From 1f09c03d4897206e7ed4a3d90cac6c577c486aed Mon Sep 17 00:00:00 2001 From: GCHQ 77703 Date: Fri, 15 Feb 2019 14:23:16 +0000 Subject: [PATCH] Add De Bruijn Operation --- src/core/config/Categories.json | 1 + .../operations/GenerateDeBruijnSequence.mjs | 87 +++++++++++++++++++ tests/operations/index.mjs | 1 + .../tests/GenerateDeBruijnSequence.mjs | 33 +++++++ 4 files changed, 122 insertions(+) create mode 100644 src/core/operations/GenerateDeBruijnSequence.mjs create mode 100644 tests/operations/tests/GenerateDeBruijnSequence.mjs diff --git a/src/core/config/Categories.json b/src/core/config/Categories.json index 8235ab10..238c7282 100755 --- a/src/core/config/Categories.json +++ b/src/core/config/Categories.json @@ -370,6 +370,7 @@ "Chi Square", "Disassemble x86", "Pseudo-Random Number Generator", + "Generate De Bruijn Sequence", "Generate UUID", "Generate TOTP", "Generate HOTP", diff --git a/src/core/operations/GenerateDeBruijnSequence.mjs b/src/core/operations/GenerateDeBruijnSequence.mjs new file mode 100644 index 00000000..647d3c7f --- /dev/null +++ b/src/core/operations/GenerateDeBruijnSequence.mjs @@ -0,0 +1,87 @@ +/** + * @author gchq77703 [gchq77703@gchq.gov.uk] + * @copyright Crown Copyright 2019 + * @license Apache-2.0 + */ + +import Operation from "../Operation"; +import OperationError from "../errors/OperationError"; + +/** + * Generate De Bruijn Sequence operation + */ +class GenerateDeBruijnSequence extends Operation { + + /** + * GenerateDeBruijnSequence constructor + */ + constructor() { + super(); + + this.name = "Generate De Bruijn Sequence"; + this.module = "Default"; + this.description = "Generates rolling keycode combinations given a certain alphabet size and key length."; + this.infoURL = "https://wikipedia.org/wiki/De_Bruijn_sequence"; + this.inputType = "string"; + this.outputType = "string"; + this.args = [ + { + name: "Alphabet size (k)", + type: "number", + value: 2 + }, + { + name: "Key length (n)", + type: "number", + value: 3 + } + ]; + } + + /** + * @param {string} input + * @param {Object[]} args + * @returns {string} + */ + run(input, args) { + const [k, n] = args; + + if (k < 2 || k > 9) { + throw new OperationError("Invalid alphabet size, required to be between 2 and 9 (inclusive)."); + } + + if (n < 2) { + throw new OperationError("Invalid key length, required to be at least 2."); + } + + if (Math.pow(k, n) > 50000) { + throw new OperationError("Too many permutations, please reduce k^n to under 50,000."); + } + + const a = []; + for (let i = 0; i < k * n; i++) a.push(0); + + const sequence = []; + + (function db(t = 1, p = 1) { + if (t > n) { + if (n % p !== 0) return; + for (let j = 1; j <= p; j++) { + sequence.push(a[j]); + } + return; + } + + a[t] = a[t - p]; + db(t + 1, p); + for (let j = a[t - p] + 1; j < k; j++) { + a[t] = j; + db(t + 1, t); + } + })(); + + return sequence.join(""); + } +} + +export default GenerateDeBruijnSequence; diff --git a/tests/operations/index.mjs b/tests/operations/index.mjs index fb68ed9c..316e934c 100644 --- a/tests/operations/index.mjs +++ b/tests/operations/index.mjs @@ -45,6 +45,7 @@ import "./tests/DateTime"; import "./tests/ExtractEmailAddresses"; import "./tests/Fork"; import "./tests/FromDecimal"; +import "./tests/GenerateDeBruijnSequence"; import "./tests/Hash"; import "./tests/HaversineDistance"; import "./tests/Hexdump"; diff --git a/tests/operations/tests/GenerateDeBruijnSequence.mjs b/tests/operations/tests/GenerateDeBruijnSequence.mjs new file mode 100644 index 00000000..b68a843f --- /dev/null +++ b/tests/operations/tests/GenerateDeBruijnSequence.mjs @@ -0,0 +1,33 @@ +/** + * De Brujin Sequence tests. + * + * @author gchq77703 [gchq77703@gchq.gov.uk] + * @copyright Crown Copyright 2017 + * @license Apache-2.0 + */ +import TestRegister from "../TestRegister"; + +TestRegister.addTests([ + { + name: "Small Sequence", + input: "", + expectedOutput: "00010111", + recipeConfig: [ + { + "op": "Generate De Bruijn Sequence", + "args": [2, 3] + } + ] + }, + { + name: "Long Sequence", + input: "", + expectedOutput: "0000010000200003000110001200013000210002200023000310003200033001010010200103001110011200113001210012200123001310013200133002010020200203002110021200213002210022200223002310023200233003010030200303003110031200313003210032200323003310033200333010110101201013010210102201023010310103201033011020110301111011120111301121011220112301131011320113301202012030121101212012130122101222012230123101232012330130201303013110131201313013210132201323013310133201333020210202202023020310203202033021030211102112021130212102122021230213102132021330220302211022120221302221022220222302231022320223302303023110231202313023210232202323023310233202333030310303203033031110311203113031210312203123031310313203133032110321203213032210322203223032310323203233033110331203313033210332203323033310333203333111112111131112211123111321113311212112131122211223112321123311312113131132211323113321133312122121231213212133122131222212223122321223312313123221232312332123331313213133132221322313232132331332213323133321333322222322233223232233323233233333", + recipeConfig: [ + { + "op": "Generate De Bruijn Sequence", + "args": [4, 5] + } + ] + } +]) \ No newline at end of file