com.signalfx.shaded.jetty.util.TreeTrie Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2019 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
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package com.signalfx.shaded.jetty.util;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* A Trie String lookup data structure using a tree
* This implementation is always case insensitive and is optimal for
* a variable number of fixed strings with few special characters.
*
* This Trie is stored in a Tree and is unlimited in capacity
*
* This Trie is not Threadsafe and contains no mutual exclusion
* or deliberate memory barriers. It is intended for an TreeTrie to be
* built by a single thread and then used concurrently by multiple threads
* and not mutated during that access. If concurrent mutations of the
* Trie is required external locks need to be applied.
*
*
* @param the entry type
*/
public class TreeTrie extends AbstractTrie
{
private static final int[] LOOKUP =
{
// 0 1 2 3 4 5 6 7 8 9 A B C D E F
/*0*/-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
/*1*/-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
/*2*/31, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 26, -1, 27, 30, -1,
/*3*/-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 28, 29, -1, -1, -1, -1,
/*4*/-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
/*5*/15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
/*6*/-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
/*7*/15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1
};
private static final int INDEX = 32;
private final TreeTrie[] _nextIndex;
private final List> _nextOther = new ArrayList<>();
private final char _c;
private String _key;
private V _value;
public TreeTrie()
{
super(true);
_nextIndex = new TreeTrie[INDEX];
_c = 0;
}
private TreeTrie(char c)
{
super(true);
_nextIndex = new TreeTrie[INDEX];
this._c = c;
}
@Override
public void clear()
{
Arrays.fill(_nextIndex, null);
_nextOther.clear();
_key = null;
_value = null;
}
@Override
public boolean put(String s, V v)
{
TreeTrie t = this;
int limit = s.length();
for (int k = 0; k < limit; k++)
{
char c = s.charAt(k);
int index = c >= 0 && c < 0x7f ? LOOKUP[c] : -1;
if (index >= 0)
{
if (t._nextIndex[index] == null)
t._nextIndex[index] = new TreeTrie(c);
t = t._nextIndex[index];
}
else
{
TreeTrie n = null;
for (int i = t._nextOther.size(); i-- > 0; )
{
n = t._nextOther.get(i);
if (n._c == c)
break;
n = null;
}
if (n == null)
{
n = new TreeTrie(c);
t._nextOther.add(n);
}
t = n;
}
}
t._key = v == null ? null : s;
t._value = v;
return true;
}
@Override
public V get(String s, int offset, int len)
{
TreeTrie t = this;
for (int i = 0; i < len; i++)
{
char c = s.charAt(offset + i);
int index = c >= 0 && c < 0x7f ? LOOKUP[c] : -1;
if (index >= 0)
{
if (t._nextIndex[index] == null)
return null;
t = t._nextIndex[index];
}
else
{
TreeTrie n = null;
for (int j = t._nextOther.size(); j-- > 0; )
{
n = t._nextOther.get(j);
if (n._c == c)
break;
n = null;
}
if (n == null)
return null;
t = n;
}
}
return t._value;
}
@Override
public V get(ByteBuffer b, int offset, int len)
{
TreeTrie t = this;
for (int i = 0; i < len; i++)
{
byte c = b.get(offset + i);
int index = c >= 0 && c < 0x7f ? LOOKUP[c] : -1;
if (index >= 0)
{
if (t._nextIndex[index] == null)
return null;
t = t._nextIndex[index];
}
else
{
TreeTrie n = null;
for (int j = t._nextOther.size(); j-- > 0; )
{
n = t._nextOther.get(j);
if (n._c == c)
break;
n = null;
}
if (n == null)
return null;
t = n;
}
}
return t._value;
}
@Override
public V getBest(byte[] b, int offset, int len)
{
TreeTrie t = this;
for (int i = 0; i < len; i++)
{
byte c = b[offset + i];
int index = c >= 0 && c < 0x7f ? LOOKUP[c] : -1;
if (index >= 0)
{
if (t._nextIndex[index] == null)
break;
t = t._nextIndex[index];
}
else
{
TreeTrie n = null;
for (int j = t._nextOther.size(); j-- > 0; )
{
n = t._nextOther.get(j);
if (n._c == c)
break;
n = null;
}
if (n == null)
break;
t = n;
}
// Is the next Trie is a match
if (t._key != null)
{
// Recurse so we can remember this possibility
V best = t.getBest(b, offset + i + 1, len - i - 1);
if (best != null)
return best;
break;
}
}
return t._value;
}
@Override
public V getBest(String s, int offset, int len)
{
TreeTrie t = this;
for (int i = 0; i < len; i++)
{
byte c = (byte)(0xff & s.charAt(offset + i));
int index = c >= 0 && c < 0x7f ? LOOKUP[c] : -1;
if (index >= 0)
{
if (t._nextIndex[index] == null)
break;
t = t._nextIndex[index];
}
else
{
TreeTrie n = null;
for (int j = t._nextOther.size(); j-- > 0; )
{
n = t._nextOther.get(j);
if (n._c == c)
break;
n = null;
}
if (n == null)
break;
t = n;
}
// Is the next Trie is a match
if (t._key != null)
{
// Recurse so we can remember this possibility
V best = t.getBest(s, offset + i + 1, len - i - 1);
if (best != null)
return best;
break;
}
}
return t._value;
}
@Override
public V getBest(ByteBuffer b, int offset, int len)
{
if (b.hasArray())
return getBest(b.array(), b.arrayOffset() + b.position() + offset, len);
return getBestByteBuffer(b, offset, len);
}
private V getBestByteBuffer(ByteBuffer b, int offset, int len)
{
TreeTrie t = this;
int pos = b.position() + offset;
for (int i = 0; i < len; i++)
{
byte c = b.get(pos++);
int index = c >= 0 && c < 0x7f ? LOOKUP[c] : -1;
if (index >= 0)
{
if (t._nextIndex[index] == null)
break;
t = t._nextIndex[index];
}
else
{
TreeTrie n = null;
for (int j = t._nextOther.size(); j-- > 0; )
{
n = t._nextOther.get(j);
if (n._c == c)
break;
n = null;
}
if (n == null)
break;
t = n;
}
// Is the next Trie is a match
if (t._key != null)
{
// Recurse so we can remember this possibility
V best = t.getBest(b, offset + i + 1, len - i - 1);
if (best != null)
return best;
break;
}
}
return t._value;
}
@Override
public String toString()
{
StringBuilder buf = new StringBuilder();
toString(buf, this);
if (buf.length() == 0)
return "{}";
buf.setCharAt(0, '{');
buf.append('}');
return buf.toString();
}
private static void toString(Appendable out, TreeTrie t)
{
if (t != null)
{
if (t._value != null)
{
try
{
out.append(',');
out.append(t._key);
out.append('=');
out.append(t._value.toString());
}
catch (IOException e)
{
throw new RuntimeException(e);
}
}
for (int i = 0; i < INDEX; i++)
{
if (t._nextIndex[i] != null)
toString(out, t._nextIndex[i]);
}
for (int i = t._nextOther.size(); i-- > 0; )
{
toString(out, t._nextOther.get(i));
}
}
}
@Override
public Set keySet()
{
Set keys = new HashSet<>();
keySet(keys, this);
return keys;
}
private static void keySet(Set set, TreeTrie t)
{
if (t != null)
{
if (t._key != null)
set.add(t._key);
for (int i = 0; i < INDEX; i++)
{
if (t._nextIndex[i] != null)
keySet(set, t._nextIndex[i]);
}
for (int i = t._nextOther.size(); i-- > 0; )
{
keySet(set, t._nextOther.get(i));
}
}
}
@Override
public boolean isFull()
{
return false;
}
}