deno.land / x / msgpack_javascript@v3.0.0-beta2 / src / Decoder.ts
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export type DecoderOptions<ContextType = undefined> = Readonly< Partial<{ extensionCodec: ExtensionCodecType<ContextType>;
/** * Decodes Int64 and Uint64 as bigint if it's set to true. * Depends on ES2020's {@link DataView#getBigInt64} and * {@link DataView#getBigUint64}. * * Defaults to false. */ useBigInt64: boolean;
/** * Maximum string length. * * Defaults to 4_294_967_295 (UINT32_MAX). */ maxStrLength: number; /** * Maximum binary length. * * Defaults to 4_294_967_295 (UINT32_MAX). */ maxBinLength: number; /** * Maximum array length. * * Defaults to 4_294_967_295 (UINT32_MAX). */ maxArrayLength: number; /** * Maximum map length. * * Defaults to 4_294_967_295 (UINT32_MAX). */ maxMapLength: number; /** * Maximum extension length. * * Defaults to 4_294_967_295 (UINT32_MAX). */ maxExtLength: number;
/** * An object key decoder. Defaults to the shared instance of {@link CachedKeyDecoder}. * `null` is a special value to disable the use of the key decoder at all. */ keyDecoder: KeyDecoder | null; }>> & ContextOf<ContextType>;
const STATE_ARRAY = "array";const STATE_MAP_KEY = "map_key";const STATE_MAP_VALUE = "map_value";
type MapKeyType = string | number;
const isValidMapKeyType = (key: unknown): key is MapKeyType => { return typeof key === "string" || typeof key === "number";};
type StackMapState = { type: typeof STATE_MAP_KEY | typeof STATE_MAP_VALUE; size: number; key: MapKeyType | null; readCount: number; map: Record<string, unknown>;};
type StackArrayState = { type: typeof STATE_ARRAY; size: number; array: Array<unknown>; position: number;};
type StackState = StackArrayState | StackMapState;
const HEAD_BYTE_REQUIRED = -1;
const EMPTY_VIEW = new DataView(new ArrayBuffer(0));const EMPTY_BYTES = new Uint8Array(EMPTY_VIEW.buffer);
try { // IE11: The spec says it should throw RangeError, // IE11: but in IE11 it throws TypeError. EMPTY_VIEW.getInt8(0);} catch (e) { if (!(e instanceof RangeError)) { throw new Error("This module is not supported in the current JavaScript engine because DataView does not throw RangeError on out-of-bounds access"); }}export const DataViewIndexOutOfBoundsError = RangeError;
const MORE_DATA = new DataViewIndexOutOfBoundsError("Insufficient data");
const sharedCachedKeyDecoder = new CachedKeyDecoder();
export class Decoder<ContextType = undefined> { private readonly extensionCodec: ExtensionCodecType<ContextType>; private readonly context: ContextType; private readonly useBigInt64: boolean; private readonly maxStrLength: number; private readonly maxBinLength: number; private readonly maxArrayLength: number; private readonly maxMapLength: number; private readonly maxExtLength: number; private readonly keyDecoder: KeyDecoder | null;
private totalPos = 0; private pos = 0;
private view = EMPTY_VIEW; private bytes = EMPTY_BYTES; private headByte = HEAD_BYTE_REQUIRED; private readonly stack: Array<StackState> = [];
public constructor(options?: DecoderOptions<ContextType>) { this.extensionCodec = options?.extensionCodec ?? (ExtensionCodec.defaultCodec as ExtensionCodecType<ContextType>); this.context = (options as { context: ContextType } | undefined)?.context as ContextType; // needs a type assertion because EncoderOptions has no context property when ContextType is undefined
this.useBigInt64 = options?.useBigInt64 ?? false; this.maxStrLength = options?.maxStrLength ?? UINT32_MAX; this.maxBinLength = options?.maxBinLength ?? UINT32_MAX; this.maxArrayLength = options?.maxArrayLength ?? UINT32_MAX; this.maxMapLength = options?.maxMapLength ?? UINT32_MAX; this.maxExtLength = options?.maxExtLength ?? UINT32_MAX; this.keyDecoder = (options?.keyDecoder !== undefined) ? options.keyDecoder : sharedCachedKeyDecoder; }
private reinitializeState() { this.totalPos = 0; this.headByte = HEAD_BYTE_REQUIRED; this.stack.length = 0;
// view, bytes, and pos will be re-initialized in setBuffer() }
private setBuffer(buffer: ArrayLike<number> | BufferSource): void { this.bytes = ensureUint8Array(buffer); this.view = createDataView(this.bytes); this.pos = 0; }
private appendBuffer(buffer: ArrayLike<number> | BufferSource) { if (this.headByte === HEAD_BYTE_REQUIRED && !this.hasRemaining(1)) { this.setBuffer(buffer); } else { const remainingData = this.bytes.subarray(this.pos); const newData = ensureUint8Array(buffer);
// concat remainingData + newData const newBuffer = new Uint8Array(remainingData.length + newData.length); newBuffer.set(remainingData); newBuffer.set(newData, remainingData.length); this.setBuffer(newBuffer); } }
private hasRemaining(size: number) { return this.view.byteLength - this.pos >= size; }
private createExtraByteError(posToShow: number): Error { const { view, pos } = this; return new RangeError(`Extra ${view.byteLength - pos} of ${view.byteLength} byte(s) found at buffer[${posToShow}]`); }
/** * @throws {@link DecodeError} * @throws {@link RangeError} */ public decode(buffer: ArrayLike<number> | BufferSource): unknown { this.reinitializeState(); this.setBuffer(buffer);
const object = this.doDecodeSync(); if (this.hasRemaining(1)) { throw this.createExtraByteError(this.pos); } return object; }
public *decodeMulti(buffer: ArrayLike<number> | BufferSource): Generator<unknown, void, unknown> { this.reinitializeState(); this.setBuffer(buffer);
while (this.hasRemaining(1)) { yield this.doDecodeSync(); } }
public async decodeAsync(stream: AsyncIterable<ArrayLike<number> | BufferSource>): Promise<unknown> { let decoded = false; let object: unknown; for await (const buffer of stream) { if (decoded) { throw this.createExtraByteError(this.totalPos); }
this.appendBuffer(buffer);
try { object = this.doDecodeSync(); decoded = true; } catch (e) { if (!(e instanceof DataViewIndexOutOfBoundsError)) { throw e; // rethrow } // fallthrough } this.totalPos += this.pos; }
if (decoded) { if (this.hasRemaining(1)) { throw this.createExtraByteError(this.totalPos); } return object; }
const { headByte, pos, totalPos } = this; throw new RangeError( `Insufficient data in parsing ${prettyByte(headByte)} at ${totalPos} (${pos} in the current buffer)`, ); }
public decodeArrayStream( stream: AsyncIterable<ArrayLike<number> | BufferSource>, ): AsyncGenerator<unknown, void, unknown> { return this.decodeMultiAsync(stream, true); }
public decodeStream(stream: AsyncIterable<ArrayLike<number> | BufferSource>): AsyncGenerator<unknown, void, unknown> { return this.decodeMultiAsync(stream, false); }
private async *decodeMultiAsync(stream: AsyncIterable<ArrayLike<number> | BufferSource>, isArray: boolean) { let isArrayHeaderRequired = isArray; let arrayItemsLeft = -1;
for await (const buffer of stream) { if (isArray && arrayItemsLeft === 0) { throw this.createExtraByteError(this.totalPos); }
this.appendBuffer(buffer);
if (isArrayHeaderRequired) { arrayItemsLeft = this.readArraySize(); isArrayHeaderRequired = false; this.complete(); }
try { while (true) { yield this.doDecodeSync(); if (--arrayItemsLeft === 0) { break; } } } catch (e) { if (!(e instanceof DataViewIndexOutOfBoundsError)) { throw e; // rethrow } // fallthrough } this.totalPos += this.pos; } }
private doDecodeSync(): unknown { DECODE: while (true) { const headByte = this.readHeadByte(); let object: unknown;
if (headByte >= 0xe0) { // negative fixint (111x xxxx) 0xe0 - 0xff object = headByte - 0x100; } else if (headByte < 0xc0) { if (headByte < 0x80) { // positive fixint (0xxx xxxx) 0x00 - 0x7f object = headByte; } else if (headByte < 0x90) { // fixmap (1000 xxxx) 0x80 - 0x8f const size = headByte - 0x80; if (size !== 0) { this.pushMapState(size); this.complete(); continue DECODE; } else { object = {}; } } else if (headByte < 0xa0) { // fixarray (1001 xxxx) 0x90 - 0x9f const size = headByte - 0x90; if (size !== 0) { this.pushArrayState(size); this.complete(); continue DECODE; } else { object = []; } } else { // fixstr (101x xxxx) 0xa0 - 0xbf const byteLength = headByte - 0xa0; object = this.decodeUtf8String(byteLength, 0); } } else if (headByte === 0xc0) { // nil object = null; } else if (headByte === 0xc2) { // false object = false; } else if (headByte === 0xc3) { // true object = true; } else if (headByte === 0xca) { // float 32 object = this.readF32(); } else if (headByte === 0xcb) { // float 64 object = this.readF64(); } else if (headByte === 0xcc) { // uint 8 object = this.readU8(); } else if (headByte === 0xcd) { // uint 16 object = this.readU16(); } else if (headByte === 0xce) { // uint 32 object = this.readU32(); } else if (headByte === 0xcf) { // uint 64 if (this.useBigInt64) { object = this.readU64AsBigInt(); } else { object = this.readU64(); } } else if (headByte === 0xd0) { // int 8 object = this.readI8(); } else if (headByte === 0xd1) { // int 16 object = this.readI16(); } else if (headByte === 0xd2) { // int 32 object = this.readI32(); } else if (headByte === 0xd3) { // int 64 if (this.useBigInt64) { object = this.readI64AsBigInt(); } else { object = this.readI64(); } } else if (headByte === 0xd9) { // str 8 const byteLength = this.lookU8(); object = this.decodeUtf8String(byteLength, 1); } else if (headByte === 0xda) { // str 16 const byteLength = this.lookU16(); object = this.decodeUtf8String(byteLength, 2); } else if (headByte === 0xdb) { // str 32 const byteLength = this.lookU32(); object = this.decodeUtf8String(byteLength, 4); } else if (headByte === 0xdc) { // array 16 const size = this.readU16(); if (size !== 0) { this.pushArrayState(size); this.complete(); continue DECODE; } else { object = []; } } else if (headByte === 0xdd) { // array 32 const size = this.readU32(); if (size !== 0) { this.pushArrayState(size); this.complete(); continue DECODE; } else { object = []; } } else if (headByte === 0xde) { // map 16 const size = this.readU16(); if (size !== 0) { this.pushMapState(size); this.complete(); continue DECODE; } else { object = {}; } } else if (headByte === 0xdf) { // map 32 const size = this.readU32(); if (size !== 0) { this.pushMapState(size); this.complete(); continue DECODE; } else { object = {}; } } else if (headByte === 0xc4) { // bin 8 const size = this.lookU8(); object = this.decodeBinary(size, 1); } else if (headByte === 0xc5) { // bin 16 const size = this.lookU16(); object = this.decodeBinary(size, 2); } else if (headByte === 0xc6) { // bin 32 const size = this.lookU32(); object = this.decodeBinary(size, 4); } else if (headByte === 0xd4) { // fixext 1 object = this.decodeExtension(1, 0); } else if (headByte === 0xd5) { // fixext 2 object = this.decodeExtension(2, 0); } else if (headByte === 0xd6) { // fixext 4 object = this.decodeExtension(4, 0); } else if (headByte === 0xd7) { // fixext 8 object = this.decodeExtension(8, 0); } else if (headByte === 0xd8) { // fixext 16 object = this.decodeExtension(16, 0); } else if (headByte === 0xc7) { // ext 8 const size = this.lookU8(); object = this.decodeExtension(size, 1); } else if (headByte === 0xc8) { // ext 16 const size = this.lookU16(); object = this.decodeExtension(size, 2); } else if (headByte === 0xc9) { // ext 32 const size = this.lookU32(); object = this.decodeExtension(size, 4); } else { throw new DecodeError(`Unrecognized type byte: ${prettyByte(headByte)}`); }
this.complete();
const stack = this.stack; while (stack.length > 0) { // arrays and maps const state = stack[stack.length - 1]!; if (state.type === STATE_ARRAY) { state.array[state.position] = object; state.position++; if (state.position === state.size) { stack.pop(); object = state.array; } else { continue DECODE; } } else if (state.type === STATE_MAP_KEY) { if (!isValidMapKeyType(object)) { throw new DecodeError("The type of key must be string or number but " + typeof object); } if (object === "__proto__") { throw new DecodeError("The key __proto__ is not allowed"); }
state.key = object; state.type = STATE_MAP_VALUE; continue DECODE; } else { // it must be `state.type === State.MAP_VALUE` here
state.map[state.key!] = object; state.readCount++;
if (state.readCount === state.size) { stack.pop(); object = state.map; } else { state.key = null; state.type = STATE_MAP_KEY; continue DECODE; } } }
return object; } }
private readHeadByte(): number { if (this.headByte === HEAD_BYTE_REQUIRED) { this.headByte = this.readU8(); // console.log("headByte", prettyByte(this.headByte)); }
return this.headByte; }
private complete(): void { this.headByte = HEAD_BYTE_REQUIRED; }
private readArraySize(): number { const headByte = this.readHeadByte();
switch (headByte) { case 0xdc: return this.readU16(); case 0xdd: return this.readU32(); default: { if (headByte < 0xa0) { return headByte - 0x90; } else { throw new DecodeError(`Unrecognized array type byte: ${prettyByte(headByte)}`); } } } }
private pushMapState(size: number) { if (size > this.maxMapLength) { throw new DecodeError(`Max length exceeded: map length (${size}) > maxMapLengthLength (${this.maxMapLength})`); }
this.stack.push({ type: STATE_MAP_KEY, size, key: null, readCount: 0, map: {}, }); }
private pushArrayState(size: number) { if (size > this.maxArrayLength) { throw new DecodeError(`Max length exceeded: array length (${size}) > maxArrayLength (${this.maxArrayLength})`); }
this.stack.push({ type: STATE_ARRAY, size, array: new Array<unknown>(size), position: 0, }); }
private decodeUtf8String(byteLength: number, headerOffset: number): string { if (byteLength > this.maxStrLength) { throw new DecodeError( `Max length exceeded: UTF-8 byte length (${byteLength}) > maxStrLength (${this.maxStrLength})`, ); }
if (this.bytes.byteLength < this.pos + headerOffset + byteLength) { throw MORE_DATA; }
const offset = this.pos + headerOffset; let object: string; if (this.stateIsMapKey() && this.keyDecoder?.canBeCached(byteLength)) { object = this.keyDecoder.decode(this.bytes, offset, byteLength); } else { object = utf8Decode(this.bytes, offset, byteLength); } this.pos += headerOffset + byteLength; return object; }
private stateIsMapKey(): boolean { if (this.stack.length > 0) { const state = this.stack[this.stack.length - 1]!; return state.type === STATE_MAP_KEY; } return false; }
private decodeBinary(byteLength: number, headOffset: number): Uint8Array { if (byteLength > this.maxBinLength) { throw new DecodeError(`Max length exceeded: bin length (${byteLength}) > maxBinLength (${this.maxBinLength})`); }
if (!this.hasRemaining(byteLength + headOffset)) { throw MORE_DATA; }
const offset = this.pos + headOffset; const object = this.bytes.subarray(offset, offset + byteLength); this.pos += headOffset + byteLength; return object; }
private decodeExtension(size: number, headOffset: number): unknown { if (size > this.maxExtLength) { throw new DecodeError(`Max length exceeded: ext length (${size}) > maxExtLength (${this.maxExtLength})`); }
const extType = this.view.getInt8(this.pos + headOffset); const data = this.decodeBinary(size, headOffset + 1 /* extType */); return this.extensionCodec.decode(data, extType, this.context); }
private lookU8() { return this.view.getUint8(this.pos); }
private lookU16() { return this.view.getUint16(this.pos); }
private lookU32() { return this.view.getUint32(this.pos); }
private readU8(): number { const value = this.view.getUint8(this.pos); this.pos++; return value; }
private readI8(): number { const value = this.view.getInt8(this.pos); this.pos++; return value; }
private readU16(): number { const value = this.view.getUint16(this.pos); this.pos += 2; return value; }
private readI16(): number { const value = this.view.getInt16(this.pos); this.pos += 2; return value; }
private readU32(): number { const value = this.view.getUint32(this.pos); this.pos += 4; return value; }
private readI32(): number { const value = this.view.getInt32(this.pos); this.pos += 4; return value; }
private readU64(): number { const value = getUint64(this.view, this.pos); this.pos += 8; return value; }
private readI64(): number { const value = getInt64(this.view, this.pos); this.pos += 8; return value; }
private readU64AsBigInt(): bigint { const value = this.view.getBigUint64(this.pos); this.pos += 8; return value; }
private readI64AsBigInt(): bigint { const value = this.view.getBigInt64(this.pos); this.pos += 8; return value; }
private readF32() { const value = this.view.getFloat32(this.pos); this.pos += 4; return value; }
private readF64() { const value = this.view.getFloat64(this.pos); this.pos += 8; return value; }}
msgpack_javascript
Version Info
a year ago
