Started rewrite of matching algorithm, got concatenation and alternation done, kleene and zero-state stuff is next
This commit is contained in:
@@ -1,7 +1,6 @@
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package regex
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import (
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"container/heap"
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"fmt"
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"slices"
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"sort"
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@@ -267,16 +266,15 @@ func findAllSubmatchHelper(start *nfaState, str []rune, offset int, numGroups in
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// chosen as the match for the entire string.
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// This allows us to pick the longest possible match (which is how greedy matching works).
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// COMMENT ABOVE IS CURRENTLY NOT UP-TO-DATE
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tempIndices := newMatch(numGroups + 1)
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// tempIndices := newMatch(numGroups + 1)
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foundPath := false
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startIdx := offset
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endIdx := offset
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currentStates := &priorityQueue{}
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heap.Init(currentStates)
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tempStates := make([]*nfaState, 0) // Used to store states that should be used in next loop iteration
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i := offset // Index in string
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startingFrom := i // Store starting index
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// foundPath := false
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//startIdx := offset
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//endIdx := offset
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currentStates := make([]*nfaState, 0)
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// tempStates := make([]*nfaState, 0) // Used to store states that should be used in next loop iteration
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i := offset // Index in string
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//startingFrom := i // Store starting index
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// If the first state is an assertion, makes sure the assertion
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// is true before we do _anything_ else.
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@@ -287,214 +285,266 @@ func findAllSubmatchHelper(start *nfaState, str []rune, offset int, numGroups in
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}
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}
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// Increment until we hit a character matching the start state (assuming not 0-state)
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if start.isEmpty == false {
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for i < len(str) && !start.contentContains(str, i) {
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i++
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}
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startIdx = i
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startingFrom = i
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i++ // Advance to next character (if we aren't at a 0-state, which doesn't match anything), so that we can check for transitions. If we advance at a 0-state, we will never get a chance to match the first character
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}
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// if start.isEmpty == false {
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// for i < len(str) && !start.contentContains(str, i) {
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// i++
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// }
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// startIdx = i
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// startingFrom = i
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// i++ // Advance to next character (if we aren't at a 0-state, which doesn't match anything), so that we can check for transitions. If we advance at a 0-state, we will never get a chance to match the first character
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// }
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start.threadGroups = newMatch(numGroups + 1)
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// start.threadGroups = newMatch(numGroups + 1)
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// Check if the start state begins a group - if so, add the start index to our list
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if start.groupBegin {
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start.threadGroups[start.groupNum].StartIdx = i
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// tempIndices[start.groupNum].startIdx = i
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}
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//if start.groupBegin {
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// start.threadGroups[start.groupNum].StartIdx = i
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// tempIndices[start.groupNum].startIdx = i
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//}
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start.threadSP = i
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heap.Push(currentStates, newPriorQueueItem(start))
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currentStates = append(currentStates, start)
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var foundMatch bool
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// Main loop
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for currentStates.Len() > 0 {
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currentState := heap.Pop(currentStates)
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foundPath = false
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for len(currentStates) > 0 {
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currentState, _ := pop(¤tStates)
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idx := currentState.threadSP
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foundMatch = false
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zeroStates := make([]*nfaState, 0)
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// Keep taking zero-states, until there are no more left to take
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// Objective: If any of our current states have transitions to 0-states, replace them with the 0-state. Do this until there are no more transitions to 0-states, or there are no more unique 0-states to take.
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topStateItem := currentStates.peek()
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topState := topStateItem.(*priorQueueItem).state
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zeroStates, isZero := takeZeroState([]*nfaState{topState}, numGroups, i)
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tempStates = append(tempStates, zeroStates...)
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num_appended := 0
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for isZero == true {
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zeroStates, isZero = takeZeroState(tempStates, numGroups, i)
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tempStates, num_appended = uniqueAppend(tempStates, zeroStates...)
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if num_appended == 0 { // Break if we haven't appended any more unique values
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break
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}
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if currentState.threadGroups == nil {
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currentState.threadGroups = newMatch(numGroups + 1)
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currentState.threadGroups[0].StartIdx = idx
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}
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if isZero == true {
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currentStates.Pop()
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}
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for _, state := range tempStates {
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heap.Push(currentStates, newPriorQueueItem(state))
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}
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tempStates = nil
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// Take any transitions corresponding to current character
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numStatesMatched := 0 // The number of states which had at least 1 match for this round
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assertionFailed := false // Whether or not an assertion failed for this round
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lastStateInList := false // Whether or not a last state was in our list of states
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var lastStatePtr *nfaState = nil // Pointer to the last-state, if it was found
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lastLookaroundInList := false // Whether or not a last state (that is a lookaround) was in our list of states
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for numStatesMatched == 0 && lastStateInList == false {
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if currentStates.Len() == 0 {
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break
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if currentState.groupBegin {
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currentState.threadGroups[currentState.groupNum].StartIdx = idx
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} else if currentState.groupEnd {
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currentState.threadGroups[currentState.groupNum].EndIdx = idx
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} else if currentState.isKleene {
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// Append the
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} else if currentState.isAlternation {
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rightState := currentState.rightState
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rightState.threadGroups = currentState.threadGroups
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rightState.threadSP = currentState.threadSP
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currentStates = append(currentStates, currentState.rightState)
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leftState := currentState.leftState
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leftState.threadGroups = currentState.threadGroups
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leftState.threadSP = currentState.threadSP
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currentStates = append(currentStates, currentState.leftState)
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continue
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} else if currentState.contentContains(str, idx) {
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foundMatch = true
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allMatches := make([]*nfaState, 0)
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for _, v := range currentState.transitions {
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allMatches = append(allMatches, v...)
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}
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stateItem := heap.Pop(currentStates)
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state := stateItem.(*priorQueueItem).state
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matches, numMatches := state.matchesFor(str, i)
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if numMatches > 0 {
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numStatesMatched++
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tempStates = append([]*nfaState(nil), matches...)
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foundPath = true
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for _, m := range matches {
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if m.threadGroups == nil {
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m.threadGroups = newMatch(numGroups + 1)
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}
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m.threadSP = state.threadSP + 1
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copy(m.threadGroups, state.threadGroups)
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}
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}
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if numMatches < 0 {
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assertionFailed = true
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}
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if state.isLast {
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if state.isLookaround() {
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lastLookaroundInList = true
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}
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lastStateInList = true
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lastStatePtr = state
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}
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}
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if assertionFailed && numStatesMatched == 0 { // Nothing has matched and an assertion has failed
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// If I'm being completely honest, I'm not sure why I have to check specifically for a _lookaround_
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// state. The explanation below is my attempt to explain this behavior.
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// If you replace 'lastLookaroundInList' with 'lastStateInList', one of the test cases fails.
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//
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// One of the states in our list was a last state and a lookaround. In this case, we
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// don't abort upon failure of the assertion, because we have found
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// another path to a final state.
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// Even if the last state _was_ an assertion, we can use the previously
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// saved indices to find a match.
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if lastLookaroundInList {
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break
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} else {
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if i == startingFrom {
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i++
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}
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return false, []Group{}, i
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}
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}
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// Check if we can find a state in our list that is:
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// a. A last-state
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// b. Empty
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// c. Doesn't assert anything
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for _, stateItem := range *currentStates {
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s := stateItem.state
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if s.isLast && s.isEmpty && s.assert == noneAssert {
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lastStatePtr = s
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lastStateInList = true
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}
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}
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if lastStateInList && numStatesMatched == 0 { // A last-state was in the list of states. add the matchIndex to our MatchIndex list
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for j := 1; j < numGroups+1; j++ {
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tempIndices[j] = lastStatePtr.threadGroups[j]
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}
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endIdx = i
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tempIndices[0] = Group{startIdx, endIdx}
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if tempIndices[0].StartIdx == tempIndices[0].EndIdx {
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return true, tempIndices, tempIndices[0].EndIdx + 1
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} else {
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return true, tempIndices, tempIndices[0].EndIdx
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}
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}
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// Check if we can find a zero-length match
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if foundPath == false {
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currentStatesList := funcMap(*currentStates, func(item *priorQueueItem) *nfaState {
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return item.state
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})
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if ok := zeroMatchPossible(str, i, numGroups, currentStatesList...); ok {
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if tempIndices[0].IsValid() == false {
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tempIndices[0] = Group{startIdx, startIdx}
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}
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}
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// If we haven't moved in the string, increment the counter by 1
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// to ensure we don't keep trying the same string over and over.
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// if i == startingFrom {
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startIdx++
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// i++
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// }
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if tempIndices.numValidGroups() > 0 && tempIndices[0].IsValid() {
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if tempIndices[0].StartIdx == tempIndices[0].EndIdx { // If we have a zero-length match, we have to shift the index at which we start. Otherwise we keep looking at the same paert of the string over and over.
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return true, tempIndices, tempIndices[0].EndIdx + 1
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slices.Reverse(allMatches)
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for _, m := range allMatches {
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m.threadGroups = currentState.threadGroups
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if currentState.assert == noneAssert {
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m.threadSP = idx + 1
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} else {
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return true, tempIndices, tempIndices[0].EndIdx
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m.threadSP = idx
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}
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}
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return false, []Group{}, startIdx
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currentStates = append(currentStates, allMatches...)
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}
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currentStates = &priorityQueue{}
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slices.Reverse(tempStates)
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for _, state := range tempStates {
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heap.Push(currentStates, newPriorQueueItem(state))
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}
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tempStates = nil
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i++
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}
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if currentState.isLast && foundMatch { // Last state reached
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currentState.threadGroups[0].EndIdx = idx + 1
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return true, currentState.threadGroups, idx + 1
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// End-of-string reached. Go to any 0-states, until there are no more 0-states to go to. Then check if any of our states are in the end position.
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// This is the exact same algorithm used inside the loop, so I should probably put it in a function.
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if currentStates.Len() > 0 {
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topStateItem := currentStates.peek()
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topState := topStateItem.(*priorQueueItem).state
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zeroStates, isZero := takeZeroState([]*nfaState{topState}, numGroups, i)
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tempStates = append(tempStates, zeroStates...)
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num_appended := 0 // Number of unique states addded to tempStates
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for isZero == true {
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zeroStates, isZero = takeZeroState(tempStates, numGroups, i)
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tempStates, num_appended = uniqueAppend(tempStates, zeroStates...)
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if num_appended == 0 { // Break if we haven't appended any more unique values
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break
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}
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}
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}
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for _, state := range tempStates {
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heap.Push(currentStates, newPriorQueueItem(state))
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}
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tempStates = nil
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for _, stateItem := range *currentStates {
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state := stateItem.state
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// Only add the match if the start index is in bounds. If the state has an assertion,
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// make sure the assertion checks out.
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if state.isLast && i <= len(str) {
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if state.assert == noneAssert || state.checkAssertion(str, i) {
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for j := 1; j < numGroups+1; j++ {
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tempIndices[j] = state.threadGroups[j]
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}
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endIdx = i
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tempIndices[0] = Group{startIdx, endIdx}
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}
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}
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}
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if tempIndices.numValidGroups() > 0 {
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if tempIndices[0].StartIdx == tempIndices[0].EndIdx { // If we have a zero-length match, we have to shift the index at which we start. Otherwise we keep looking at the same paert of the string over and over.
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return true, tempIndices, tempIndices[0].EndIdx + 1
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} else {
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return true, tempIndices, tempIndices[0].EndIdx
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}
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}
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if startIdx == startingFrom { // Increment starting index if we haven't moved in the string. Prevents us from matching the same part of the string over and over.
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startIdx++
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}
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return false, []Group{}, startIdx
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return false, []Group{}, i + 1
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// zeroStates := make([]*nfaState, 0)
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// // Keep taking zero-states, until there are no more left to take
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// // Objective: If any of our current states have transitions to 0-states, replace them with the 0-state. Do this until there are no more transitions to 0-states, or there are no more unique 0-states to take.
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// topStateItem := currentStates.peek()
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// topState := topStateItem.(*priorQueueItem).state
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// zeroStates, isZero := takeZeroState([]*nfaState{topState}, numGroups, i)
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// tempStates = append(tempStates, zeroStates...)
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// num_appended := 0
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// for isZero == true {
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// zeroStates, isZero = takeZeroState(tempStates, numGroups, i)
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// tempStates, num_appended = uniqueAppend(tempStates, zeroStates...)
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// if num_appended == 0 { // Break if we haven't appended any more unique values
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// break
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// }
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// }
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// if isZero == true {
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// currentStates.Pop()
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// }
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//
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// for _, state := range tempStates {
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// heap.Push(currentStates, newPriorQueueItem(state))
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// }
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// tempStates = nil
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//
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// // Take any transitions corresponding to current character
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// numStatesMatched := 0 // The number of states which had at least 1 match for this round
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// assertionFailed := false // Whether or not an assertion failed for this round
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// lastStateInList := false // Whether or not a last state was in our list of states
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// var lastStatePtr *nfaState = nil // Pointer to the last-state, if it was found
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// lastLookaroundInList := false // Whether or not a last state (that is a lookaround) was in our list of states
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// for numStatesMatched == 0 && lastStateInList == false {
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// if currentStates.Len() == 0 {
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// break
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// }
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// stateItem := heap.Pop(currentStates)
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// state := stateItem.(*priorQueueItem).state
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// matches, numMatches := state.matchesFor(str, i)
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// if numMatches > 0 {
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// numStatesMatched++
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// tempStates = append([]*nfaState(nil), matches...)
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// foundPath = true
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// for _, m := range matches {
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// if m.threadGroups == nil {
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// m.threadGroups = newMatch(numGroups + 1)
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// }
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// m.threadSP = state.threadSP + 1
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// copy(m.threadGroups, state.threadGroups)
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// }
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// }
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// if numMatches < 0 {
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// assertionFailed = true
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// }
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// if state.isLast {
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// if state.isLookaround() {
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// lastLookaroundInList = true
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// }
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// lastStateInList = true
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// lastStatePtr = state
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// }
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// }
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//
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// if assertionFailed && numStatesMatched == 0 { // Nothing has matched and an assertion has failed
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// // If I'm being completely honest, I'm not sure why I have to check specifically for a _lookaround_
|
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// // state. The explanation below is my attempt to explain this behavior.
|
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// // If you replace 'lastLookaroundInList' with 'lastStateInList', one of the test cases fails.
|
||||
// //
|
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// // One of the states in our list was a last state and a lookaround. In this case, we
|
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// // don't abort upon failure of the assertion, because we have found
|
||||
// // another path to a final state.
|
||||
// // Even if the last state _was_ an assertion, we can use the previously
|
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// // saved indices to find a match.
|
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// if lastLookaroundInList {
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// break
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// } else {
|
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// if i == startingFrom {
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// i++
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// }
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// return false, []Group{}, i
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// }
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// }
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// // Check if we can find a state in our list that is:
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// // a. A last-state
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// // b. Empty
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// // c. Doesn't assert anything
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// for _, stateItem := range *currentStates {
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// s := stateItem.state
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// if s.isLast && s.isEmpty && s.assert == noneAssert {
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// lastStatePtr = s
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// lastStateInList = true
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// }
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// }
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// if lastStateInList && numStatesMatched == 0 { // A last-state was in the list of states. add the matchIndex to our MatchIndex list
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// for j := 1; j < numGroups+1; j++ {
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// tempIndices[j] = lastStatePtr.threadGroups[j]
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// }
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// endIdx = i
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// tempIndices[0] = Group{startIdx, endIdx}
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// if tempIndices[0].StartIdx == tempIndices[0].EndIdx {
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// return true, tempIndices, tempIndices[0].EndIdx + 1
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// } else {
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// return true, tempIndices, tempIndices[0].EndIdx
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// }
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// }
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//
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// // Check if we can find a zero-length match
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// if foundPath == false {
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// currentStatesList := funcMap(*currentStates, func(item *priorQueueItem) *nfaState {
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// return item.state
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// })
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// if ok := zeroMatchPossible(str, i, numGroups, currentStatesList...); ok {
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// if tempIndices[0].IsValid() == false {
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// tempIndices[0] = Group{startIdx, startIdx}
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// }
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// }
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// // If we haven't moved in the string, increment the counter by 1
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// // to ensure we don't keep trying the same string over and over.
|
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// // if i == startingFrom {
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// startIdx++
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// // i++
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// // }
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// if tempIndices.numValidGroups() > 0 && tempIndices[0].IsValid() {
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// if tempIndices[0].StartIdx == tempIndices[0].EndIdx { // If we have a zero-length match, we have to shift the index at which we start. Otherwise we keep looking at the same paert of the string over and over.
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// return true, tempIndices, tempIndices[0].EndIdx + 1
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// } else {
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// return true, tempIndices, tempIndices[0].EndIdx
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// }
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// }
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// return false, []Group{}, startIdx
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// }
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// currentStates = &priorityQueue{}
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// slices.Reverse(tempStates)
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// for _, state := range tempStates {
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// heap.Push(currentStates, newPriorQueueItem(state))
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// }
|
||||
// tempStates = nil
|
||||
//
|
||||
// i++
|
||||
// }
|
||||
//
|
||||
// // End-of-string reached. Go to any 0-states, until there are no more 0-states to go to. Then check if any of our states are in the end position.
|
||||
// // This is the exact same algorithm used inside the loop, so I should probably put it in a function.
|
||||
//
|
||||
// if currentStates.Len() > 0 {
|
||||
// topStateItem := currentStates.peek()
|
||||
// topState := topStateItem.(*priorQueueItem).state
|
||||
// zeroStates, isZero := takeZeroState([]*nfaState{topState}, numGroups, i)
|
||||
// tempStates = append(tempStates, zeroStates...)
|
||||
// num_appended := 0 // Number of unique states addded to tempStates
|
||||
// for isZero == true {
|
||||
// zeroStates, isZero = takeZeroState(tempStates, numGroups, i)
|
||||
// tempStates, num_appended = uniqueAppend(tempStates, zeroStates...)
|
||||
// if num_appended == 0 { // Break if we haven't appended any more unique values
|
||||
// break
|
||||
// }
|
||||
// }
|
||||
// }
|
||||
//
|
||||
// for _, state := range tempStates {
|
||||
// heap.Push(currentStates, newPriorQueueItem(state))
|
||||
// }
|
||||
//
|
||||
// tempStates = nil
|
||||
//
|
||||
// for _, stateItem := range *currentStates {
|
||||
// state := stateItem.state
|
||||
// // Only add the match if the start index is in bounds. If the state has an assertion,
|
||||
// // make sure the assertion checks out.
|
||||
// if state.isLast && i <= len(str) {
|
||||
// if state.assert == noneAssert || state.checkAssertion(str, i) {
|
||||
// for j := 1; j < numGroups+1; j++ {
|
||||
// tempIndices[j] = state.threadGroups[j]
|
||||
// }
|
||||
// endIdx = i
|
||||
// tempIndices[0] = Group{startIdx, endIdx}
|
||||
// }
|
||||
// }
|
||||
// }
|
||||
//
|
||||
// if tempIndices.numValidGroups() > 0 {
|
||||
// if tempIndices[0].StartIdx == tempIndices[0].EndIdx { // If we have a zero-length match, we have to shift the index at which we start. Otherwise we keep looking at the same paert of the string over and over.
|
||||
// return true, tempIndices, tempIndices[0].EndIdx + 1
|
||||
// } else {
|
||||
// return true, tempIndices, tempIndices[0].EndIdx
|
||||
// }
|
||||
// }
|
||||
//
|
||||
// if startIdx == startingFrom { // Increment starting index if we haven't moved in the string. Prevents us from matching the same part of the string over and over.
|
||||
//
|
||||
// startIdx++
|
||||
// }
|
||||
//
|
||||
// return false, []Group{}, startIdx
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user