83 lines
2.1 KiB
JavaScript
83 lines
2.1 KiB
JavaScript
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// ported from https://www.npmjs.com/package/fast-fifo
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class FixedFIFO {
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buffer;
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mask;
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top;
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btm;
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next;
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constructor(hwm) {
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if (!(hwm > 0) || ((hwm - 1) & hwm) !== 0) {
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throw new Error('Max size for a FixedFIFO should be a power of two');
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}
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this.buffer = new Array(hwm);
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this.mask = hwm - 1;
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this.top = 0;
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this.btm = 0;
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this.next = null;
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}
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push(data) {
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if (this.buffer[this.top] !== undefined) {
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return false;
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}
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this.buffer[this.top] = data;
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this.top = (this.top + 1) & this.mask;
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return true;
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}
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shift() {
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const last = this.buffer[this.btm];
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if (last === undefined) {
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return undefined;
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}
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this.buffer[this.btm] = undefined;
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this.btm = (this.btm + 1) & this.mask;
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return last;
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}
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isEmpty() {
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return this.buffer[this.btm] === undefined;
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}
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}
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export class FIFO {
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size;
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hwm;
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head;
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tail;
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constructor(options = {}) {
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this.hwm = options.splitLimit ?? 16;
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this.head = new FixedFIFO(this.hwm);
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this.tail = this.head;
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this.size = 0;
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}
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calculateSize(obj) {
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if (obj?.byteLength != null) {
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return obj.byteLength;
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}
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return 1;
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}
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push(val) {
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if (val?.value != null) {
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this.size += this.calculateSize(val.value);
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}
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if (!this.head.push(val)) {
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const prev = this.head;
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this.head = prev.next = new FixedFIFO(2 * this.head.buffer.length);
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this.head.push(val);
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}
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}
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shift() {
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let val = this.tail.shift();
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if (val === undefined && (this.tail.next != null)) {
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const next = this.tail.next;
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this.tail.next = null;
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this.tail = next;
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val = this.tail.shift();
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}
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if (val?.value != null) {
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this.size -= this.calculateSize(val.value);
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}
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return val;
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}
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isEmpty() {
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return this.head.isEmpty();
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}
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}
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//# sourceMappingURL=fifo.js.map
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