/// <summary>
/// Creates the transitions file if it doesn't exist.
/// </summary>
private void CreateTransitionsWithMinOffsets(string fileName, Func <IStateMachineBuilder> createBuilder,
int wordLength)
{
var targetPath = Path.Combine(_workingDirectory, fileName);
if (File.Exists(targetPath))
{
return;
}
var builder = createBuilder();
var compacter = new TransitionCompacter(builder);
var minOffsets = GetMinOffsets(builder, compacter, wordLength);
var minOffsetTransitions = SubtractOffsets(builder, compacter, minOffsets, wordLength);
var lines = minOffsetTransitions.Select(t => t.ToString(CultureInfo.InvariantCulture));
File.WriteAllLines(targetPath, lines);
var offsetPath = Path.Combine(_workingDirectory, $"o_{fileName}");
var offsets = compacter.Offsets.Select(t => t.ToString(CultureInfo.InvariantCulture));
File.WriteAllLines(offsetPath, offsets);
var minOffsetPath = Path.Combine(_workingDirectory, $"m_{fileName}");
var minOffsetLines = minOffsets.Select(t => t.ToString(CultureInfo.InvariantCulture));
File.WriteAllLines(minOffsetPath, minOffsetLines);
}
private static IEnumerable <int> SubtractOffsets(IStateMachineBuilder builder, TransitionCompacter compacter,
IReadOnlyList <int> minOffsets, int wordLength)
{
var alphabet = Enumerable.Range(0, builder.AlphabetSize).ToList();
var transitionsInCurrentLevel = new HashSet <int>(builder.EntryStates.Select(e => e * builder.AlphabetSize));
var compactTransitionsInCurrentLevel =
new HashSet <int>(builder.EntryStates.Select(e => e * builder.AlphabetSize - compacter.Offsets[e]));
var transitionsWithMinOffsets = new int[compacter.Transitions.Count];
Array.Fill(transitionsWithMinOffsets, -1);
for (var i = 0; i < wordLength; ++i)
{
var statesInPreviousLevel = transitionsInCurrentLevel;
var compactStatesInPreviousLevel = compactTransitionsInCurrentLevel;
transitionsInCurrentLevel = new HashSet <int>();
compactTransitionsInCurrentLevel = new HashSet <int>();
var orderedPrevious = statesInPreviousLevel.OrderBy(x => x).ToList();
var orderedCompactPrevious = compactStatesInPreviousLevel.OrderBy(x => x).ToList();
for (var j = 0; j < orderedPrevious.Count; ++j)
{
var previous = orderedPrevious[j];
var compactPrevious = orderedCompactPrevious[j];
foreach (var c in alphabet)
{
if (builder.IsNull(previous + c))
{
continue;
}
var n = builder.Transitions[previous + c];
var m = compacter.Transitions[compactPrevious + c];
transitionsInCurrentLevel.Add(n);
compactTransitionsInCurrentLevel.Add(m);
transitionsWithMinOffsets[compactPrevious + c] = m - minOffsets[i];
}
}
}
return(transitionsWithMinOffsets);
}
private static IReadOnlyList <int> GetMinOffsets(IStateMachineBuilder builder, TransitionCompacter compacter,
int wordLength)
{
var alphabet = Enumerable.Range(0, builder.AlphabetSize).ToList();
var minOffsets = new int[wordLength];
var maxOffsets = new int[wordLength];
var transitionsInCurrentLevel = new HashSet <int>(builder.EntryStates.Select(e => e * builder.AlphabetSize));
var compactTransitionsInCurrentLevel =
new HashSet <int>(builder.EntryStates.Select(e => e * builder.AlphabetSize - compacter.Offsets[e]));
for (var i = 0; i < wordLength; ++i)
{
var transitionsInPreviousLevel = transitionsInCurrentLevel;
var compactTransitionsInPreviousLevel = compactTransitionsInCurrentLevel;
transitionsInCurrentLevel = new HashSet <int>();
compactTransitionsInCurrentLevel = new HashSet <int>();
var orderedPrevious = transitionsInPreviousLevel.OrderBy(x => x).ToList();
var orderedCompactPrevious = compactTransitionsInPreviousLevel.OrderBy(x => x).ToList();
for (var j = 0; j < orderedPrevious.Count; ++j)
{
var previous = orderedPrevious[j];
var compactPrevious = orderedCompactPrevious[j];
foreach (var c in alphabet)
{
if (builder.IsNull(previous + c))
{
continue;
}
var n = builder.Transitions[previous + c];
var m = compacter.Transitions[compactPrevious + c];
transitionsInCurrentLevel.Add(n);
compactTransitionsInCurrentLevel.Add(m);
}
}
minOffsets[i] = compactTransitionsInCurrentLevel.Min();
maxOffsets[i] = compactTransitionsInCurrentLevel.Max();
}
if (maxOffsets.Max() < ushort.MaxValue)
{
return(Enumerable.Repeat(0, wordLength).ToList());
}
var largestDistance = Enumerable.Range(0, wordLength).Max(i => maxOffsets[i] - minOffsets[i]);
for (var i = 0; i < wordLength; ++i)
{
if (maxOffsets[i] < largestDistance)
{
minOffsets[i] = 0;
}
}
return(minOffsets);
}
