urbit-ob

commit fcd249d382dc369870bcc89046595983f679edf4
parent a23d08314790f6edbe7f0df9bc64c00a23d4cfd0
Author: Jared Tobin <jared@jtobin.io>
Date:   Mon,  8 Oct 2018 10:09:11 +1300

Merge pull request #8 from urbit/jt-add-inv-patq

Add hex2patq and patq2hex functions
Diffstat:
M
package.json
 | 
17
++++++++++-------
M
src/index.js
 | 
25
++++++++++++++++++++++++-
M
test/core.test.js
 | 
6
++++++
A
test/property.js
 | 
38
++++++++++++++++++++++++++++++++++++++

4 files changed, 78 insertions(+), 8 deletions(-)
diff --git a/package.json b/package.json
@@ -4,7 +4,7 @@
   "description": "utilities to convert urbit ship names back and forth between @p and @ud",
   "main": "dist/index.js",
   "scripts": {
-    "test": "jest",
+    "test": "jest test/*.test.js && mocha test/property.js",
     "build": "gulp"
   },
   "keywords": [
@@ -15,21 +15,24 @@
   "devDependencies": {
     "@babel/core": "^7.0.0",
     "@babel/preset-env": "^7.0.0-beta.34",
-    "isomorphic-webcrypto": "^1.6.0",
+    "babel-jest": "^23.4.2",
+    "chai": "^4.2.0",
     "gulp": "github:gulpjs/gulp#4.0",
+    "isomorphic-webcrypto": "^1.6.0",
+    "jest": "^23.5.0",
+    "jsverify": "^0.8.3",
+    "mocha": "^5.2.0",
+    "regenerator-runtime": "^0.12.1",
     "rollup-plugin-babel": "github:rollup/rollup-plugin-babel",
     "rollup-plugin-commonjs": "^8.3.0",
     "rollup-plugin-json": "^3.0.0",
     "rollup-plugin-node-builtins": "^2.1.2",
+    "rollup-plugin-node-globals": "^1.2.1",
     "rollup-plugin-node-resolve": "^3.3.0",
     "rollup-plugin-replace": "^2.0.0",
     "rollup-plugin-root-import": "^0.2.3",
     "rollup-stream": "^1.24.1",
-    "vinyl-source-stream": "^2.0.0",
-    "babel-jest": "^23.4.2",
-    "jest": "^23.5.0",
-    "regenerator-runtime": "^0.12.1",
-    "rollup-plugin-node-globals": "^1.2.1"
+    "vinyl-source-stream": "^2.0.0"
   },
   "dependencies": {
     "babel-plugin-lodash": "^3.3.4",
diff --git a/src/index.js b/src/index.js
@@ -4,7 +4,7 @@
 
 const bnjs = require('bn.js')
 const { reduce, concat, chunk, isUndefined,
-        isString, every, map } = require('lodash')
+        isString, every, map, split } = require('lodash')
 
 const raku = [
   3077398253,
@@ -51,6 +51,12 @@ remlysfynwerrycsugnysnyllyndyndemluxfedsedbecmun\
 lyrtesmudnytbyrsenwegfyrmurtelreptegpecnelnevfes\
 `
 
+// split string at the indicated index
+const splitAt = (index, str) => [str.slice(0, index), str.slice(index)];
+
+// convert a decimal number to a hex string
+const dec2hex = dec => dec.toString(16).padStart(2, '0')
+
 // groups suffixes into array of syllables
 const suffixes = suf.match(/.{1,3}/g)
 
@@ -398,6 +404,21 @@ const patq = (n) => {
     acc + (acc === '~' ? '' : '-') + name(elem), '~')
 }
 
+hex2patq = hex => patq(new bnjs(hex, 'hex'))
+
+patq2hex = str => {
+  const chunks = split(str.slice(1), '-')
+  const splat = map(chunks, chunk => {
+    let syls = splitAt(3, chunk)
+    let hex =
+      syls[1] === ''
+      ? dec2hex(getSuffixIndex(syls[0]))
+      : dec2hex(getPrefixIndex(syls[0])) +
+        dec2hex(getSuffixIndex(syls[1]))
+    return hex
+  })
+  return splat.join('')
+}
 
 // returns the class of a ship from it's name
 const tierOfpatp = name => {
@@ -544,6 +565,8 @@ module.exports = {
 
   patp: patp,
   patq: patq,
+  hex2patq: hex2patq,
+  patq2hex: patq2hex,
 
   sein: sein,
   _clan: clan,
diff --git a/test/core.test.js b/test/core.test.js
@@ -155,6 +155,12 @@ test('patq correctly encodes 0x1010101010101010102 as @q', () => {
   expect(ob.patq(input)).toBe(expected);
 });
 
+test('hex2patq works', () => {
+  let hex = '6d7920617765736f6d65207572626974207469636b65742c206920616d20736f206c75636b79';
+  let expected = '~tastud-holruc-sidwet-salpel-taswet-holdeg-paddec-davdut-holdut-davwex-balwet-divwen-holdet-holruc-taslun-salpel-holtux-dacwex-baltud';
+  expect(ob.hex2patq(hex)).toBe(expected);
+})
+
 test('clan works as expected', () => {
   expect(ob._clan(new bnjs(0))).toBe('czar');
   expect(ob._clan(new bnjs(255))).toBe('czar');
diff --git a/test/property.js b/test/property.js
@@ -0,0 +1,38 @@
+
+const expect = require('chai').expect
+const jsc = require('jsverify')
+const ob = require('../src')
+const bn = require('bn.js')
+
+removeLeadingZeroBytes = str =>
+  str.slice(0, 2) === '00'
+  ? removeLeadingZeroBytes(str.slice(2))
+  : str
+
+eqModLeadingZeroBytes = (s, t) =>
+  removeLeadingZeroBytes(s) === removeLeadingZeroBytes(t)
+
+describe('@q encoding', () => {
+  let hexString = jsc.string.smap(
+    x => Buffer.from(x).toString('hex'),
+    x => Buffer.from(x, 'hex').toString()
+  )
+
+  let patq = hexString.smap(
+    hex => ob.patq(new bn(hex, 'hex')),
+    pq => ob.patq2hex(pq)
+  )
+
+  it('patq2hex and hex2patq are inverses', () => {
+    let iso0 = jsc.forall(hexString, hex =>
+      eqModLeadingZeroBytes(ob.patq2hex(ob.hex2patq(hex)), hex)
+    )
+
+    let iso1 = jsc.forall(patq, str =>
+      ob.hex2patq(ob.patq2hex(str)) === str
+    )
+
+    jsc.assert(iso0)
+    jsc.assert(iso1)
+  })
+})