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xterm.js/src/BufferLine.ts
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/**
* Copyright (c) 2018 The xterm.js authors. All rights reserved.
* @license MIT
*/
import { CharData, IBufferLine, ICellData } from './Types';
import { NULL_CELL_CODE, NULL_CELL_WIDTH, NULL_CELL_CHAR, CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, WHITESPACE_CELL_CHAR, CHAR_DATA_ATTR_INDEX } from './Buffer';
import { stringFromCodePoint } from './core/input/TextDecoder';
/**
* buffer memory layout:
*
* | uint32_t | uint32_t | uint32_t |
* | `content` | `FG` | `BG` |
* | wcwidth(2) comb(1) codepoint(21) | flags(8) R(8) G(8) B(8) | flags(8) R(8) G(8) B(8) |
*/
/** typed array slots taken by one cell */
const CELL_SIZE = 3;
/**
* Cell member indices.
*
* Direct access:
* `content = data[column * CELL_SIZE + Cell.CONTENT];`
* `fg = data[column * CELL_SIZE + Cell.FG];`
* `bg = data[column * CELL_SIZE + Cell.BG];`
*/
const enum Cell {
CONTENT = 0,
FG = 1, // currently simply holds all known attrs
BG = 2 // currently unused
}
/**
* Bitmasks and helper for accessing data in `content`.
*/
export const enum Content {
/**
* bit 1..21 codepoint, max allowed in UTF32 is 0x10FFFF (21 bits taken)
* read: `codepoint = content & Content.codepointMask;`
* write: `content |= codepoint & Content.codepointMask;`
* shortcut if precondition `codepoint <= 0x10FFFF` is met:
* `content |= codepoint;`
*/
CODEPOINT_MASK = 0x1FFFFF,
/**
* bit 22 flag indication whether a cell contains combined content
* read: `isCombined = content & Content.isCombined;`
* set: `content |= Content.isCombined;`
* clear: `content &= ~Content.isCombined;`
*/
IS_COMBINED = 0x200000, // 1 << 21
/**
* bit 1..22 mask to check whether a cell contains any string data
* we need to check for codepoint and isCombined bits to see
* whether a cell contains anything
* read: `isEmtpy = !(content & Content.hasContent)`
*/
HAS_CONTENT = 0x3FFFFF,
/**
* bit 23..24 wcwidth value of cell, takes 2 bits (ranges from 0..2)
* read: `width = (content & Content.widthMask) >> Content.widthShift;`
* `hasWidth = content & Content.widthMask;`
* as long as wcwidth is highest value in `content`:
* `width = content >> Content.widthShift;`
* write: `content |= (width << Content.widthShift) & Content.widthMask;`
* shortcut if precondition `0 <= width <= 3` is met:
* `content |= width << Content.widthShift;`
*/
WIDTH_MASK = 0xC00000, // 3 << 22
WIDTH_SHIFT = 22
}
/**
* CellData - represents a single Cell in the terminal buffer.
*/
export class CellData implements ICellData {
/** Helper to create CellData from CharData. */
public static fromCharData(value: CharData): CellData {
const obj = new CellData();
obj.setFromCharData(value);
return obj;
}
/** Primitives from terminal buffer. */
public content: number = 0;
public fg: number = 0;
public bg: number = 0;
public combinedData: string = '';
/** Whether cell contains a combined string. */
public isCombined(): number {
return this.content & Content.IS_COMBINED;
}
/** Width of the cell. */
public getWidth(): number {
return this.content >> Content.WIDTH_SHIFT;
}
/** JS string of the content. */
public getChars(): string {
if (this.content & Content.IS_COMBINED) {
return this.combinedData;
}
if (this.content & Content.CODEPOINT_MASK) {
return stringFromCodePoint(this.content & Content.CODEPOINT_MASK);
}
return '';
}
/**
* Codepoint of cell
* Note this returns the UTF32 codepoint of single chars,
* if content is a combined string it returns the codepoint
* of the last char in string to be in line with code in CharData.
* */
public getCode(): number {
return (this.isCombined())
? this.combinedData.charCodeAt(this.combinedData.length - 1)
: this.content & Content.CODEPOINT_MASK;
}
/** Set data from CharData */
public setFromCharData(value: CharData): void {
this.fg = value[CHAR_DATA_ATTR_INDEX];
this.bg = 0;
let combined = false;
// surrogates and combined strings need special treatment
if (value[CHAR_DATA_CHAR_INDEX].length > 2) {
combined = true;
} else if (value[CHAR_DATA_CHAR_INDEX].length === 2) {
const code = value[CHAR_DATA_CHAR_INDEX].charCodeAt(0);
// if the 2-char string is a surrogate create single codepoint
// everything else is combined
if (0xD800 <= code && code <= 0xDBFF) {
const second = value[CHAR_DATA_CHAR_INDEX].charCodeAt(1);
if (0xDC00 <= second && second <= 0xDFFF) {
this.content = ((code - 0xD800) * 0x400 + second - 0xDC00 + 0x10000) | (value[CHAR_DATA_WIDTH_INDEX] << Content.WIDTH_SHIFT);
} else {
combined = true;
}
} else {
combined = true;
}
} else {
this.content = value[CHAR_DATA_CHAR_INDEX].charCodeAt(0) | (value[CHAR_DATA_WIDTH_INDEX] << Content.WIDTH_SHIFT);
}
if (combined) {
this.combinedData = value[CHAR_DATA_CHAR_INDEX];
this.content = Content.IS_COMBINED | (value[CHAR_DATA_WIDTH_INDEX] << Content.WIDTH_SHIFT);
}
}
/** Get data as CharData. */
public getAsCharData(): CharData {
return [this.fg, this.getChars(), this.getWidth(), this.getCode()];
}
}
/**
* Typed array based bufferline implementation.
*
* There are 2 ways to insert data into the cell buffer:
* - `setCellFromCodepoint` + `addCodepointToCell`
* Use these for data that is already UTF32.
* Used during normal input in `InputHandler` for faster buffer access.
* - `setCell`
* This method takes a CellData object and stores the data in the buffer.
* Use `CellData.fromCharData` to create the CellData object (e.g. from JS string).
*
* To retrieve data from the buffer use either one of the primitive methods
* (if only one particular value is needed) or `loadCell`. For `loadCell` in a loop
* memory allocs / GC pressure can be greatly reduced by reusing the CellData object.
*/
export class BufferLine implements IBufferLine {
protected _data: Uint32Array | null = null;
protected _combined: {[index: number]: string} = {};
public length: number;
constructor(cols: number, fillCellData?: ICellData, public isWrapped: boolean = false) {
if (cols) {
this._data = new Uint32Array(cols * CELL_SIZE);
const cell = fillCellData || CellData.fromCharData([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
for (let i = 0; i < cols; ++i) {
this.setCell(i, cell);
}
}
this.length = cols;
}
/**
* Get cell data CharData.
* @deprecated
*/
public get(index: number): CharData {
const content = this._data[index * CELL_SIZE + Cell.CONTENT];
const cp = content & Content.CODEPOINT_MASK;
return [
this._data[index * CELL_SIZE + Cell.FG],
(content & Content.IS_COMBINED)
? this._combined[index]
: (cp) ? stringFromCodePoint(cp) : '',
content >> Content.WIDTH_SHIFT,
(content & Content.IS_COMBINED)
? this._combined[index].charCodeAt(this._combined[index].length - 1)
: cp
];
}
/**
* Set cell data from CharData.
* @deprecated
*/
public set(index: number, value: CharData): void {
this._data[index * CELL_SIZE + Cell.FG] = value[CHAR_DATA_ATTR_INDEX];
if (value[CHAR_DATA_CHAR_INDEX].length > 1) {
this._combined[index] = value[1];
this._data[index * CELL_SIZE + Cell.CONTENT] = index | Content.IS_COMBINED | (value[CHAR_DATA_WIDTH_INDEX] << Content.WIDTH_SHIFT);
} else {
this._data[index * CELL_SIZE + Cell.CONTENT] = value[CHAR_DATA_CHAR_INDEX].charCodeAt(0) | (value[CHAR_DATA_WIDTH_INDEX] << Content.WIDTH_SHIFT);
}
}
/**
* primitive getters
* use these when only one value is needed, otherwise use `loadCell`
*/
public getWidth(index: number): number {
return this._data[index * CELL_SIZE + Cell.CONTENT] >> Content.WIDTH_SHIFT;
}
/** Test whether content has width. */
public hasWidth(index: number): number {
return this._data[index * CELL_SIZE + Cell.CONTENT] & Content.WIDTH_MASK;
}
/** Get FG cell component. */
public getFG(index: number): number {
return this._data[index * CELL_SIZE + Cell.FG];
}
/** Get BG cell component. */
public getBG(index: number): number {
return this._data[index * CELL_SIZE + Cell.BG];
}
/**
* Test whether contains any chars.
* Basically an empty has no content, but other cells might differ in FG/BG
* from real empty cells.
* */
public hasContent(index: number): number {
return this._data[index * CELL_SIZE + Cell.CONTENT] & Content.HAS_CONTENT;
}
/**
* Get codepoint of the cell.
* To be in line with `code` in CharData this either returns
* a single UTF32 codepoint or the last codepoint of a combined string.
*/
public getCodePoint(index: number): number {
const content = this._data[index * CELL_SIZE + Cell.CONTENT];
if (content & Content.IS_COMBINED) {
return this._combined[index].charCodeAt(this._combined[index].length - 1);
}
return content & Content.CODEPOINT_MASK;
}
/** Test whether the cell contains a combined string. */
public isCombined(index: number): number {
return this._data[index * CELL_SIZE + Cell.CONTENT] & Content.IS_COMBINED;
}
/** Returns the string content of the cell. */
public getString(index: number): string {
const content = this._data[index * CELL_SIZE + Cell.CONTENT];
if (content & Content.IS_COMBINED) {
return this._combined[index];
}
if (content & Content.CODEPOINT_MASK) {
return stringFromCodePoint(content & Content.CODEPOINT_MASK);
}
// return empty string for empty cells
return '';
}
/**
* Load data at `index` into `cell`.
*/
public loadCell(index: number, cell: ICellData): ICellData {
cell.content = this._data[index * CELL_SIZE + Cell.CONTENT];
cell.fg = this._data[index * CELL_SIZE + Cell.FG];
cell.bg = this._data[index * CELL_SIZE + Cell.BG];
if (cell.content & Content.IS_COMBINED) {
cell.combinedData = this._combined[index];
}
return cell;
}
/**
* Set data at `index` to `cell`.
*/
public setCell(index: number, cell: ICellData): void {
if (cell.content & Content.IS_COMBINED) {
this._combined[index] = cell.combinedData;
}
this._data[index * CELL_SIZE + Cell.CONTENT] = cell.content;
this._data[index * CELL_SIZE + Cell.FG] = cell.fg;
this._data[index * CELL_SIZE + Cell.BG] = cell.bg;
}
/**
* Set cell data from input handler.
* Since the input handler see the incoming chars as UTF32 codepoints,
* it gets an optimized access method.
*/
public setCellFromCodePoint(index: number, codePoint: number, width: number, fg: number, bg: number): void {
this._data[index * CELL_SIZE + Cell.CONTENT] = codePoint | (width << Content.WIDTH_SHIFT);
this._data[index * CELL_SIZE + Cell.FG] = fg;
this._data[index * CELL_SIZE + Cell.BG] = bg;
}
/**
* Add a codepoint to a cell from input handler.
* During input stage combining chars with a width of 0 follow and stack
* onto a leading char. Since we already set the attrs
* by the previous `setDataFromCodePoint` call, we can omit it here.
*/
public addCodepointToCell(index: number, codePoint: number): void {
let content = this._data[index * CELL_SIZE + Cell.CONTENT];
if (content & Content.IS_COMBINED) {
// we already have a combined string, simply add
this._combined[index] += stringFromCodePoint(codePoint);
} else {
if (content & Content.CODEPOINT_MASK) {
// normal case for combining chars:
// - move current leading char + new one into combined string
// - set combined flag
this._combined[index] = stringFromCodePoint(content & Content.CODEPOINT_MASK) + stringFromCodePoint(codePoint);
content &= ~Content.CODEPOINT_MASK; // set codepoint in buffer to 0
content |= Content.IS_COMBINED;
} else {
// should not happen - we actually have no data in the cell yet
// simply set the data in the cell buffer with a width of 1
content = codePoint | (1 << Content.WIDTH_SHIFT);
}
this._data[index * CELL_SIZE + Cell.CONTENT] = content;
}
}
public insertCells(pos: number, n: number, fillCellData: ICellData): void {
pos %= this.length;
if (n < this.length - pos) {
const cell = new CellData();
for (let i = this.length - pos - n - 1; i >= 0; --i) {
this.setCell(pos + n + i, this.loadCell(pos + i, cell));
}
for (let i = 0; i < n; ++i) {
this.setCell(pos + i, fillCellData);
}
} else {
for (let i = pos; i < this.length; ++i) {
this.setCell(i, fillCellData);
}
}
}
public deleteCells(pos: number, n: number, fillCellData: ICellData): void {
pos %= this.length;
if (n < this.length - pos) {
const cell = new CellData();
for (let i = 0; i < this.length - pos - n; ++i) {
this.setCell(pos + i, this.loadCell(pos + n + i, cell));
}
for (let i = this.length - n; i < this.length; ++i) {
this.setCell(i, fillCellData);
}
} else {
for (let i = pos; i < this.length; ++i) {
this.setCell(i, fillCellData);
}
}
}
public replaceCells(start: number, end: number, fillCellData: ICellData): void {
while (start < end && start < this.length) {
this.setCell(start++, fillCellData);
}
}
public resize(cols: number, fillCellData: ICellData): void {
if (cols === this.length) {
return;
}
if (cols > this.length) {
const data = new Uint32Array(cols * CELL_SIZE);
if (this.length) {
if (cols * CELL_SIZE < this._data.length) {
data.set(this._data.subarray(0, cols * CELL_SIZE));
} else {
data.set(this._data);
}
}
this._data = data;
for (let i = this.length; i < cols; ++i) {
this.setCell(i, fillCellData);
}
} else {
if (cols) {
const data = new Uint32Array(cols * CELL_SIZE);
data.set(this._data.subarray(0, cols * CELL_SIZE));
this._data = data;
// Remove any cut off combined data
const keys = Object.keys(this._combined);
for (let i = 0; i < keys.length; i++) {
const key = parseInt(keys[i], 10);
if (key >= cols) {
delete this._combined[key];
}
}
} else {
this._data = null;
this._combined = {};
}
}
this.length = cols;
}
/** fill a line with fillCharData */
public fill(fillCellData: ICellData): void {
this._combined = {};
for (let i = 0; i < this.length; ++i) {
this.setCell(i, fillCellData);
}
}
/** alter to a full copy of line */
public copyFrom(line: BufferLine): void {
if (this.length !== line.length) {
this._data = new Uint32Array(line._data);
} else {
// use high speed copy if lengths are equal
this._data.set(line._data);
}
this.length = line.length;
this._combined = {};
for (const el in line._combined) {
this._combined[el] = line._combined[el];
}
this.isWrapped = line.isWrapped;
}
/** create a new clone */
public clone(): IBufferLine {
const newLine = new BufferLine(0);
newLine._data = new Uint32Array(this._data);
newLine.length = this.length;
for (const el in this._combined) {
newLine._combined[el] = this._combined[el];
}
newLine.isWrapped = this.isWrapped;
return newLine;
}
public getTrimmedLength(): number {
for (let i = this.length - 1; i >= 0; --i) {
if ((this._data[i * CELL_SIZE + Cell.CONTENT] & Content.HAS_CONTENT)) {
return i + (this._data[i * CELL_SIZE + Cell.CONTENT] >> Content.WIDTH_SHIFT);
}
}
return 0;
}
public copyCellsFrom(src: BufferLine, srcCol: number, destCol: number, length: number, applyInReverse: boolean): void {
const srcData = src._data;
if (applyInReverse) {
for (let cell = length - 1; cell >= 0; cell--) {
for (let i = 0; i < CELL_SIZE; i++) {
this._data[(destCol + cell) * CELL_SIZE + i] = srcData[(srcCol + cell) * CELL_SIZE + i];
}
}
} else {
for (let cell = 0; cell < length; cell++) {
for (let i = 0; i < CELL_SIZE; i++) {
this._data[(destCol + cell) * CELL_SIZE + i] = srcData[(srcCol + cell) * CELL_SIZE + i];
}
}
}
// Move any combined data over as needed
const srcCombinedKeys = Object.keys(src._combined);
for (let i = 0; i < srcCombinedKeys.length; i++) {
const key = parseInt(srcCombinedKeys[i], 10);
if (key >= srcCol) {
this._combined[key - srcCol + destCol] = src._combined[key];
}
}
}
public translateToString(trimRight: boolean = false, startCol: number = 0, endCol: number = this.length): string {
if (trimRight) {
endCol = Math.min(endCol, this.getTrimmedLength());
}
let result = '';
while (startCol < endCol) {
const content = this._data[startCol * CELL_SIZE + Cell.CONTENT];
const cp = content & Content.CODEPOINT_MASK;
result += (content & Content.IS_COMBINED) ? this._combined[startCol] : (cp) ? stringFromCodePoint(cp) : WHITESPACE_CELL_CHAR;
startCol += (content >> Content.WIDTH_SHIFT) || 1; // always advance by 1
}
return result;
}
}