/// <summary>
/// Returns index position
/// </summary>
/// <param name="text"></param>
/// <returns></returns>
public int Store(ReadOnlySpan <char> text)
{
int hash = hashSequence(text);
int foundPos = findByHash(hash, text);
if (foundPos != -1)
{
return(foundPos);
}
int pos = charBuffer.Store(text);
if (pos == -1)
{
int newSize = charBuffer.Capacity * 2;
if (newSize < text.Length + charBuffer.Capacity + 2) // Allow 2 for null terminators
{
newSize = charBuffer.Capacity + text.Length + 2;
}
charBuffer.Resize(newSize);
pos = charBuffer.Store(text);
if (pos == -1)
{
throw new Exception("Resizing charBuffer didn't give us enough space");
}
}
if (!chainedLookup.Store(hash, pos))
{
rebuildLookup();
chainedLookup.Store(hash, pos);
}
return(pos);
}
private void rebuildLookup()
{
// Doubling capacity will halve the number of moduloed hash collisions
var newLookup = new HashBucket(chainedLookup.Capacity * 2, linearSearchLimit);
// Populate a new lookup from our existing data.
foreach (var itm in charBuffer)
{
if (!newLookup.Store(hashSequence(itm.Span), itm.Pos))
{
throw new Exception($"Too many hash collisions. Increase {nameof(LinearSearchLimit)} to overcome.");
}
}
// Use the new lookup
chainedLookup = newLookup;
}
private void rebuildBuckets()
{
var newBuckets = new HashBucket(buckets.Capacity * 2, buckets.MaxChain);
for (int idx = 0; idx < entries.Count; idx++)
{
var hashCode = newHashCode();
foreach (var textRef in chain(idx).Reverse())
{
var text = buf.Retrieve(textRef);
foreach (var elem in text)
{
hashCode.Add(elem);
}
}
int hash = hashCode.ToHashCode();
newBuckets.Store(hash, idx);
}
this.buckets = newBuckets;
}
