persistence.antlr.collections.impl.BitSet Maven / Gradle / Ivy
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package persistence.antlr.collections.impl;
/* ANTLR Translator Generator
* Project led by Terence Parr at http://www.jGuru.com
* Software rights: http://www.antlr.org/license.html
*
*/
import persistence.antlr.CharFormatter;
/**A BitSet to replace java.util.BitSet.
* Primary differences are that most set operators return new sets
* as opposed to oring and anding "in place". Further, a number of
* operations were added. I cannot contain a BitSet because there
* is no way to access the internal bits (which I need for speed)
* and, because it is final, I cannot subclass to add functionality.
* Consider defining set degree. Without access to the bits, I must
* call a method n times to test the ith bit...ack!
*
* Also seems like or() from util is wrong when size of incoming set is bigger
* than this.bits.length.
*
* @author Terence Parr
* @author
Pete Wells
*/
public class BitSet implements Cloneable {
protected final static int BITS = 64; // number of bits / long
protected final static int NIBBLE = 4;
protected final static int LOG_BITS = 6; // 2^6 == 64
/* We will often need to do a mod operator (i mod nbits). Its
* turns out that, for powers of two, this mod operation is
* same as (i & (nbits-1)). Since mod is slow, we use a
* precomputed mod mask to do the mod instead.
*/
protected final static int MOD_MASK = BITS - 1;
/** The actual data bits */
protected long bits[];
/** Construct a bitset of size one word (64 bits) */
public BitSet() {
this(BITS);
}
/** Construction from a static array of longs */
public BitSet(long[] bits_) {
bits = bits_;
}
/** Construct a bitset given the size
* @param nbits The size of the bitset in bits
*/
public BitSet(int nbits) {
bits = new long[((nbits - 1) >> LOG_BITS) + 1];
}
/** or this element into this set (grow as necessary to accommodate) */
public void add(int el) {
//System.out.println("add("+el+")");
int n = wordNumber(el);
//System.out.println("word number is "+n);
//System.out.println("bits.length "+bits.length);
if (n >= bits.length) {
growToInclude(el);
}
bits[n] |= bitMask(el);
}
public BitSet and(BitSet a) {
BitSet s = (BitSet)this.clone();
s.andInPlace(a);
return s;
}
public void andInPlace(BitSet a) {
int min = Math.min(bits.length, a.bits.length);
for (int i = min - 1; i >= 0; i--) {
bits[i] &= a.bits[i];
}
// clear all bits in this not present in a (if this bigger than a).
for (int i = min; i < bits.length; i++) {
bits[i] = 0;
}
}
private final static long bitMask(int bitNumber) {
int bitPosition = bitNumber & MOD_MASK; // bitNumber mod BITS
return 1L << bitPosition;
}
public void clear() {
for (int i = bits.length - 1; i >= 0; i--) {
bits[i] = 0;
}
}
public void clear(int el) {
int n = wordNumber(el);
if (n >= bits.length) { // grow as necessary to accommodate
growToInclude(el);
}
bits[n] &= ~bitMask(el);
}
public Object clone() {
BitSet s;
try {
s = (BitSet)super.clone();
s.bits = new long[bits.length];
System.arraycopy(bits, 0, s.bits, 0, bits.length);
}
catch (CloneNotSupportedException e) {
throw new InternalError();
}
return s;
}
public int degree() {
int deg = 0;
for (int i = bits.length - 1; i >= 0; i--) {
long word = bits[i];
if (word != 0L) {
for (int bit = BITS - 1; bit >= 0; bit--) {
if ((word & (1L << bit)) != 0) {
deg++;
}
}
}
}
return deg;
}
/** code "inherited" from java.util.BitSet */
public boolean equals(Object obj) {
if ((obj != null) && (obj instanceof BitSet)) {
BitSet set = (BitSet)obj;
int n = Math.min(bits.length, set.bits.length);
for (int i = n; i-- > 0;) {
if (bits[i] != set.bits[i]) {
return false;
}
}
if (bits.length > n) {
for (int i = bits.length; i-- > n;) {
if (bits[i] != 0) {
return false;
}
}
}
else if (set.bits.length > n) {
for (int i = set.bits.length; i-- > n;) {
if (set.bits[i] != 0) {
return false;
}
}
}
return true;
}
return false;
}
/** Find ranges in a set element array. @param elems The array of
* elements representing the set, usually from Bit Set.toArray().
* @return Vector of ranges.
*/
public static Vector getRanges(int[] elems) {
if (elems.length == 0) {
return null;
}
int begin = elems[0];
int end = elems[elems.length - 1];
if (elems.length <= 2) {
// Not enough elements for a range expression
return null;
}
Vector ranges = new Vector(5);
// look for ranges
for (int i = 0; i < elems.length - 2; i++) {
int lastInRange;
lastInRange = elems.length - 1;
for (int j = i + 1; j < elems.length; j++) {
if (elems[j] != elems[j - 1] + 1) {
lastInRange = j - 1;
break;
}
}
// found a range
if (lastInRange - i > 2) {
ranges.appendElement(new IntRange(elems[i], elems[lastInRange]));
}
}
return ranges;
}
/**
* Grows the set to a larger number of bits.
* @param bit element that must fit in set
*/
public void growToInclude(int bit) {
int newSize = Math.max(bits.length << 1, numWordsToHold(bit));
long newbits[] = new long[newSize];
System.arraycopy(bits, 0, newbits, 0, bits.length);
bits = newbits;
}
public boolean member(int el) {
int n = wordNumber(el);
if (n >= bits.length) return false;
return (bits[n] & bitMask(el)) != 0;
}
public boolean nil() {
for (int i = bits.length - 1; i >= 0; i--) {
if (bits[i] != 0) return false;
}
return true;
}
public BitSet not() {
BitSet s = (BitSet)this.clone();
s.notInPlace();
return s;
}
public void notInPlace() {
for (int i = bits.length - 1; i >= 0; i--) {
bits[i] = ~bits[i];
}
}
/** complement bits in the range 0..maxBit. */
public void notInPlace(int maxBit) {
notInPlace(0, maxBit);
}
/** complement bits in the range minBit..maxBit.*/
public void notInPlace(int minBit, int maxBit) {
// make sure that we have room for maxBit
growToInclude(maxBit);
for (int i = minBit; i <= maxBit; i++) {
int n = wordNumber(i);
bits[n] ^= bitMask(i);
}
}
private final int numWordsToHold(int el) {
return (el >> LOG_BITS) + 1;
}
public static BitSet of(int el) {
BitSet s = new BitSet(el + 1);
s.add(el);
return s;
}
/** return this | a in a new set */
public BitSet or(BitSet a) {
BitSet s = (BitSet)this.clone();
s.orInPlace(a);
return s;
}
public void orInPlace(BitSet a) {
// If this is smaller than a, grow this first
if (a.bits.length > bits.length) {
setSize(a.bits.length);
}
int min = Math.min(bits.length, a.bits.length);
for (int i = min - 1; i >= 0; i--) {
bits[i] |= a.bits[i];
}
}
// remove this element from this set
public void remove(int el) {
int n = wordNumber(el);
if (n >= bits.length) {
growToInclude(el);
}
bits[n] &= ~bitMask(el);
}
/**
* Sets the size of a set.
* @param nwords how many words the new set should be
*/
private void setSize(int nwords) {
long newbits[] = new long[nwords];
int n = Math.min(nwords, bits.length);
System.arraycopy(bits, 0, newbits, 0, n);
bits = newbits;
}
public int size() {
return bits.length << LOG_BITS; // num words * bits per word
}
/** return how much space is being used by the bits array not
* how many actually have member bits on.
*/
public int lengthInLongWords() {
return bits.length;
}
/**Is this contained within a? */
public boolean subset(BitSet a) {
if (a == null || !(a instanceof BitSet)) return false;
return this.and(a).equals(this);
}
/**Subtract the elements of 'a' from 'this' in-place.
* Basically, just turn off all bits of 'this' that are in 'a'.
*/
public void subtractInPlace(BitSet a) {
if (a == null) return;
// for all words of 'a', turn off corresponding bits of 'this'
for (int i = 0; i < bits.length && i < a.bits.length; i++) {
bits[i] &= ~a.bits[i];
}
}
public int[] toArray() {
int[] elems = new int[degree()];
int en = 0;
for (int i = 0; i < (bits.length << LOG_BITS); i++) {
if (member(i)) {
elems[en++] = i;
}
}
return elems;
}
public long[] toPackedArray() {
return bits;
}
public String toString() {
return toString(",");
}
/** Transform a bit set into a string by formatting each element as an integer
* @separator The string to put in between elements
* @return A commma-separated list of values
*/
public String toString(String separator) {
String str = "";
for (int i = 0; i < (bits.length << LOG_BITS); i++) {
if (member(i)) {
if (str.length() > 0) {
str += separator;
}
str = str + i;
}
}
return str;
}
/** Transform a bit set into a string of characters.
* @separator The string to put in between elements
* @param formatter An object implementing the CharFormatter interface.
* @return A commma-separated list of character constants.
*/
public String toString(String separator, CharFormatter formatter) {
String str = "";
for (int i = 0; i < (bits.length << LOG_BITS); i++) {
if (member(i)) {
if (str.length() > 0) {
str += separator;
}
str = str + formatter.literalChar(i);
}
}
return str;
}
/**Create a string representation where instead of integer elements, the
* ith element of vocabulary is displayed instead. Vocabulary is a Vector
* of Strings.
* @separator The string to put in between elements
* @return A commma-separated list of character constants.
*/
public String toString(String separator, Vector vocabulary) {
if (vocabulary == null) {
return toString(separator);
}
String str = "";
for (int i = 0; i < (bits.length << LOG_BITS); i++) {
if (member(i)) {
if (str.length() > 0) {
str += separator;
}
if (i >= vocabulary.size()) {
str += "";
}
else if (vocabulary.elementAt(i) == null) {
str += "<" + i + ">";
}
else {
str += (String)vocabulary.elementAt(i);
}
}
}
return str;
}
/**
* Dump a comma-separated list of the words making up the bit set.
* Split each 64 bit number into two more manageable 32 bit numbers.
* This generates a comma-separated list of C++-like unsigned long constants.
*/
public String toStringOfHalfWords() {
String s = new String();
for (int i = 0; i < bits.length; i++) {
if (i != 0) s += ", ";
long tmp = bits[i];
tmp &= 0xFFFFFFFFL;
s += (tmp + "UL");
s += ", ";
tmp = bits[i] >>> 32;
tmp &= 0xFFFFFFFFL;
s += (tmp + "UL");
}
return s;
}
/**
* Dump a comma-separated list of the words making up the bit set.
* This generates a comma-separated list of Java-like long int constants.
*/
public String toStringOfWords() {
String s = new String();
for (int i = 0; i < bits.length; i++) {
if (i != 0) s += ", ";
s += (bits[i] + "L");
}
return s;
}
/** Print out the bit set but collapse char ranges. */
public String toStringWithRanges(String separator, CharFormatter formatter) {
String str = "";
int[] elems = this.toArray();
if (elems.length == 0) {
return "";
}
// look for ranges
int i = 0;
while (i < elems.length) {
int lastInRange;
lastInRange = 0;
for (int j = i + 1; j < elems.length; j++) {
if (elems[j] != elems[j - 1] + 1) {
break;
}
lastInRange = j;
}
// found a range
if (str.length() > 0) {
str += separator;
}
if (lastInRange - i >= 2) {
str += formatter.literalChar(elems[i]);
str += "..";
str += formatter.literalChar(elems[lastInRange]);
i = lastInRange; // skip past end of range for next range
}
else { // no range, just print current char and move on
str += formatter.literalChar(elems[i]);
}
i++;
}
return str;
}
private final static int wordNumber(int bit) {
return bit >> LOG_BITS; // bit / BITS
}
}