Fixes #45735: Fix implementation of getLineCharCode

src/vs/editor/common/model/pieceTreeTextBuffer/pieceTreeBase.ts

@@ -538,7 +538,7 @@ export class PieceTreeBase {
 		let nodePos = this.nodeAt2(lineNumber, index + 1);
 		let buffer = this._buffers[nodePos.node.piece.bufferIndex];
 		let startOffset = this.offsetInBuffer(nodePos.node.piece.bufferIndex, nodePos.node.piece.start);
-		let targetOffset = startOffset + index;
+		let targetOffset = startOffset + nodePos.remainder;
 
 		return buffer.buffer.charCodeAt(targetOffset);
 	}

src/vs/editor/test/common/model/pieceTreeTextBuffer/pieceTreeTextBuffer.test.ts

@@ -1571,6 +1571,15 @@ suite('buffer api', () => {
 
 		assert(!a.equal(b));
 	});
+
+	test('getLineCharCode - issue #45735', () => {
+		let pieceTable = createTextBuffer(['LINE1\nline2']);
+		assert.equal(pieceTable.getLineCharCode(2, 0), 'l'.charCodeAt(0), 'l');
+		assert.equal(pieceTable.getLineCharCode(2, 1), 'i'.charCodeAt(0), 'i');
+		assert.equal(pieceTable.getLineCharCode(2, 2), 'n'.charCodeAt(0), 'n');
+		assert.equal(pieceTable.getLineCharCode(2, 3), 'e'.charCodeAt(0), 'e');
+		assert.equal(pieceTable.getLineCharCode(2, 4), '2'.charCodeAt(0), '2');
+	});
 });
 
 suite('search offset cache', () => {