新增bitVector用于优化bitSet
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yhh
353
source/src/ECS/Utils/BitVector.ts
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353
source/src/ECS/Utils/BitVector.ts
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module es {
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/**
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* 性能优化的位组实现。某些操作是以不安全为前缀的, 这些方法不执行验证，主要是在内部利用来优化实体ID位集的访问
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*/
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export class BitVector {
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private words: number[] = [0];
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/**
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* 创建一个初始大小足够大的bitset，以明确表示0到nbits-1范围内指数的bit
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* @param nbits nbits 位集的初始大小
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*/
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constructor(nbits?: number | BitVector) {
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if (nbits) {
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if (typeof nbits == 'number')
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this.checkCapacity(nbits >>> 6);
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else {
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// 基于另一个位向量创建一个位集
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this.words = nbits.words.slice(0);
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}
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}
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}
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/**
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*
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* @param index 位的索引
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* @returns 该位是否被设置
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*/
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public get(index: number): boolean {
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const word = index >>> 6;
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return word < this.words.length &&
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(this.words[word] & (1 << index)) != 0;
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}
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/**
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*
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* @param index 位的索引
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*/
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public set(index: number, value: boolean = true) {
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if (value) {
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const word = index >>> 6;
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this.checkCapacity(word);
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this.words[word] |= 1 << index;
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} else {
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this.clear(index);
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}
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}
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/**
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*
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* @param index 位的索引
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* @returns 该位是否被设置
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*/
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public unsafeGet(index: number): boolean {
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return (this.words[index >>> 6] & (1 << index)) != 0;
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}
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/**
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*
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* @param index 要设置的位的索引
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*/
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public unsafeSet(index: number) {
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this.words[index >>> 6] |= 1 << index;
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}
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/**
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*
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* @param index 要翻转的位的索引
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*/
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public flip(index: number) {
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const word = index >>> 6;
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this.checkCapacity(word);
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this.words[word] ^= 1 << index;
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}
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/**
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* 要清除的位的索引
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* @param index
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*/
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public clear(index?: number) {
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if (index != null) {
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const word = index >>> 6;
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if (word >= this.words.length) return;
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this.words[word] &= ~(1 << index);
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} else {
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this.words.fill(0);
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}
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}
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/**
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* 返回该位组的 "逻辑大小"：位组中最高设置位的索引加1。如果比特集不包含集合位，则返回0
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*/
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public length(): number {
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let bits = this.words.slice(0);
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for (let word = bits.length - 1; word >= 0; --word) {
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let bitsAtWord = bits[word];
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if (bitsAtWord != 0)
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return (word << 6) + 64 - this.numberOfLeadingZeros(bitsAtWord);
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}
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return 0;
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}
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/**
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* @returns 如果这个位组中没有设置为true的位，则为true
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*/
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public isEmpty(): boolean {
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let bits = this.words.slice(0);
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let length = bits.length;
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for (let i = 0; i < length; i++) {
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if (bits[i] != 0)
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return false;
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}
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return true;
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}
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/**
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* 返回在指定的起始索引上或之后出现的第一个被设置为真的位的索引。
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* 如果不存在这样的位，则返回-1
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* @param fromIndex
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*/
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public nextSetBit(fromIndex: number): number {
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let word = fromIndex >>> 6;
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if (word >= this.words.length)
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return -1;
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let bitmap = this.words[word] >>> fromIndex;
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if (bitmap != 0)
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return fromIndex + this.numberOfTrailingZeros(bitmap);
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for (let i = 1 + word; i < this.words.length; i++) {
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bitmap = this.words[i];
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if (bitmap != 0) {
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return i * 64 + this.numberOfTrailingZeros(bitmap);
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}
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}
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return -1;
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}
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/**
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* 返回在指定的起始索引上或之后发生的第一个被设置为false的位的索引
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* @param fromIndex
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*/
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public nextClearBit(fromIndex: number): number {
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let word = fromIndex >>> 6;
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if (word >= this.words.length)
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return Math.min(fromIndex, this.words.length << 6);
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let bitmap = ~(this.words[word] >>> fromIndex);
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if (bitmap != 0)
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return fromIndex + this.numberOfTrailingZeros(bitmap);
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for (let i = 1 + word; i < this.words.length; i++) {
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bitmap = ~this.words[i];
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if (bitmap != 0) {
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return i * 64 + this.numberOfTrailingZeros(bitmap);
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}
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}
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return Math.min(fromIndex, this.words.length << 6);
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}
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/**
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* 对这个目标位集和参数位集进行逻辑AND。
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* 这个位集被修改，使它的每一个位都有值为真，如果且仅当它最初的值为真，并且位集参数中的相应位也有值为真
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* @param other
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*/
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public and(other: BitVector) {
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let commonWords = Math.min(this.words.length, other.words.length);
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for (let i = 0; commonWords > i; i++) {
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this.words[i] &= other.words[i];
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}
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if (this.words.length > commonWords) {
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for (let i = commonWords, s = this.words.length; s > i; i++) {
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this.words[i] = 0;
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}
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}
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}
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/**
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* 清除该位集的所有位，其对应的位被设置在指定的位集中
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* @param other
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*/
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public andNot(other: BitVector) {
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let commonWords = Math.min(this.words.length, other.words.length);
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for (let i = 0; commonWords > i; i++)
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this.words[i] &= ~other.words[i];
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}
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/**
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* 用位集参数执行这个位集的逻辑OR。
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* 如果且仅当位集参数中的位已经有值为真或位集参数中的对应位有值为真时，该位集才会被修改，从而使位集中的位有值为真
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* @param other
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*/
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public or(other: BitVector) {
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let commonWords = Math.min(this.words.length, other.words.length);
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for (let i = 0; commonWords > i; i++)
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this.words[i] |= other.words[i];
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if (commonWords < other.words.length) {
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this.checkCapacity(other.words.length);
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for (let i = commonWords, s = other.words.length; s > i; i++) {
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this.words[i] = other.words[i];
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}
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}
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}
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/**
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* 用位集参数对这个位集进行逻辑XOR。
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* 这个位集被修改了，所以如果且仅当以下语句之一成立时，位集中的一个位的值为真
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* @param other
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*/
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public xor(other: BitVector) {
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let commonWords = Math.min(this.words.length, other.words.length);
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for (let i = 0; commonWords > i; i++)
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this.words[i] ^= other.words[i];
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if (commonWords < other.words.length) {
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this.checkCapacity(other.words.length);
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for (let i = commonWords, s = other.words.length; s > i; i++) {
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this.words[i] = other.words[i];
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}
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}
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}
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/**
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* 如果指定的BitVector有任何位被设置为true，并且在这个BitVector中也被设置为true，则返回true
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* @param other
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*/
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public intersects(other: BitVector): boolean {
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let bits = this.words.slice(0);
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let otherBits = other.words;
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for (let i = 0, s = Math.min(bits.length, otherBits.length); s > i; i++) {
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if ((bits[i] & otherBits[i]) != 0)
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return true;
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}
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return false;
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}
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/**
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* 如果这个位集是指定位集的超级集，即它的所有位都被设置为真，那么返回true
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* @param other
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*/
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public containsAll(other: BitVector): boolean {
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let bits = this.words.slice(0);
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let otherBits = other.words;
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let otherBitsLength = otherBits.length;
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let bitsLength = bits.length;
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for (let i = bitsLength; i < otherBitsLength; i++) {
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if (otherBits[i] != 0) {
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return false;
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}
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}
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for (let i = 0, s = Math.min(bitsLength, otherBitsLength); s > i; i++) {
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if ((bits[i] & otherBits[i]) != otherBits[i]) {
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return false;
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}
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}
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return true;
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}
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public cardinality() {
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let count = 0;
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for (let i = 0; i < this.words.length; i++)
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count += this.bitCount(this.words[i]);
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return count;
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}
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public hashCode() {
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const word = this.length() >>> 6;
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let hash = 0;
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for (let i = 0; word >= i; i++)
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hash = 127 * hash + (this.words[i] ^ (this.words[i] >>> 32));
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return hash;
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}
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private bitCount(i: number) {
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i = i - ((i >>> 1) & 0x55555555);
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i = (i & 0x33333333) + ((i >>> 2) & 0x33333333);
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i = (i + (i >>> 4)) & 0x0f0f0f0f;
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i = i + (i >>> 8);
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i = i + (i >>> 16);
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return i & 0x3f;
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}
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/**
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* 返回二进制补码二进制表示形式中最高位（“最左端”）一位之前的零位数量
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* @param i
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*/
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private numberOfLeadingZeros(i: number) {
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if (i == 0) return 64;
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let n = 1;
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let x = i >>> 32;
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if (x == 0) { n += 32; x = i; }
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if (x >>> 16 == 0) { n += 16; x <<= 16; }
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if (x >>> 24 == 0) { n += 8; x <<= 8; }
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if (x >>> 28 == 0) { n += 4; x <<= 4; }
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if (x >>> 30 == 0) { n += 2; x <<= 2; }
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n -= x >>> 31;
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return n;
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}
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/**
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* 返回指定二进制数的补码二进制表示形式中最低序（“最右”）一位之后的零位数量
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* @param i
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*/
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public numberOfTrailingZeros(i: number) {
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let x: number = 0, y: number = 0;
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if (i == 0) return 64;
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let n = 63;
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y = i; if (y != 0) { n = n - 32; x = y; } else x = (i >>> 32);
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y = x << 16; if (y != 0) { n = n - 16; x = y; }
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y = x << 8; if (y != 0) { n = n - 8; x = y; }
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y = x << 4; if (y != 0) { n = n - 4; x = y; }
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y = x << 2; if (y != 0) { n = n - 2; x = y; }
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return n - ((x << 1) >>> 31);
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}
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/**
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*
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* @param index 要清除的位的索引
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*/
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public unsafeClear(index: number) {
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this.words[index >>> 6] &= ~(1 << index);
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}
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/**
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* 增长支持数组，使其能够容纳所请求的位
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* @param bits 位数
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*/
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public ensureCapacity(bits: number) {
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this.checkCapacity(bits >>> 6);
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}
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private checkCapacity(len: number) {
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if (len >= this.words.length) {
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let newBits: number[] = new Array(len + 1);
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for (let i = 0; i < this.words.length; i++) {
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newBits[i] = this.words[i];
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}
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this.words = newBits;
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}
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}
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}
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}
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