diff --git a/src/core/operations/CRC8Checksum.mjs b/src/core/operations/CRC8Checksum.mjs
index fdcd5d1d..c25a8a2e 100644
--- a/src/core/operations/CRC8Checksum.mjs
+++ b/src/core/operations/CRC8Checksum.mjs
@@ -5,6 +5,9 @@
*/
import Operation from "../Operation";
+import OperationError from "../errors/OperationError";
+
+import { toHex } from "../lib/Hex";
/**
* CRC-8 Checksum operation
@@ -19,8 +22,8 @@ class CRC8Checksum extends Operation {
this.name = "CRC-8 Checksum";
this.module = "Crypto";
- this.description = "";
- this.infoURL = "";
+ this.description = "A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw data.
The CRC was invented by W. Wesley Peterson in 1961.";
+ this.infoURL = "https://wikipedia.org/wiki/Cyclic_redundancy_check";
this.inputType = "ArrayBuffer";
this.outputType = "string";
this.args = [
@@ -28,36 +31,97 @@ class CRC8Checksum extends Operation {
"name": "Algorithm",
"type": "option",
"value": [
- "CRC-8"
+ "CRC-8",
+ "CRC-8/CDMA2000",
+ "CRC-8/DARC",
+ "CRC-8/DVB-S2",
+ "CRC-8/EBU",
+ "CRC-8/I-CODE",
+ "CRC-8/ITU",
+ "CRC-8/MAXIM",
+ "CRC-8/ROHC",
+ "CRC-8/WCDMA"
]
}
]
}
- calculateCRC8(algorithmName, polynomial, initializationValue, refIn, refOut, xorOut, check) {
- let initializationValue = this.reverseBits();
+ /**
+ * Generates the pre-computed lookup table for byte division
+ *
+ * @param polynomial
+ */
+ calculateCRC8LookupTable(polynomial) {
+ const crc8Table = new Uint8Array(256);
- return crc;
+ let currentByte;
+ for (let i = 0; i < 256; i++) {
+ currentByte = i;
+ for (let bit = 0; bit < 8; bit++) {
+ if ((currentByte & 0x80) != 0) {
+ currentByte <<= 1;
+ currentByte ^= polynomial;
+ } else {
+ currentByte <<= 1;
+ }
+ }
+
+ crc8Table[i] = currentByte;
+ }
+
+ return crc8Table;
}
/**
- * For an 8 bit initialization value reverse the bits.
+ * Calculates the CRC-8 Checksum from an input
*
- * @param input
+ * @param {ArrayBuffer} input
+ * @param {number} polynomial
+ * @param {number} initializationValue
+ * @param {boolean} inputReflection
+ * @param {boolean} outputReflection
+ * @param {number} xorOut
+ * @param {number} check
*/
- reverseBits(input) {
- let reflectedBits = input.toString(2).split('');
- for (let i = 0; i < hashSize / 2; i++) {
- let x = reflectedBits[i];
- reflectedBits[i] = reflectedBits[hashSize - i - 1];
- reflectedBits[hashSize - i - 1] = x;
+ calculateCRC8(input, polynomial, initializationValue, inputReflection, outputReflection, xorOut, check) {
+ const crcSize = 8;
+ const crcTable = this.calculateCRC8LookupTable(polynomial);
+
+ let crc = initializationValue != 0 ? initializationValue : 0;
+ let currentByte, position;
+
+ input = new Uint8Array(input);
+ for (let inputByte of input) {
+ currentByte = inputReflection ? this.reverseBits(inputByte, crcSize) : inputByte;
+
+ position = (currentByte ^ crc ) & 255;
+ crc = crcTable[position];
}
- return parseInt(reflectedBits.join(''));
+ crc = outputReflection ? this.reverseBits(crc, crcSize) : crc;
+
+ if (xorOut != 0) crc = crc ^ xorOut;
+
+ return toHex(new Uint8Array([crc]));
}
/**
- * @param {byteArray} input
+ * Reverse the bits for a given input byte.
+ *
+ * @param {number} input
+ */
+ reverseBits(input, hashSize) {
+ let reversedByte = 0;
+ for (let i = hashSize - 1; i >= 0; i--) {
+ reversedByte |= ((input & 1) << i);
+ input >>= 1;
+ }
+
+ return reversedByte;
+ }
+
+ /**
+ * @param {ArrayBuffer} input
* @param {Object[]} args
* @returns {string}
*/
@@ -65,18 +129,29 @@ class CRC8Checksum extends Operation {
const algorithm = args[0];
if (algorithm === "CRC-8") {
- return this.calculateCRC8(algorithm, 0x7, 0x0, false, false, 0x0, 0xF4)
+ return this.calculateCRC8(input, 0x7, 0x0, false, false, 0x0, 0xF4);
+ } else if (algorithm === "CRC-8/CDMA2000") {
+ return this.calculateCRC8(input, 0x9B, 0xFF, false, false, 0x0, 0xDA);
+ } else if (algorithm === "CRC-8/DARC") {
+ return this.calculateCRC8(input, 0x39, 0x0, true, true, 0x0, 0x15);
+ } else if (algorithm === "CRC-8/DVB-S2") {
+ return this.calculateCRC8(input, 0xD5, 0x0, false, false, 0x0, 0xBC);
+ } else if (algorithm === "CRC-8/EBU") {
+ return this.calculateCRC8(input, 0x1D, 0xFF, true, true, 0x0, 0x97);
+ } else if (algorithm === "CRC-8/I-CODE") {
+ return this.calculateCRC8(input, 0x1D, 0xFD, false, false, 0x0, 0x7E);
+ } else if (algorithm === "CRC-8/ITU") {
+ return this.calculateCRC8(input, 0x7, 0x0, false, false, 0x55, 0xA1);
+ } else if (algorithm === "CRC-8/MAXIM") {
+ return this.calculateCRC8(input, 0x31, 0x0, true, true, 0x0, 0xA1);
+ } else if (algorithm === "CRC-8/ROHC") {
+ return this.calculateCRC8(input, 0x7, 0xFF, true, true, 0x0, 0xD0);
+ } else if (algorithm === "CRC-8/WCDMA") {
+ return this.calculateCRC8(input, 0x9B, 0x0, true, true, 0x0, 0x25);
}
- return "";
+ throw new OperationError("Unknown checksum algorithm");
}
-
}
-const hashSize = 8;
-
-// const CRC8AlgoParameters = {
-// 'CRC8'
-// }
-
export default CRC8Checksum;