change NULL_CHAR and trim

src/Buffer.ts

@@ -16,9 +16,13 @@ export const CHAR_DATA_WIDTH_INDEX = 2;
 export const CHAR_DATA_CODE_INDEX = 3;
 export const MAX_BUFFER_SIZE = 4294967295; // 2^32 - 1
 
-export const NULL_CELL_CHAR = ' ';
-export const NULL_CELL_WIDTH = 1;
-export const NULL_CELL_CODE = 32;
+// export const NULL_CELL_CHAR = ' ';
+// export const NULL_CELL_WIDTH = 1;
+// export const NULL_CELL_CODE = 32;
+
+export const NULL_CELL_CHAR = '';
+export const NULL_CELL_WIDTH = 0;
+export const NULL_CELL_CODE = 0;
 
 /**
  * This class represents a terminal buffer (an internal state of the terminal), where the
@@ -273,6 +277,7 @@ export class Buffer implements IBuffer {
     if (!line) {
       return '';
     }
+    return line.translateToString(trimRight, startCol, endCol);
 
     // Initialize column and index values. Column values represent the actual
     // cell column, indexes represent the index in the string. Indexes are

src/BufferLine.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 import { CharData, IBufferLine } from './Types';
-import { NULL_CELL_CODE, NULL_CELL_WIDTH, NULL_CELL_CHAR } from './Buffer';
+import { NULL_CELL_CODE, NULL_CELL_WIDTH, NULL_CELL_CHAR, CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX } from './Buffer';
 
 /**
  * Class representing a terminal line.
@@ -108,6 +108,27 @@ export class BufferLine implements IBufferLine {
     newLine.copyFrom(this);
     return newLine;
   }
+
+  public getTrimmedLength(): number {
+    for (let i = this.length - 1; i >= 0; --i) {
+      const ch = this.get(i);
+      if (ch[CHAR_DATA_CHAR_INDEX] !== '') {
+        return i + ch[CHAR_DATA_WIDTH_INDEX] - 1;
+      }
+    }
+    return 0;
+  }
+
+  public translateToString(trimRight: boolean = false, startCol: number = 0, endCol: number = null): string {
+    let length = endCol || this.length;
+    if (trimRight)
+      length = Math.min(length, this.getTrimmedLength());
+    let result = '';
+    for (let i = startCol; i < length; ++i) {
+      result += this.get(i)[CHAR_DATA_CHAR_INDEX] || ' ';
+    }
+    return result;
+  }
 }
 
 /** typed array slots taken by one cell */
@@ -279,4 +300,25 @@ export class BufferLineTypedArray implements IBufferLine {
     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.STRING] !== 0) {  // 0 ==> ''.charCodeAt(0) ==> NaN ==> 0
+        return i + 1;
+      }
+    }
+    return 0;
+  }
+
+  public translateToString(trimRight: boolean = false, startCol: number = 0, endCol: number = null): string {
+    let length = endCol || this.length;
+    if (trimRight)
+      length = Math.min(length, this.getTrimmedLength());
+    let result = '';
+    for (let i = startCol; i < length; ++i) {
+      const stringData = this._data[i * CELL_SIZE + Cell.STRING];
+      result += (stringData & 0x80000000) ? this._combined[i] : (stringData) ? String.fromCharCode(stringData) : ' ';
+    }
+    return result;
+  }
 }

src/Terminal.integration.ts

@@ -67,7 +67,7 @@ function terminalToString(term: Terminal): string {
   for (let line = term.buffer.ybase; line < term.buffer.ybase + term.rows; line++) {
     lineText = '';
     for (let cell = 0; cell < term.cols; ++cell) {
-      lineText += term.buffer.lines.get(line).get(cell)[CHAR_DATA_CHAR_INDEX];
+      lineText += term.buffer.lines.get(line).get(cell)[CHAR_DATA_CHAR_INDEX] || ' ';
     }
     // rtrim empty cells as xterm does
     lineText = lineText.replace(/\s+$/, '');

src/Types.ts

@@ -524,6 +524,8 @@ export interface IBufferLine {
   fill(fillCharData: CharData): void;
   copyFrom(line: IBufferLine): void;
   clone(): IBufferLine;
+  getTrimmedLength(): number;
+  translateToString(trimRight?: boolean, startCol?: number, endCol?: number): string;
 }
 
 export interface IBufferLineConstructor {