buf.copy_from_slice("TEXTFI~2TXT".as_bytes()); assert_eq!(&buf, "TEXTFI~2TXT".as_bytes());
gen.add_existing(&buf); gen.add_existing(&buf);
buf.copy_from_slice("TEXTFI~3TXT".as_bytes()); buf = gen.generate().unwrap();
assert_eq!(&buf, "TEXTFI~3TXT".as_bytes());
gen.add_existing(&buf); gen.add_existing(&buf);
buf.copy_from_slice("TEXTFI~4TXT".as_bytes()); buf = gen.generate().unwrap();
assert_eq!(&buf, "TEXTFI~4TXT".as_bytes());
gen.add_existing(&buf); gen.add_existing(&buf);
assert_eq!(&gen.generate().unwrap(), "TE527D~1TXT".as_bytes()); buf = gen.generate().unwrap();
assert_eq!(&buf, "TE527D~1TXT".as_bytes());
gen.add_existing(&buf);
buf = gen.generate().unwrap();
assert_eq!(&buf, "TE527D~2TXT".as_bytes());
}
#[test]
fn test_generate_short_name_collisions_short() {
let mut buf: [u8; 11];
let mut gen = ShortNameGenerator::new("x.txt");
buf = gen.generate().unwrap();
assert_eq!(&buf, "X TXT".as_bytes());
gen.add_existing(&buf);
buf = gen.generate().unwrap();
assert_eq!(&buf, "X~1 TXT".as_bytes());
gen.add_existing(&buf);
buf = gen.generate().unwrap();
assert_eq!(&buf, "X~2 TXT".as_bytes());
gen.add_existing(&buf);
buf = gen.generate().unwrap();
assert_eq!(&buf, "X~3 TXT".as_bytes());
gen.add_existing(&buf);
buf = gen.generate().unwrap();
assert_eq!(&buf, "X~4 TXT".as_bytes());
gen.add_existing(&buf);
buf = gen.generate().unwrap();
assert_eq!(&buf, "X40DA~1 TXT".as_bytes());
gen.add_existing(&buf);
buf = gen.generate().unwrap();
assert_eq!(&buf, "X40DA~2 TXT".as_bytes());
} }
} }