1 // Copyright 2000-2005 the Contributors, as shown in the revision logs.
2 // Licensed under the Apache Public Source License 2.0 ("the License").
3 // You may not use this file except in compliance with the License.
7 import java.io.Serializable;
9 public interface Basket extends Serializable {
10 public boolean containsValue(Object object);
13 public void remove(Object object);
15 public interface List extends Basket {
16 public void add(Object object);
17 public void add(int index, Object object);
18 public Object set(int index, Object object);
19 public Object get(int index);
20 public Object remove(int index);
21 public int indexOf(Object object);
22 public void reverse();
23 public void sort(CompareFunc c);
26 public interface RandomAccess extends List { }
28 public interface Queue extends Basket {
29 public void enqueue(Object o);
30 public Object dequeue();
33 public interface Stack extends Basket {
36 public void push(Object object);
39 public interface Map extends Basket {
40 public boolean containsKey(Object key);
41 public Object get(Object key);
42 public Object put(Object key, Object value);
45 public interface CompareFunc {
46 public int compare(Object a, Object b);
50 // Implementations ////////////////////////////////////////////////////////
52 public class Array implements RandomAccess, Stack, Queue {
53 private static final long serialVersionUID = 1233428092L;
58 public Array() { this(10); }
59 public Array(int initialCapacity) { o = new Object[initialCapacity]; }
60 public Array(Object entry) { this(1); add(entry); }
62 public void enqueue(Object o) { add(o); }
64 // FEATURE: make this more efficient with general wraparound
65 public Object dequeue() {
66 if (size==0) return null;
68 for(int i=1; i<size; i++) o[i-1]=o[i];
72 public void add(Object obj) { add(size, obj); }
73 public void add(int i, Object obj) {
75 if (size - 1 > i) System.arraycopy(o, i, o, size, size - i - 1);
78 public Object set(int i, Object obj) {
79 if (i >= size) throw new IndexOutOfBoundsException(
80 "index "+i+" is beyond list boundary "+size);
81 Object old = o[i]; o[i] = obj; return old;
83 public Object get(int i) {
84 if (i >= size) throw new IndexOutOfBoundsException(
85 "index "+i+" is beyond list boundary "+size);
88 public Object remove(int i) {
89 if (i >= size || i < 0) throw new IndexOutOfBoundsException(
90 "index "+i+" is beyond list boundary "+size);
91 Object old = o[i]; o[i] = null;
92 if (size - 1 > i) System.arraycopy(o, i + 1, o, i, size - i - 1);
95 public void remove(Object obj) { remove(indexOf(obj)); }
97 public int indexOf(Object obj) {
98 for (int i=0; i < size; i++)
99 if ((obj == null && o[i] == null) || obj.equals(o[i])) return i;
103 public boolean containsValue(Object obj) {
104 for (int i=0; i < size; i++)
105 if ((obj == null && o[i] == null) || obj.equals(o[i])) return true;
108 public void clear() { for (int i=0; i < size; i++) o[i] = null; size = 0; }
109 public int size() { return size; }
110 public void size(int s) {
111 if (o.length >= s) return;
112 Object[] newo = new Object[s];
113 System.arraycopy(o, 0, newo, 0, size);
117 public void reverse() {
118 Object tmp; int max = (int)Math.floor((double)size / 2);
119 for (int i=0; i < size; i++) { tmp = o[i]; o[i] = o[size - i]; o[size - i] = tmp; }
122 public void sort(CompareFunc c) { sort(this, null, c, 0, size); }
124 public static void sort(Array a, Array b, CompareFunc c, int start, int end) {
125 Object tmpa, tmpb = null;
126 if(start >= end) return;
128 for(int i=start+1;i<=end;i++) {
130 if (b != null) tmpb = b.o[i];
132 for(j=i-1;j>=start;j--) {
133 if(c.compare(a.o[j],tmpa) <= 0) break;
135 if (b != null) b.o[j+1] = b.o[j];
138 if (b != null) b.o[j+1] = tmpb;
142 Object pivot = a.o[end];
146 while(c.compare(a.o[++lo],pivot) < 0) { }
147 while((hi > lo) && c.compare(a.o[--hi],pivot) > 0) { }
149 if (b != null) swap(b, lo,hi);
153 if (b != null) swap(b, lo,end);
154 sort(a, b, c, start, lo-1);
155 sort(a, b, c, lo+1, end);
158 private static final void swap(Array vec, int a, int b) {
160 Object tmp = vec.o[a];
166 public Object peek() {
167 if (size < 1) throw new IndexOutOfBoundsException("array is empty");
170 public Object pop() { return remove(size - 1); }
171 public void push(Object o) { add(o); }
174 /** Implementation of a hash table using Radke's quadratic residue
175 * linear probing. Uses a single array to store all entries.
177 * <p>See C. Radke, Communications of the ACM, 1970, 103-105</p>
179 * @author adam@ibex.org, crawshaw@ibex.org
181 public class Hash implements Basket, Map {
182 static final long serialVersionUID = 3948384093L;
184 /** Used internally to record used slots. */
185 final Object placeholder = new java.io.Serializable() { private static final long serialVersionUID = 1331L; };
187 /** When <tt>loadFactor * usedslots > num_slots</tt>, call
188 * <tt>rehash()</tt>. */
189 final float loadFactor;
191 /** Used to determine the number of array slots required by each
193 final int indexmultiple;
195 /** Number of currently active entries. */
196 private int size = 0;
198 /** Number of placeholders in entries[]. */
199 private int placeholders = 0;
201 /** Array of mappings.
203 * <p>Each map requires multiple slots in the array, and subclasses
204 * can vary the number of required slots without reimplementing all
205 * the functions of this class by changing the value of
206 * <tt>indexmultiple</tt>.</p>
208 * Default implementation uses <tt>indexmultiple == 1</tt>, and
209 * stores only the keys in <tt>entries</tt>.
211 private Object[] entries = null;
213 public Hash() { this(16, 0.75F); }
214 public Hash(int cap, float load) { this(2, cap, load); }
215 public Hash(int indexmultiple, int initialCapacity, float loadFactor) {
216 // using a pseudoprime in the form 4x+3 ensures full coverage
217 initialCapacity = (initialCapacity / 4) * 4 + 3;
218 this.loadFactor = loadFactor;
219 this.indexmultiple = indexmultiple;
220 this.entries = new Object[initialCapacity * indexmultiple];
223 public int size() { return size; }
224 public void clear() { for (int i = 0; i<entries.length; i++) entries[i] = null; size = 0; }
226 public boolean containsKey(Object k) { return indexOf(k) >= 0; }
228 /** <b>Warning:</b> This function is equivalent here to
229 * <tt>containsKey()</tt>. For a value map, use Basket.HashMap. */
230 public boolean containsValue(Object k) { return containsKey(k); }
234 public Object[] dumpkeys() {
235 Object[] ret = new Object[size];
237 for(int i=0; i<entries.length; i+=indexmultiple)
238 if (placeholder!=entries[i] && entries[i]!=null) {
239 ret[pos++] = entries[i];
244 public void remove(Object k) { remove(indexOf(k)); }
245 public void remove(int dest) {
246 if (dest < 0) return;
247 // instead of removing, insert a placeholder
248 entries[dest] = placeholder;
249 for (int inc=1; inc < indexmultiple; inc++) entries[dest + inc] = null;
254 public Object get(Object key) { return get(key, 0); }
255 public Object get(Object key, int whichval) {
256 int i = indexOf(key);
257 return i >= 0 ? entries[i + 1 + whichval] : null;
260 public Object put(Object key, Object value) { return put(key, value, 0); }
261 public Object put(Object key, Object value, int whichval) {
262 if (loadFactor * (size + placeholders) > entries.length) rehash();
263 int dest = indexOf(key);
266 dest = -1 * (dest + 1);
267 if (entries[dest] != placeholder) size++;
269 for(int i=1; i<indexmultiple; i++) entries[dest+i] = null;
271 old = entries[dest + 1 + whichval];
273 entries[dest + 1 + whichval] = value;
278 public boolean containsKey(Object k) { return super.containsValue(k); }
279 public boolean containsValue(Object v) {
280 for (int i=0; i < entries.length/indexmultiple; i++)
281 if ((i == 0 || entries[i * indexmultiple] != null) && // exception for null key
282 !equals(placeholder, entries[i * indexmultiple]) &&
283 v == null ? entries[i + 1] == null : v.equals(entries[i + 1]))
289 /** Compares two keys for equality. <tt>userKey</tt> is the key
290 * passed to the map, <tt>storedKey</tt> is from the map.
292 * <p>Default implementation provides standard Java equality
293 * testing, <tt>k1 == null ? k2 == null : k1.equals(k2)</tt>.</p>
295 protected boolean equals(Object userKey, Object storedKey) {
296 return userKey == null ? storedKey == null : userKey.equals(storedKey);
299 /** Returns the array position in <tt>entries</tt>, adjusted for
300 * <tt>indexmultiple</tt>, where <tt>k</tt> is/should be stored
301 * using Radke's quadratic residue linear probing.
303 * <p><tt>entries[0]</tt> is a hard coded exception for the null
306 * <p>If the key is not found, this function returns
307 * <tt>(-1 * indexPosition) - 1</tt>, where <tt>indexPosition</tt>
308 * is the array position where the mapping should be stored.</p>
310 * <p>Uses <tt>placeholder</tt> as a placeholder object, and
311 * compares keys using <tt>equals(Object, Object)</tt>.</p>
313 private int indexOf(Object k) {
314 // special case null key
315 if (k == null) return equals(placeholder, entries[0]) ? -1 : 0;
317 int hash = k == null ? 0 : k.hashCode();
318 final int orig = Math.abs(hash) % (entries.length / indexmultiple);
319 int dest = orig * indexmultiple;
323 while (entries[dest] != null) {
324 if (equals(k, entries[dest])) return dest;
325 dest = Math.abs((orig + (plus ? 1 : -1) * tries * tries) % (entries.length / indexmultiple)) * indexmultiple;
329 return -1 * dest - 1;
332 /** Doubles the available entry space, first by packing the data
333 * set (removes <tt>placeholder</tt> references) and if necessary
334 * by increasing the size of the <tt>entries</tt> array.
336 private void rehash() {
337 Object[] oldentries = entries;
338 entries = new Object[oldentries.length * indexmultiple];
340 for (int i=0; i < (oldentries.length/indexmultiple); i++) {
341 int pos = i * indexmultiple;
342 if (pos > 0 && oldentries[pos] == null) continue;
343 if (oldentries[pos] == placeholder) continue;
345 // dont adjust any of the support entries
346 int dest = indexOf(oldentries[pos]);
347 dest = -1 * dest - 1; size++; // always new entry
348 for (int inc=0; inc < indexmultiple; inc++)
349 entries[dest + inc] = oldentries[pos + inc];
355 // FIXME, BalancedTree goes here