Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 | 3x 3x 3x 3x 39x 93x 112x 112x 112x 80x 80x 80x 80x 80x 80x 80x 12x 12x 68x 4x 4x 4x 80x 19x 19x 80x 29x 5x 11x 11x 11x 13x 13x 13x 51x 8x 8x 8x 8x 6x 6x 8x 21x 21x 21x 21x 7x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x | import {StreamingOctetReader} from '@jsonjoy.com/buffers/lib/StreamingOctetReader';
import {WsFrameOpcode} from './constants';
import {WsFrameDecodingError} from './errors';
import {WsCloseFrame, WsFrameHeader, WsPingFrame, WsPongFrame} from './frames';
export class WsFrameDecoder {
public readonly reader = new StreamingOctetReader();
public push(uint8: Uint8Array): void {
this.reader.push(uint8);
}
public readFrameHeader(): WsFrameHeader | undefined {
try {
const reader = this.reader;
if (reader.size() < 2) return undefined;
const b0 = reader.u8();
const b1 = reader.u8();
const fin = <0 | 1>(b0 >>> 7);
const opcode = b0 & 0b1111;
const maskBit = b1 >>> 7;
let length = b1 & 0b01111111;
if (length === 126) {
Iif (reader.size() < 2) return undefined;
length = (reader.u8() << 8) | reader.u8();
} else if (length === 127) {
Iif (reader.size() < 8) return undefined;
reader.skip(4);
length = reader.u32();
}
let mask: undefined | [number, number, number, number];
if (maskBit) {
Iif (reader.size() < 4) return undefined;
mask = [reader.u8(), reader.u8(), reader.u8(), reader.u8()];
}
if (opcode >= WsFrameOpcode.MIN_CONTROL_OPCODE) {
switch (opcode) {
case WsFrameOpcode.CLOSE: {
return new WsCloseFrame(fin, opcode, length, mask, 0, '');
}
case WsFrameOpcode.PING: {
Iif (length > 125) throw new WsFrameDecodingError();
const data = mask ? reader.bufXor(length, mask, 0) : reader.buf(length);
return new WsPingFrame(fin, opcode, length, mask, data);
}
case WsFrameOpcode.PONG: {
Iif (length > 125) throw new WsFrameDecodingError();
const data = mask ? reader.bufXor(length, mask, 0) : reader.buf(length);
return new WsPongFrame(fin, opcode, length, mask, data);
}
default: {
throw new WsFrameDecodingError();
}
}
}
return new WsFrameHeader(fin, opcode, length, mask);
} catch (err) {
if (err instanceof RangeError) return undefined;
throw err;
}
}
/**
* Read application data of a frame and copy it to the destination buffer.
* Receives the frame header and the number of bytes that still need to be
* copied, returns back the number of bytes that still need to be copied in
* subsequent calls.
*
* @param frame Frame header.
* @param remaining How many bytes are remaining to be copied.
* @param dst The destination buffer to write to.
* @param pos Position in the destination buffer to start writing to.
* @returns The number of bytes that still need to be copied in the next call.
*/
public readFrameData(frame: WsFrameHeader, remaining: number, dst: Uint8Array, pos: number): number {
const reader = this.reader;
const mask = frame.mask;
const readSize = Math.min(reader.size(), remaining);
if (!mask) reader.copy(readSize, dst, pos);
else {
const alreadyRead = frame.length - remaining;
reader.copyXor(readSize, dst, pos, mask, alreadyRead);
}
return remaining - readSize;
}
public copyFrameData(frame: WsFrameHeader, dst: Uint8Array, pos: number): void {
const reader = this.reader;
const mask = frame.mask;
const readSize = frame.length;
if (!mask) reader.copy(readSize, dst, pos);
else reader.copyXor(readSize, dst, pos, mask, 0);
}
/**
* Reads application data of the CLOSE frame and sets the code and reason
* properties of the frame.
*
* @param frame Close frame.
*/
public readCloseFrameData(frame: WsCloseFrame): void {
let length = frame.length;
Iif (length > 125) throw new WsFrameDecodingError();
let code = 0;
let reason = '';
Eif (length > 0) {
Iif (length < 2) throw new WsFrameDecodingError();
const reader = this.reader;
const mask = frame.mask;
const octet1 = reader.u8() ^ (mask ? mask[0] : 0);
const octet2 = reader.u8() ^ (mask ? mask[1] : 0);
code = (octet1 << 8) | octet2;
length -= 2;
Eif (length) reason = reader.utf8(length, mask ?? [0, 0, 0, 0], 2);
}
frame.code = code;
frame.reason = reason;
}
}
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