import { setObject, u16 } from './common2'

const POLY_TABLE = new Uint16Array([
  0x0000, 0x0589, 0x0B12, 0x0E9B, 0x1624, 0x13AD, 0x1D36, 0x18BF,
  0x2C48, 0x29C1, 0x275A, 0x22D3, 0x3A6C, 0x3FE5, 0x317E, 0x34F7,
  0x5890, 0x5D19, 0x5382, 0x560B, 0x4EB4, 0x4B3D, 0x45A6, 0x402F,
  0x74D8, 0x7151, 0x7FCA, 0x7A43, 0x62FC, 0x6775, 0x69EE, 0x6C67,
  0xB120, 0xB4A9, 0xBA32, 0xBFBB, 0xA704, 0xA28D, 0xAC16, 0xA99F,
  0x9D68, 0x98E1, 0x967A, 0x93F3, 0x8B4C, 0x8EC5, 0x805E, 0x85D7,
  0xE9B0, 0xEC39, 0xE2A2, 0xE72B, 0xFF94, 0xFA1D, 0xF486, 0xF10F,
  0xC5F8, 0xC071, 0xCEEA, 0xCB63, 0xD3DC, 0xD655, 0xD8CE, 0xDD47,
  0x67C9, 0x6240, 0x6CDB, 0x6952, 0x71ED, 0x7464, 0x7AFF, 0x7F76,
  0x4B81, 0x4E08, 0x4093, 0x451A, 0x5DA5, 0x582C, 0x56B7, 0x533E,
  0x3F59, 0x3AD0, 0x344B, 0x31C2, 0x297D, 0x2CF4, 0x226F, 0x27E6,
  0x1311, 0x1698, 0x1803, 0x1D8A, 0x0535, 0x00BC, 0x0E27, 0x0BAE,
  0xD6E9, 0xD360, 0xDDFB, 0xD872, 0xC0CD, 0xC544, 0xCBDF, 0xCE56,
  0xFAA1, 0xFF28, 0xF1B3, 0xF43A, 0xEC85, 0xE90C, 0xE797, 0xE21E,
  0x8E79, 0x8BF0, 0x856B, 0x80E2, 0x985D, 0x9DD4, 0x934F, 0x96C6,
  0xA231, 0xA7B8, 0xA923, 0xACAA, 0xB415, 0xB19C, 0xBF07, 0xBA8E,
  0xCF92, 0xCA1B, 0xC480, 0xC109, 0xD9B6, 0xDC3F, 0xD2A4, 0xD72D,
  0xE3DA, 0xE653, 0xE8C8, 0xED41, 0xF5FE, 0xF077, 0xFEEC, 0xFB65,
  0x9702, 0x928B, 0x9C10, 0x9999, 0x8126, 0x84AF, 0x8A34, 0x8FBD,
  0xBB4A, 0xBEC3, 0xB058, 0xB5D1, 0xAD6E, 0xA8E7, 0xA67C, 0xA3F5,
  0x7EB2, 0x7B3B, 0x75A0, 0x7029, 0x6896, 0x6D1F, 0x6384, 0x660D,
  0x52FA, 0x5773, 0x59E8, 0x5C61, 0x44DE, 0x4157, 0x4FCC, 0x4A45,
  0x2622, 0x23AB, 0x2D30, 0x28B9, 0x3006, 0x358F, 0x3B14, 0x3E9D,
  0x0A6A, 0x0FE3, 0x0178, 0x04F1, 0x1C4E, 0x19C7, 0x175C, 0x12D5,
  0xA85B, 0xADD2, 0xA349, 0xA6C0, 0xBE7F, 0xBBF6, 0xB56D, 0xB0E4,
  0x8413, 0x819A, 0x8F01, 0x8A88, 0x9237, 0x97BE, 0x9925, 0x9CAC,
  0xF0CB, 0xF542, 0xFBD9, 0xFE50, 0xE6EF, 0xE366, 0xEDFD, 0xE874,
  0xDC83, 0xD90A, 0xD791, 0xD218, 0xCAA7, 0xCF2E, 0xC1B5, 0xC43C,
  0x197B, 0x1CF2, 0x1269, 0x17E0, 0x0F5F, 0x0AD6, 0x044D, 0x01C4,
  0x3533, 0x30BA, 0x3E21, 0x3BA8, 0x2317, 0x269E, 0x2805, 0x2D8C,
  0x41EB, 0x4462, 0x4AF9, 0x4F70, 0x57CF, 0x5246, 0x5CDD, 0x5954,
  0x6DA3, 0x682A, 0x66B1, 0x6338, 0x7B87, 0x7E0E, 0x7095, 0x751C,
])

/**
 * - poly: 0x0589
 * - initial: 0x0000
 * - xorout: 0x0001
 * - refin: false
 * - refout: false
 */
export default function crc16dectr (buf: Uint8Array = new Uint8Array(), prev: number = 0x0001): number {
  u16[0] = prev ^ 0x0001 // revert of refout and xorout
  for (const b of buf) u16[0] = POLY_TABLE[(u16[0] >>> 8) ^ b] ^ (u16[0] << 8)
  return u16[0] ^ 0x0001
}

setObject(globalThis, ['taichunmin', 'crc', 'crc16dectr'], crc16dectr)