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kraken/stdlib/regex.krak

271 lines
11 KiB
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import io
import string
import util
import vector
import string
import mem
import set
import util
import serialize
fun regex(in: *char):regex {
return regex(string::string(in))
}
fun regex(in: string::string):regex {
var out.construct(in):regex
return out
}
fun regexState(): regexState {
var to_ret.construct(): regexState
return to_ret
}
fun regexState(charIn: char): regexState {
var to_ret.construct(charIn): regexState
return to_ret
}
fun regexState(first: char, last: char): regexState {
var to_ret.construct(first, last): regexState
return to_ret
}
obj regexState (Object) {
// if only one character, both are the same
var characterBegin: char
var characterEnd: char
var next_states: set::set<int>
fun construct(charIn:char): *regexState {
return construct(charIn, charIn)
}
fun construct(charFirst:char, charSecond:char): *regexState {
characterBegin = charFirst
characterEnd = charSecond
next_states.construct()
return this
}
fun construct(): *regexState {
return construct((0) cast char)
}
fun copy_construct(old:*regexState): void {
characterBegin = old->characterBegin
characterEnd = old->characterEnd
next_states.copy_construct(&old->next_states)
}
fun destruct():void {
next_states.destruct()
}
fun match_char(input: char, states: ref vector::vector<regexState>, flags: *vector::vector<bool>, num_states: *int) {
next_states.for_each(fun(it:int) {
if (states[it].characterBegin <= input && input <= states[it].characterEnd) {
(*flags)[it] = true
(*num_states)++
}
})
}
fun is_end(states: ref vector::vector<regexState>):bool {
return next_states.any_true(fun(state: int):bool { return states[state].characterBegin == 1; })
}
}
obj regex (Object, Serializable) {
var regexString: string::string
var states: vector::vector<regexState>
var flagsA: vector::vector<bool>
var flagsB: vector::vector<bool>
var is_straight_string: bool
fun construct(): *regex {
regexString.construct()
states.construct()
flagsA.construct()
flagsB.construct()
is_straight_string = false
return this
}
fun construct(regexStringIn: string::string): *regex {
regexString.copy_construct(&regexStringIn)
states.construct()
is_straight_string = true
for (var i = 0; i < regexString.length(); i++;) {
// simple implementation doesn't count escaped characters as straight string
if (regexString[i] == '\\' || regexString[i] == '(' || regexString[i] == ')' || regexString[i] == '[' || regexString[i] == '*' || regexString[i] == '+' || regexString[i] == '?' || regexString[i] == '|') {
is_straight_string = false
break
}
}
if (!is_straight_string) {
var beginningAndEnd = compile(regexStringIn)
// init our begin, and the end state as the next state of each end
var end = states.size
states.add(regexState((1) cast char))
beginningAndEnd.second.for_each(fun(it: int): void { states[it].next_states.add(end); })
}
flagsA.construct(states.size); flagsA.size = states.size
flagsB.construct(states.size); flagsB.size = states.size
return this
}
fun copy_construct(old:*regex):void {
regexString.copy_construct(&old->regexString)
is_straight_string = old->is_straight_string
states.copy_construct(&old->states)
flagsA.construct(states.size); flagsA.size = states.size
flagsB.construct(states.size); flagsB.size = states.size
}
fun destruct():void {
regexString.destruct()
states.destruct()
flagsA.destruct()
flagsB.destruct()
}
fun serialize(): vector::vector<char> {
return serialize::serialize(regexString)
}
fun unserialize(it: ref vector::vector<char>, pos: int): int {
pos = regexString.unserialize(it, pos)
states.construct()
construct(regexString)
flagsA.construct(states.size); flagsA.size = states.size
flagsB.construct(states.size); flagsB.size = states.size
return pos
}
fun operator==(other: regex):bool {
return regexString == other.regexString
}
fun operator=(other: regex):void {
destruct()
copy_construct(&other)
}
fun compile(regex_string: string::string): util::pair<int, set::set<int>> {
/*io::println(regex_string)*/
var first = states.size; states.add(regexState())
var previous_begin = set::set<int>()
var previous_end = set::set<int>()
var current_begin = set::set(first)
var current_end = set::set(first)
var alternating = false
var escapeing = false
for (var i = 0; i < regex_string.length(); i++;) {
if (regex_string[i] == '*' && !escapeing) {
current_end.for_each(fun(item: int) states[item].next_states.add_all(current_begin);)
current_begin.add_all(previous_begin)
current_end.add_all(previous_end)
} else if (regex_string[i] == '+' && !escapeing) {
current_end.for_each(fun(item: int) states[item].next_states.add_all(current_begin);)
} else if (regex_string[i] == '?' && !escapeing) {
current_begin.add_all(previous_begin)
current_end.add_all(previous_end)
} else if (regex_string[i] == '|' && !escapeing) {
alternating = true
} else if (regex_string[i] == '(' && !escapeing) {
// note that we don't have a ')' case, as we skip past it with our indicies
var perenEnd = i + 1
for (var depth = 1; depth > 0; perenEnd++;) {
if (perenEnd >= regex_string.length())
util::error(string::string("can't find matching peren in: ") + regex_string)
// be careful, this isn't quite right yet
/*var not_non_special = perenEnd == 0 || (regex_string[perenEnd-1] != '\\' && regex_string[perenEnd-1] != '[' && (perenEnd+1 >= regex_string.length() || regex_string[perenEnd+1] != ']'))*/
var not_non_special = perenEnd == 0 || (regex_string[perenEnd-1] != '[' && (perenEnd+1 >= regex_string.length() || regex_string[perenEnd+1] != ']'))
if (regex_string[perenEnd] == '(' && not_non_special)
depth++
else if (regex_string[perenEnd] == ')' && not_non_special)
depth--
}
var innerBeginEnd = compile(regex_string.slice(i+1, perenEnd-1))
// NOTE: perenEnd is one past the close peren
i = perenEnd-1
if (alternating) {
previous_end.for_each(fun(it: int):void { states[it].next_states.add_all(states[innerBeginEnd.first].next_states); } )
current_begin.add_all(states[innerBeginEnd.first].next_states)
current_end.add_all(innerBeginEnd.second)
} else {
current_end.for_each(fun(it: int):void { states[it].next_states.add_all(states[innerBeginEnd.first].next_states); } )
previous_begin = current_begin
previous_end = current_end
current_begin = states[innerBeginEnd.first].next_states
current_end = innerBeginEnd.second
}
alternating = false
} else if (regex_string[i] == '\\' && !escapeing) {
escapeing = true
} else {
var next: int
if (regex_string[i] == '[' && !escapeing) {
next = states.size; states.add(regexState(regex_string[i+1], regex_string[i+3]))
i += 4 // [a-b] is 5, i++ adds one
} else {
next = states.size; states.add(regexState(regex_string[i]))
}
if (alternating) {
previous_end.for_each(fun(it: int):void { states[it].next_states.add(next); })
current_begin.add(next)
current_end.add(next)
} else {
current_end.for_each(fun(it: int):void { states[it].next_states.add(next); })
previous_begin = current_begin
previous_end = current_end
current_begin = set::set(next)
current_end = set::set(next)
}
escapeing = false
alternating = false
}
}
var beginAndEnd = util::make_pair(first, current_end)
return beginAndEnd
}
fun long_match(to_match: *char): int { return long_match(string::string(to_match)); }
fun long_match(to_match: string::string): int return long_match(to_match.getBackingMemory(), 0, to_match.length())
fun long_match(to_match: *char, position: int, end: int): int {
if (is_straight_string) {
if (regexString.length() > end-position)
return -1
for (var i = 0; i < regexString.length(); i++;)
if (regexString[i] != to_match[position+i])
return -1
return regexString.length();
}
/*var next = set::set(begin)*/
for (var i = 1; i < flagsA.size; i++;)
flagsA[i] = false;
flagsA[0] = true
var num_active = 1
var longest = -1
var flags = &flagsA
var next_flags = &flagsB
for (var i = 0; i < end-position; i++;) {
if (num_active == 0)
return longest
num_active = 0
for (var state = 0; state < flags->size; state++;) {
if ((*flags)[state] && states[state].is_end(states)) {
longest = i
break
}
}
for (var j = 0; j < next_flags->size; j++;)
(*next_flags)[j] = false;
for (var state = 0; state < flags->size; state++;)
if ((*flags)[state])
states[state].match_char(to_match[position+i], states, next_flags, &num_active)
var tmp = flags
flags = next_flags
next_flags = tmp
}
for (var state = 0; state < flags->size; state++;)
if ((*flags)[state] && states[state].is_end(states))
return end-position
return longest
}
}