/**
* Copyright (c) Karl Krukow. All rights reserved.
* The use and distribution terms for this software are covered by the
* Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
* which can be found in the file epl-v10.html at the root of this distribution.
* By using this software in any fashion, you are agreeing to be bound by
* the terms of this license.
* You must not remove this notice, or any other, from this software.
**/
package com.trifork.clj_ds;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Random;
/*
A persistent rendition of Nikolas Askitis' HAT Trie
Uses path copying for persistence
Any errors are my own
*/
@SuppressWarnings({"rawtypes","unchecked"})
public class InlineArrayPersistentHATTrie<T> extends APersistentTrie<T> implements IObj {
/**
*
*/
private static final long serialVersionUID = 6864541653381702688L;
final IPersistentMap meta;
final HATTrieNode<T> root;
final int count;
private static final int seed = new Random().nextInt();
private static final int slotPageSize = 64;
/**
* getHashCode() differs from the standard Java hashcode algorithm. It's an
* shift-add-xor class algorithm, as tested in <em>"Performance
* in Practise of String Hashing Functions"</em>, Jobel & Ramakrishna, 1997;
* and is implemented as efficiently as possible.
*/
public static int getHashCode(String inputString) {
int result = InlineArrayPersistentHATTrie.seed;
int length = inputString.length();
for (int i = 0; i < length; i++) {
result ^= ((result << 5) + inputString.charAt(i) + (result >>> 2));
}
return ((result & 0x7fffffff) & 0x1ff);
}
public static final InlineArrayPersistentHATTrie EMPTY = new InlineArrayPersistentHATTrie(null, null, 0);
public InlineArrayPersistentHATTrie(HATTrieNode root, IPersistentMap meta, int count) {
this.root = root;
this.meta = meta;
this.count = count;
}
public IPersistentMap meta() {
return meta;
}
private static interface HATTrieNode<T> {
T get(String s, int j);
Iterator<Map.Entry<String, T>> nodeIt(String prefix);
HATTrieNode add(RandomAccessChars s, int start, int end, T t);
}
private static interface ToStringWithPrefix {
String toStringWithPrefix(String prefix);
}
private static interface RandomAccessChars {
public char charAt(int index);
public int length();
}
private static class StringRandomAccessChars implements RandomAccessChars {
private final String s;
public StringRandomAccessChars(String s) {
this.s = s;
}
@Override
public char charAt(int index) {
return s.charAt(index);
}
@Override
public int length() {
return s.length();
}
}
private static class CharArrayRandomAccessChars implements RandomAccessChars {
private final char[] s;
public CharArrayRandomAccessChars(char[] s) {
this.s = s;
}
@Override
public char charAt(int index) {
return s[index];
}
@Override
public int length() {
return s.length;
}
}
private static final class AccessNode<T> implements HATTrieNode<T>,ToStringWithPrefix {
private final HATTrieNode<T> children[];
private final T emptyPtr;
public AccessNode(HATTrieNode[] children, T emptyPtr) {
this.children = children;
this.emptyPtr = emptyPtr;
}
public String toString() {
return toStringWithPrefix("");
}
public String toStringWithPrefix(String prefix) {
StringBuilder sb = new StringBuilder();
String nestedPrefix = prefix+" ";
sb.append(prefix);
sb.append("(access-node\n").append(nestedPrefix);
for (int i=0;i<children.length;i++) {
HATTrieNode node = children[i];
if (node != null) {
sb.append((char) i).append(" -> ").append(((ToStringWithPrefix) node)
.toStringWithPrefix(nestedPrefix)).append(";\n").append(nestedPrefix);
}
}
if (emptyPtr != null) {
sb.append("\n").append(prefix).append("**");
}
sb.append(prefix).append(")");
return sb.toString();
}
public HATTrieNode<T> add(RandomAccessChars s, int start, int end, T t) {
int length = s.length();
if (start < length) {
char ichar = s.charAt(start);
HATTrieNode hatTrieNode = children[ichar];
if (hatTrieNode != null) {
HATTrieNode newNode = hatTrieNode.add(s, start+1, end, t);
if (newNode == hatTrieNode) {
return this;
}
HATTrieNode[] newArr = new HATTrieNode[children.length];
System.arraycopy(children, 0, newArr, 0, children.length);
newArr[ichar] = newNode;
return new AccessNode(newArr, emptyPtr);
}
ContainerNode c = singletonContainer(s,start+1, end, t);
HATTrieNode[] newArr = new HATTrieNode[children.length];
System.arraycopy(children, 0, newArr, 0, children.length);
newArr[ichar] = c;
return new AccessNode(newArr, emptyPtr);
}
if (start == length && emptyPtr == null) {
return new AccessNode(children, t);
}
return this;
}
public T get(String s, int i) {
if (i == s.length()) {
return emptyPtr;
}
HATTrieNode<T> c = children[s.charAt(i)];
if (c == null) {
return null;
}
return c.get(s, i+1);
}
private static final class AccessNodeIterator<T> implements Iterator<MapEntry<String, T>> {
private final HATTrieNode children[];
private final T emptyPtr;
private int index = -1;
private final String prefix;
Iterator<MapEntry<String, T>> current = null;
AccessNodeIterator(AccessNode<T> node, String prefix) {
children = node.children;
emptyPtr = node.emptyPtr;
this.prefix = prefix;
moveCurIfNeeded();
}
private void moveCurIfNeeded() {
if (index == -1){
if (emptyPtr == null) {
index = 0;
} else {
return;
}
}
if (current != null && current.hasNext()) return;
while (index < children.length && children[index] == null) {index += 1;};
if (index == children.length) { current = null;}
else {
String prefix = new StringBuilder(this.prefix).append((char) index).toString();
current = children[index++].nodeIt(prefix);
}
}
public boolean hasNext() {
if (index == -1 && emptyPtr != null) {
return true;
}
while (current != null && !current.hasNext()) {
moveCurIfNeeded();
}
return current != null && current.hasNext();
}
@Override
public MapEntry<String, T> next() {
if (index == -1 && emptyPtr != null) {
index = 0;
moveCurIfNeeded();
return new MapEntry<String,T>(prefix, emptyPtr);
}
return current.next();
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
@Override
public Iterator<Map.Entry<String, T>> nodeIt(String prefix) {
return new AccessNodeIterator(this,prefix);
}
}
private static final <T> ContainerNode<T> singletonContainer(RandomAccessChars s, int start,int end, T t) {
char[] strings = new char[slotPageSize];
int slen = end-start;
int k = encodeNumber(0, slen, strings);
for (int j=start;j<end;j++) {
strings[k++] = s.charAt(j);
}
strings[k++] = 0;
k = encodeNumber(k,0,strings);
return new ContainerNode<T>(strings, new Object[]{t});
}
private static final int encodeNumber(int j, int inputlength, char[] tmp) {
// Add String to end of contents array.
// First encode the length of the string (this allows us to
// skip forward rapidly in the array when string matching if we
// get an early negative)
tmp[j++] = (char)(inputlength & 0xffff);
tmp[j++] = (char)((inputlength >> 16) & 0xffff);
return j;
}
private static final class ContainerNode<T> implements HATTrieNode<T>,ToStringWithPrefix {
private final char[] contents;
private final Object[] values;
public ContainerNode(char[] strings, Object[] values) {
this.contents = strings;
this.values = values;
}
public String toString() {
return "NOTIMPLE";
}
@Override
public HATTrieNode add(RandomAccessChars s, int start, int end, T t) {
int id = getIndex(s,start,end);
if (Util.equals(values[id], t)) {
return this;
}
if (shouldBurst()) {
return burst(contents,start,end,t);
}
return addString(contents,start,end,t);
}
public T get(String s, int i) {
int idx = getIndex(new StringRandomAccessChars(s),i, s.length());
if (idx != -1) {
return (T) values[idx];
}
return null;
}
private HATTrieNode burst(RandomAccessChars s, int start, int end, T t) {
HATTrieNode[] children = new HATTrieNode[256];
int length = end-start;
T empty = s.length() == start ? t : null;
int j = 0;
length = 0;
int index = -1;
int slotlength = this.contents.length;
while (j < slotlength) {
// if there's nothing left in the slot, jump out
if (this.contents[j] == 0) { break; }
// first decode the length of the string
length = (int) (this.contents[j++] | (this.contents[j++] << 16));
if (empty == null && length == 0) {//can only happen once
j += 1;//skip 0
index = (int) (this.contents[j++] | (this.contents[j++] << 16));
empty = (T) this.values[index];
} else {
char f = this.contents[j++];
children[f] = addToNode(children[f],this.contents,j,length,this.values);
}
j += length + 3;
}
if (empty != t) {//i < s.length()
char f = s.charAt(start);
children[f] = addToNode(children[f],s,start+1,end,t);
}
return new AccessNode(children, empty);
}
private HATTrieNode burst(char[] s, int start, int end, T t) {
HATTrieNode[] children = new HATTrieNode[256];
T empty = (end == start) ? t : null;
int j = 0;
int length = 0;
int index = -1;
int slotlength = this.contents.length;
while (j < slotlength) {
// if there's nothing left in the slot, jump out
if (this.contents[j] == 0) { break; }
// first decode the length of the string
length = (int) (this.contents[j++] | (this.contents[j++] << 16));
if (empty == null && length == 0) {//can only happen once
j += 1;//skip 0
index = (int) (this.contents[j++] | (this.contents[j++] << 16));
empty = (T) this.values[index];
} else {
char f = this.contents[j++];
children[f] = addToNode(children[f],this.contents,j,length,this.values);
}
j += length + 3;
}
if (empty != t) {//i < s.length()
char f = s[start];
children[f] = addToNode(children[f],s,start+1,(end-start-1), values);
}
return new AccessNode(children, empty);
}
private static final <T> HATTrieNode addToNode(HATTrieNode hatTrieNode, char[] contents, int j, int length, Object[] values) {
int idIndex = j + length + 1;
int id = (int) (contents[idIndex++] | (contents[idIndex++] << 16));;
if (hatTrieNode == null) {
char[] newcontents = new char[InlineArrayPersistentHATTrie.slotPageSize];
int nextindex = encodeNumber(0, length, newcontents);
System.arraycopy(contents, j, newcontents, nextindex++, length);
newcontents[nextindex++] = 0;
return new ContainerNode<T>(newcontents, new Object[]{values[id]});
} else {
return hatTrieNode.add(new CharArrayRandomAccessChars(contents), j,j+length, (T) values[id]);
}
}
private static final <T> HATTrieNode addToNode(HATTrieNode hatTrieNode, RandomAccessChars s, int start, int end, T t) {
if (hatTrieNode == null) {
return singletonContainer(s, start,end, t);
} else {
return hatTrieNode.add(s, start,end,t);
}
}
private ContainerNode<T> addString(String inputString, int index, T t)
{
int j = 0;
int k = 0;
int length = 0;
int slotlength = this.contents.length;
int inputlength = inputString.length()-index;
boolean match = false;
while (j < slotlength) {
// if there's nothing left in the slot, jump out and return -1
if (this.contents[j] == 0) { break; }
match = true;
// first decode the length of the string
length = (int) (this.contents[j++] | (this.contents[j++] << 16));
// if the length does not match, then don't bother checking the characters
if (inputlength != length) {
match = false;
} else {
// then start checking, character by character until we hit
// the null terminator to see if we have a match.
int strIdx = index;
for (k = j; this.contents[k] != 0; k++) {
if (this.contents[k] != inputString.charAt(strIdx++)) {
// if we find we do not have a match, it'll happen
// earlier than finding we do, so jump right out of
// the loop.
match = false;
break;
}
}
k++;
}
// If we found the string, we don't bother to add it, we
// just return back.
if (match) return this;
// skip ahead to the next string in the array and do it again.
j += length + 3;
}
// Do we need to grow this slot in the array? If so, do so
// now...
char tmp[] = this.contents;
int newslotlength = slotlength;
while ((newslotlength - inputlength) < (j+5)) {
tmp = new char[newslotlength + InlineArrayPersistentHATTrie.slotPageSize];
System.arraycopy(this.contents, 0, tmp, 0, newslotlength);
newslotlength = tmp.length;
}
j = encodeNumber(j, inputlength, tmp);
// Now copy over the inputString characters
System.arraycopy(inputString, 0, tmp, j, inputlength);
j += inputlength;
// null-terminate
tmp[j++] = 0;
// Now encode the id int after the null termination.
encodeNumber(j, values.length, tmp);
Object[] newValues = new Object[values.length+1];
System.arraycopy(values, 0, newValues, 0, values.length);
newValues[values.length] = t;
return new ContainerNode<T>(tmp, values);
}
private ContainerNode<T> addString(char[] inputString, int start, int end, T t)
{
int j = 0;
int k = 0;
int length = 0;
int slotlength = this.contents.length;
int inputlength = end-start;
boolean match = false;
while (j < slotlength) {
// if there's nothing left in the slot, jump out and return -1
if (this.contents[j] == 0) { break; }
match = true;
// first decode the length of the string
length = (int) (this.contents[j++] | (this.contents[j++] << 16));
// if the length does not match, then don't bother checking the characters
if (inputlength != length) {
match = false;
} else {
// then start checking, character by character until we hit
// the null terminator to see if we have a match.
int strIdx = start;
for (k = j; this.contents[k] != 0; k++) {
if (this.contents[k] != inputString[strIdx++]) {
// if we find we do not have a match, it'll happen
// earlier than finding we do, so jump right out of
// the loop.
match = false;
break;
}
}
k++;
}
// If we found the string, we don't bother to add it, we
// just return back.
if (match) return this;
// skip ahead to the next string in the array and do it again.
j += length + 3;
}
// Do we need to grow this slot in the array? If so, do so
// now...
char tmp[] = this.contents;
int newslotlength = slotlength;
while ((newslotlength - inputlength) < (j+5)) {
tmp = new char[newslotlength + InlineArrayPersistentHATTrie.slotPageSize];
System.arraycopy(this.contents, 0, tmp, 0, newslotlength);
newslotlength = tmp.length;
}
j = encodeNumber(j, inputlength, tmp);
// Now copy over the inputString characters
System.arraycopy(inputString, 0, tmp, j, inputlength);
j += inputlength;
// null-terminate
tmp[j++] = 0;
// Now encode the id int after the null termination.
encodeNumber(j, values.length, tmp);
Object[] newValues = new Object[values.length+1];
System.arraycopy(values, 0, newValues, 0, values.length);
newValues[values.length] = t;
return new ContainerNode<T>(tmp, values);
}
public int getIndex(RandomAccessChars input, int start, int end)
{
int j = 0;
int k = 0;
int length = 0;
int inputlength = end-start;
int slotlength = this.contents.length;
boolean match = false;
while (j < slotlength) {
// if there's nothing left in the slot, jump out and return -1
if (this.contents[j] == 0) { break; }
match = true;
// first decode the length of the string
length = (int) (this.contents[j++] | (this.contents[j++] << 16));
// if the length does not match, then don't bother checking the characters
if (inputlength != length) {
match = false;
} else {
// then start checking, character by character until we hit
// the null terminator to see if we have a match.
int strIdx = start;
for (k = j; this.contents[k] != 0; k++) {
if (this.contents[k] != input.charAt(strIdx++)) {
// if we find we do not have a match, it'll happen
// earlier than finding we do, so jump right out of
// the loop.
match = false;
break;
}
}
k++;
}
// If we did find a match, return the id int.
if (match) {
return (int) (this.contents[k++] | (this.contents[k] << 16));
}
// skip ahead to the next string in the array and do it again.
j += length + 3;
}
return -1;
}
private boolean shouldBurst() {
return values.length == 4;
}
@Override
public Iterator<Map.Entry<String, T>> nodeIt(final String prefix) {
return new Iterator<Map.Entry<String, T>>() {
int j = 0;
@Override
public boolean hasNext() {
return ContainerNode.this.contents[j] == 0;
}
@Override
public Map.Entry<String, T> next() {
int length = (int) (ContainerNode.this.contents[j++] | (ContainerNode.this.contents[j++] << 16));
char[] str = new char[length];
int i = 0;
while (i<length) {
str[i++] = ContainerNode.this.contents[j++];
}
j++;//skip 0 terminating char
String key = new String(str);
int idx = (int) (ContainerNode.this.contents[j++] | (ContainerNode.this.contents[j++] << 16));
return new MapEntry(key, ContainerNode.this.values[idx]);
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override
public String toStringWithPrefix(String prefix) {
return prefix+toString();
}
}
@Override
public T getMember(String s) {
if (root == null || s == null) return null;
return root.get(s,0);
}
@Override
public IPersistentTrie<T> addMember(String s, T t) {
if (root == null) {
return new InlineArrayPersistentHATTrie(singletonContainer(new StringRandomAccessChars(s), 0,s.length(), t),null,1);
}
HATTrieNode<T> newRoot = root.add(new StringRandomAccessChars(s), 0,s.length(),t);
if (root == newRoot) {
return this;
}
return new InlineArrayPersistentHATTrie(newRoot,meta,count+1);
}
@Override
public IPersistentSet disjoin(Object key) throws Exception {
throw new UnsupportedOperationException();
}
@Override
public boolean contains(Object key) {
return (key instanceof String) && getMember((String) key) != null;
}
@Override
public Boolean get(Object key) {
return contains(key);
}
@Override
public int count() {
return count;
}
@Override
public IPersistentCollection cons(Object o) {
if (!(o instanceof Map.Entry)) {
throw new IllegalArgumentException("Only adding strings is supported");
}
Map.Entry<String, T> e = (Entry<String, T>) o;
return (IPersistentCollection) this.addMember(e.getKey(),e.getValue());
}
@Override
public IPersistentCollection empty() {
return EMPTY;
}
@Override
public Iterator<Map.Entry<String, T>> iterator() {
return root != null ? root.nodeIt("") : new EmptyIterator();
}
@Override
public ISeq<String> seq() {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean containsAll(Collection<?> c) {
for (Object o : c) {
if (!contains(o)) {
return false;
}
}
return true;
}
@Override
public boolean removeAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(Collection<?> c) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
@Override
public IObj withMeta(IPersistentMap meta) {
return new InlineArrayPersistentHATTrie(root,meta,count);
}
@Override
public String toString() {
if (root == null) {return "{}";}
return root.toString();
}
@Override
public boolean add(Entry<String, T> e) {
throw new UnsupportedOperationException();
}
@Override
public boolean addAll(Collection<? extends Entry<String, T>> c) {
throw new UnsupportedOperationException();
}
}