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Diffstat (limited to 'third_party/rust/regex-syntax/src/hir/literal/mod.rs')
| -rw-r--r-- | third_party/rust/regex-syntax/src/hir/literal/mod.rs | 1686 |
1 files changed, 1686 insertions, 0 deletions
diff --git a/third_party/rust/regex-syntax/src/hir/literal/mod.rs b/third_party/rust/regex-syntax/src/hir/literal/mod.rs new file mode 100644 index 0000000000..fbc5d3c975 --- /dev/null +++ b/third_party/rust/regex-syntax/src/hir/literal/mod.rs @@ -0,0 +1,1686 @@ +/*! +Provides routines for extracting literal prefixes and suffixes from an `Hir`. +*/ + +use std::cmp; +use std::fmt; +use std::iter; +use std::mem; +use std::ops; + +use crate::hir::{self, Hir, HirKind}; + +/// A set of literal byte strings extracted from a regular expression. +/// +/// Every member of the set is a `Literal`, which is represented by a +/// `Vec<u8>`. (Notably, it may contain invalid UTF-8.) Every member is +/// said to be either *complete* or *cut*. A complete literal means that +/// it extends until the beginning (or end) of the regular expression. In +/// some circumstances, this can be used to indicate a match in the regular +/// expression. +/// +/// A key aspect of literal extraction is knowing when to stop. It is not +/// feasible to blindly extract all literals from a regular expression, even if +/// there are finitely many. For example, the regular expression `[0-9]{10}` +/// has `10^10` distinct literals. For this reason, literal extraction is +/// bounded to some low number by default using heuristics, but the limits can +/// be tweaked. +/// +/// **WARNING**: Literal extraction uses stack space proportional to the size +/// of the `Hir` expression. At some point, this drawback will be eliminated. +/// To protect yourself, set a reasonable +/// [`nest_limit` on your `Parser`](../../struct.ParserBuilder.html#method.nest_limit). +/// This is done for you by default. +#[derive(Clone, Eq, PartialEq)] +pub struct Literals { + lits: Vec<Literal>, + limit_size: usize, + limit_class: usize, +} + +/// A single member of a set of literals extracted from a regular expression. +/// +/// This type has `Deref` and `DerefMut` impls to `Vec<u8>` so that all slice +/// and `Vec` operations are available. +#[derive(Clone, Eq, Ord)] +pub struct Literal { + v: Vec<u8>, + cut: bool, +} + +impl Literals { + /// Returns a new empty set of literals using default limits. + pub fn empty() -> Literals { + Literals { lits: vec![], limit_size: 250, limit_class: 10 } + } + + /// Returns a set of literal prefixes extracted from the given `Hir`. + pub fn prefixes(expr: &Hir) -> Literals { + let mut lits = Literals::empty(); + lits.union_prefixes(expr); + lits + } + + /// Returns a set of literal suffixes extracted from the given `Hir`. + pub fn suffixes(expr: &Hir) -> Literals { + let mut lits = Literals::empty(); + lits.union_suffixes(expr); + lits + } + + /// Get the approximate size limit (in bytes) of this set. + pub fn limit_size(&self) -> usize { + self.limit_size + } + + /// Set the approximate size limit (in bytes) of this set. + /// + /// If extracting a literal would put the set over this limit, then + /// extraction stops. + /// + /// The new limits will only apply to additions to this set. Existing + /// members remain unchanged, even if the set exceeds the new limit. + pub fn set_limit_size(&mut self, size: usize) -> &mut Literals { + self.limit_size = size; + self + } + + /// Get the character class size limit for this set. + pub fn limit_class(&self) -> usize { + self.limit_class + } + + /// Limits the size of character(or byte) classes considered. + /// + /// A value of `0` prevents all character classes from being considered. + /// + /// This limit also applies to case insensitive literals, since each + /// character in the case insensitive literal is converted to a class, and + /// then case folded. + /// + /// The new limits will only apply to additions to this set. Existing + /// members remain unchanged, even if the set exceeds the new limit. + pub fn set_limit_class(&mut self, size: usize) -> &mut Literals { + self.limit_class = size; + self + } + + /// Returns the set of literals as a slice. Its order is unspecified. + pub fn literals(&self) -> &[Literal] { + &self.lits + } + + /// Returns the length of the smallest literal. + /// + /// Returns None is there are no literals in the set. + pub fn min_len(&self) -> Option<usize> { + let mut min = None; + for lit in &self.lits { + match min { + None => min = Some(lit.len()), + Some(m) if lit.len() < m => min = Some(lit.len()), + _ => {} + } + } + min + } + + /// Returns true if all members in this set are complete. + pub fn all_complete(&self) -> bool { + !self.lits.is_empty() && self.lits.iter().all(|l| !l.is_cut()) + } + + /// Returns true if any member in this set is complete. + pub fn any_complete(&self) -> bool { + self.lits.iter().any(|lit| !lit.is_cut()) + } + + /// Returns true if this set contains an empty literal. + pub fn contains_empty(&self) -> bool { + self.lits.iter().any(|lit| lit.is_empty()) + } + + /// Returns true if this set is empty or if all of its members is empty. + pub fn is_empty(&self) -> bool { + self.lits.is_empty() || self.lits.iter().all(|lit| lit.is_empty()) + } + + /// Returns a new empty set of literals using this set's limits. + pub fn to_empty(&self) -> Literals { + let mut lits = Literals::empty(); + lits.set_limit_size(self.limit_size).set_limit_class(self.limit_class); + lits + } + + /// Returns the longest common prefix of all members in this set. + pub fn longest_common_prefix(&self) -> &[u8] { + if self.is_empty() { + return &[]; + } + let lit0 = &*self.lits[0]; + let mut len = lit0.len(); + for lit in &self.lits[1..] { + len = cmp::min( + len, + lit.iter().zip(lit0).take_while(|&(a, b)| a == b).count(), + ); + } + &self.lits[0][..len] + } + + /// Returns the longest common suffix of all members in this set. + pub fn longest_common_suffix(&self) -> &[u8] { + if self.is_empty() { + return &[]; + } + let lit0 = &*self.lits[0]; + let mut len = lit0.len(); + for lit in &self.lits[1..] { + len = cmp::min( + len, + lit.iter() + .rev() + .zip(lit0.iter().rev()) + .take_while(|&(a, b)| a == b) + .count(), + ); + } + &self.lits[0][self.lits[0].len() - len..] + } + + /// Returns a new set of literals with the given number of bytes trimmed + /// from the suffix of each literal. + /// + /// If any literal would be cut out completely by trimming, then None is + /// returned. + /// + /// Any duplicates that are created as a result of this transformation are + /// removed. + pub fn trim_suffix(&self, num_bytes: usize) -> Option<Literals> { + if self.min_len().map(|len| len <= num_bytes).unwrap_or(true) { + return None; + } + let mut new = self.to_empty(); + for mut lit in self.lits.iter().cloned() { + let new_len = lit.len() - num_bytes; + lit.truncate(new_len); + lit.cut(); + new.lits.push(lit); + } + new.lits.sort(); + new.lits.dedup(); + Some(new) + } + + /// Returns a new set of prefixes of this set of literals that are + /// guaranteed to be unambiguous. + /// + /// Any substring match with a member of the set is returned is guaranteed + /// to never overlap with a substring match of another member of the set + /// at the same starting position. + /// + /// Given any two members of the returned set, neither is a substring of + /// the other. + pub fn unambiguous_prefixes(&self) -> Literals { + if self.lits.is_empty() { + return self.to_empty(); + } + let mut old = self.lits.to_vec(); + let mut new = self.to_empty(); + 'OUTER: while let Some(mut candidate) = old.pop() { + if candidate.is_empty() { + continue; + } + if new.lits.is_empty() { + new.lits.push(candidate); + continue; + } + for lit2 in &mut new.lits { + if lit2.is_empty() { + continue; + } + if &candidate == lit2 { + // If the literal is already in the set, then we can + // just drop it. But make sure that cut literals are + // infectious! + candidate.cut = candidate.cut || lit2.cut; + lit2.cut = candidate.cut; + continue 'OUTER; + } + if candidate.len() < lit2.len() { + if let Some(i) = position(&candidate, &lit2) { + candidate.cut(); + let mut lit3 = lit2.clone(); + lit3.truncate(i); + lit3.cut(); + old.push(lit3); + lit2.clear(); + } + } else if let Some(i) = position(&lit2, &candidate) { + lit2.cut(); + let mut new_candidate = candidate.clone(); + new_candidate.truncate(i); + new_candidate.cut(); + old.push(new_candidate); + candidate.clear(); + } + // Oops, the candidate is already represented in the set. + if candidate.is_empty() { + continue 'OUTER; + } + } + new.lits.push(candidate); + } + new.lits.retain(|lit| !lit.is_empty()); + new.lits.sort(); + new.lits.dedup(); + new + } + + /// Returns a new set of suffixes of this set of literals that are + /// guaranteed to be unambiguous. + /// + /// Any substring match with a member of the set is returned is guaranteed + /// to never overlap with a substring match of another member of the set + /// at the same ending position. + /// + /// Given any two members of the returned set, neither is a substring of + /// the other. + pub fn unambiguous_suffixes(&self) -> Literals { + // This is a touch wasteful... + let mut lits = self.clone(); + lits.reverse(); + let mut unamb = lits.unambiguous_prefixes(); + unamb.reverse(); + unamb + } + + /// Unions the prefixes from the given expression to this set. + /// + /// If prefixes could not be added (for example, this set would exceed its + /// size limits or the set of prefixes from `expr` includes the empty + /// string), then false is returned. + /// + /// Note that prefix literals extracted from `expr` are said to be complete + /// if and only if the literal extends from the beginning of `expr` to the + /// end of `expr`. + pub fn union_prefixes(&mut self, expr: &Hir) -> bool { + let mut lits = self.to_empty(); + prefixes(expr, &mut lits); + !lits.is_empty() && !lits.contains_empty() && self.union(lits) + } + + /// Unions the suffixes from the given expression to this set. + /// + /// If suffixes could not be added (for example, this set would exceed its + /// size limits or the set of suffixes from `expr` includes the empty + /// string), then false is returned. + /// + /// Note that prefix literals extracted from `expr` are said to be complete + /// if and only if the literal extends from the end of `expr` to the + /// beginning of `expr`. + pub fn union_suffixes(&mut self, expr: &Hir) -> bool { + let mut lits = self.to_empty(); + suffixes(expr, &mut lits); + lits.reverse(); + !lits.is_empty() && !lits.contains_empty() && self.union(lits) + } + + /// Unions this set with another set. + /// + /// If the union would cause the set to exceed its limits, then the union + /// is skipped and it returns false. Otherwise, if the union succeeds, it + /// returns true. + pub fn union(&mut self, lits: Literals) -> bool { + if self.num_bytes() + lits.num_bytes() > self.limit_size { + return false; + } + if lits.is_empty() { + self.lits.push(Literal::empty()); + } else { + self.lits.extend(lits.lits); + } + true + } + + /// Extends this set with another set. + /// + /// The set of literals is extended via a cross product. + /// + /// If a cross product would cause this set to exceed its limits, then the + /// cross product is skipped and it returns false. Otherwise, if the cross + /// product succeeds, it returns true. + pub fn cross_product(&mut self, lits: &Literals) -> bool { + if lits.is_empty() { + return true; + } + // Check that we make sure we stay in our limits. + let mut size_after; + if self.is_empty() || !self.any_complete() { + size_after = self.num_bytes(); + for lits_lit in lits.literals() { + size_after += lits_lit.len(); + } + } else { + size_after = self.lits.iter().fold(0, |accum, lit| { + accum + if lit.is_cut() { lit.len() } else { 0 } + }); + for lits_lit in lits.literals() { + for self_lit in self.literals() { + if !self_lit.is_cut() { + size_after += self_lit.len() + lits_lit.len(); + } + } + } + } + if size_after > self.limit_size { + return false; + } + + let mut base = self.remove_complete(); + if base.is_empty() { + base = vec![Literal::empty()]; + } + for lits_lit in lits.literals() { + for mut self_lit in base.clone() { + self_lit.extend(&**lits_lit); + self_lit.cut = lits_lit.cut; + self.lits.push(self_lit); + } + } + true + } + + /// Extends each literal in this set with the bytes given. + /// + /// If the set is empty, then the given literal is added to the set. + /// + /// If adding any number of bytes to all members of this set causes a limit + /// to be exceeded, then no bytes are added and false is returned. If a + /// prefix of `bytes` can be fit into this set, then it is used and all + /// resulting literals are cut. + pub fn cross_add(&mut self, bytes: &[u8]) -> bool { + // N.B. This could be implemented by simply calling cross_product with + // a literal set containing just `bytes`, but we can be smarter about + // taking shorter prefixes of `bytes` if they'll fit. + if bytes.is_empty() { + return true; + } + if self.lits.is_empty() { + let i = cmp::min(self.limit_size, bytes.len()); + self.lits.push(Literal::new(bytes[..i].to_owned())); + self.lits[0].cut = i < bytes.len(); + return !self.lits[0].is_cut(); + } + let size = self.num_bytes(); + if size + self.lits.len() >= self.limit_size { + return false; + } + let mut i = 1; + while size + (i * self.lits.len()) <= self.limit_size + && i < bytes.len() + { + i += 1; + } + for lit in &mut self.lits { + if !lit.is_cut() { + lit.extend(&bytes[..i]); + if i < bytes.len() { + lit.cut(); + } + } + } + true + } + + /// Adds the given literal to this set. + /// + /// Returns false if adding this literal would cause the class to be too + /// big. + pub fn add(&mut self, lit: Literal) -> bool { + if self.num_bytes() + lit.len() > self.limit_size { + return false; + } + self.lits.push(lit); + true + } + + /// Extends each literal in this set with the character class given. + /// + /// Returns false if the character class was too big to add. + pub fn add_char_class(&mut self, cls: &hir::ClassUnicode) -> bool { + self._add_char_class(cls, false) + } + + /// Extends each literal in this set with the character class given, + /// writing the bytes of each character in reverse. + /// + /// Returns false if the character class was too big to add. + fn add_char_class_reverse(&mut self, cls: &hir::ClassUnicode) -> bool { + self._add_char_class(cls, true) + } + + fn _add_char_class( + &mut self, + cls: &hir::ClassUnicode, + reverse: bool, + ) -> bool { + use std::char; + + if self.class_exceeds_limits(cls_char_count(cls)) { + return false; + } + let mut base = self.remove_complete(); + if base.is_empty() { + base = vec![Literal::empty()]; + } + for r in cls.iter() { + let (s, e) = (r.start as u32, r.end as u32 + 1); + for c in (s..e).filter_map(char::from_u32) { + for mut lit in base.clone() { + let mut bytes = c.to_string().into_bytes(); + if reverse { + bytes.reverse(); + } + lit.extend(&bytes); + self.lits.push(lit); + } + } + } + true + } + + /// Extends each literal in this set with the byte class given. + /// + /// Returns false if the byte class was too big to add. + pub fn add_byte_class(&mut self, cls: &hir::ClassBytes) -> bool { + if self.class_exceeds_limits(cls_byte_count(cls)) { + return false; + } + let mut base = self.remove_complete(); + if base.is_empty() { + base = vec![Literal::empty()]; + } + for r in cls.iter() { + let (s, e) = (r.start as u32, r.end as u32 + 1); + for b in (s..e).map(|b| b as u8) { + for mut lit in base.clone() { + lit.push(b); + self.lits.push(lit); + } + } + } + true + } + + /// Cuts every member of this set. When a member is cut, it can never + /// be extended. + pub fn cut(&mut self) { + for lit in &mut self.lits { + lit.cut(); + } + } + + /// Reverses all members in place. + pub fn reverse(&mut self) { + for lit in &mut self.lits { + lit.reverse(); + } + } + + /// Clears this set of all members. + pub fn clear(&mut self) { + self.lits.clear(); + } + + /// Pops all complete literals out of this set. + fn remove_complete(&mut self) -> Vec<Literal> { + let mut base = vec![]; + for lit in mem::replace(&mut self.lits, vec![]) { + if lit.is_cut() { + self.lits.push(lit); + } else { + base.push(lit); + } + } + base + } + + /// Returns the total number of bytes in this set. + fn num_bytes(&self) -> usize { + self.lits.iter().fold(0, |accum, lit| accum + lit.len()) + } + + /// Returns true if a character class with the given size would cause this + /// set to exceed its limits. + /// + /// The size given should correspond to the number of items in the class. + fn class_exceeds_limits(&self, size: usize) -> bool { + if size > self.limit_class { + return true; + } + // This is an approximation since codepoints in a char class can encode + // to 1-4 bytes. + let new_byte_count = if self.lits.is_empty() { + size + } else { + self.lits.iter().fold(0, |accum, lit| { + accum + + if lit.is_cut() { + // If the literal is cut, then we'll never add + // anything to it, so don't count it. + 0 + } else { + (lit.len() + 1) * size + } + }) + }; + new_byte_count > self.limit_size + } +} + +fn prefixes(expr: &Hir, lits: &mut Literals) { + match *expr.kind() { + HirKind::Literal(hir::Literal::Unicode(c)) => { + let mut buf = [0; 4]; + lits.cross_add(c.encode_utf8(&mut buf).as_bytes()); + } + HirKind::Literal(hir::Literal::Byte(b)) => { + lits.cross_add(&[b]); + } + HirKind::Class(hir::Class::Unicode(ref cls)) => { + if !lits.add_char_class(cls) { + lits.cut(); + } + } + HirKind::Class(hir::Class::Bytes(ref cls)) => { + if !lits.add_byte_class(cls) { + lits.cut(); + } + } + HirKind::Group(hir::Group { ref hir, .. }) => { + prefixes(&**hir, lits); + } + HirKind::Repetition(ref x) => match x.kind { + hir::RepetitionKind::ZeroOrOne => { + repeat_zero_or_one_literals(&x.hir, lits, prefixes); + } + hir::RepetitionKind::ZeroOrMore => { + repeat_zero_or_more_literals(&x.hir, lits, prefixes); + } + hir::RepetitionKind::OneOrMore => { + repeat_one_or_more_literals(&x.hir, lits, prefixes); + } + hir::RepetitionKind::Range(ref rng) => { + let (min, max) = match *rng { + hir::RepetitionRange::Exactly(m) => (m, Some(m)), + hir::RepetitionRange::AtLeast(m) => (m, None), + hir::RepetitionRange::Bounded(m, n) => (m, Some(n)), + }; + repeat_range_literals( + &x.hir, min, max, x.greedy, lits, prefixes, + ) + } + }, + HirKind::Concat(ref es) if es.is_empty() => {} + HirKind::Concat(ref es) if es.len() == 1 => prefixes(&es[0], lits), + HirKind::Concat(ref es) => { + for e in es { + if let HirKind::Anchor(hir::Anchor::StartText) = *e.kind() { + if !lits.is_empty() { + lits.cut(); + break; + } + lits.add(Literal::empty()); + continue; + } + let mut lits2 = lits.to_empty(); + prefixes(e, &mut lits2); + if !lits.cross_product(&lits2) || !lits2.any_complete() { + // If this expression couldn't yield any literal that + // could be extended, then we need to quit. Since we're + // short-circuiting, we also need to freeze every member. + lits.cut(); + break; + } + } + } + HirKind::Alternation(ref es) => { + alternate_literals(es, lits, prefixes); + } + _ => lits.cut(), + } +} + +fn suffixes(expr: &Hir, lits: &mut Literals) { + match *expr.kind() { + HirKind::Literal(hir::Literal::Unicode(c)) => { + let mut buf = [0u8; 4]; + let i = c.encode_utf8(&mut buf).len(); + let buf = &mut buf[..i]; + buf.reverse(); + lits.cross_add(buf); + } + HirKind::Literal(hir::Literal::Byte(b)) => { + lits.cross_add(&[b]); + } + HirKind::Class(hir::Class::Unicode(ref cls)) => { + if !lits.add_char_class_reverse(cls) { + lits.cut(); + } + } + HirKind::Class(hir::Class::Bytes(ref cls)) => { + if !lits.add_byte_class(cls) { + lits.cut(); + } + } + HirKind::Group(hir::Group { ref hir, .. }) => { + suffixes(&**hir, lits); + } + HirKind::Repetition(ref x) => match x.kind { + hir::RepetitionKind::ZeroOrOne => { + repeat_zero_or_one_literals(&x.hir, lits, suffixes); + } + hir::RepetitionKind::ZeroOrMore => { + repeat_zero_or_more_literals(&x.hir, lits, suffixes); + } + hir::RepetitionKind::OneOrMore => { + repeat_one_or_more_literals(&x.hir, lits, suffixes); + } + hir::RepetitionKind::Range(ref rng) => { + let (min, max) = match *rng { + hir::RepetitionRange::Exactly(m) => (m, Some(m)), + hir::RepetitionRange::AtLeast(m) => (m, None), + hir::RepetitionRange::Bounded(m, n) => (m, Some(n)), + }; + repeat_range_literals( + &x.hir, min, max, x.greedy, lits, suffixes, + ) + } + }, + HirKind::Concat(ref es) if es.is_empty() => {} + HirKind::Concat(ref es) if es.len() == 1 => suffixes(&es[0], lits), + HirKind::Concat(ref es) => { + for e in es.iter().rev() { + if let HirKind::Anchor(hir::Anchor::EndText) = *e.kind() { + if !lits.is_empty() { + lits.cut(); + break; + } + lits.add(Literal::empty()); + continue; + } + let mut lits2 = lits.to_empty(); + suffixes(e, &mut lits2); + if !lits.cross_product(&lits2) || !lits2.any_complete() { + // If this expression couldn't yield any literal that + // could be extended, then we need to quit. Since we're + // short-circuiting, we also need to freeze every member. + lits.cut(); + break; + } + } + } + HirKind::Alternation(ref es) => { + alternate_literals(es, lits, suffixes); + } + _ => lits.cut(), + } +} + +fn repeat_zero_or_one_literals<F: FnMut(&Hir, &mut Literals)>( + e: &Hir, + lits: &mut Literals, + mut f: F, +) { + f( + &Hir::repetition(hir::Repetition { + kind: hir::RepetitionKind::ZeroOrMore, + // FIXME: Our literal extraction doesn't care about greediness. + // Which is partially why we're treating 'e?' as 'e*'. Namely, + // 'ab??' yields [Complete(ab), Complete(a)], but it should yield + // [Complete(a), Complete(ab)] because of the non-greediness. + greedy: true, + hir: Box::new(e.clone()), + }), + lits, + ); +} + +fn repeat_zero_or_more_literals<F: FnMut(&Hir, &mut Literals)>( + e: &Hir, + lits: &mut Literals, + mut f: F, +) { + let (mut lits2, mut lits3) = (lits.clone(), lits.to_empty()); + lits3.set_limit_size(lits.limit_size() / 2); + f(e, &mut lits3); + + if lits3.is_empty() || !lits2.cross_product(&lits3) { + lits.cut(); + return; + } + lits2.cut(); + lits2.add(Literal::empty()); + if !lits.union(lits2) { + lits.cut(); + } +} + +fn repeat_one_or_more_literals<F: FnMut(&Hir, &mut Literals)>( + e: &Hir, + lits: &mut Literals, + mut f: F, +) { + f(e, lits); + lits.cut(); +} + +fn repeat_range_literals<F: FnMut(&Hir, &mut Literals)>( + e: &Hir, + min: u32, + max: Option<u32>, + greedy: bool, + lits: &mut Literals, + mut f: F, +) { + if min == 0 { + // This is a bit conservative. If `max` is set, then we could + // treat this as a finite set of alternations. For now, we + // just treat it as `e*`. + f( + &Hir::repetition(hir::Repetition { + kind: hir::RepetitionKind::ZeroOrMore, + greedy, + hir: Box::new(e.clone()), + }), + lits, + ); + } else { + if min > 0 { + let n = cmp::min(lits.limit_size, min as usize); + let es = iter::repeat(e.clone()).take(n).collect(); + f(&Hir::concat(es), lits); + if n < min as usize || lits.contains_empty() { + lits.cut(); + } + } + if max.map_or(true, |max| min < max) { + lits.cut(); + } + } +} + +fn alternate_literals<F: FnMut(&Hir, &mut Literals)>( + es: &[Hir], + lits: &mut Literals, + mut f: F, +) { + let mut lits2 = lits.to_empty(); + for e in es { + let mut lits3 = lits.to_empty(); + lits3.set_limit_size(lits.limit_size() / 5); + f(e, &mut lits3); + if lits3.is_empty() || !lits2.union(lits3) { + // If we couldn't find suffixes for *any* of the + // alternates, then the entire alternation has to be thrown + // away and any existing members must be frozen. Similarly, + // if the union couldn't complete, stop and freeze. + lits.cut(); + return; + } + } + if !lits.cross_product(&lits2) { + lits.cut(); + } +} + +impl fmt::Debug for Literals { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Literals") + .field("lits", &self.lits) + .field("limit_size", &self.limit_size) + .field("limit_class", &self.limit_class) + .finish() + } +} + +impl Literal { + /// Returns a new complete literal with the bytes given. + pub fn new(bytes: Vec<u8>) -> Literal { + Literal { v: bytes, cut: false } + } + + /// Returns a new complete empty literal. + pub fn empty() -> Literal { + Literal { v: vec![], cut: false } + } + + /// Returns true if this literal was "cut." + pub fn is_cut(&self) -> bool { + self.cut + } + + /// Cuts this literal. + pub fn cut(&mut self) { + self.cut = true; + } +} + +impl PartialEq for Literal { + fn eq(&self, other: &Literal) -> bool { + self.v == other.v + } +} + +impl PartialOrd for Literal { + fn partial_cmp(&self, other: &Literal) -> Option<cmp::Ordering> { + self.v.partial_cmp(&other.v) + } +} + +impl fmt::Debug for Literal { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + if self.is_cut() { + write!(f, "Cut({})", escape_unicode(&self.v)) + } else { + write!(f, "Complete({})", escape_unicode(&self.v)) + } + } +} + +impl AsRef<[u8]> for Literal { + fn as_ref(&self) -> &[u8] { + &self.v + } +} + +impl ops::Deref for Literal { + type Target = Vec<u8>; + fn deref(&self) -> &Vec<u8> { + &self.v + } +} + +impl ops::DerefMut for Literal { + fn deref_mut(&mut self) -> &mut Vec<u8> { + &mut self.v + } +} + +fn position(needle: &[u8], mut haystack: &[u8]) -> Option<usize> { + let mut i = 0; + while haystack.len() >= needle.len() { + if needle == &haystack[..needle.len()] { + return Some(i); + } + i += 1; + haystack = &haystack[1..]; + } + None +} + +fn escape_unicode(bytes: &[u8]) -> String { + let show = match ::std::str::from_utf8(bytes) { + Ok(v) => v.to_string(), + Err(_) => escape_bytes(bytes), + }; + let mut space_escaped = String::new(); + for c in show.chars() { + if c.is_whitespace() { + let escaped = if c as u32 <= 0x7F { + escape_byte(c as u8) + } else if c as u32 <= 0xFFFF { + format!(r"\u{{{:04x}}}", c as u32) + } else { + format!(r"\U{{{:08x}}}", c as u32) + }; + space_escaped.push_str(&escaped); + } else { + space_escaped.push(c); + } + } + space_escaped +} + +fn escape_bytes(bytes: &[u8]) -> String { + let mut s = String::new(); + for &b in bytes { + s.push_str(&escape_byte(b)); + } + s +} + +fn escape_byte(byte: u8) -> String { + use std::ascii::escape_default; + + let escaped: Vec<u8> = escape_default(byte).collect(); + String::from_utf8_lossy(&escaped).into_owned() +} + +fn cls_char_count(cls: &hir::ClassUnicode) -> usize { + cls.iter().map(|&r| 1 + (r.end as u32) - (r.start as u32)).sum::<u32>() + as usize +} + +fn cls_byte_count(cls: &hir::ClassBytes) -> usize { + cls.iter().map(|&r| 1 + (r.end as u32) - (r.start as u32)).sum::<u32>() + as usize +} + +#[cfg(test)] +mod tests { + use std::fmt; + + use super::{escape_bytes, Literal, Literals}; + use crate::hir::Hir; + use crate::ParserBuilder; + + // To make test failures easier to read. + #[derive(Debug, Eq, PartialEq)] + struct Bytes(Vec<ULiteral>); + #[derive(Debug, Eq, PartialEq)] + struct Unicode(Vec<ULiteral>); + + fn escape_lits(blits: &[Literal]) -> Vec<ULiteral> { + let mut ulits = vec![]; + for blit in blits { + ulits + .push(ULiteral { v: escape_bytes(&blit), cut: blit.is_cut() }); + } + ulits + } + + fn create_lits<I: IntoIterator<Item = Literal>>(it: I) -> Literals { + Literals { + lits: it.into_iter().collect(), + limit_size: 0, + limit_class: 0, + } + } + + // Needs to be pub for 1.3? + #[derive(Clone, Eq, PartialEq)] + pub struct ULiteral { + v: String, + cut: bool, + } + + impl ULiteral { + fn is_cut(&self) -> bool { + self.cut + } + } + + impl fmt::Debug for ULiteral { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + if self.is_cut() { + write!(f, "Cut({})", self.v) + } else { + write!(f, "Complete({})", self.v) + } + } + } + + impl PartialEq<Literal> for ULiteral { + fn eq(&self, other: &Literal) -> bool { + self.v.as_bytes() == &*other.v && self.is_cut() == other.is_cut() + } + } + + impl PartialEq<ULiteral> for Literal { + fn eq(&self, other: &ULiteral) -> bool { + &*self.v == other.v.as_bytes() && self.is_cut() == other.is_cut() + } + } + + #[allow(non_snake_case)] + fn C(s: &'static str) -> ULiteral { + ULiteral { v: s.to_owned(), cut: true } + } + #[allow(non_snake_case)] + fn M(s: &'static str) -> ULiteral { + ULiteral { v: s.to_owned(), cut: false } + } + + fn prefixes(lits: &mut Literals, expr: &Hir) { + lits.union_prefixes(expr); + } + + fn suffixes(lits: &mut Literals, expr: &Hir) { + lits.union_suffixes(expr); + } + + macro_rules! assert_lit_eq { + ($which:ident, $got_lits:expr, $($expected_lit:expr),*) => {{ + let expected: Vec<ULiteral> = vec![$($expected_lit),*]; + let lits = $got_lits; + assert_eq!( + $which(expected.clone()), + $which(escape_lits(lits.literals()))); + assert_eq!( + !expected.is_empty() && expected.iter().all(|l| !l.is_cut()), + lits.all_complete()); + assert_eq!( + expected.iter().any(|l| !l.is_cut()), + lits.any_complete()); + }}; + } + + macro_rules! test_lit { + ($name:ident, $which:ident, $re:expr) => { + test_lit!($name, $which, $re,); + }; + ($name:ident, $which:ident, $re:expr, $($lit:expr),*) => { + #[test] + fn $name() { + let expr = ParserBuilder::new() + .build() + .parse($re) + .unwrap(); + let lits = Literals::$which(&expr); + assert_lit_eq!(Unicode, lits, $($lit),*); + + let expr = ParserBuilder::new() + .allow_invalid_utf8(true) + .unicode(false) + .build() + .parse($re) + .unwrap(); + let lits = Literals::$which(&expr); + assert_lit_eq!(Bytes, lits, $($lit),*); + } + }; + } + + // ************************************************************************ + // Tests for prefix literal extraction. + // ************************************************************************ + + // Elementary tests. + test_lit!(pfx_one_lit1, prefixes, "a", M("a")); + test_lit!(pfx_one_lit2, prefixes, "abc", M("abc")); + test_lit!(pfx_one_lit3, prefixes, "(?u)☃", M("\\xe2\\x98\\x83")); + #[cfg(feature = "unicode-case")] + test_lit!(pfx_one_lit4, prefixes, "(?ui)☃", M("\\xe2\\x98\\x83")); + test_lit!(pfx_class1, prefixes, "[1-4]", M("1"), M("2"), M("3"), M("4")); + test_lit!( + pfx_class2, + prefixes, + "(?u)[☃Ⅰ]", + M("\\xe2\\x85\\xa0"), + M("\\xe2\\x98\\x83") + ); + #[cfg(feature = "unicode-case")] + test_lit!( + pfx_class3, + prefixes, + "(?ui)[☃Ⅰ]", + M("\\xe2\\x85\\xa0"), + M("\\xe2\\x85\\xb0"), + M("\\xe2\\x98\\x83") + ); + test_lit!(pfx_one_lit_casei1, prefixes, "(?i-u)a", M("A"), M("a")); + test_lit!( + pfx_one_lit_casei2, + prefixes, + "(?i-u)abc", + M("ABC"), + M("aBC"), + M("AbC"), + M("abC"), + M("ABc"), + M("aBc"), + M("Abc"), + M("abc") + ); + test_lit!(pfx_group1, prefixes, "(a)", M("a")); + test_lit!(pfx_rep_zero_or_one1, prefixes, "a?"); + test_lit!(pfx_rep_zero_or_one2, prefixes, "(?:abc)?"); + test_lit!(pfx_rep_zero_or_one_cat1, prefixes, "ab?", C("ab"), M("a")); + // FIXME: This should return [M("a"), M("ab")] because of the non-greedy + // repetition. As a work-around, we rewrite ab?? as ab*?, and thus we get + // a cut literal. + test_lit!(pfx_rep_zero_or_one_cat2, prefixes, "ab??", C("ab"), M("a")); + test_lit!(pfx_rep_zero_or_more1, prefixes, "a*"); + test_lit!(pfx_rep_zero_or_more2, prefixes, "(?:abc)*"); + test_lit!(pfx_rep_one_or_more1, prefixes, "a+", C("a")); + test_lit!(pfx_rep_one_or_more2, prefixes, "(?:abc)+", C("abc")); + test_lit!(pfx_rep_nested_one_or_more, prefixes, "(?:a+)+", C("a")); + test_lit!(pfx_rep_range1, prefixes, "a{0}"); + test_lit!(pfx_rep_range2, prefixes, "a{0,}"); + test_lit!(pfx_rep_range3, prefixes, "a{0,1}"); + test_lit!(pfx_rep_range4, prefixes, "a{1}", M("a")); + test_lit!(pfx_rep_range5, prefixes, "a{2}", M("aa")); + test_lit!(pfx_rep_range6, prefixes, "a{1,2}", C("a")); + test_lit!(pfx_rep_range7, prefixes, "a{2,3}", C("aa")); + + // Test regexes with concatenations. + test_lit!(pfx_cat1, prefixes, "(?:a)(?:b)", M("ab")); + test_lit!(pfx_cat2, prefixes, "[ab]z", M("az"), M("bz")); + test_lit!( + pfx_cat3, + prefixes, + "(?i-u)[ab]z", + M("AZ"), + M("BZ"), + M("aZ"), + M("bZ"), + M("Az"), + M("Bz"), + M("az"), + M("bz") + ); + test_lit!( + pfx_cat4, + prefixes, + "[ab][yz]", + M("ay"), + M("by"), + M("az"), + M("bz") + ); + test_lit!(pfx_cat5, prefixes, "a*b", C("a"), M("b")); + test_lit!(pfx_cat6, prefixes, "a*b*c", C("a"), C("b"), M("c")); + test_lit!(pfx_cat7, prefixes, "a*b*c+", C("a"), C("b"), C("c")); + test_lit!(pfx_cat8, prefixes, "a*b+c", C("a"), C("b")); + test_lit!(pfx_cat9, prefixes, "a*b+c*", C("a"), C("b")); + test_lit!(pfx_cat10, prefixes, "ab*", C("ab"), M("a")); + test_lit!(pfx_cat11, prefixes, "ab*c", C("ab"), M("ac")); + test_lit!(pfx_cat12, prefixes, "ab+", C("ab")); + test_lit!(pfx_cat13, prefixes, "ab+c", C("ab")); + test_lit!(pfx_cat14, prefixes, "a^", C("a")); + test_lit!(pfx_cat15, prefixes, "$a"); + test_lit!(pfx_cat16, prefixes, r"ab*c", C("ab"), M("ac")); + test_lit!(pfx_cat17, prefixes, r"ab+c", C("ab")); + test_lit!(pfx_cat18, prefixes, r"z*azb", C("z"), M("azb")); + test_lit!(pfx_cat19, prefixes, "a.z", C("a")); + + // Test regexes with alternations. + test_lit!(pfx_alt1, prefixes, "a|b", M("a"), M("b")); + test_lit!(pfx_alt2, prefixes, "[1-3]|b", M("1"), M("2"), M("3"), M("b")); + test_lit!(pfx_alt3, prefixes, "y(?:a|b)z", M("yaz"), M("ybz")); + test_lit!(pfx_alt4, prefixes, "a|b*"); + test_lit!(pfx_alt5, prefixes, "a|b+", M("a"), C("b")); + test_lit!(pfx_alt6, prefixes, "a|(?:b|c*)"); + test_lit!( + pfx_alt7, + prefixes, + "(a|b)*c|(a|ab)*c", + C("a"), + C("b"), + M("c"), + C("a"), + C("ab"), + M("c") + ); + test_lit!(pfx_alt8, prefixes, "a*b|c", C("a"), M("b"), M("c")); + + // Test regexes with empty assertions. + test_lit!(pfx_empty1, prefixes, "^a", M("a")); + test_lit!(pfx_empty2, prefixes, "a${2}", C("a")); + test_lit!(pfx_empty3, prefixes, "^abc", M("abc")); + test_lit!(pfx_empty4, prefixes, "(?:^abc)|(?:^z)", M("abc"), M("z")); + + // Make sure some curious regexes have no prefixes. + test_lit!(pfx_nothing1, prefixes, "."); + test_lit!(pfx_nothing2, prefixes, "(?s)."); + test_lit!(pfx_nothing3, prefixes, "^"); + test_lit!(pfx_nothing4, prefixes, "$"); + test_lit!(pfx_nothing6, prefixes, "(?m)$"); + test_lit!(pfx_nothing7, prefixes, r"\b"); + test_lit!(pfx_nothing8, prefixes, r"\B"); + + // Test a few regexes that defeat any prefix literal detection. + test_lit!(pfx_defeated1, prefixes, ".a"); + test_lit!(pfx_defeated2, prefixes, "(?s).a"); + test_lit!(pfx_defeated3, prefixes, "a*b*c*"); + test_lit!(pfx_defeated4, prefixes, "a|."); + test_lit!(pfx_defeated5, prefixes, ".|a"); + test_lit!(pfx_defeated6, prefixes, "a|^"); + test_lit!(pfx_defeated7, prefixes, ".(?:a(?:b)(?:c))"); + test_lit!(pfx_defeated8, prefixes, "$a"); + test_lit!(pfx_defeated9, prefixes, "(?m)$a"); + test_lit!(pfx_defeated10, prefixes, r"\ba"); + test_lit!(pfx_defeated11, prefixes, r"\Ba"); + test_lit!(pfx_defeated12, prefixes, "^*a"); + test_lit!(pfx_defeated13, prefixes, "^+a"); + + test_lit!( + pfx_crazy1, + prefixes, + r"M[ou]'?am+[ae]r .*([AEae]l[- ])?[GKQ]h?[aeu]+([dtz][dhz]?)+af[iy]", + C("Mo\\'"), + C("Mu\\'"), + C("Moam"), + C("Muam") + ); + + // ************************************************************************ + // Tests for quiting prefix literal search. + // ************************************************************************ + + macro_rules! test_exhausted { + ($name:ident, $which:ident, $re:expr) => { + test_exhausted!($name, $which, $re,); + }; + ($name:ident, $which:ident, $re:expr, $($lit:expr),*) => { + #[test] + fn $name() { + let expr = ParserBuilder::new() + .build() + .parse($re) + .unwrap(); + let mut lits = Literals::empty(); + lits.set_limit_size(20).set_limit_class(10); + $which(&mut lits, &expr); + assert_lit_eq!(Unicode, lits, $($lit),*); + + let expr = ParserBuilder::new() + .allow_invalid_utf8(true) + .unicode(false) + .build() + .parse($re) + .unwrap(); + let mut lits = Literals::empty(); + lits.set_limit_size(20).set_limit_class(10); + $which(&mut lits, &expr); + assert_lit_eq!(Bytes, lits, $($lit),*); + } + }; + } + + // These test use a much lower limit than the default so that we can + // write test cases of reasonable size. + test_exhausted!(pfx_exhausted1, prefixes, "[a-z]"); + test_exhausted!(pfx_exhausted2, prefixes, "[a-z]*A"); + test_exhausted!(pfx_exhausted3, prefixes, "A[a-z]Z", C("A")); + test_exhausted!( + pfx_exhausted4, + prefixes, + "(?i-u)foobar", + C("FO"), + C("fO"), + C("Fo"), + C("fo") + ); + test_exhausted!( + pfx_exhausted5, + prefixes, + "(?:ab){100}", + C("abababababababababab") + ); + test_exhausted!( + pfx_exhausted6, + prefixes, + "(?:(?:ab){100})*cd", + C("ababababab"), + M("cd") + ); + test_exhausted!( + pfx_exhausted7, + prefixes, + "z(?:(?:ab){100})*cd", + C("zababababab"), + M("zcd") + ); + test_exhausted!( + pfx_exhausted8, + prefixes, + "aaaaaaaaaaaaaaaaaaaaz", + C("aaaaaaaaaaaaaaaaaaaa") + ); + + // ************************************************************************ + // Tests for suffix literal extraction. + // ************************************************************************ + + // Elementary tests. + test_lit!(sfx_one_lit1, suffixes, "a", M("a")); + test_lit!(sfx_one_lit2, suffixes, "abc", M("abc")); + test_lit!(sfx_one_lit3, suffixes, "(?u)☃", M("\\xe2\\x98\\x83")); + #[cfg(feature = "unicode-case")] + test_lit!(sfx_one_lit4, suffixes, "(?ui)☃", M("\\xe2\\x98\\x83")); + test_lit!(sfx_class1, suffixes, "[1-4]", M("1"), M("2"), M("3"), M("4")); + test_lit!( + sfx_class2, + suffixes, + "(?u)[☃Ⅰ]", + M("\\xe2\\x85\\xa0"), + M("\\xe2\\x98\\x83") + ); + #[cfg(feature = "unicode-case")] + test_lit!( + sfx_class3, + suffixes, + "(?ui)[☃Ⅰ]", + M("\\xe2\\x85\\xa0"), + M("\\xe2\\x85\\xb0"), + M("\\xe2\\x98\\x83") + ); + test_lit!(sfx_one_lit_casei1, suffixes, "(?i-u)a", M("A"), M("a")); + test_lit!( + sfx_one_lit_casei2, + suffixes, + "(?i-u)abc", + M("ABC"), + M("ABc"), + M("AbC"), + M("Abc"), + M("aBC"), + M("aBc"), + M("abC"), + M("abc") + ); + test_lit!(sfx_group1, suffixes, "(a)", M("a")); + test_lit!(sfx_rep_zero_or_one1, suffixes, "a?"); + test_lit!(sfx_rep_zero_or_one2, suffixes, "(?:abc)?"); + test_lit!(sfx_rep_zero_or_more1, suffixes, "a*"); + test_lit!(sfx_rep_zero_or_more2, suffixes, "(?:abc)*"); + test_lit!(sfx_rep_one_or_more1, suffixes, "a+", C("a")); + test_lit!(sfx_rep_one_or_more2, suffixes, "(?:abc)+", C("abc")); + test_lit!(sfx_rep_nested_one_or_more, suffixes, "(?:a+)+", C("a")); + test_lit!(sfx_rep_range1, suffixes, "a{0}"); + test_lit!(sfx_rep_range2, suffixes, "a{0,}"); + test_lit!(sfx_rep_range3, suffixes, "a{0,1}"); + test_lit!(sfx_rep_range4, suffixes, "a{1}", M("a")); + test_lit!(sfx_rep_range5, suffixes, "a{2}", M("aa")); + test_lit!(sfx_rep_range6, suffixes, "a{1,2}", C("a")); + test_lit!(sfx_rep_range7, suffixes, "a{2,3}", C("aa")); + + // Test regexes with concatenations. + test_lit!(sfx_cat1, suffixes, "(?:a)(?:b)", M("ab")); + test_lit!(sfx_cat2, suffixes, "[ab]z", M("az"), M("bz")); + test_lit!( + sfx_cat3, + suffixes, + "(?i-u)[ab]z", + M("AZ"), + M("Az"), + M("BZ"), + M("Bz"), + M("aZ"), + M("az"), + M("bZ"), + M("bz") + ); + test_lit!( + sfx_cat4, + suffixes, + "[ab][yz]", + M("ay"), + M("az"), + M("by"), + M("bz") + ); + test_lit!(sfx_cat5, suffixes, "a*b", C("ab"), M("b")); + test_lit!(sfx_cat6, suffixes, "a*b*c", C("bc"), C("ac"), M("c")); + test_lit!(sfx_cat7, suffixes, "a*b*c+", C("c")); + test_lit!(sfx_cat8, suffixes, "a*b+c", C("bc")); + test_lit!(sfx_cat9, suffixes, "a*b+c*", C("c"), C("b")); + test_lit!(sfx_cat10, suffixes, "ab*", C("b"), M("a")); + test_lit!(sfx_cat11, suffixes, "ab*c", C("bc"), M("ac")); + test_lit!(sfx_cat12, suffixes, "ab+", C("b")); + test_lit!(sfx_cat13, suffixes, "ab+c", C("bc")); + test_lit!(sfx_cat14, suffixes, "a^"); + test_lit!(sfx_cat15, suffixes, "$a", C("a")); + test_lit!(sfx_cat16, suffixes, r"ab*c", C("bc"), M("ac")); + test_lit!(sfx_cat17, suffixes, r"ab+c", C("bc")); + test_lit!(sfx_cat18, suffixes, r"z*azb", C("zazb"), M("azb")); + test_lit!(sfx_cat19, suffixes, "a.z", C("z")); + + // Test regexes with alternations. + test_lit!(sfx_alt1, suffixes, "a|b", M("a"), M("b")); + test_lit!(sfx_alt2, suffixes, "[1-3]|b", M("1"), M("2"), M("3"), M("b")); + test_lit!(sfx_alt3, suffixes, "y(?:a|b)z", M("yaz"), M("ybz")); + test_lit!(sfx_alt4, suffixes, "a|b*"); + test_lit!(sfx_alt5, suffixes, "a|b+", M("a"), C("b")); + test_lit!(sfx_alt6, suffixes, "a|(?:b|c*)"); + test_lit!( + sfx_alt7, + suffixes, + "(a|b)*c|(a|ab)*c", + C("ac"), + C("bc"), + M("c"), + C("ac"), + C("abc"), + M("c") + ); + test_lit!(sfx_alt8, suffixes, "a*b|c", C("ab"), M("b"), M("c")); + + // Test regexes with empty assertions. + test_lit!(sfx_empty1, suffixes, "a$", M("a")); + test_lit!(sfx_empty2, suffixes, "${2}a", C("a")); + + // Make sure some curious regexes have no suffixes. + test_lit!(sfx_nothing1, suffixes, "."); + test_lit!(sfx_nothing2, suffixes, "(?s)."); + test_lit!(sfx_nothing3, suffixes, "^"); + test_lit!(sfx_nothing4, suffixes, "$"); + test_lit!(sfx_nothing6, suffixes, "(?m)$"); + test_lit!(sfx_nothing7, suffixes, r"\b"); + test_lit!(sfx_nothing8, suffixes, r"\B"); + + // Test a few regexes that defeat any suffix literal detection. + test_lit!(sfx_defeated1, suffixes, "a."); + test_lit!(sfx_defeated2, suffixes, "(?s)a."); + test_lit!(sfx_defeated3, suffixes, "a*b*c*"); + test_lit!(sfx_defeated4, suffixes, "a|."); + test_lit!(sfx_defeated5, suffixes, ".|a"); + test_lit!(sfx_defeated6, suffixes, "a|^"); + test_lit!(sfx_defeated7, suffixes, "(?:a(?:b)(?:c))."); + test_lit!(sfx_defeated8, suffixes, "a^"); + test_lit!(sfx_defeated9, suffixes, "(?m)a$"); + test_lit!(sfx_defeated10, suffixes, r"a\b"); + test_lit!(sfx_defeated11, suffixes, r"a\B"); + test_lit!(sfx_defeated12, suffixes, "a^*"); + test_lit!(sfx_defeated13, suffixes, "a^+"); + + // These test use a much lower limit than the default so that we can + // write test cases of reasonable size. + test_exhausted!(sfx_exhausted1, suffixes, "[a-z]"); + test_exhausted!(sfx_exhausted2, suffixes, "A[a-z]*"); + test_exhausted!(sfx_exhausted3, suffixes, "A[a-z]Z", C("Z")); + test_exhausted!( + sfx_exhausted4, + suffixes, + "(?i-u)foobar", + C("AR"), + C("Ar"), + C("aR"), + C("ar") + ); + test_exhausted!( + sfx_exhausted5, + suffixes, + "(?:ab){100}", + C("abababababababababab") + ); + test_exhausted!( + sfx_exhausted6, + suffixes, + "cd(?:(?:ab){100})*", + C("ababababab"), + M("cd") + ); + test_exhausted!( + sfx_exhausted7, + suffixes, + "cd(?:(?:ab){100})*z", + C("abababababz"), + M("cdz") + ); + test_exhausted!( + sfx_exhausted8, + suffixes, + "zaaaaaaaaaaaaaaaaaaaa", + C("aaaaaaaaaaaaaaaaaaaa") + ); + + // ************************************************************************ + // Tests for generating unambiguous literal sets. + // ************************************************************************ + + macro_rules! test_unamb { + ($name:ident, $given:expr, $expected:expr) => { + #[test] + fn $name() { + let given: Vec<Literal> = $given + .into_iter() + .map(|ul| { + let cut = ul.is_cut(); + Literal { v: ul.v.into_bytes(), cut: cut } + }) + .collect(); + let lits = create_lits(given); + let got = lits.unambiguous_prefixes(); + assert_eq!($expected, escape_lits(got.literals())); + } + }; + } + + test_unamb!(unambiguous1, vec![M("z"), M("azb")], vec![C("a"), C("z")]); + test_unamb!( + unambiguous2, + vec![M("zaaaaaa"), M("aa")], + vec![C("aa"), C("z")] + ); + test_unamb!( + unambiguous3, + vec![M("Sherlock"), M("Watson")], + vec![M("Sherlock"), M("Watson")] + ); + test_unamb!(unambiguous4, vec![M("abc"), M("bc")], vec![C("a"), C("bc")]); + test_unamb!(unambiguous5, vec![M("bc"), M("abc")], vec![C("a"), C("bc")]); + test_unamb!(unambiguous6, vec![M("a"), M("aa")], vec![C("a")]); + test_unamb!(unambiguous7, vec![M("aa"), M("a")], vec![C("a")]); + test_unamb!(unambiguous8, vec![M("ab"), M("a")], vec![C("a")]); + test_unamb!( + unambiguous9, + vec![M("ac"), M("bc"), M("c"), M("ac"), M("abc"), M("c")], + vec![C("a"), C("b"), C("c")] + ); + test_unamb!( + unambiguous10, + vec![M("Mo'"), M("Mu'"), M("Mo"), M("Mu")], + vec![C("Mo"), C("Mu")] + ); + test_unamb!( + unambiguous11, + vec![M("zazb"), M("azb")], + vec![C("a"), C("z")] + ); + test_unamb!(unambiguous12, vec![M("foo"), C("foo")], vec![C("foo")]); + test_unamb!( + unambiguous13, + vec![M("ABCX"), M("CDAX"), M("BCX")], + vec![C("A"), C("BCX"), C("CD")] + ); + test_unamb!( + unambiguous14, + vec![M("IMGX"), M("MVIX"), M("MGX"), M("DSX")], + vec![M("DSX"), C("I"), C("MGX"), C("MV")] + ); + test_unamb!( + unambiguous15, + vec![M("IMG_"), M("MG_"), M("CIMG")], + vec![C("C"), C("I"), C("MG_")] + ); + + // ************************************************************************ + // Tests for suffix trimming. + // ************************************************************************ + macro_rules! test_trim { + ($name:ident, $trim:expr, $given:expr, $expected:expr) => { + #[test] + fn $name() { + let given: Vec<Literal> = $given + .into_iter() + .map(|ul| { + let cut = ul.is_cut(); + Literal { v: ul.v.into_bytes(), cut: cut } + }) + .collect(); + let lits = create_lits(given); + let got = lits.trim_suffix($trim).unwrap(); + assert_eq!($expected, escape_lits(got.literals())); + } + }; + } + + test_trim!(trim1, 1, vec![M("ab"), M("yz")], vec![C("a"), C("y")]); + test_trim!(trim2, 1, vec![M("abc"), M("abd")], vec![C("ab")]); + test_trim!(trim3, 2, vec![M("abc"), M("abd")], vec![C("a")]); + test_trim!(trim4, 2, vec![M("abc"), M("ghij")], vec![C("a"), C("gh")]); + + // ************************************************************************ + // Tests for longest common prefix. + // ************************************************************************ + + macro_rules! test_lcp { + ($name:ident, $given:expr, $expected:expr) => { + #[test] + fn $name() { + let given: Vec<Literal> = $given + .into_iter() + .map(|s: &str| Literal { + v: s.to_owned().into_bytes(), + cut: false, + }) + .collect(); + let lits = create_lits(given); + let got = lits.longest_common_prefix(); + assert_eq!($expected, escape_bytes(got)); + } + }; + } + + test_lcp!(lcp1, vec!["a"], "a"); + test_lcp!(lcp2, vec![], ""); + test_lcp!(lcp3, vec!["a", "b"], ""); + test_lcp!(lcp4, vec!["ab", "ab"], "ab"); + test_lcp!(lcp5, vec!["ab", "a"], "a"); + test_lcp!(lcp6, vec!["a", "ab"], "a"); + test_lcp!(lcp7, vec!["ab", "b"], ""); + test_lcp!(lcp8, vec!["b", "ab"], ""); + test_lcp!(lcp9, vec!["foobar", "foobaz"], "fooba"); + test_lcp!(lcp10, vec!["foobar", "foobaz", "a"], ""); + test_lcp!(lcp11, vec!["a", "foobar", "foobaz"], ""); + test_lcp!(lcp12, vec!["foo", "flub", "flab", "floo"], "f"); + + // ************************************************************************ + // Tests for longest common suffix. + // ************************************************************************ + + macro_rules! test_lcs { + ($name:ident, $given:expr, $expected:expr) => { + #[test] + fn $name() { + let given: Vec<Literal> = $given + .into_iter() + .map(|s: &str| Literal { + v: s.to_owned().into_bytes(), + cut: false, + }) + .collect(); + let lits = create_lits(given); + let got = lits.longest_common_suffix(); + assert_eq!($expected, escape_bytes(got)); + } + }; + } + + test_lcs!(lcs1, vec!["a"], "a"); + test_lcs!(lcs2, vec![], ""); + test_lcs!(lcs3, vec!["a", "b"], ""); + test_lcs!(lcs4, vec!["ab", "ab"], "ab"); + test_lcs!(lcs5, vec!["ab", "a"], ""); + test_lcs!(lcs6, vec!["a", "ab"], ""); + test_lcs!(lcs7, vec!["ab", "b"], "b"); + test_lcs!(lcs8, vec!["b", "ab"], "b"); + test_lcs!(lcs9, vec!["barfoo", "bazfoo"], "foo"); + test_lcs!(lcs10, vec!["barfoo", "bazfoo", "a"], ""); + test_lcs!(lcs11, vec!["a", "barfoo", "bazfoo"], ""); + test_lcs!(lcs12, vec!["flub", "bub", "boob", "dub"], "b"); +} |