550 lines
18 KiB
TypeScript
550 lines
18 KiB
TypeScript
import { BitWidth } from './bit-width'
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import { paddingSize, iwidth, uwidth, fwidth, toByteWidth, fromByteWidth } from './bit-width-util'
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import { toUTF8Array } from './flexbuffers-util'
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import { ValueType } from './value-type'
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import { isNumber, isTypedVectorElement, toTypedVector } from './value-type-util'
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import { StackValue } from './stack-value'
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interface StackPointer {
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stackPosition: number,
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isVector: boolean
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presorted?: boolean
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}
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export class Builder {
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buffer: ArrayBuffer
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view: DataView
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readonly stack: Array<StackValue> = [];
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readonly stackPointers: Array<StackPointer> = [];
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offset = 0;
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finished = false;
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readonly stringLookup: Record<string, StackValue> = {};
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readonly keyLookup: Record<string, StackValue> = {};
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readonly keyVectorLookup: Record<string, StackValue> = {};
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readonly indirectIntLookup: Record<number, StackValue> = {};
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readonly indirectUIntLookup: Record<number, StackValue> = {};
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readonly indirectFloatLookup: Record<number, StackValue> = {};
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constructor(size = 2048, private dedupStrings = true, private dedupKeys = true, private dedupKeyVectors = true) {
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this.buffer = new ArrayBuffer(size > 0 ? size : 2048);
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this.view = new DataView(this.buffer);
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}
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private align(width: BitWidth) {
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const byteWidth = toByteWidth(width);
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this.offset += paddingSize(this.offset, byteWidth);
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return byteWidth;
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}
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computeOffset(newValueSize: number): number {
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const targetOffset = this.offset + newValueSize;
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let size = this.buffer.byteLength;
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const prevSize = size;
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while (size < targetOffset) {
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size <<= 1;
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}
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if (prevSize < size) {
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const prevBuffer = this.buffer;
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this.buffer = new ArrayBuffer(size);
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this.view = new DataView(this.buffer);
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new Uint8Array(this.buffer).set(new Uint8Array(prevBuffer), 0);
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}
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return targetOffset;
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}
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pushInt(value: number, width: BitWidth): void {
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if (width === BitWidth.WIDTH8) {
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this.view.setInt8(this.offset, value);
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} else if (width === BitWidth.WIDTH16) {
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this.view.setInt16(this.offset, value, true);
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} else if (width === BitWidth.WIDTH32) {
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this.view.setInt32(this.offset, value, true);
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} else if (width === BitWidth.WIDTH64) {
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this.view.setBigInt64(this.offset, BigInt(value), true);
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} else {
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throw `Unexpected width: ${width} for value: ${value}`;
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}
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}
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pushUInt(value: number, width: BitWidth): void {
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if (width === BitWidth.WIDTH8) {
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this.view.setUint8(this.offset, value);
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} else if (width === BitWidth.WIDTH16) {
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this.view.setUint16(this.offset, value, true);
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} else if (width === BitWidth.WIDTH32) {
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this.view.setUint32(this.offset, value, true);
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} else if (width === BitWidth.WIDTH64) {
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this.view.setBigUint64(this.offset, BigInt(value), true);
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} else {
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throw `Unexpected width: ${width} for value: ${value}`;
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}
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}
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private writeInt(value: number, byteWidth: number) {
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const newOffset = this.computeOffset(byteWidth);
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this.pushInt(value, fromByteWidth(byteWidth));
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this.offset = newOffset;
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}
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private writeUInt(value: number, byteWidth: number) {
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const newOffset = this.computeOffset(byteWidth);
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this.pushUInt(value, fromByteWidth(byteWidth));
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this.offset = newOffset;
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}
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private writeBlob(arrayBuffer: ArrayBuffer) {
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const length = arrayBuffer.byteLength;
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const bitWidth = uwidth(length);
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const byteWidth = this.align(bitWidth);
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this.writeUInt(length, byteWidth);
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const blobOffset = this.offset;
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const newOffset = this.computeOffset(length);
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new Uint8Array(this.buffer).set(new Uint8Array(arrayBuffer), blobOffset);
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this.stack.push(this.offsetStackValue(blobOffset, ValueType.BLOB, bitWidth));
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this.offset = newOffset;
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}
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private writeString(str: string): void {
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if (this.dedupStrings && Object.prototype.hasOwnProperty.call(this.stringLookup, str)) {
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this.stack.push(this.stringLookup[str]);
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return;
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}
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const utf8 = toUTF8Array(str);
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const length = utf8.length;
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const bitWidth = uwidth(length);
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const byteWidth = this.align(bitWidth);
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this.writeUInt(length, byteWidth);
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const stringOffset = this.offset;
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const newOffset = this.computeOffset(length + 1);
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new Uint8Array(this.buffer).set(utf8, stringOffset);
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const stackValue = this.offsetStackValue(stringOffset, ValueType.STRING, bitWidth);
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this.stack.push(stackValue);
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if (this.dedupStrings) {
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this.stringLookup[str] = stackValue;
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}
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this.offset = newOffset;
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}
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private writeKey(str: string): void {
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if (this.dedupKeys && Object.prototype.hasOwnProperty.call(this.keyLookup, str)) {
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this.stack.push(this.keyLookup[str]);
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return;
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}
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const utf8 = toUTF8Array(str);
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const length = utf8.length;
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const newOffset = this.computeOffset(length + 1);
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new Uint8Array(this.buffer).set(utf8, this.offset);
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const stackValue = this.offsetStackValue(this.offset, ValueType.KEY, BitWidth.WIDTH8);
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this.stack.push(stackValue);
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if (this.dedupKeys) {
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this.keyLookup[str] = stackValue;
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}
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this.offset = newOffset;
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}
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private writeStackValue(value: StackValue, byteWidth: number): void {
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const newOffset = this.computeOffset(byteWidth);
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if (value.isOffset()) {
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const relativeOffset = this.offset - value.offset;
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if (byteWidth === 8 || BigInt(relativeOffset) < (BigInt(1) << BigInt(byteWidth * 8))) {
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this.writeUInt(relativeOffset, byteWidth);
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} else {
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throw `Unexpected size ${byteWidth}. This might be a bug. Please create an issue https://github.com/google/flatbuffers/issues/new`
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}
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} else {
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value.writeToBuffer(byteWidth);
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}
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this.offset = newOffset;
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}
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private integrityCheckOnValueAddition() {
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if (this.finished) {
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throw "Adding values after finish is prohibited";
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}
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if (this.stackPointers.length !== 0 && this.stackPointers[this.stackPointers.length - 1].isVector === false) {
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if (this.stack[this.stack.length - 1].type !== ValueType.KEY) {
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throw "Adding value to a map before adding a key is prohibited";
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}
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}
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}
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private integrityCheckOnKeyAddition() {
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if (this.finished) {
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throw "Adding values after finish is prohibited";
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}
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if (this.stackPointers.length === 0 || this.stackPointers[this.stackPointers.length - 1].isVector) {
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throw "Adding key before starting a map is prohibited";
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}
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}
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startVector(): void {
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this.stackPointers.push({ stackPosition: this.stack.length, isVector: true });
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}
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startMap(presorted = false): void {
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this.stackPointers.push({ stackPosition: this.stack.length, isVector: false, presorted: presorted });
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}
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private endVector(stackPointer: StackPointer) {
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const vecLength = this.stack.length - stackPointer.stackPosition;
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const vec = this.createVector(stackPointer.stackPosition, vecLength, 1);
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this.stack.splice(stackPointer.stackPosition, vecLength);
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this.stack.push(vec);
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}
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private endMap(stackPointer: StackPointer) {
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if (!stackPointer.presorted) {
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this.sort(stackPointer);
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}
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let keyVectorHash = "";
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for (let i = stackPointer.stackPosition; i < this.stack.length; i += 2) {
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keyVectorHash += `,${this.stack[i].offset}`;
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}
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const vecLength = (this.stack.length - stackPointer.stackPosition) >> 1;
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if (this.dedupKeyVectors && !Object.prototype.hasOwnProperty.call(this.keyVectorLookup, keyVectorHash)) {
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this.keyVectorLookup[keyVectorHash] = this.createVector(stackPointer.stackPosition, vecLength, 2);
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}
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const keysStackValue = this.dedupKeyVectors ? this.keyVectorLookup[keyVectorHash] : this.createVector(stackPointer.stackPosition, vecLength, 2);
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const valuesStackValue = this.createVector(stackPointer.stackPosition + 1, vecLength, 2, keysStackValue);
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this.stack.splice(stackPointer.stackPosition, vecLength << 1);
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this.stack.push(valuesStackValue);
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}
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private sort(stackPointer: StackPointer) {
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const view = this.view
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const stack = this.stack
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function shouldFlip(v1: StackValue, v2: StackValue) {
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if (v1.type !== ValueType.KEY || v2.type !== ValueType.KEY) {
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throw `Stack values are not keys ${v1} | ${v2}. Check if you combined [addKey] with add... method calls properly.`
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}
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let c1, c2;
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let index = 0;
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do {
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c1 = view.getUint8(v1.offset + index);
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c2 = view.getUint8(v2.offset + index);
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if (c2 < c1) return true;
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if (c1 < c2) return false;
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index += 1;
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} while (c1 !== 0 && c2 !== 0);
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return false;
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}
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function swap(stack: Array<StackValue>, flipIndex: number, i: number) {
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if (flipIndex === i) return;
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const k = stack[flipIndex];
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const v = stack[flipIndex + 1];
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stack[flipIndex] = stack[i];
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stack[flipIndex + 1] = stack[i + 1];
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stack[i] = k;
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stack[i + 1] = v;
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}
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function selectionSort() {
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for (let i = stackPointer.stackPosition; i < stack.length; i += 2) {
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let flipIndex = i;
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for (let j = i + 2; j < stack.length; j += 2) {
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if (shouldFlip(stack[flipIndex], stack[j])) {
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flipIndex = j;
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}
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}
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if (flipIndex !== i) {
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swap(stack, flipIndex, i);
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}
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}
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}
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function smaller(v1: StackValue, v2: StackValue) {
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if (v1.type !== ValueType.KEY || v2.type !== ValueType.KEY) {
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throw `Stack values are not keys ${v1} | ${v2}. Check if you combined [addKey] with add... method calls properly.`
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}
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if (v1.offset === v2.offset) {
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return false;
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}
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let c1, c2;
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let index = 0;
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do {
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c1 = view.getUint8(v1.offset + index);
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c2 = view.getUint8(v2.offset + index);
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if (c1 < c2) return true;
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if (c2 < c1) return false;
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index += 1;
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} while (c1 !== 0 && c2 !== 0);
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return false;
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}
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function quickSort(left: number, right: number) {
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if (left < right) {
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const mid = left + (((right - left) >> 2)) * 2;
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const pivot = stack[mid];
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let left_new = left;
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let right_new = right;
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do {
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while (smaller(stack[left_new], pivot)) {
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left_new += 2;
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}
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while (smaller(pivot, stack[right_new])) {
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right_new -= 2;
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}
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if (left_new <= right_new) {
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swap(stack, left_new, right_new);
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left_new += 2;
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right_new -= 2;
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}
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} while (left_new <= right_new);
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quickSort(left, right_new);
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quickSort(left_new, right);
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}
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}
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let sorted = true;
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for (let i = stackPointer.stackPosition; i < this.stack.length - 2; i += 2) {
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if (shouldFlip(this.stack[i], this.stack[i + 2])) {
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sorted = false;
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break;
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}
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}
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if (!sorted) {
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if (this.stack.length - stackPointer.stackPosition > 40) {
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quickSort(stackPointer.stackPosition, this.stack.length - 2);
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} else {
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selectionSort();
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}
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}
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}
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end(): void {
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if (this.stackPointers.length < 1) return;
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const pointer = this.stackPointers.pop() as StackPointer;
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if (pointer.isVector) {
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this.endVector(pointer);
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} else {
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this.endMap(pointer);
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}
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}
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private createVector(start: number, vecLength: number, step: number, keys: StackValue | null = null) {
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let bitWidth = uwidth(vecLength);
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let prefixElements = 1;
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if (keys !== null) {
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const elementWidth = keys.elementWidth(this.offset, 0);
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if (elementWidth > bitWidth) {
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bitWidth = elementWidth;
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}
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prefixElements += 2;
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}
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let vectorType = ValueType.KEY;
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let typed = keys === null;
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for (let i = start; i < this.stack.length; i += step) {
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const elementWidth = this.stack[i].elementWidth(this.offset, i + prefixElements);
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if (elementWidth > bitWidth) {
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bitWidth = elementWidth;
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}
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if (i === start) {
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vectorType = this.stack[i].type;
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typed = typed && isTypedVectorElement(vectorType);
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} else {
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if (vectorType !== this.stack[i].type) {
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typed = false;
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}
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}
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}
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const byteWidth = this.align(bitWidth);
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const fix = typed && isNumber(vectorType) && vecLength >= 2 && vecLength <= 4;
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if (keys !== null) {
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this.writeStackValue(keys, byteWidth);
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this.writeUInt(1 << keys.width, byteWidth);
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}
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if (!fix) {
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this.writeUInt(vecLength, byteWidth);
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}
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const vecOffset = this.offset;
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for (let i = start; i < this.stack.length; i += step) {
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this.writeStackValue(this.stack[i], byteWidth);
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}
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if (!typed) {
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for (let i = start; i < this.stack.length; i += step) {
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this.writeUInt(this.stack[i].storedPackedType(), 1);
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}
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}
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if (keys !== null) {
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return this.offsetStackValue(vecOffset, ValueType.MAP, bitWidth);
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}
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if (typed) {
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const vType = toTypedVector(vectorType, fix ? vecLength : 0);
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return this.offsetStackValue(vecOffset, vType, bitWidth);
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}
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return this.offsetStackValue(vecOffset, ValueType.VECTOR, bitWidth);
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}
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private nullStackValue() {
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return new StackValue(this, ValueType.NULL, BitWidth.WIDTH8);
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}
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private boolStackValue(value: boolean) {
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return new StackValue(this, ValueType.BOOL, BitWidth.WIDTH8, value);
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}
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private intStackValue(value: number | bigint) {
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return new StackValue(this, ValueType.INT, iwidth(value), value as number);
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}
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private uintStackValue(value: number) {
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return new StackValue(this, ValueType.UINT, uwidth(value), value);
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}
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private floatStackValue(value: number) {
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return new StackValue(this, ValueType.FLOAT, fwidth(value), value);
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}
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private offsetStackValue(offset: number, valueType: ValueType, bitWidth: BitWidth): StackValue {
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return new StackValue(this, valueType, bitWidth, null, offset);
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}
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private finishBuffer() {
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if (this.stack.length !== 1) {
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throw `Stack has to be exactly 1, but it is ${this.stack.length}. You have to end all started vectors and maps before calling [finish]`;
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}
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const value = this.stack[0];
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const byteWidth = this.align(value.elementWidth(this.offset, 0));
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this.writeStackValue(value, byteWidth);
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this.writeUInt(value.storedPackedType(), 1);
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this.writeUInt(byteWidth, 1);
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this.finished = true;
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}
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add(value: undefined | null | boolean | bigint | number | DataView | string | Array<unknown> | Record<string, unknown> | unknown): void {
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this.integrityCheckOnValueAddition();
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if (typeof value === 'undefined') {
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throw "You need to provide a value";
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}
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if (value === null) {
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this.stack.push(this.nullStackValue());
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} else if (typeof value === "boolean") {
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this.stack.push(this.boolStackValue(value));
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} else if (typeof value === "bigint") {
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this.stack.push(this.intStackValue(value));
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} else if (typeof value == 'number') {
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if (Number.isInteger(value)) {
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this.stack.push(this.intStackValue(value));
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} else {
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this.stack.push(this.floatStackValue(value));
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}
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} else if (ArrayBuffer.isView(value)) {
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this.writeBlob(value.buffer);
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} else if (typeof value === 'string' || value instanceof String) {
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this.writeString(value as string);
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} else if (Array.isArray(value)) {
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this.startVector();
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for (let i = 0; i < value.length; i++) {
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this.add(value[i]);
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}
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this.end();
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} else if (typeof value === 'object') {
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const properties = Object.getOwnPropertyNames(value).sort();
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this.startMap(true);
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for (let i = 0; i < properties.length; i++) {
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const key = properties[i];
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this.addKey(key);
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this.add((value as Record<string, unknown>)[key]);
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}
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this.end();
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} else {
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throw `Unexpected value input ${value}`;
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}
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}
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finish(): Uint8Array {
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if (!this.finished) {
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this.finishBuffer();
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}
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const result = this.buffer.slice(0, this.offset);
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return new Uint8Array(result);
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}
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isFinished(): boolean {
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return this.finished;
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}
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addKey(key: string): void {
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this.integrityCheckOnKeyAddition();
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this.writeKey(key);
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}
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addInt(value: number, indirect = false, deduplicate = false): void {
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this.integrityCheckOnValueAddition();
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if (!indirect) {
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this.stack.push(this.intStackValue(value));
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return;
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}
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if (deduplicate && Object.prototype.hasOwnProperty.call(this.indirectIntLookup, value)) {
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this.stack.push(this.indirectIntLookup[value]);
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return;
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}
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const stackValue = this.intStackValue(value);
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const byteWidth = this.align(stackValue.width);
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|
const newOffset = this.computeOffset(byteWidth);
|
|
const valueOffset = this.offset;
|
|
stackValue.writeToBuffer(byteWidth);
|
|
const stackOffset = this.offsetStackValue(valueOffset, ValueType.INDIRECT_INT, stackValue.width);
|
|
this.stack.push(stackOffset);
|
|
this.offset = newOffset;
|
|
if (deduplicate) {
|
|
this.indirectIntLookup[value] = stackOffset;
|
|
}
|
|
}
|
|
|
|
addUInt(value: number, indirect = false, deduplicate = false): void {
|
|
this.integrityCheckOnValueAddition();
|
|
if (!indirect) {
|
|
this.stack.push(this.uintStackValue(value));
|
|
return;
|
|
}
|
|
if (deduplicate && Object.prototype.hasOwnProperty.call(this.indirectUIntLookup, value)) {
|
|
this.stack.push(this.indirectUIntLookup[value]);
|
|
return;
|
|
}
|
|
const stackValue = this.uintStackValue(value);
|
|
const byteWidth = this.align(stackValue.width);
|
|
const newOffset = this.computeOffset(byteWidth);
|
|
const valueOffset = this.offset;
|
|
stackValue.writeToBuffer(byteWidth);
|
|
const stackOffset = this.offsetStackValue(valueOffset, ValueType.INDIRECT_UINT, stackValue.width);
|
|
this.stack.push(stackOffset);
|
|
this.offset = newOffset;
|
|
if (deduplicate) {
|
|
this.indirectUIntLookup[value] = stackOffset;
|
|
}
|
|
}
|
|
|
|
addFloat(value: number, indirect = false, deduplicate = false): void {
|
|
this.integrityCheckOnValueAddition();
|
|
if (!indirect) {
|
|
this.stack.push(this.floatStackValue(value));
|
|
return;
|
|
}
|
|
if (deduplicate && Object.prototype.hasOwnProperty.call(this.indirectFloatLookup, value)) {
|
|
this.stack.push(this.indirectFloatLookup[value]);
|
|
return;
|
|
}
|
|
const stackValue = this.floatStackValue(value);
|
|
const byteWidth = this.align(stackValue.width);
|
|
const newOffset = this.computeOffset(byteWidth);
|
|
const valueOffset = this.offset;
|
|
stackValue.writeToBuffer(byteWidth);
|
|
const stackOffset = this.offsetStackValue(valueOffset, ValueType.INDIRECT_FLOAT, stackValue.width);
|
|
this.stack.push(stackOffset);
|
|
this.offset = newOffset;
|
|
if (deduplicate) {
|
|
this.indirectFloatLookup[value] = stackOffset;
|
|
}
|
|
}
|
|
}
|