diff --git a/src/vs/editor/common/model/chunksTextBuffer/bufferPiece.ts b/src/vs/editor/common/model/chunksTextBuffer/bufferPiece.ts
new file mode 100644
index 00000000000..53063409aea
--- /dev/null
+++ b/src/vs/editor/common/model/chunksTextBuffer/bufferPiece.ts
@@ -0,0 +1,323 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import { CharCode } from 'vs/base/common/charCode';
+
+export class LeafOffsetLenEdit {
+	constructor(
+		public readonly start: number,
+		public readonly length: number,
+		public readonly text: string
+	) { }
+}
+
+export class BufferPiece {
+	private readonly _str: string;
+	public get text(): string { return this._str; }
+
+	private readonly _lineStarts: Uint32Array;
+
+	constructor(str: string, lineStarts: Uint32Array = null) {
+		this._str = str;
+		if (lineStarts === null) {
+			this._lineStarts = createLineStartsFast(str);
+		} else {
+			this._lineStarts = lineStarts;
+		}
+	}
+
+	public length(): number {
+		return this._str.length;
+	}
+
+	public newLineCount(): number {
+		return this._lineStarts.length;
+	}
+
+	public lineStartFor(relativeLineIndex: number): number {
+		return this._lineStarts[relativeLineIndex];
+	}
+
+	public charCodeAt(index: number): number {
+		return this._str.charCodeAt(index);
+	}
+
+	public substr(from: number, length: number): string {
+		return this._str.substr(from, length);
+	}
+
+	public findLineStartBeforeOffset(offset: number): number {
+		if (this._lineStarts.length === 0 || offset < this._lineStarts[0]) {
+			return -1;
+		}
+
+		let low = 0, high = this._lineStarts.length - 1;
+
+		while (low < high) {
+			let mid = low + Math.ceil((high - low) / 2);
+			let lineStart = this._lineStarts[mid];
+
+			if (offset === lineStart) {
+				return mid;
+			} else if (offset < lineStart) {
+				high = mid - 1;
+			} else {
+				low = mid;
+			}
+		}
+
+		return low;
+	}
+
+	public findLineFirstNonWhitespaceIndex(searchStartOffset: number): number {
+		for (let i = searchStartOffset, len = this._str.length; i < len; i++) {
+			const chCode = this._str.charCodeAt(i);
+			if (chCode === CharCode.CarriageReturn || chCode === CharCode.LineFeed) {
+				// Reached EOL
+				return -2;
+			}
+			if (chCode !== CharCode.Space && chCode !== CharCode.Tab) {
+				return i;
+			}
+		}
+		return -1;
+	}
+
+	public findLineLastNonWhitespaceIndex(searchStartOffset: number): number {
+		for (let i = searchStartOffset - 1; i >= 0; i--) {
+			const chCode = this._str.charCodeAt(i);
+			if (chCode === CharCode.CarriageReturn || chCode === CharCode.LineFeed) {
+				// Reached EOL
+				return -2;
+			}
+			if (chCode !== CharCode.Space && chCode !== CharCode.Tab) {
+				return i;
+			}
+		}
+		return -1;
+	}
+
+	public static normalizeEOL(target: BufferPiece, eol: '\r\n' | '\n'): BufferPiece {
+		return new BufferPiece(target._str.replace(/\r\n|\r|\n/g, eol));
+	}
+
+	public static deleteLastChar(target: BufferPiece): BufferPiece {
+		const targetCharsLength = target.length();
+		const targetLineStartsLength = target.newLineCount();
+		const targetLineStarts = target._lineStarts;
+
+		let newLineStartsLength;
+		if (targetLineStartsLength > 0 && targetLineStarts[targetLineStartsLength - 1] === targetCharsLength) {
+			newLineStartsLength = targetLineStartsLength - 1;
+		} else {
+			newLineStartsLength = targetLineStartsLength;
+		}
+
+		let newLineStarts = new Uint32Array(newLineStartsLength);
+		newLineStarts.set(targetLineStarts);
+
+		return new BufferPiece(
+			target._str.substr(0, targetCharsLength - 1),
+			newLineStarts
+		);
+	}
+
+	public static insertFirstChar(target: BufferPiece, character: number): BufferPiece {
+		const targetLineStartsLength = target.newLineCount();
+		const targetLineStarts = target._lineStarts;
+		const insertLineStart = ((character === CharCode.CarriageReturn && (targetLineStartsLength === 0 || targetLineStarts[0] !== 1 || target.charCodeAt(0) !== CharCode.LineFeed)) || (character === CharCode.LineFeed));
+
+		const newLineStartsLength = (insertLineStart ? targetLineStartsLength + 1 : targetLineStartsLength);
+		let newLineStarts = new Uint32Array(newLineStartsLength);
+
+		if (insertLineStart) {
+			newLineStarts[0] = 1;
+			for (let i = 0; i < targetLineStartsLength; i++) {
+				newLineStarts[i + 1] = targetLineStarts[i] + 1;
+			}
+		} else {
+			for (let i = 0; i < targetLineStartsLength; i++) {
+				newLineStarts[i] = targetLineStarts[i] + 1;
+			}
+		}
+
+		return new BufferPiece(
+			String.fromCharCode(character) + target._str,
+			newLineStarts
+		);
+	}
+
+	public static join(first: BufferPiece, second: BufferPiece): BufferPiece {
+		const firstCharsLength = first._str.length;
+
+		const firstLineStartsLength = first._lineStarts.length;
+		const secondLineStartsLength = second._lineStarts.length;
+
+		const firstLineStarts = first._lineStarts;
+		const secondLineStarts = second._lineStarts;
+
+		const newLineStartsLength = firstLineStartsLength + secondLineStartsLength;
+		let newLineStarts = new Uint32Array(newLineStartsLength);
+		newLineStarts.set(firstLineStarts, 0);
+		for (let i = 0; i < secondLineStartsLength; i++) {
+			newLineStarts[i + firstLineStartsLength] = secondLineStarts[i] + firstCharsLength;
+		}
+
+		return new BufferPiece(first._str + second._str, newLineStarts);
+	}
+
+	public static replaceOffsetLen(target: BufferPiece, edits: LeafOffsetLenEdit[], idealLeafLength: number, maxLeafLength: number, result: BufferPiece[]): void {
+		const editsSize = edits.length;
+		const originalCharsLength = target.length();
+		if (editsSize === 1 && edits[0].text.length === 0 && edits[0].start === 0 && edits[0].length === originalCharsLength) {
+			// special case => deleting everything
+			return;
+		}
+
+		let pieces: string[] = new Array<string>(2 * editsSize + 1);
+		let originalFromIndex = 0;
+		let piecesTextLength = 0;
+		for (let i = 0; i < editsSize; i++) {
+			const edit = edits[i];
+
+			const originalText = target._str.substr(originalFromIndex, edit.start - originalFromIndex);
+			pieces[2 * i] = originalText;
+			piecesTextLength += originalText.length;
+
+			originalFromIndex = edit.start + edit.length;
+			pieces[2 * i + 1] = edit.text;
+			piecesTextLength += edit.text.length;
+		}
+
+		// maintain the chars that survive to the right of the last edit
+		let text = target._str.substr(originalFromIndex, originalCharsLength - originalFromIndex);
+		pieces[2 * editsSize] = text;
+		piecesTextLength += text.length;
+
+		let targetDataLength = piecesTextLength > maxLeafLength ? idealLeafLength : piecesTextLength;
+		let targetDataOffset = 0;
+
+		let data: string = '';
+
+		for (let pieceIndex = 0, pieceCount = pieces.length; pieceIndex < pieceCount; pieceIndex++) {
+			const pieceText = pieces[pieceIndex];
+			const pieceLength = pieceText.length;
+			if (pieceLength === 0) {
+				continue;
+			}
+
+			let pieceOffset = 0;
+			while (pieceOffset < pieceLength) {
+				if (targetDataOffset >= targetDataLength) {
+					result.push(new BufferPiece(data));
+					targetDataLength = piecesTextLength > maxLeafLength ? idealLeafLength : piecesTextLength;
+					targetDataOffset = 0;
+					data = '';
+				}
+
+				let writingCnt = min(pieceLength - pieceOffset, targetDataLength - targetDataOffset);
+				data += pieceText.substr(pieceOffset, writingCnt);
+				pieceOffset += writingCnt;
+				targetDataOffset += writingCnt;
+				piecesTextLength -= writingCnt;
+
+				// check that the buffer piece does not end in a \r or high surrogate
+				if (targetDataOffset === targetDataLength && piecesTextLength > 0) {
+					const lastChar = data.charCodeAt(targetDataLength - 1);
+					if (lastChar === CharCode.CarriageReturn || (0xD800 <= lastChar && lastChar <= 0xDBFF)) {
+						// move lastChar over to next buffer piece
+						targetDataLength -= 1;
+						pieceOffset -= 1;
+						targetDataOffset -= 1;
+						piecesTextLength += 1;
+						data = data.substr(0, data.length - 1);
+					}
+				}
+			}
+		}
+
+		result.push(new BufferPiece(data));
+	}
+}
+
+function min(a: number, b: number): number {
+	return (a < b ? a : b);
+}
+
+export function createUint32Array(arr: number[]): Uint32Array {
+	let r = new Uint32Array(arr.length);
+	r.set(arr, 0);
+	return r;
+}
+
+export class LineStarts {
+	constructor(
+		public readonly lineStarts: Uint32Array,
+		public readonly cr: number,
+		public readonly lf: number,
+		public readonly crlf: number,
+		public readonly isBasicASCII: boolean
+	) { }
+}
+
+export function createLineStartsFast(str: string): Uint32Array {
+	let r: number[] = [], rLength = 0;
+	for (let i = 0, len = str.length; i < len; i++) {
+		const chr = str.charCodeAt(i);
+
+		if (chr === CharCode.CarriageReturn) {
+			if (i + 1 < len && str.charCodeAt(i + 1) === CharCode.LineFeed) {
+				// \r\n... case
+				r[rLength++] = i + 2;
+				i++; // skip \n
+			} else {
+				// \r... case
+				r[rLength++] = i + 1;
+			}
+		} else if (chr === CharCode.LineFeed) {
+			r[rLength++] = i + 1;
+		}
+	}
+	return createUint32Array(r);
+}
+
+export function createLineStarts(r: number[], str: string): LineStarts {
+	r.length = 0;
+
+	let rLength = 0;
+	let cr = 0, lf = 0, crlf = 0;
+	let isBasicASCII = true;
+	for (let i = 0, len = str.length; i < len; i++) {
+		const chr = str.charCodeAt(i);
+
+		if (chr === CharCode.CarriageReturn) {
+			if (i + 1 < len && str.charCodeAt(i + 1) === CharCode.LineFeed) {
+				// \r\n... case
+				crlf++;
+				r[rLength++] = i + 2;
+				i++; // skip \n
+			} else {
+				cr++;
+				// \r... case
+				r[rLength++] = i + 1;
+			}
+		} else if (chr === CharCode.LineFeed) {
+			lf++;
+			r[rLength++] = i + 1;
+		} else {
+			if (isBasicASCII) {
+				if (chr !== CharCode.Tab && (chr < 32 || chr > 126)) {
+					isBasicASCII = false;
+				}
+			}
+		}
+	}
+
+	const result = new LineStarts(createUint32Array(r), cr, lf, crlf, isBasicASCII);
+	r.length = 0;
+
+	return result;
+}
diff --git a/src/vs/editor/common/model/chunksTextBuffer/chunksTextBuffer.ts b/src/vs/editor/common/model/chunksTextBuffer/chunksTextBuffer.ts
new file mode 100644
index 00000000000..d089cd00af0
--- /dev/null
+++ b/src/vs/editor/common/model/chunksTextBuffer/chunksTextBuffer.ts
@@ -0,0 +1,1527 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import { CharCode } from 'vs/base/common/charCode';
+import { ITextBuffer, EndOfLinePreference, IIdentifiedSingleEditOperation, ApplyEditsResult, ISingleEditOperationIdentifier, IInternalModelContentChange } from 'vs/editor/common/model';
+import { BufferPiece, LeafOffsetLenEdit } from 'vs/editor/common/model/chunksTextBuffer/bufferPiece';
+import { Position } from 'vs/editor/common/core/position';
+import { Range } from 'vs/editor/common/core/range';
+import * as strings from 'vs/base/common/strings';
+import { ITextSnapshot } from 'vs/platform/files/common/files';
+
+export interface IValidatedEditOperation {
+	sortIndex: number;
+	identifier: ISingleEditOperationIdentifier;
+	range: Range;
+	rangeOffset: number;
+	rangeLength: number;
+	lines: string[];
+	forceMoveMarkers: boolean;
+	isAutoWhitespaceEdit: boolean;
+}
+
+export class ChunksTextBuffer implements ITextBuffer {
+
+	private _BOM: string;
+	private _actual: Buffer;
+	private _mightContainRTL: boolean;
+	private _mightContainNonBasicASCII: boolean;
+
+	constructor(pieces: BufferPiece[], _averageChunkSize: number, BOM: string, eol: '\r\n' | '\n', containsRTL: boolean, isBasicASCII: boolean) {
+		this._BOM = BOM;
+		const averageChunkSize = Math.floor(Math.min(65536.0, Math.max(128.0, _averageChunkSize)));
+		const delta = Math.floor(averageChunkSize / 3);
+		const min = averageChunkSize - delta;
+		const max = 2 * min;
+		this._actual = new Buffer(pieces, min, max, eol);
+		this._mightContainRTL = containsRTL;
+		this._mightContainNonBasicASCII = !isBasicASCII;
+	}
+
+	equals(other: ITextBuffer): boolean {
+		if (!(other instanceof ChunksTextBuffer)) {
+			return false;
+		}
+		return this._actual.equals(other._actual);
+	}
+	mightContainRTL(): boolean {
+		return this._mightContainRTL;
+	}
+	mightContainNonBasicASCII(): boolean {
+		return this._mightContainNonBasicASCII;
+	}
+	getBOM(): string {
+		return this._BOM;
+	}
+	getEOL(): string {
+		return this._actual.getEOL();
+	}
+	getOffsetAt(lineNumber: number, column: number): number {
+		return this._actual.convertPositionToOffset(lineNumber, column);
+	}
+	getPositionAt(offset: number): Position {
+		return this._actual.convertOffsetToPosition(offset);
+	}
+	getRangeAt(offset: number, length: number): Range {
+		return this._actual.convertOffsetLenToRange(offset, length);
+	}
+	getValueInRange(range: Range, eol: EndOfLinePreference): string {
+		if (range.isEmpty()) {
+			return '';
+		}
+
+		const text = this._actual.getValueInRange(range);
+		switch (eol) {
+			case EndOfLinePreference.TextDefined:
+				return text;
+			case EndOfLinePreference.LF:
+				if (this.getEOL() === '\n') {
+					return text;
+				} else {
+					return text.replace(/\r\n/g, '\n');
+				}
+			case EndOfLinePreference.CRLF:
+				if (this.getEOL() === '\r\n') {
+					return text;
+				} else {
+					return text.replace(/\n/g, '\r\n');
+				}
+		}
+		return null;
+	}
+
+	public createSnapshot(preserveBOM: boolean): ITextSnapshot {
+		return this._actual.createSnapshot(preserveBOM ? this._BOM : '');
+	}
+
+	getValueLengthInRange(range: Range, eol: EndOfLinePreference): number {
+		if (range.isEmpty()) {
+			return 0;
+		}
+		const eolCount = range.endLineNumber - range.startLineNumber;
+		const result = this._actual.getValueLengthInRange(range);
+		switch (eol) {
+			case EndOfLinePreference.TextDefined:
+				return result;
+			case EndOfLinePreference.LF:
+				if (this.getEOL() === '\n') {
+					return result;
+				} else {
+					return result - eolCount; // \r\n => \n
+				}
+			case EndOfLinePreference.CRLF:
+				if (this.getEOL() === '\r\n') {
+					return result;
+				} else {
+					return result + eolCount; // \n => \r\n
+				}
+		}
+		return 0;
+	}
+
+	public getLength(): number {
+		return this._actual.getLength();
+	}
+
+	getLineCount(): number {
+		return this._actual.getLineCount();
+	}
+
+	getLinesContent(): string[] {
+		return this._actual.getLinesContent();
+	}
+
+	getLineContent(lineNumber: number): string {
+		return this._actual.getLineContent(lineNumber);
+	}
+
+	getLineCharCode(lineNumber: number, index: number): number {
+		return this._actual.getLineCharCode(lineNumber, index);
+	}
+
+	getLineLength(lineNumber: number): number {
+		return this._actual.getLineLength(lineNumber);
+	}
+
+	getLineFirstNonWhitespaceColumn(lineNumber: number): number {
+		const result = this._actual.getLineFirstNonWhitespaceIndex(lineNumber);
+		if (result === -1) {
+			return 0;
+		}
+		return result + 1;
+	}
+	getLineLastNonWhitespaceColumn(lineNumber: number): number {
+		const result = this._actual.getLineLastNonWhitespaceIndex(lineNumber);
+		if (result === -1) {
+			return 0;
+		}
+		return result + 1;
+	}
+	setEOL(newEOL: '\r\n' | '\n'): void {
+		if (this.getEOL() === newEOL) {
+			// nothing to do...
+			return;
+		}
+		this._actual.setEOL(newEOL);
+	}
+
+	private static _sortOpsAscending(a: IValidatedEditOperation, b: IValidatedEditOperation): number {
+		let r = Range.compareRangesUsingEnds(a.range, b.range);
+		if (r === 0) {
+			return a.sortIndex - b.sortIndex;
+		}
+		return r;
+	}
+
+	private static _sortOpsDescending(a: IValidatedEditOperation, b: IValidatedEditOperation): number {
+		let r = Range.compareRangesUsingEnds(a.range, b.range);
+		if (r === 0) {
+			return b.sortIndex - a.sortIndex;
+		}
+		return -r;
+	}
+
+	applyEdits(rawOperations: IIdentifiedSingleEditOperation[], recordTrimAutoWhitespace: boolean): ApplyEditsResult {
+		if (rawOperations.length === 0) {
+			return new ApplyEditsResult([], [], []);
+		}
+
+		let mightContainRTL = this._mightContainRTL;
+		let mightContainNonBasicASCII = this._mightContainNonBasicASCII;
+		let canReduceOperations = true;
+
+		let operations: IValidatedEditOperation[] = [];
+		for (let i = 0; i < rawOperations.length; i++) {
+			let op = rawOperations[i];
+			if (canReduceOperations && op._isTracked) {
+				canReduceOperations = false;
+			}
+			let validatedRange = op.range;
+			if (!mightContainRTL && op.text) {
+				// check if the new inserted text contains RTL
+				mightContainRTL = strings.containsRTL(op.text);
+			}
+			if (!mightContainNonBasicASCII && op.text) {
+				mightContainNonBasicASCII = !strings.isBasicASCII(op.text);
+			}
+			operations[i] = {
+				sortIndex: i,
+				identifier: op.identifier || null,
+				range: validatedRange,
+				rangeOffset: this.getOffsetAt(validatedRange.startLineNumber, validatedRange.startColumn),
+				rangeLength: this.getValueLengthInRange(validatedRange, EndOfLinePreference.TextDefined),
+				lines: op.text ? op.text.split(/\r\n|\r|\n/) : null,
+				forceMoveMarkers: op.forceMoveMarkers || false,
+				isAutoWhitespaceEdit: op.isAutoWhitespaceEdit || false
+			};
+		}
+
+		// Sort operations ascending
+		operations.sort(ChunksTextBuffer._sortOpsAscending);
+
+		for (let i = 0, count = operations.length - 1; i < count; i++) {
+			let rangeEnd = operations[i].range.getEndPosition();
+			let nextRangeStart = operations[i + 1].range.getStartPosition();
+
+			if (nextRangeStart.isBefore(rangeEnd)) {
+				// overlapping ranges
+				throw new Error('Overlapping ranges are not allowed!');
+			}
+		}
+
+		if (canReduceOperations) {
+			operations = this._reduceOperations(operations);
+		}
+
+		// Delta encode operations
+		let reverseRanges = ChunksTextBuffer._getInverseEditRanges(operations);
+		let newTrimAutoWhitespaceCandidates: { lineNumber: number, oldContent: string }[] = [];
+
+		for (let i = 0; i < operations.length; i++) {
+			let op = operations[i];
+			let reverseRange = reverseRanges[i];
+
+			if (recordTrimAutoWhitespace && op.isAutoWhitespaceEdit && op.range.isEmpty()) {
+				// Record already the future line numbers that might be auto whitespace removal candidates on next edit
+				for (let lineNumber = reverseRange.startLineNumber; lineNumber <= reverseRange.endLineNumber; lineNumber++) {
+					let currentLineContent = '';
+					if (lineNumber === reverseRange.startLineNumber) {
+						currentLineContent = this.getLineContent(op.range.startLineNumber);
+						if (strings.firstNonWhitespaceIndex(currentLineContent) !== -1) {
+							continue;
+						}
+					}
+					newTrimAutoWhitespaceCandidates.push({ lineNumber: lineNumber, oldContent: currentLineContent });
+				}
+			}
+		}
+
+		let reverseOperations: IIdentifiedSingleEditOperation[] = [];
+		for (let i = 0; i < operations.length; i++) {
+			let op = operations[i];
+			let reverseRange = reverseRanges[i];
+
+			reverseOperations[i] = {
+				identifier: op.identifier,
+				range: reverseRange,
+				text: this.getValueInRange(op.range, EndOfLinePreference.TextDefined),
+				forceMoveMarkers: op.forceMoveMarkers
+			};
+		}
+
+		this._mightContainRTL = mightContainRTL;
+		this._mightContainNonBasicASCII = mightContainNonBasicASCII;
+
+		const contentChanges = this._doApplyEdits(operations);
+
+		let trimAutoWhitespaceLineNumbers: number[] = null;
+		if (recordTrimAutoWhitespace && newTrimAutoWhitespaceCandidates.length > 0) {
+			// sort line numbers auto whitespace removal candidates for next edit descending
+			newTrimAutoWhitespaceCandidates.sort((a, b) => b.lineNumber - a.lineNumber);
+
+			trimAutoWhitespaceLineNumbers = [];
+			for (let i = 0, len = newTrimAutoWhitespaceCandidates.length; i < len; i++) {
+				let lineNumber = newTrimAutoWhitespaceCandidates[i].lineNumber;
+				if (i > 0 && newTrimAutoWhitespaceCandidates[i - 1].lineNumber === lineNumber) {
+					// Do not have the same line number twice
+					continue;
+				}
+
+				let prevContent = newTrimAutoWhitespaceCandidates[i].oldContent;
+				let lineContent = this.getLineContent(lineNumber);
+
+				if (lineContent.length === 0 || lineContent === prevContent || strings.firstNonWhitespaceIndex(lineContent) !== -1) {
+					continue;
+				}
+
+				trimAutoWhitespaceLineNumbers.push(lineNumber);
+			}
+		}
+
+		return new ApplyEditsResult(
+			reverseOperations,
+			contentChanges,
+			trimAutoWhitespaceLineNumbers
+		);
+	}
+
+	/**
+	 * Transform operations such that they represent the same logic edit,
+	 * but that they also do not cause OOM crashes.
+	 */
+	private _reduceOperations(operations: IValidatedEditOperation[]): IValidatedEditOperation[] {
+		if (operations.length < 1000) {
+			// We know from empirical testing that a thousand edits work fine regardless of their shape.
+			return operations;
+		}
+
+		// At one point, due to how events are emitted and how each operation is handled,
+		// some operations can trigger a high ammount of temporary string allocations,
+		// that will immediately get edited again.
+		// e.g. a formatter inserting ridiculous ammounts of \n on a model with a single line
+		// Therefore, the strategy is to collapse all the operations into a huge single edit operation
+		return [this._toSingleEditOperation(operations)];
+	}
+
+	_toSingleEditOperation(operations: IValidatedEditOperation[]): IValidatedEditOperation {
+		let forceMoveMarkers = false,
+			firstEditRange = operations[0].range,
+			lastEditRange = operations[operations.length - 1].range,
+			entireEditRange = new Range(firstEditRange.startLineNumber, firstEditRange.startColumn, lastEditRange.endLineNumber, lastEditRange.endColumn),
+			lastEndLineNumber = firstEditRange.startLineNumber,
+			lastEndColumn = firstEditRange.startColumn,
+			result: string[] = [];
+
+		for (let i = 0, len = operations.length; i < len; i++) {
+			let operation = operations[i],
+				range = operation.range;
+
+			forceMoveMarkers = forceMoveMarkers || operation.forceMoveMarkers;
+
+			// (1) -- Push old text
+			for (let lineNumber = lastEndLineNumber; lineNumber < range.startLineNumber; lineNumber++) {
+				if (lineNumber === lastEndLineNumber) {
+					result.push(this.getLineContent(lineNumber).substring(lastEndColumn - 1));
+				} else {
+					result.push('\n');
+					result.push(this.getLineContent(lineNumber));
+				}
+			}
+
+			if (range.startLineNumber === lastEndLineNumber) {
+				result.push(this.getLineContent(range.startLineNumber).substring(lastEndColumn - 1, range.startColumn - 1));
+			} else {
+				result.push('\n');
+				result.push(this.getLineContent(range.startLineNumber).substring(0, range.startColumn - 1));
+			}
+
+			// (2) -- Push new text
+			if (operation.lines) {
+				for (let j = 0, lenJ = operation.lines.length; j < lenJ; j++) {
+					if (j !== 0) {
+						result.push('\n');
+					}
+					result.push(operation.lines[j]);
+				}
+			}
+
+			lastEndLineNumber = operation.range.endLineNumber;
+			lastEndColumn = operation.range.endColumn;
+		}
+
+		return {
+			sortIndex: 0,
+			identifier: operations[0].identifier,
+			range: entireEditRange,
+			rangeOffset: this.getOffsetAt(entireEditRange.startLineNumber, entireEditRange.startColumn),
+			rangeLength: this.getValueLengthInRange(entireEditRange, EndOfLinePreference.TextDefined),
+			lines: result.join('').split('\n'),
+			forceMoveMarkers: forceMoveMarkers,
+			isAutoWhitespaceEdit: false
+		};
+	}
+
+	private _doApplyEdits(operations: IValidatedEditOperation[]): IInternalModelContentChange[] {
+
+		// Sort operations descending
+		operations.sort(ChunksTextBuffer._sortOpsDescending);
+
+		let contentChanges: IInternalModelContentChange[] = [];
+		let edits: OffsetLenEdit[] = [];
+
+		for (let i = 0, len = operations.length; i < len; i++) {
+			const op = operations[i];
+
+			const text = (op.lines ? op.lines.join(this.getEOL()) : '');
+			edits[i] = new OffsetLenEdit(op.sortIndex, op.rangeOffset, op.rangeLength, text);
+
+			const startLineNumber = op.range.startLineNumber;
+			const startColumn = op.range.startColumn;
+			const endLineNumber = op.range.endLineNumber;
+			const endColumn = op.range.endColumn;
+
+			if (startLineNumber === endLineNumber && startColumn === endColumn && (!op.lines || op.lines.length === 0)) {
+				// no-op
+				continue;
+			}
+
+			contentChanges.push({
+				range: op.range,
+				rangeLength: op.rangeLength,
+				text: text,
+				lines: op.lines,
+				rangeOffset: op.rangeOffset,
+				forceMoveMarkers: op.forceMoveMarkers
+			});
+		}
+
+		this._actual.replaceOffsetLen(edits);
+
+		return contentChanges;
+	}
+
+	/**
+	 * Assumes `operations` are validated and sorted ascending
+	 */
+	public static _getInverseEditRanges(operations: IValidatedEditOperation[]): Range[] {
+		let result: Range[] = [];
+
+		let prevOpEndLineNumber: number;
+		let prevOpEndColumn: number;
+		let prevOp: IValidatedEditOperation = null;
+		for (let i = 0, len = operations.length; i < len; i++) {
+			let op = operations[i];
+
+			let startLineNumber: number;
+			let startColumn: number;
+
+			if (prevOp) {
+				if (prevOp.range.endLineNumber === op.range.startLineNumber) {
+					startLineNumber = prevOpEndLineNumber;
+					startColumn = prevOpEndColumn + (op.range.startColumn - prevOp.range.endColumn);
+				} else {
+					startLineNumber = prevOpEndLineNumber + (op.range.startLineNumber - prevOp.range.endLineNumber);
+					startColumn = op.range.startColumn;
+				}
+			} else {
+				startLineNumber = op.range.startLineNumber;
+				startColumn = op.range.startColumn;
+			}
+
+			let resultRange: Range;
+
+			if (op.lines && op.lines.length > 0) {
+				// the operation inserts something
+				let lineCount = op.lines.length;
+				let firstLine = op.lines[0];
+				let lastLine = op.lines[lineCount - 1];
+
+				if (lineCount === 1) {
+					// single line insert
+					resultRange = new Range(startLineNumber, startColumn, startLineNumber, startColumn + firstLine.length);
+				} else {
+					// multi line insert
+					resultRange = new Range(startLineNumber, startColumn, startLineNumber + lineCount - 1, lastLine.length + 1);
+				}
+			} else {
+				// There is nothing to insert
+				resultRange = new Range(startLineNumber, startColumn, startLineNumber, startColumn);
+			}
+
+			prevOpEndLineNumber = resultRange.endLineNumber;
+			prevOpEndColumn = resultRange.endColumn;
+
+			result.push(resultRange);
+			prevOp = op;
+		}
+
+		return result;
+	}
+}
+
+
+class BufferNodes {
+
+	public length: Uint32Array;
+	public newLineCount: Uint32Array;
+
+	constructor(count: number) {
+		this.length = new Uint32Array(count);
+		this.newLineCount = new Uint32Array(count);
+	}
+
+}
+
+class BufferCursor {
+	constructor(
+		public offset: number,
+		public leafIndex: number,
+		public leafStartOffset: number,
+		public leafStartNewLineCount: number
+	) { }
+
+	public set(offset: number, leafIndex: number, leafStartOffset: number, leafStartNewLineCount: number) {
+		this.offset = offset;
+		this.leafIndex = leafIndex;
+		this.leafStartOffset = leafStartOffset;
+		this.leafStartNewLineCount = leafStartNewLineCount;
+	}
+}
+
+class OffsetLenEdit {
+	constructor(
+		public readonly initialIndex: number,
+		public readonly offset: number,
+		public length: number,
+		public text: string
+	) { }
+}
+
+class InternalOffsetLenEdit {
+	constructor(
+		public readonly startLeafIndex: number,
+		public readonly startInnerOffset: number,
+		public readonly endLeafIndex: number,
+		public readonly endInnerOffset: number,
+		public text: string
+	) { }
+}
+
+class LeafReplacement {
+	constructor(
+		public readonly startLeafIndex: number,
+		public readonly endLeafIndex: number,
+		public readonly replacements: BufferPiece[]
+	) { }
+}
+
+const BUFFER_CURSOR_POOL_SIZE = 10;
+const BufferCursorPool = new class {
+	private _pool: BufferCursor[];
+	private _len: number;
+
+	constructor() {
+		this._pool = [];
+		for (let i = 0; i < BUFFER_CURSOR_POOL_SIZE; i++) {
+			this._pool[i] = new BufferCursor(0, 0, 0, 0);
+		}
+		this._len = this._pool.length;
+	}
+
+	public put(cursor: BufferCursor): void {
+		if (this._len > this._pool.length) {
+			// oh, well
+			return;
+		}
+		this._pool[this._len++] = cursor;
+	}
+
+	public take(): BufferCursor {
+		if (this._len === 0) {
+			// oh, well
+			console.log(`insufficient BufferCursor pool`);
+			return new BufferCursor(0, 0, 0, 0);
+		}
+		const result = this._pool[this._len - 1];
+		this._pool[this._len--] = null;
+		return result;
+	}
+};
+
+class BufferSnapshot implements ITextSnapshot {
+
+	private readonly _pieces: BufferPiece[];
+	private readonly _piecesLength: number;
+	private readonly _BOM: string;
+	private _piecesIndex: number;
+
+	constructor(pieces: BufferPiece[], BOM: string) {
+		this._pieces = pieces;
+		this._piecesLength = this._pieces.length;
+		this._BOM = BOM;
+		this._piecesIndex = 0;
+	}
+
+	public read(): string {
+		if (this._piecesIndex >= this._piecesLength) {
+			return null;
+		}
+
+		let result: string = null;
+		if (this._piecesIndex === 0) {
+			result = this._BOM + this._pieces[this._piecesIndex].text;
+		} else {
+			result = this._pieces[this._piecesIndex].text;
+		}
+
+		this._piecesIndex++;
+		return result;
+	}
+}
+
+class Buffer {
+
+	private _minLeafLength: number;
+	private _maxLeafLength: number;
+	private _idealLeafLength: number;
+
+	private _eol: '\r\n' | '\n';
+	private _eolLength: number;
+
+	private _leafs: BufferPiece[];
+	private _nodes: BufferNodes;
+	private _nodesCount: number;
+	private _leafsStart: number;
+	private _leafsEnd: number;
+
+	constructor(pieces: BufferPiece[], minLeafLength: number, maxLeafLength: number, eol: '\r\n' | '\n') {
+		if (!(2 * minLeafLength >= maxLeafLength)) {
+			throw new Error(`assertion violation`);
+		}
+
+		this._minLeafLength = minLeafLength;
+		this._maxLeafLength = maxLeafLength;
+		this._idealLeafLength = (minLeafLength + maxLeafLength) >>> 1;
+
+		this._eol = eol;
+		this._eolLength = this._eol.length;
+
+		this._leafs = pieces;
+		this._nodes = null;
+		this._nodesCount = 0;
+		this._leafsStart = 0;
+		this._leafsEnd = 0;
+
+		this._rebuildNodes();
+	}
+
+	equals(other: Buffer): boolean {
+		return Buffer.equals(this, other);
+	}
+
+	private static equals(a: Buffer, b: Buffer): boolean {
+		const aLength = a.getLength();
+		const bLength = b.getLength();
+		if (aLength !== bLength) {
+			return false;
+		}
+		if (a.getLineCount() !== b.getLineCount()) {
+			return false;
+		}
+
+		let remaining = aLength;
+		let aLeafIndex = -1, aLeaf = null, aLeafLength = 0, aLeafRemaining = 0;
+		let bLeafIndex = -1, bLeaf = null, bLeafLength = 0, bLeafRemaining = 0;
+
+		while (remaining > 0) {
+			if (aLeafRemaining === 0) {
+				aLeafIndex++;
+				aLeaf = a._leafs[aLeafIndex];
+				aLeafLength = aLeaf.length();
+				aLeafRemaining = aLeafLength;
+			}
+
+			if (bLeafRemaining === 0) {
+				bLeafIndex++;
+				bLeaf = b._leafs[bLeafIndex];
+				bLeafLength = bLeaf.length();
+				bLeafRemaining = bLeafLength;
+			}
+
+			let consuming = Math.min(aLeafRemaining, bLeafRemaining);
+
+			let aStr = aLeaf.substr(aLeafLength - aLeafRemaining, consuming);
+			let bStr = bLeaf.substr(bLeafLength - bLeafRemaining, consuming);
+
+			if (aStr !== bStr) {
+				return false;
+			}
+
+			remaining -= consuming;
+			aLeafRemaining -= consuming;
+			bLeafRemaining -= consuming;
+		}
+
+		return true;
+	}
+
+	public getEOL(): string {
+		return this._eol;
+	}
+
+	private _rebuildNodes() {
+		const leafsCount = this._leafs.length;
+
+		this._nodesCount = (1 << log2(leafsCount));
+		this._leafsStart = this._nodesCount;
+		this._leafsEnd = this._leafsStart + leafsCount;
+
+		this._nodes = new BufferNodes(this._nodesCount);
+		for (let i = this._nodesCount - 1; i >= 1; i--) {
+			this._updateSingleNode(i);
+		}
+	}
+
+	private _updateSingleNode(nodeIndex: number): void {
+		const left = LEFT_CHILD(nodeIndex);
+		const right = RIGHT_CHILD(nodeIndex);
+
+		let length = 0;
+		let newLineCount = 0;
+
+		if (this.IS_NODE(left)) {
+			length += this._nodes.length[left];
+			newLineCount += this._nodes.newLineCount[left];
+		} else if (this.IS_LEAF(left)) {
+			const leaf = this._leafs[this.NODE_TO_LEAF_INDEX(left)];
+			length += leaf.length();
+			newLineCount += leaf.newLineCount();
+		}
+
+		if (this.IS_NODE(right)) {
+			length += this._nodes.length[right];
+			newLineCount += this._nodes.newLineCount[right];
+		} else if (this.IS_LEAF(right)) {
+			const leaf = this._leafs[this.NODE_TO_LEAF_INDEX(right)];
+			length += leaf.length();
+			newLineCount += leaf.newLineCount();
+		}
+
+		this._nodes.length[nodeIndex] = length;
+		this._nodes.newLineCount[nodeIndex] = newLineCount;
+	}
+
+	private _findOffset(offset: number, result: BufferCursor): boolean {
+		if (offset > this._nodes.length[1]) {
+			return false;
+		}
+
+		let it = 1;
+		let searchOffset = offset;
+		let leafStartOffset = 0;
+		let leafStartNewLineCount = 0;
+		while (!this.IS_LEAF(it)) {
+			const left = LEFT_CHILD(it);
+			const right = RIGHT_CHILD(it);
+
+			let leftNewLineCount = 0;
+			let leftLength = 0;
+			if (this.IS_NODE(left)) {
+				leftNewLineCount = this._nodes.newLineCount[left];
+				leftLength = this._nodes.length[left];
+			} else if (this.IS_LEAF(left)) {
+				const leaf = this._leafs[this.NODE_TO_LEAF_INDEX(left)];
+				leftNewLineCount = leaf.newLineCount();
+				leftLength = leaf.length();
+			}
+
+			let rightLength = 0;
+			if (this.IS_NODE(right)) {
+				rightLength += this._nodes.length[right];
+			} else if (this.IS_LEAF(right)) {
+				rightLength += this._leafs[this.NODE_TO_LEAF_INDEX(right)].length();
+			}
+
+			if (searchOffset < leftLength || rightLength === 0) {
+				// go left
+				it = left;
+			} else {
+				// go right
+				searchOffset -= leftLength;
+				leafStartOffset += leftLength;
+				leafStartNewLineCount += leftNewLineCount;
+				it = right;
+			}
+		}
+		it = this.NODE_TO_LEAF_INDEX(it);
+
+		result.set(offset, it, leafStartOffset, leafStartNewLineCount);
+		return true;
+	}
+
+	private _findOffsetCloseAfter(offset: number, start: BufferCursor, result: BufferCursor): boolean {
+		if (offset > this._nodes.length[1]) {
+			return false;
+		}
+
+		let innerOffset = offset - start.leafStartOffset;
+		const leafsCount = this._leafs.length;
+
+		let leafIndex = start.leafIndex;
+		let leafStartOffset = start.leafStartOffset;
+		let leafStartNewLineCount = start.leafStartNewLineCount;
+
+		while (true) {
+			const leaf = this._leafs[leafIndex];
+
+			if (innerOffset < leaf.length() || (innerOffset === leaf.length() && leafIndex + 1 === leafsCount)) {
+				result.set(offset, leafIndex, leafStartOffset, leafStartNewLineCount);
+				return true;
+			}
+
+			leafIndex++;
+
+			if (leafIndex >= leafsCount) {
+				result.set(offset, leafIndex, leafStartOffset, leafStartNewLineCount);
+				return true;
+			}
+
+			leafStartOffset += leaf.length();
+			leafStartNewLineCount += leaf.newLineCount();
+			innerOffset -= leaf.length();
+		}
+	}
+
+	private _findLineStart(lineNumber: number, result: BufferCursor): boolean {
+		let lineIndex = lineNumber - 1;
+		if (lineIndex < 0 || lineIndex > this._nodes.newLineCount[1]) {
+			result.set(0, 0, 0, 0);
+			return false;
+		}
+
+		let it = 1;
+		let leafStartOffset = 0;
+		let leafStartNewLineCount = 0;
+		while (!this.IS_LEAF(it)) {
+			const left = LEFT_CHILD(it);
+			const right = RIGHT_CHILD(it);
+
+			let leftNewLineCount = 0;
+			let leftLength = 0;
+			if (this.IS_NODE(left)) {
+				leftNewLineCount = this._nodes.newLineCount[left];
+				leftLength = this._nodes.length[left];
+			} else if (this.IS_LEAF(left)) {
+				const leaf = this._leafs[this.NODE_TO_LEAF_INDEX(left)];
+				leftNewLineCount = leaf.newLineCount();
+				leftLength = leaf.length();
+			}
+
+			if (lineIndex <= leftNewLineCount) {
+				// go left
+				it = left;
+				continue;
+			}
+
+			// go right
+			lineIndex -= leftNewLineCount;
+			leafStartOffset += leftLength;
+			leafStartNewLineCount += leftNewLineCount;
+			it = right;
+		}
+		it = this.NODE_TO_LEAF_INDEX(it);
+
+		const innerLineStartOffset = (lineIndex === 0 ? 0 : this._leafs[it].lineStartFor(lineIndex - 1));
+
+		result.set(leafStartOffset + innerLineStartOffset, it, leafStartOffset, leafStartNewLineCount);
+		return true;
+	}
+
+	private _findLineEnd(start: BufferCursor, lineNumber: number, result: BufferCursor): void {
+		let innerLineIndex = lineNumber - 1 - start.leafStartNewLineCount;
+		const leafsCount = this._leafs.length;
+
+		let leafIndex = start.leafIndex;
+		let leafStartOffset = start.leafStartOffset;
+		let leafStartNewLineCount = start.leafStartNewLineCount;
+		while (true) {
+			const leaf = this._leafs[leafIndex];
+
+			if (innerLineIndex < leaf.newLineCount()) {
+				const lineEndOffset = this._leafs[leafIndex].lineStartFor(innerLineIndex);
+				result.set(leafStartOffset + lineEndOffset, leafIndex, leafStartOffset, leafStartNewLineCount);
+				return;
+			}
+
+			leafIndex++;
+
+			if (leafIndex >= leafsCount) {
+				result.set(leafStartOffset + leaf.length(), leafIndex - 1, leafStartOffset, leafStartNewLineCount);
+				return;
+			}
+
+			leafStartOffset += leaf.length();
+			leafStartNewLineCount += leaf.newLineCount();
+			innerLineIndex = 0;
+		}
+	}
+
+	private _findLine(lineNumber: number, start: BufferCursor, end: BufferCursor): boolean {
+		if (!this._findLineStart(lineNumber, start)) {
+			return false;
+		}
+
+		this._findLineEnd(start, lineNumber, end);
+		return true;
+	}
+
+	public getLength(): number {
+		return this._nodes.length[1];
+	}
+
+	public getLineCount(): number {
+		return this._nodes.newLineCount[1] + 1;
+	}
+
+	public getLineContent(lineNumber: number): string {
+		const start = BufferCursorPool.take();
+		const end = BufferCursorPool.take();
+
+		if (!this._findLine(lineNumber, start, end)) {
+			BufferCursorPool.put(start);
+			BufferCursorPool.put(end);
+			throw new Error(`Line not found`);
+		}
+
+		let result: string;
+		if (lineNumber === this.getLineCount()) {
+			// last line is not trailed by an eol
+			result = this.extractString(start, end.offset - start.offset);
+		} else {
+			result = this.extractString(start, end.offset - start.offset - this._eolLength);
+		}
+
+		BufferCursorPool.put(start);
+		BufferCursorPool.put(end);
+		return result;
+	}
+
+	public getLineCharCode(lineNumber: number, index: number): number {
+		const start = BufferCursorPool.take();
+
+		if (!this._findLineStart(lineNumber, start)) {
+			BufferCursorPool.put(start);
+			throw new Error(`Line not found`);
+		}
+
+		const tmp = BufferCursorPool.take();
+		this._findOffsetCloseAfter(start.offset + index, start, tmp);
+		const result = this._leafs[tmp.leafIndex].charCodeAt(tmp.offset - tmp.leafStartNewLineCount);
+		BufferCursorPool.put(tmp);
+
+		BufferCursorPool.put(start);
+		return result;
+	}
+
+	public getLineLength(lineNumber: number): number {
+		const start = BufferCursorPool.take();
+		const end = BufferCursorPool.take();
+
+		if (!this._findLine(lineNumber, start, end)) {
+			BufferCursorPool.put(start);
+			BufferCursorPool.put(end);
+			throw new Error(`Line not found`);
+		}
+
+		let result: number;
+		if (lineNumber === this.getLineCount()) {
+			// last line is not trailed by an eol
+			result = end.offset - start.offset;
+		} else {
+			result = end.offset - start.offset - this._eolLength;
+		}
+
+		BufferCursorPool.put(start);
+		BufferCursorPool.put(end);
+		return result;
+	}
+
+	public getLineFirstNonWhitespaceIndex(lineNumber: number): number {
+		const start = BufferCursorPool.take();
+
+		if (!this._findLineStart(lineNumber, start)) {
+			BufferCursorPool.put(start);
+			throw new Error(`Line not found`);
+		}
+
+		let leafIndex = start.leafIndex;
+		let searchStartOffset = start.offset - start.leafStartOffset;
+		BufferCursorPool.put(start);
+
+		const leafsCount = this._leafs.length;
+		let totalDelta = 0;
+		while (true) {
+			const leaf = this._leafs[leafIndex];
+
+			const leafResult = leaf.findLineFirstNonWhitespaceIndex(searchStartOffset);
+			if (leafResult === -2) {
+				// reached EOL
+				return -1;
+			}
+			if (leafResult !== -1) {
+				return (leafResult - searchStartOffset) + totalDelta;
+			}
+
+			leafIndex++;
+
+			if (leafIndex >= leafsCount) {
+				return -1;
+			}
+
+			totalDelta += (leaf.length() - searchStartOffset);
+			searchStartOffset = 0;
+		}
+	}
+
+	public getLineLastNonWhitespaceIndex(lineNumber: number): number {
+		const start = BufferCursorPool.take();
+		const end = BufferCursorPool.take();
+
+		if (!this._findLineStart(lineNumber, start)) {
+			BufferCursorPool.put(start);
+			BufferCursorPool.put(end);
+			throw new Error(`Line not found`);
+		}
+
+		this._findLineEnd(start, lineNumber, end);
+
+		const startOffset = start.offset;
+		const endOffset = end.offset;
+		let leafIndex = end.leafIndex;
+		let searchStartOffset = end.offset - end.leafStartOffset - this._eolLength;
+
+		BufferCursorPool.put(start);
+		BufferCursorPool.put(end);
+
+		let totalDelta = 0;
+		while (true) {
+			const leaf = this._leafs[leafIndex];
+
+			const leafResult = leaf.findLineLastNonWhitespaceIndex(searchStartOffset);
+			if (leafResult === -2) {
+				// reached EOL
+				return -1;
+			}
+			if (leafResult !== -1) {
+				const delta = (searchStartOffset - 1 - leafResult);
+				const absoluteOffset = (endOffset - this._eolLength) - delta - totalDelta;
+				return absoluteOffset - startOffset;
+			}
+
+			leafIndex--;
+
+			if (leafIndex < 0) {
+				return -1;
+			}
+
+			totalDelta += searchStartOffset;
+			searchStartOffset = leaf.length();
+		}
+	}
+
+	public getLinesContent(): string[] {
+		let result: string[] = new Array<string>(this.getLineCount());
+		let resultIndex = 0;
+
+		let currentLine = '';
+		for (let leafIndex = 0, leafsCount = this._leafs.length; leafIndex < leafsCount; leafIndex++) {
+			const leaf = this._leafs[leafIndex];
+			const leafNewLineCount = leaf.newLineCount();
+
+			if (leafNewLineCount === 0) {
+				// special case => push entire leaf text
+				currentLine += leaf.text;
+				continue;
+			}
+
+			let leafSubstrOffset = 0;
+			for (let newLineIndex = 0; newLineIndex < leafNewLineCount; newLineIndex++) {
+				const newLineStart = leaf.lineStartFor(newLineIndex);
+				currentLine += leaf.substr(leafSubstrOffset, newLineStart - leafSubstrOffset - this._eolLength);
+				result[resultIndex++] = currentLine;
+
+				currentLine = '';
+				leafSubstrOffset = newLineStart;
+			}
+			currentLine += leaf.substr(leafSubstrOffset, leaf.length());
+		}
+		result[resultIndex++] = currentLine;
+
+		return result;
+	}
+
+	public extractString(start: BufferCursor, len: number): string {
+		if (!(start.offset + len <= this._nodes.length[1])) {
+			throw new Error(`assertion violation`);
+		}
+
+		let innerLeafOffset = start.offset - start.leafStartOffset;
+		let leafIndex = start.leafIndex;
+		let res = '';
+		while (len > 0) {
+			const leaf = this._leafs[leafIndex];
+			const cnt = Math.min(len, leaf.length() - innerLeafOffset);
+			res += leaf.substr(innerLeafOffset, cnt);
+
+			len -= cnt;
+			innerLeafOffset = 0;
+
+			if (len === 0) {
+				break;
+			}
+
+			leafIndex++;
+		}
+		return res;
+	}
+
+	private _getOffsetAt(lineNumber: number, column: number, result: BufferCursor): boolean {
+		const lineStart = BufferCursorPool.take();
+
+		if (!this._findLineStart(lineNumber, lineStart)) {
+			BufferCursorPool.put(lineStart);
+			return false;
+		}
+
+		const startOffset = lineStart.offset + column - 1;
+		if (!this._findOffsetCloseAfter(startOffset, lineStart, result)) {
+			BufferCursorPool.put(lineStart);
+			return false;
+		}
+
+		BufferCursorPool.put(lineStart);
+		return true;
+	}
+
+	public convertPositionToOffset(lineNumber: number, column: number): number {
+		const r = BufferCursorPool.take();
+
+		if (!this._findLineStart(lineNumber, r)) {
+			BufferCursorPool.put(r);
+			throw new Error(`Position not found`);
+		}
+
+		const result = r.offset + column - 1;
+
+		BufferCursorPool.put(r);
+		return result;
+	}
+
+	/**
+	 * returns `lineNumber`
+	 */
+	private _findLineStartBeforeOffsetInLeaf(offset: number, leafIndex: number, leafStartOffset: number, leafStartNewLineCount: number, result: BufferCursor): number {
+		const leaf = this._leafs[leafIndex];
+		const lineStartIndex = leaf.findLineStartBeforeOffset(offset - leafStartOffset);
+		const lineStartOffset = leafStartOffset + leaf.lineStartFor(lineStartIndex);
+
+		result.set(lineStartOffset, leafIndex, leafStartOffset, leafStartNewLineCount);
+		return leafStartNewLineCount + lineStartIndex + 2;
+	}
+
+	/**
+	 * returns `lineNumber`.
+	 */
+	private _findLineStartBeforeOffset(offset: number, location: BufferCursor, result: BufferCursor): number {
+
+		let leafIndex = location.leafIndex;
+		let leafStartOffset = location.leafStartOffset;
+		let leafStartNewLineCount = location.leafStartNewLineCount;
+		while (true) {
+			const leaf = this._leafs[leafIndex];
+
+			if (leaf.newLineCount() >= 1 && leaf.lineStartFor(0) + leafStartOffset <= offset) {
+				// must be in this leaf
+				return this._findLineStartBeforeOffsetInLeaf(offset, leafIndex, leafStartOffset, leafStartNewLineCount, result);
+			}
+
+			// continue looking in previous leaf
+			leafIndex--;
+
+			if (leafIndex < 0) {
+				result.set(0, 0, 0, 0);
+				return 1;
+			}
+
+			leafStartOffset -= this._leafs[leafIndex].length();
+			leafStartNewLineCount -= this._leafs[leafIndex].newLineCount();
+		}
+	}
+
+	public convertOffsetToPosition(offset: number): Position {
+		const r = BufferCursorPool.take();
+		const lineStart = BufferCursorPool.take();
+
+		if (!this._findOffset(offset, r)) {
+			BufferCursorPool.put(r);
+			BufferCursorPool.put(lineStart);
+			throw new Error(`Offset not found`);
+		}
+
+		const lineNumber = this._findLineStartBeforeOffset(offset, r, lineStart);
+		const column = offset - lineStart.offset + 1;
+
+		BufferCursorPool.put(r);
+		BufferCursorPool.put(lineStart);
+
+		return new Position(lineNumber, column);
+	}
+
+	public convertOffsetLenToRange(offset: number, len: number): Range {
+		const r = BufferCursorPool.take();
+		const lineStart = BufferCursorPool.take();
+
+		if (!this._findOffset(offset, r)) {
+			BufferCursorPool.put(r);
+			BufferCursorPool.put(lineStart);
+			throw new Error(`Offset not found`);
+		}
+		const startLineNumber = this._findLineStartBeforeOffset(offset, r, lineStart);
+		const startColumn = offset - lineStart.offset + 1;
+
+		if (!this._findOffset(offset + len, r)) {
+			BufferCursorPool.put(r);
+			BufferCursorPool.put(lineStart);
+			throw new Error(`Offset not found`);
+		}
+		const endLineNumber = this._findLineStartBeforeOffset(offset + len, r, lineStart);
+		const endColumn = offset + len - lineStart.offset + 1;
+
+		BufferCursorPool.put(r);
+		BufferCursorPool.put(lineStart);
+
+		return new Range(startLineNumber, startColumn, endLineNumber, endColumn);
+	}
+
+	public getValueInRange(range: Range): string {
+		const start = BufferCursorPool.take();
+
+		if (!this._getOffsetAt(range.startLineNumber, range.startColumn, start)) {
+			BufferCursorPool.put(start);
+			throw new Error(`Line not found`);
+		}
+
+		const endOffset = this.convertPositionToOffset(range.endLineNumber, range.endColumn);
+		const result = this.extractString(start, endOffset - start.offset);
+
+		BufferCursorPool.put(start);
+		return result;
+	}
+
+	public createSnapshot(BOM: string): ITextSnapshot {
+		return new BufferSnapshot(this._leafs, BOM);
+	}
+
+	public getValueLengthInRange(range: Range): number {
+		const startOffset = this.convertPositionToOffset(range.startLineNumber, range.startColumn);
+		const endOffset = this.convertPositionToOffset(range.endLineNumber, range.endColumn);
+		return endOffset - startOffset;
+	}
+
+	//#region Editing
+
+	private _mergeAdjacentEdits(edits: OffsetLenEdit[]): OffsetLenEdit[] {
+		// Check if we must merge adjacent edits
+		let merged: OffsetLenEdit[] = [], mergedLength = 0;
+		let prev = edits[0];
+		for (let i = 1, len = edits.length; i < len; i++) {
+			const curr = edits[i];
+			if (prev.offset + prev.length === curr.offset) {
+				// merge into `prev`
+				prev.length = prev.length + curr.length;
+				prev.text = prev.text + curr.text;
+			} else {
+				merged[mergedLength++] = prev;
+				prev = curr;
+			}
+		}
+		merged[mergedLength++] = prev;
+
+		return merged;
+	}
+
+	private _resolveEdits(edits: OffsetLenEdit[]): InternalOffsetLenEdit[] {
+		edits = this._mergeAdjacentEdits(edits);
+
+		let result: InternalOffsetLenEdit[] = [];
+		let tmp = new BufferCursor(0, 0, 0, 0);
+		let tmp2 = new BufferCursor(0, 0, 0, 0);
+		for (let i = 0, len = edits.length; i < len; i++) {
+			const edit = edits[i];
+
+			let text = edit.text;
+
+			this._findOffset(edit.offset, tmp);
+			let startLeafIndex = tmp.leafIndex;
+			let startInnerOffset = tmp.offset - tmp.leafStartOffset;
+			if (startInnerOffset > 0) {
+				const startLeaf = this._leafs[startLeafIndex];
+				const charBefore = startLeaf.charCodeAt(startInnerOffset - 1);
+				if (charBefore === CharCode.CarriageReturn) {
+					// include the replacement of \r in the edit
+					text = '\r' + text;
+
+					this._findOffsetCloseAfter(edit.offset - 1, tmp, tmp2);
+					startLeafIndex = tmp2.leafIndex;
+					startInnerOffset = tmp2.offset - tmp2.leafStartOffset;
+					// this._findOffset(edit.offset - 1, tmp);
+					// startLeafIndex = tmp.leafIndex;
+					// startInnerOffset = tmp.offset - tmp.leafStartOffset;
+				}
+			}
+
+			this._findOffset(edit.offset + edit.length, tmp);
+			let endLeafIndex = tmp.leafIndex;
+			let endInnerOffset = tmp.offset - tmp.leafStartOffset;
+			const endLeaf = this._leafs[endLeafIndex];
+			if (endInnerOffset < endLeaf.length()) {
+				const charAfter = endLeaf.charCodeAt(endInnerOffset);
+				if (charAfter === CharCode.LineFeed) {
+					// include the replacement of \n in the edit
+					text = text + '\n';
+
+					this._findOffsetCloseAfter(edit.offset + edit.length + 1, tmp, tmp2);
+					endLeafIndex = tmp2.leafIndex;
+					endInnerOffset = tmp2.offset - tmp2.leafStartOffset;
+					// this._findOffset(edit.offset + edit.length + 1, tmp);
+					// endLeafIndex = tmp.leafIndex;
+					// endInnerOffset = tmp.offset - tmp.leafStartOffset;
+				}
+			}
+
+			result[i] = new InternalOffsetLenEdit(
+				startLeafIndex, startInnerOffset,
+				endLeafIndex, endInnerOffset,
+				text
+			);
+		}
+
+		return result;
+	}
+
+	private _pushLeafReplacement(startLeafIndex: number, endLeafIndex: number, replacements: LeafReplacement[]): LeafReplacement {
+		const res = new LeafReplacement(startLeafIndex, endLeafIndex, []);
+		replacements.push(res);
+		return res;
+	}
+
+	private _flushLeafEdits(accumulatedLeafIndex: number, accumulatedLeafEdits: LeafOffsetLenEdit[], replacements: LeafReplacement[]): void {
+		if (accumulatedLeafEdits.length > 0) {
+			const rep = this._pushLeafReplacement(accumulatedLeafIndex, accumulatedLeafIndex, replacements);
+			BufferPiece.replaceOffsetLen(this._leafs[accumulatedLeafIndex], accumulatedLeafEdits, this._idealLeafLength, this._maxLeafLength, rep.replacements);
+		}
+		accumulatedLeafEdits.length = 0;
+	}
+
+	private _pushLeafEdits(start: number, length: number, text: string, accumulatedLeafEdits: LeafOffsetLenEdit[]): void {
+		if (length !== 0 || text.length !== 0) {
+			accumulatedLeafEdits.push(new LeafOffsetLenEdit(start, length, text));
+		}
+	}
+
+	private _appendLeaf(leaf: BufferPiece, leafs: BufferPiece[], prevLeaf: BufferPiece): BufferPiece {
+		if (prevLeaf === null) {
+			leafs.push(leaf);
+			prevLeaf = leaf;
+			return prevLeaf;
+		}
+
+		let prevLeafLength = prevLeaf.length();
+		let currLeafLength = leaf.length();
+
+		if ((prevLeafLength < this._minLeafLength || currLeafLength < this._minLeafLength) && prevLeafLength + currLeafLength <= this._maxLeafLength) {
+			const joinedLeaf = BufferPiece.join(prevLeaf, leaf);
+			leafs[leafs.length - 1] = joinedLeaf;
+			prevLeaf = joinedLeaf;
+			return prevLeaf;
+		}
+
+		const lastChar = prevLeaf.charCodeAt(prevLeafLength - 1);
+		const firstChar = leaf.charCodeAt(0);
+
+		if (
+			(lastChar >= 0xd800 && lastChar <= 0xdbff) || (lastChar === CharCode.CarriageReturn && firstChar === CharCode.LineFeed)
+		) {
+			const modifiedPrevLeaf = BufferPiece.deleteLastChar(prevLeaf);
+			leafs[leafs.length - 1] = modifiedPrevLeaf;
+
+			const modifiedLeaf = BufferPiece.insertFirstChar(leaf, lastChar);
+			leaf = modifiedLeaf;
+		}
+
+		leafs.push(leaf);
+		prevLeaf = leaf;
+		return prevLeaf;
+	}
+
+	private static _compareEdits(a: OffsetLenEdit, b: OffsetLenEdit): number {
+		if (a.offset === b.offset) {
+			if (a.length === b.length) {
+				return (a.initialIndex - b.initialIndex);
+			}
+			return (a.length - b.length);
+		}
+		return a.offset - b.offset;
+	}
+
+	public replaceOffsetLen(_edits: OffsetLenEdit[]): void {
+		_edits.sort(Buffer._compareEdits);
+
+		const initialLeafLength = this._leafs.length;
+		const edits = this._resolveEdits(_edits);
+
+		let accumulatedLeafIndex = 0;
+		let accumulatedLeafEdits: LeafOffsetLenEdit[] = [];
+		let replacements: LeafReplacement[] = [];
+
+		for (let i = 0, len = edits.length; i < len; i++) {
+			const edit = edits[i];
+
+			const startLeafIndex = edit.startLeafIndex;
+			const endLeafIndex = edit.endLeafIndex;
+
+			if (startLeafIndex !== accumulatedLeafIndex) {
+				this._flushLeafEdits(accumulatedLeafIndex, accumulatedLeafEdits, replacements);
+				accumulatedLeafIndex = startLeafIndex;
+			}
+
+			const leafEditStart = edit.startInnerOffset;
+			const leafEditEnd = (startLeafIndex === endLeafIndex ? edit.endInnerOffset : this._leafs[startLeafIndex].length());
+			this._pushLeafEdits(leafEditStart, leafEditEnd - leafEditStart, edit.text, accumulatedLeafEdits);
+
+			if (startLeafIndex < endLeafIndex) {
+				this._flushLeafEdits(accumulatedLeafIndex, accumulatedLeafEdits, replacements);
+				accumulatedLeafIndex = endLeafIndex;
+
+				// delete leafs in the middle
+				if (startLeafIndex + 1 < endLeafIndex) {
+					this._pushLeafReplacement(startLeafIndex + 1, endLeafIndex - 1, replacements);
+				}
+
+				// delete on last leaf
+				const leafEditStart = 0;
+				const leafEditEnd = edit.endInnerOffset;
+				this._pushLeafEdits(leafEditStart, leafEditEnd - leafEditStart, '', accumulatedLeafEdits);
+			}
+		}
+		this._flushLeafEdits(accumulatedLeafIndex, accumulatedLeafEdits, replacements);
+
+		let leafs: BufferPiece[] = [];
+		let leafIndex = 0;
+		let prevLeaf: BufferPiece = null;
+
+		for (let i = 0, len = replacements.length; i < len; i++) {
+			const replaceStartLeafIndex = replacements[i].startLeafIndex;
+			const replaceEndLeafIndex = replacements[i].endLeafIndex;
+			const innerLeafs = replacements[i].replacements;
+
+			// add leafs to the left of this replace op.
+			while (leafIndex < replaceStartLeafIndex) {
+				prevLeaf = this._appendLeaf(this._leafs[leafIndex], leafs, prevLeaf);
+				leafIndex++;
+			}
+
+			// delete leafs that get replaced.
+			while (leafIndex <= replaceEndLeafIndex) {
+				leafIndex++;
+			}
+
+			// add new leafs.
+			for (let j = 0, lenJ = innerLeafs.length; j < lenJ; j++) {
+				prevLeaf = this._appendLeaf(innerLeafs[j], leafs, prevLeaf);
+			}
+		}
+
+		// add remaining leafs to the right of the last replacement.
+		while (leafIndex < initialLeafLength) {
+			prevLeaf = this._appendLeaf(this._leafs[leafIndex], leafs, prevLeaf);
+			leafIndex++;
+		}
+
+		if (leafs.length === 0) {
+			// don't leave behind an empty leafs array
+			leafs.push(new BufferPiece(''));
+		}
+
+		this._leafs = leafs;
+		this._rebuildNodes();
+	}
+
+	public setEOL(newEOL: '\r\n' | '\n'): void {
+		let leafs: BufferPiece[] = [];
+		for (let i = 0, len = this._leafs.length; i < len; i++) {
+			leafs[i] = BufferPiece.normalizeEOL(this._leafs[i], newEOL);
+		}
+		this._leafs = leafs;
+		this._rebuildNodes();
+		this._eol = newEOL;
+		this._eolLength = this._eol.length;
+	}
+
+	//#endregion
+
+	private IS_NODE(i: number): boolean {
+		return (i < this._nodesCount);
+	}
+	private IS_LEAF(i: number): boolean {
+		return (i >= this._leafsStart && i < this._leafsEnd);
+	}
+	private NODE_TO_LEAF_INDEX(i: number): number {
+		return (i - this._leafsStart);
+	}
+	// private LEAF_TO_NODE_INDEX(i: number): number {
+	// 	return (i + this._leafsStart);
+	// }
+}
+
+function log2(n: number): number {
+	let v = 1;
+	for (let pow = 1; ; pow++) {
+		v = v << 1;
+		if (v >= n) {
+			return pow;
+		}
+	}
+	// return -1;
+}
+
+function LEFT_CHILD(i: number): number {
+	return (i << 1);
+}
+
+function RIGHT_CHILD(i: number): number {
+	return (i << 1) + 1;
+}
diff --git a/src/vs/editor/common/model/chunksTextBuffer/chunksTextBufferBuilder.ts b/src/vs/editor/common/model/chunksTextBuffer/chunksTextBufferBuilder.ts
new file mode 100644
index 00000000000..12eaf167b28
--- /dev/null
+++ b/src/vs/editor/common/model/chunksTextBuffer/chunksTextBufferBuilder.ts
@@ -0,0 +1,186 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import * as strings from 'vs/base/common/strings';
+import { ITextBufferBuilder, ITextBufferFactory, ITextBuffer, DefaultEndOfLine } from 'vs/editor/common/model';
+import { BufferPiece, createLineStarts } from 'vs/editor/common/model/chunksTextBuffer/bufferPiece';
+import { ChunksTextBuffer } from 'vs/editor/common/model/chunksTextBuffer/chunksTextBuffer';
+import { CharCode } from 'vs/base/common/charCode';
+
+export class TextBufferFactory implements ITextBufferFactory {
+
+	constructor(
+		private readonly _pieces: BufferPiece[],
+		private readonly _averageChunkSize: number,
+		private readonly _BOM: string,
+		private readonly _cr: number,
+		private readonly _lf: number,
+		private readonly _crlf: number,
+		private readonly _containsRTL: boolean,
+		private readonly _isBasicASCII: boolean,
+	) {
+	}
+
+	/**
+	 * if text source is empty or with precisely one line, returns null. No end of line is detected.
+	 * if text source contains more lines ending with '\r\n', returns '\r\n'.
+	 * Otherwise returns '\n'. More lines end with '\n'.
+	 */
+	private _getEOL(defaultEOL: DefaultEndOfLine): '\r\n' | '\n' {
+		const totalEOLCount = this._cr + this._lf + this._crlf;
+		const totalCRCount = this._cr + this._crlf;
+		if (totalEOLCount === 0) {
+			// This is an empty file or a file with precisely one line
+			return (defaultEOL === DefaultEndOfLine.LF ? '\n' : '\r\n');
+		}
+		if (totalCRCount > totalEOLCount / 2) {
+			// More than half of the file contains \r\n ending lines
+			return '\r\n';
+		}
+		// At least one line more ends in \n
+		return '\n';
+	}
+
+	public create(defaultEOL: DefaultEndOfLine): ITextBuffer {
+		const eol = this._getEOL(defaultEOL);
+		let pieces = this._pieces;
+
+		if (
+			(eol === '\r\n' && (this._cr > 0 || this._lf > 0))
+			|| (eol === '\n' && (this._cr > 0 || this._crlf > 0))
+		) {
+			// Normalize pieces
+			for (let i = 0, len = pieces.length; i < len; i++) {
+				pieces[i] = BufferPiece.normalizeEOL(pieces[i], eol);
+			}
+		}
+		return new ChunksTextBuffer(pieces, this._averageChunkSize, this._BOM, eol, this._containsRTL, this._isBasicASCII);
+	}
+
+	public getFirstLineText(lengthLimit: number): string {
+		const firstPiece = this._pieces[0];
+		if (firstPiece.newLineCount() === 0) {
+			return firstPiece.substr(0, lengthLimit);
+		}
+
+		const firstEOLOffset = firstPiece.lineStartFor(0);
+		return firstPiece.substr(0, Math.min(lengthLimit, firstEOLOffset));
+	}
+}
+
+export class ChunksTextBufferBuilder implements ITextBufferBuilder {
+
+	private _rawPieces: BufferPiece[];
+	private _hasPreviousChar: boolean;
+	private _previousChar: number;
+	private _averageChunkSize: number;
+	private _tmpLineStarts: number[];
+
+	private BOM: string;
+	private cr: number;
+	private lf: number;
+	private crlf: number;
+	private containsRTL: boolean;
+	private isBasicASCII: boolean;
+
+	constructor() {
+		this._rawPieces = [];
+		this._hasPreviousChar = false;
+		this._previousChar = 0;
+		this._averageChunkSize = 0;
+		this._tmpLineStarts = [];
+
+		this.BOM = '';
+		this.cr = 0;
+		this.lf = 0;
+		this.crlf = 0;
+		this.containsRTL = false;
+		this.isBasicASCII = true;
+	}
+
+	public acceptChunk(chunk: string): void {
+		if (chunk.length === 0) {
+			return;
+		}
+
+		if (this._rawPieces.length === 0) {
+			if (strings.startsWithUTF8BOM(chunk)) {
+				this.BOM = strings.UTF8_BOM_CHARACTER;
+				chunk = chunk.substr(1);
+			}
+		}
+
+		this._averageChunkSize = (this._averageChunkSize * this._rawPieces.length + chunk.length) / (this._rawPieces.length + 1);
+
+		const lastChar = chunk.charCodeAt(chunk.length - 1);
+		if (lastChar === CharCode.CarriageReturn || (lastChar >= 0xd800 && lastChar <= 0xdbff)) {
+			// last character is \r or a high surrogate => keep it back
+			this._acceptChunk1(chunk.substr(0, chunk.length - 1), false);
+			this._hasPreviousChar = true;
+			this._previousChar = lastChar;
+		} else {
+			this._acceptChunk1(chunk, false);
+			this._hasPreviousChar = false;
+			this._previousChar = lastChar;
+		}
+	}
+
+	private _acceptChunk1(chunk: string, allowEmptyStrings: boolean): void {
+		if (!allowEmptyStrings && chunk.length === 0) {
+			// Nothing to do
+			return;
+		}
+
+		if (this._hasPreviousChar) {
+			this._acceptChunk2(chunk + String.fromCharCode(this._previousChar));
+		} else {
+			this._acceptChunk2(chunk);
+		}
+	}
+
+	private _acceptChunk2(chunk: string): void {
+		const lineStarts = createLineStarts(this._tmpLineStarts, chunk);
+
+		this._rawPieces.push(new BufferPiece(chunk, lineStarts.lineStarts));
+		this.cr += lineStarts.cr;
+		this.lf += lineStarts.lf;
+		this.crlf += lineStarts.crlf;
+
+		if (this.isBasicASCII) {
+			this.isBasicASCII = lineStarts.isBasicASCII;
+		}
+		if (!this.isBasicASCII && !this.containsRTL) {
+			// No need to check if is basic ASCII
+			this.containsRTL = strings.containsRTL(chunk);
+		}
+	}
+
+	public finish(): TextBufferFactory {
+		this._finish();
+		return new TextBufferFactory(this._rawPieces, this._averageChunkSize, this.BOM, this.cr, this.lf, this.crlf, this.containsRTL, this.isBasicASCII);
+	}
+
+	private _finish(): void {
+		if (this._rawPieces.length === 0) {
+			// no chunks => forcefully go through accept chunk
+			this._acceptChunk1('', true);
+			return;
+		}
+
+		if (this._hasPreviousChar) {
+			this._hasPreviousChar = false;
+
+			// recreate last chunk
+			const lastPiece = this._rawPieces[this._rawPieces.length - 1];
+			const tmp = new BufferPiece(String.fromCharCode(this._previousChar));
+			const newLastPiece = BufferPiece.join(lastPiece, tmp);
+			this._rawPieces[this._rawPieces.length - 1] = newLastPiece;
+			if (this._previousChar === CharCode.CarriageReturn) {
+				this.cr++;
+			}
+		}
+	}
+}
diff --git a/src/vs/editor/common/model/textModel.ts b/src/vs/editor/common/model/textModel.ts
index d0d5cd7d1fd..6506c95e3b0 100644
--- a/src/vs/editor/common/model/textModel.ts
+++ b/src/vs/editor/common/model/textModel.ts
@@ -34,9 +34,14 @@ import { TextModelSearch, SearchParams } from 'vs/editor/common/model/textModelS
 import { TPromise } from 'vs/base/common/winjs.base';
 import { IStringStream, ITextSnapshot } from 'vs/platform/files/common/files';
 import { LinesTextBufferBuilder } from 'vs/editor/common/model/linesTextBuffer/linesTextBufferBuilder';
+import { ChunksTextBufferBuilder } from 'vs/editor/common/model/chunksTextBuffer/chunksTextBufferBuilder';
 
 // Here is the master switch for the text buffer implementation:
+const USE_CHUNKS_TEXT_BUFFER = false;
 function createTextBufferBuilder() {
+	if (USE_CHUNKS_TEXT_BUFFER) {
+		return new ChunksTextBufferBuilder();
+	}
 	return new LinesTextBufferBuilder();
 }
 
diff --git a/src/vs/editor/test/common/model/chunksTextBuffer/bufferPiece.test.ts b/src/vs/editor/test/common/model/chunksTextBuffer/bufferPiece.test.ts
new file mode 100644
index 00000000000..a6cc8f6f22d
--- /dev/null
+++ b/src/vs/editor/test/common/model/chunksTextBuffer/bufferPiece.test.ts
@@ -0,0 +1,61 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+import * as assert from 'assert';
+import { BufferPiece } from 'vs/editor/common/model/chunksTextBuffer/bufferPiece';
+
+suite('BufferPiece', () => {
+	test('findLineStartBeforeOffset', () => {
+		let piece = new BufferPiece([
+			'Line1\r\n',
+			'l2\n',
+			'another\r',
+			'and\r\n',
+			'finally\n',
+			'last'
+		].join(''));
+
+		assert.equal(piece.length(), 35);
+		assert.deepEqual(piece.findLineStartBeforeOffset(0), -1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(1), -1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(2), -1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(3), -1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(4), -1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(5), -1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(6), -1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(7), 0);
+		assert.deepEqual(piece.findLineStartBeforeOffset(8), 0);
+		assert.deepEqual(piece.findLineStartBeforeOffset(9), 0);
+		assert.deepEqual(piece.findLineStartBeforeOffset(10), 1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(11), 1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(12), 1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(13), 1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(14), 1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(15), 1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(16), 1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(17), 1);
+		assert.deepEqual(piece.findLineStartBeforeOffset(18), 2);
+		assert.deepEqual(piece.findLineStartBeforeOffset(19), 2);
+		assert.deepEqual(piece.findLineStartBeforeOffset(20), 2);
+		assert.deepEqual(piece.findLineStartBeforeOffset(21), 2);
+		assert.deepEqual(piece.findLineStartBeforeOffset(22), 2);
+		assert.deepEqual(piece.findLineStartBeforeOffset(23), 3);
+		assert.deepEqual(piece.findLineStartBeforeOffset(24), 3);
+		assert.deepEqual(piece.findLineStartBeforeOffset(25), 3);
+		assert.deepEqual(piece.findLineStartBeforeOffset(26), 3);
+		assert.deepEqual(piece.findLineStartBeforeOffset(27), 3);
+		assert.deepEqual(piece.findLineStartBeforeOffset(28), 3);
+		assert.deepEqual(piece.findLineStartBeforeOffset(29), 3);
+		assert.deepEqual(piece.findLineStartBeforeOffset(30), 3);
+		assert.deepEqual(piece.findLineStartBeforeOffset(31), 4);
+		assert.deepEqual(piece.findLineStartBeforeOffset(32), 4);
+		assert.deepEqual(piece.findLineStartBeforeOffset(33), 4);
+		assert.deepEqual(piece.findLineStartBeforeOffset(34), 4);
+		assert.deepEqual(piece.findLineStartBeforeOffset(35), 4);
+		assert.deepEqual(piece.findLineStartBeforeOffset(36), 4);
+	});
+});
diff --git a/src/vs/editor/test/common/model/textModel.test.ts b/src/vs/editor/test/common/model/textModel.test.ts
index be2fd30bd13..a99bde0f438 100644
--- a/src/vs/editor/test/common/model/textModel.test.ts
+++ b/src/vs/editor/test/common/model/textModel.test.ts
@@ -891,16 +891,18 @@ suite('TextModel.createSnapshot', () => {
 		let snapshot = model.createSnapshot();
 		let actual = '';
 
-		// 70999 length => 2 read calls are necessary
+		// 70999 length => at most 2 read calls are necessary
 		let tmp1 = snapshot.read();
 		assert.ok(tmp1);
 		actual += tmp1;
 
 		let tmp2 = snapshot.read();
-		assert.ok(tmp2);
-		actual += tmp2;
-
-		assert.equal(snapshot.read(), null);
+		if (tmp2 === null) {
+			// all good
+		} else {
+			actual += tmp2;
+			assert.equal(snapshot.read(), null);
+		}
 
 		assert.equal(actual, text);