--- /dev/null
+/**
+ * Copyright (c) 2016 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { ICircularList } from 'common/Types';
+import { EventEmitter, IEvent } from 'common/EventEmitter';
+
+export interface IInsertEvent {
+ index: number;
+ amount: number;
+}
+
+export interface IDeleteEvent {
+ index: number;
+ amount: number;
+}
+
+/**
+ * Represents a circular list; a list with a maximum size that wraps around when push is called,
+ * overriding values at the start of the list.
+ */
+export class CircularList<T> implements ICircularList<T> {
+ protected _array: (T | undefined)[];
+ private _startIndex: number;
+ private _length: number;
+
+ public onDeleteEmitter = new EventEmitter<IDeleteEvent>();
+ public get onDelete(): IEvent<IDeleteEvent> { return this.onDeleteEmitter.event; }
+ public onInsertEmitter = new EventEmitter<IInsertEvent>();
+ public get onInsert(): IEvent<IInsertEvent> { return this.onInsertEmitter.event; }
+ public onTrimEmitter = new EventEmitter<number>();
+ public get onTrim(): IEvent<number> { return this.onTrimEmitter.event; }
+
+ constructor(
+ private _maxLength: number
+ ) {
+ this._array = new Array<T>(this._maxLength);
+ this._startIndex = 0;
+ this._length = 0;
+ }
+
+ public get maxLength(): number {
+ return this._maxLength;
+ }
+
+ public set maxLength(newMaxLength: number) {
+ // There was no change in maxLength, return early.
+ if (this._maxLength === newMaxLength) {
+ return;
+ }
+
+ // Reconstruct array, starting at index 0. Only transfer values from the
+ // indexes 0 to length.
+ const newArray = new Array<T | undefined>(newMaxLength);
+ for (let i = 0; i < Math.min(newMaxLength, this.length); i++) {
+ newArray[i] = this._array[this._getCyclicIndex(i)];
+ }
+ this._array = newArray;
+ this._maxLength = newMaxLength;
+ this._startIndex = 0;
+ }
+
+ public get length(): number {
+ return this._length;
+ }
+
+ public set length(newLength: number) {
+ if (newLength > this._length) {
+ for (let i = this._length; i < newLength; i++) {
+ this._array[i] = undefined;
+ }
+ }
+ this._length = newLength;
+ }
+
+ /**
+ * Gets the value at an index.
+ *
+ * Note that for performance reasons there is no bounds checking here, the index reference is
+ * circular so this should always return a value and never throw.
+ * @param index The index of the value to get.
+ * @return The value corresponding to the index.
+ */
+ public get(index: number): T | undefined {
+ return this._array[this._getCyclicIndex(index)];
+ }
+
+ /**
+ * Sets the value at an index.
+ *
+ * Note that for performance reasons there is no bounds checking here, the index reference is
+ * circular so this should always return a value and never throw.
+ * @param index The index to set.
+ * @param value The value to set.
+ */
+ public set(index: number, value: T | undefined): void {
+ this._array[this._getCyclicIndex(index)] = value;
+ }
+
+ /**
+ * Pushes a new value onto the list, wrapping around to the start of the array, overriding index 0
+ * if the maximum length is reached.
+ * @param value The value to push onto the list.
+ */
+ public push(value: T): void {
+ this._array[this._getCyclicIndex(this._length)] = value;
+ if (this._length === this._maxLength) {
+ this._startIndex = ++this._startIndex % this._maxLength;
+ this.onTrimEmitter.fire(1);
+ } else {
+ this._length++;
+ }
+ }
+
+ /**
+ * Advance ringbuffer index and return current element for recycling.
+ * Note: The buffer must be full for this method to work.
+ * @throws When the buffer is not full.
+ */
+ public recycle(): T {
+ if (this._length !== this._maxLength) {
+ throw new Error('Can only recycle when the buffer is full');
+ }
+ this._startIndex = ++this._startIndex % this._maxLength;
+ this.onTrimEmitter.fire(1);
+ return this._array[this._getCyclicIndex(this._length - 1)]!;
+ }
+
+ /**
+ * Ringbuffer is at max length.
+ */
+ public get isFull(): boolean {
+ return this._length === this._maxLength;
+ }
+
+ /**
+ * Removes and returns the last value on the list.
+ * @return The popped value.
+ */
+ public pop(): T | undefined {
+ return this._array[this._getCyclicIndex(this._length-- - 1)];
+ }
+
+ /**
+ * Deletes and/or inserts items at a particular index (in that order). Unlike
+ * Array.prototype.splice, this operation does not return the deleted items as a new array in
+ * order to save creating a new array. Note that this operation may shift all values in the list
+ * in the worst case.
+ * @param start The index to delete and/or insert.
+ * @param deleteCount The number of elements to delete.
+ * @param items The items to insert.
+ */
+ public splice(start: number, deleteCount: number, ...items: T[]): void {
+ // Delete items
+ if (deleteCount) {
+ for (let i = start; i < this._length - deleteCount; i++) {
+ this._array[this._getCyclicIndex(i)] = this._array[this._getCyclicIndex(i + deleteCount)];
+ }
+ this._length -= deleteCount;
+ }
+
+ // Add items
+ for (let i = this._length - 1; i >= start; i--) {
+ this._array[this._getCyclicIndex(i + items.length)] = this._array[this._getCyclicIndex(i)];
+ }
+ for (let i = 0; i < items.length; i++) {
+ this._array[this._getCyclicIndex(start + i)] = items[i];
+ }
+
+ // Adjust length as needed
+ if (this._length + items.length > this._maxLength) {
+ const countToTrim = (this._length + items.length) - this._maxLength;
+ this._startIndex += countToTrim;
+ this._length = this._maxLength;
+ this.onTrimEmitter.fire(countToTrim);
+ } else {
+ this._length += items.length;
+ }
+ }
+
+ /**
+ * Trims a number of items from the start of the list.
+ * @param count The number of items to remove.
+ */
+ public trimStart(count: number): void {
+ if (count > this._length) {
+ count = this._length;
+ }
+ this._startIndex += count;
+ this._length -= count;
+ this.onTrimEmitter.fire(count);
+ }
+
+ public shiftElements(start: number, count: number, offset: number): void {
+ if (count <= 0) {
+ return;
+ }
+ if (start < 0 || start >= this._length) {
+ throw new Error('start argument out of range');
+ }
+ if (start + offset < 0) {
+ throw new Error('Cannot shift elements in list beyond index 0');
+ }
+
+ if (offset > 0) {
+ for (let i = count - 1; i >= 0; i--) {
+ this.set(start + i + offset, this.get(start + i));
+ }
+ const expandListBy = (start + count + offset) - this._length;
+ if (expandListBy > 0) {
+ this._length += expandListBy;
+ while (this._length > this._maxLength) {
+ this._length--;
+ this._startIndex++;
+ this.onTrimEmitter.fire(1);
+ }
+ }
+ } else {
+ for (let i = 0; i < count; i++) {
+ this.set(start + i + offset, this.get(start + i));
+ }
+ }
+ }
+
+ /**
+ * Gets the cyclic index for the specified regular index. The cyclic index can then be used on the
+ * backing array to get the element associated with the regular index.
+ * @param index The regular index.
+ * @returns The cyclic index.
+ */
+ private _getCyclicIndex(index: number): number {
+ return (this._startIndex + index) % this._maxLength;
+ }
+}
projects / VSoRC / .git / blobdiff