Struct regex_syntax::Literals
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pub struct Literals { /* fields omitted */ }A set of literal byte strings extracted from a regular expression.
Every member of the set is a Lit, 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.
Note that 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.
Methods
impl Literals[src]
fn empty() -> Literals
Returns a new empty set of literals using default limits.
fn limit_size(&self) -> usize
Get the approximate size limit (in bytes) of this set.
fn set_limit_size(&mut self, size: usize) -> &mut Literals
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.
fn limit_class(&self) -> usize
Get the character class size limit for this set.
fn set_limit_class(&mut self, size: usize) -> &mut Literals
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.
fn literals(&self) -> &[Lit]
Returns the set of literals as a slice. Its order is unspecified.
fn min_len(&self) -> Option<usize>
Returns the length of the smallest literal.
Returns None is there are no literals in the set.
fn all_complete(&self) -> bool
Returns true if all members in this set are complete.
fn any_complete(&self) -> bool
Returns true if any member in this set is complete.
fn contains_empty(&self) -> bool
Returns true if this set contains an empty literal.
fn is_empty(&self) -> bool
Returns true if this set is empty or if all of its members is empty.
fn to_empty(&self) -> Literals
Returns a new empty set of literals using this set's limits.
fn longest_common_prefix(&self) -> &[u8]
Returns the longest common prefix of all members in this set.
fn longest_common_suffix(&self) -> &[u8]
Returns the longest common suffix of all members in this set.
fn trim_suffix(&self, num_bytes: usize) -> Option<Literals>
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.
fn unambiguous_prefixes(&self) -> Literals
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.
fn unambiguous_suffixes(&self) -> Literals
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.
fn union_prefixes(&mut self, expr: &Expr) -> bool
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.
fn union_suffixes(&mut self, expr: &Expr) -> bool
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.
fn union(&mut self, lits: Literals) -> bool
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.
fn cross_product(&mut self, lits: &Literals) -> bool
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.
fn cross_add(&mut self, bytes: &[u8]) -> bool
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.
fn add(&mut self, lit: Lit) -> bool
Adds the given literal to this set.
Returns false if adding this literal would cause the class to be too big.
fn add_char_class(&mut self, cls: &CharClass) -> bool
Extends each literal in this set with the character class given.
Returns false if the character class was too big to add.
fn add_byte_class(&mut self, cls: &ByteClass) -> bool
Extends each literal in this set with the byte class given.
Returns false if the byte class was too big to add.
fn cut(&mut self)
Cuts every member of this set. When a member is cut, it can never be extended.
fn reverse(&mut self)
Reverses all members in place.
fn clear(&mut self)
Clears this set of all members.
Trait Implementations
impl Clone for Literals[src]
fn clone(&self) -> Literals
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)1.0.0
Performs copy-assignment from source. Read more
impl Eq for Literals[src]
impl PartialEq for Literals[src]
fn eq(&self, __arg_0: &Literals) -> bool
This method tests for self and other values to be equal, and is used by ==. Read more
fn ne(&self, __arg_0: &Literals) -> bool
This method tests for !=.