@robotical/ricjs

///////////////////////////////////////////////////////////////////////////////////////////////////////////////// // // RICJS // Communications Library // // Rob Dobson & Chris Greening 2020-2022 // (C) 2020-2022 // ///////////////////////////////////////////////////////////////////////////////////////////////////////////////// /*eslint no-bitwise: ["error", { "allow": ["&", "<<", ">>", "^"] }] */ enum RICMiniHDLCState { STATE_ESCAPE, STATE_READ, } const CRC_LUT = [ 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0, ]; export default class RICMiniHDLC { private rxState: RICMiniHDLCState; private rxBuffer: Array<number> = []; private onRxFrame: ((rxFrame: Uint8Array) => void) | null; private frameCRC: Array<number> = []; private readonly FRAME_BOUNDARY_OCTET = 0xe7; private readonly CONTROL_ESCAPE_OCTET = 0xd7; private readonly INVERT_OCTET = 0x20; constructor() { this.rxState = RICMiniHDLCState.STATE_READ; this.onRxFrame = null; } setOnRxFrame(onRxFrame: (rxFrame: Uint8Array) => void) { this.onRxFrame = onRxFrame; } addRxByte(rxByte: number): void { if (rxByte === this.FRAME_BOUNDARY_OCTET) { if (this.rxBuffer.length > 2) { this.frameCRC = this.rxBuffer.slice(-2); this.rxBuffer = this.rxBuffer.slice(0, -2); if (this._checkCRC()) { if (this.onRxFrame) { const rxFrame = new Uint8Array(this.rxBuffer); this.onRxFrame(rxFrame); } } } this.rxBuffer = []; } else { if (rxByte === this.CONTROL_ESCAPE_OCTET) { this.rxState = RICMiniHDLCState.STATE_ESCAPE; } else if (this.rxState == RICMiniHDLCState.STATE_ESCAPE) { this.rxState = RICMiniHDLCState.STATE_READ; this.rxBuffer.push(rxByte ^ this.INVERT_OCTET); } else { this.rxBuffer.push(rxByte); } } } addRxBytes(rxBytes: Uint8Array): void { for (let i = 0; i < rxBytes.length; i++) { this.addRxByte(rxBytes[i]); } } _checkCRC(): boolean { const calcCRC = this._crc16(this.rxBuffer); const rxCRC = this.frameCRC[0] * 256 + this.frameCRC[1]; return calcCRC === rxCRC; } _crc16(buf: Array<number> | Uint8Array): number { let crc = 0xffff; for (let i = 0; i < buf.length; i++) { let byt = buf[i]; if (byt > 255) byt = 255; if (byt < 0) byt = 0; const lutIdx = (byt ^ (crc >> 8)) & 0xff; crc = CRC_LUT[lutIdx] ^ (crc << 8); } return crc & 0xffff; } encode(content: Uint8Array): Uint8Array { const maxBufferLen = content.length * 2 + 4; const frameData = new Uint8Array(maxBufferLen); let framePos = 0; // Prefix frameData.set([this.FRAME_BOUNDARY_OCTET], framePos++); // Data for (let i = 0; i < content.length; i++) { framePos = this._setData(frameData, content[i], framePos); } // CRC const frameCRC = this._crc16(content); framePos = this._setData(frameData, (frameCRC >> 8) & 0xff, framePos); framePos = this._setData(frameData, frameCRC & 0xff, framePos); // Suffix frameData.set([this.FRAME_BOUNDARY_OCTET], framePos++); // Frame of correct length const frameFinal = frameData.slice(0, framePos); return frameFinal; } _setData(destBuf: Uint8Array, dataVal: number, pos: number): number { if ( dataVal === this.FRAME_BOUNDARY_OCTET || dataVal === this.CONTROL_ESCAPE_OCTET ) { destBuf.set( [this.CONTROL_ESCAPE_OCTET, dataVal ^ this.INVERT_OCTET], pos, ); pos += 2; } else { destBuf.set([dataVal], pos); pos += 1; } return pos; } }