Switch away from BigNumber.js (#497)

* test hash function

* need max lengths, found a test case

* anybase is much smaller. using every testing image I could not find one that needed to be padded. small or large.

package.json

@@ -51,7 +51,7 @@
   "author": "Oliver Moran <oliver.moran@gmail.com>",
   "license": "MIT",
   "dependencies": {
-    "bignumber.js": "^7.2.1",
+    "any-base": "^1.1.0",
     "bmp-js": "0.1.0",
     "buffer": "^5.2.0",
     "exif-parser": "^0.1.12",

src/index.js

@@ -2,7 +2,7 @@ import FS from 'fs';
 import Path from 'path';
 import EventEmitter from 'events';
 
-import { BigNumber } from 'bignumber.js';
+import anyBase from 'any-base';
 import bMFont from 'load-bmfont';
 import MkDirP from 'mkdirp';
 import pixelMatch from 'pixelmatch';
@@ -29,17 +29,18 @@ if (
     require('source-map-support').install();
 }
 
-BigNumber.set({
-    ALPHABET: '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_'
-});
+const alphabet =
+    '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_';
 
 // an array storing the maximum string length of hashes at various bases
-const maxHashLength = [];
+// 0 and 1 do not exist as possible hash lengths
+const maxHashLength = [NaN, NaN];
 
-for (let i = 0; i < 65; i++) {
-    const l =
-        i > 1 ? new BigNumber(new Array(64 + 1).join('1'), 2).toString(i) : NaN;
-    maxHashLength.push(l.length);
+for (let i = 2; i < 65; i++) {
+    const maxHash = anyBase(anyBase.BIN, alphabet.slice(0, i))(
+        new Array(64 + 1).join('1')
+    );
+    maxHashLength.push(maxHash.length);
 }
 
 process.on('exit', clear);
@@ -615,7 +616,7 @@ class Jimp extends EventEmitter {
         }
 
         let hash = new ImagePHash().getHash(this);
-        hash = new BigNumber(hash, 2).toString(base);
+        hash = anyBase(anyBase.BIN, alphabet.slice(0, base))(hash);
 
         while (hash.length < maxHashLength[base]) {
             hash = '0' + hash; // pad out with leading zeros

test/hash.test.js

@@ -0,0 +1,62 @@
+/* eslint-disable no-control-regex */
+
+const { Jimp, getTestDir } = require('./test-helper');
+
+describe.only('hash', () => {
+    const imagesDir = getTestDir() + '/samples';
+
+    it('base 2', done => {
+        new Jimp(imagesDir + '/dice.png', (err, image) => {
+            if (err) done(err);
+            image
+                .hash(2)
+                .should.be.equal(
+                    '1100010000011111011010111110000000010101001011010101101000010010'
+                );
+            done();
+        });
+    });
+
+    it('base 10 (decimal)', done => {
+        new Jimp(imagesDir + '/cops.jpg', (err, image) => {
+            if (err) done(err);
+            image.hash(10).should.be.equal('13442314021806033441');
+            done();
+        });
+    });
+
+    it('base 16 (hex)', done => {
+        new Jimp(imagesDir + '/rgb.tiff', (err, image) => {
+            if (err) done(err);
+            image.hash(16).should.be.equal('949800481007044c');
+            done();
+        });
+    });
+
+    it('base 64', done => {
+        new Jimp(imagesDir + '/windows95.bmp', (err, image) => {
+            if (err) done(err);
+            image.hash(64).should.be.equal('f30wi0ww000');
+            done();
+        });
+    });
+
+    it('base 23', function(done) {
+        // large image need large timeout, but this really seems to be an issue
+        // with should. If I change the expected value it will complete quicker! :(
+        this.timeout(3000);
+        new Jimp(imagesDir + '/panoramic.jpg', (err, image) => {
+            if (err) done(err);
+            image.hash(23).should.be.exactly('0m1m2id7l7cl4fb');
+            done();
+        });
+    });
+
+    it('base 17', done => {
+        new Jimp(imagesDir + '/lenna.png', (err, image) => {
+            if (err) done(err);
+            image.hash(17).should.be.equal('4fa6aga5a64ad0c1');
+            done();
+        });
+    });
+});

yarn.lock

@@ -306,6 +306,10 @@ ansi-styles@^3.2.0, ansi-styles@^3.2.1:
   dependencies:
     color-convert "^1.9.0"
 
+any-base@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/any-base/-/any-base-1.1.0.tgz#ae101a62bc08a597b4c9ab5b7089d456630549fe"
+
 any-observable@^0.3.0:
   version "0.3.0"
   resolved "https://registry.yarnpkg.com/any-observable/-/any-observable-0.3.0.tgz#af933475e5806a67d0d7df090dd5e8bef65d119b"
@@ -1233,10 +1237,6 @@ better-assert@~1.0.0:
   dependencies:
     callsite "1.0.0"
 
-bignumber.js@^7.2.1:
-  version "7.2.1"
-  resolved "https://registry.yarnpkg.com/bignumber.js/-/bignumber.js-7.2.1.tgz#80c048759d826800807c4bfd521e50edbba57a5f"
-
 binary-extensions@^1.0.0:
   version "1.11.0"
   resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-1.11.0.tgz#46aa1751fb6a2f93ee5e689bb1087d4b14c6c205"