package BitSet
import NoWurst
import Integer
import Annotations

public constant BITSET_SIZE = 32

int array pows
int array reversePows

@compiletime function initPows()
	pows[0] = 1
	var allPows = 1
	for i = 1 to BITSET_SIZE - 1
		pows[i] = pows[i - 1] * 2
		allPows = allPows.bitOr(pows[i])
	for i = 0 to BITSET_SIZE - 1
		reversePows[i] = allPows.bitXor(pows[i])

init
	initPows()

/** Bitset represents a fixed-size sequence of BITSET_SIZE bits. The bits are contained in a single int. */
public tuple bitset(int val)

/** Creates an empty bitset. */
public function emptyBitset() returns bitset
	return bitset(0)

/** Returns the value of the bit with the specified index. */
public function bitset.get(int index) returns bool
	return this.val.bitAnd(pows[index]) != 0

/** Sets the bit at the specified index to true. */
public function bitset.set(int index) returns bitset
	return bitset(this.val.bitOr(pows[index]))

/** Sets the bit at the specified index to false. */
public function bitset.reset(int index) returns bitset
	return bitset(this.val.bitAnd(reversePows[index]))

/** Sets the bit at the specified index to the specified value. */
public function bitset.set(int index, bool value) returns bitset
	return value ? this.set(index) : this.reset(index)

/** Sets the bit at the specified index to the complement of its current value. */
public function bitset.flip(int index) returns bitset
	return bitset(this.val.bitXor(pows[index]))

/** Returns true if this bitset contains no bits that are set to true. */
public function bitset.isEmpty() returns bool
	return this.val == 0

/** Returns true if the specified bitset has any bits set to true that are also set to true in this bitset. */
public function bitset.intersects(bitset other) returns bool
	return this.val.bitAnd(other.val) != 0

/** Performs a logical AND of this bit set with the bit set argument. */
public function bitset.bitAnd(bitset other) returns bitset
	return bitset(this.val.bitAnd(other.val))

/** Performs a logical OR of this bit set with the bit set argument. */
public function bitset.bitOr(bitset other) returns bitset
	return bitset(this.val.bitOr(other.val))

/** Performs a logical XOR of this bit set with the bit set argument. */
public function bitset.bitXor(bitset other) returns bitset
	return bitset(this.val.bitXor(other.val))

/** Returns an integer representation of the data. */
public function bitset.toInt() returns int
	return this.val

// Conversion methods for generics

public function bitsetToIndex(bitset object) returns int
	return object.toInt()

public function bitsetFromIndex(int index) returns bitset
	return bitset(index)