Optimize encode/decode performance and improve benchmarks

benchmark/benchmarks.js

@@ -1,64 +1,56 @@
-var base62 = require('../lib/ascii');
-var base62custom = require('../lib/custom');
+"use strict";
 
-var encode = base62.encode;
-var decode = base62.decode;
-var encodeCustom = base62custom.encode;
-var decodeCustom = base62custom.decode;
-var indexCharset = base62custom.indexCharset;
+var base62 = require("../lib/ascii");
+var base62custom = require("../lib/custom");
 
-var intResult, strResult, now, delta, i;
-var charset = indexCharset('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz');
+var charset = base62custom.indexCharset("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
 
-function performanceNow() {
-    var t = process.hrtime();
-    return t[0] * 1000 + t[1] / 1000000;
-}
-
-// decode with default charset (ASCII)
-
-now = performanceNow();
-for (intResult = 0, i = 0; i < 1000000; i++) {
-    intResult += decode('00thing');
-}
-
-delta = performanceNow() - now;
-console.log('|', 'decoding with default charset (1000000x)', '|',
-        intResult === 432635954000000 ? 'correct' : 'incorrect', '|',
-        delta.toFixed(2), 'ms', '|');
-
-// encode with default charset (ASCII)
-
-now = performanceNow();
-for (strResult = '', i = 0; i < 1000000; i++) {
-    strResult = encode(i);
-}
-
-delta = performanceNow() - now;
-console.log('|', 'encoding with default charset (1000000x)', '|',
-        strResult === '4c91' ? 'correct' : 'incorrect', '|',
-        delta.toFixed(2), 'ms', '|');
-
-// decode with custom charset
-
-now = performanceNow();
-for (intResult = 0, i = 0; i < 1000000; i++) {
-    intResult += decodeCustom('00thing', charset);
-}
-
-delta = performanceNow() - now;
-console.log('|', 'decoding with custom charset (1000000x)', '|',
-        intResult === 823118800000000 ? 'correct' : 'incorrect', '|',
-        delta.toFixed(2), 'ms', '|');
-
-// encode with custom charset
+function bench(name, iterations, fn) {
+    // warmup
+    for (var w = 0; w < 1000; w++) { fn(w); }
 
-now = performanceNow();
-for (strResult = '', i = 0; i < 1000000; i++) {
-    strResult = encodeCustom(i, charset);
+    var start = process.hrtime.bigint();
+    for (var i = 0; i < iterations; i++) {
+        fn(i);
+    }
+    var ns = process.hrtime.bigint() - start;
+    var ms = Number(ns) / 1e6;
+    var opsPerSec = Math.round(iterations / (ms / 1000));
+    console.log("  " + name.padEnd(30) + ms.toFixed(2).padStart(10) + "ms" + opsPerSec.toLocaleString().padStart(16) + " ops/sec");
 }
 
-delta = performanceNow() - now;
-console.log('|', 'encoding with custom charset (1000000x)', '|',
-        strResult === '4C91' ? 'correct' : 'incorrect', '|',
-        delta.toFixed(2), 'ms', '|');
+var n = 5000000;
+
+console.log("ASCII charset (" + n.toLocaleString() + " iterations)\n");
+
+console.log("  Small numbers (0 to " + n.toLocaleString() + "):");
+bench("encode", n, function(i) { base62.encode(i); });
+bench("decode", n, function() { base62.decode("g7"); });
+bench("encode bigint", n, function(i) { base62.encode(BigInt(i)); });
+bench("decode bigint", n, function() { base62.decode("g7", { bigint: true }); });
+
+console.log("  Large numbers (~10^13):");
+bench("encode", n, function(i) { base62.encode(i + 10000000000000); });
+bench("decode", n, function() { base62.decode("2Q3rKTOF"); });
+bench("encode bigint", n, function(i) { base62.encode(BigInt(i) + 10000000000000n); });
+bench("decode bigint", n, function() { base62.decode("2Q3rKTOF", { bigint: true }); });
+
+console.log("  Very large bigints (~10^30):");
+var bigOffset = 123456789012345678901234567890n;
+bench("encode bigint", n, function(i) { base62.encode(BigInt(i) + bigOffset); });
+bench("decode bigint", n, function() { base62.decode("3oPBaJPMWjmDE4RUeJ", { bigint: true }); });
+
+console.log();
+console.log("Custom charset (" + n.toLocaleString() + " iterations)\n");
+
+console.log("  Small numbers (0 to " + n.toLocaleString() + "):");
+bench("encode", n, function(i) { base62custom.encode(i, charset); });
+bench("decode", n, function() { base62custom.decode("G2", charset); });
+bench("encode bigint", n, function(i) { base62custom.encode(BigInt(i), charset); });
+bench("decode bigint", n, function() { base62custom.decode("G2", charset, { bigint: true }); });
+
+console.log("  Large numbers (~10^13):");
+bench("encode", n, function(i) { base62custom.encode(i + 10000000000000, charset); });
+bench("decode", n, function() { base62custom.decode("7c3RKTOQ", charset); });
+bench("encode bigint", n, function(i) { base62custom.encode(BigInt(i) + 10000000000000n, charset); });
+bench("decode bigint", n, function() { base62custom.decode("7c3RKTOQ", charset, { bigint: true }); });

lib/ascii.js

@@ -1,6 +1,12 @@
 "use strict";
 
-var CHARSET = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".split("");
+var CHARSET = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+// Lookup table: charCode -> value (e.g. '0'=48 -> 0, 'a'=97 -> 10, 'A'=65 -> 36)
+var CHAR_TO_VAL = new Uint8Array(123);
+for (var ci = 0; ci < 62; ci++) {
+    CHAR_TO_VAL[CHARSET[ci].charCodeAt(0)] = ci;
+}
 
 // NB: does not validate input
 exports.encode = function encode(int) {
@@ -10,8 +16,9 @@ exports.encode = function encode(int) {
         }
         var res = "";
         while (int > 0n) {
-            res = CHARSET[Number(int % 62n)] + res;
-            int = int / 62n;
+            var rem = int % 62n;
+            res = CHARSET[Number(rem)] + res;
+            int = (int - rem) / 62n;
         }
         return res;
     }
@@ -22,8 +29,9 @@ exports.encode = function encode(int) {
 
     var res = "";
     while (int > 0) {
-        res = CHARSET[int % 62] + res;
-        int = Math.floor(int / 62);
+        var rem = int % 62;
+        res = CHARSET[rem] + res;
+        int = (int - rem) / 62;
     }
     return res;
 };
@@ -36,30 +44,14 @@ exports.decode = function decode(str, options) {
     if (useBigInt) {
         var res = 0n;
         for (i = 0; i < length; i++) {
-            char = str.charCodeAt(i);
-            if (char < 58) {
-                char = char - 48;
-            } else if (char < 91) {
-                char = char - 29;
-            } else {
-                char = char - 87;
-            }
-            res += BigInt(char) * 62n ** BigInt(length - i - 1);
+            res = res * 62n + BigInt(CHAR_TO_VAL[str.charCodeAt(i)]);
         }
         return res;
     }
 
     var res = 0;
     for (i = 0; i < length; i++) {
-        char = str.charCodeAt(i);
-        if (char < 58) { // 0-9
-            char = char - 48;
-        } else if (char < 91) { // A-Z
-            char = char - 29;
-        } else { // a-z
-            char = char - 87;
-        }
-        res += char * Math.pow(62, length - i - 1);
+        res = res * 62 + CHAR_TO_VAL[str.charCodeAt(i)];
     }
     return res;
 };

lib/custom.js

@@ -11,8 +11,9 @@ exports.encode = function encode(int, charset) {
         var res = "",
             max = BigInt(charset.length);
         while (int > 0n) {
-            res = byCode[Number(int % max)] + res;
-            int = int / max;
+            var rem = int % max;
+            res = byCode[Number(rem)] + res;
+            int = (int - rem) / max;
         }
         return res;
     }
@@ -24,8 +25,9 @@ exports.encode = function encode(int, charset) {
     var res = "",
         max = charset.length;
     while (int > 0) {
-        res = byCode[int % max] + res;
-        int = Math.floor(int / max);
+        var rem = int % max;
+        res = byCode[rem] + res;
+        int = (int - rem) / max;
     }
     return res;
 };
@@ -41,15 +43,15 @@ exports.decode = function decode(str, charset, options) {
             bigMax = BigInt(max);
         for (i = 0; i < length; i++) {
             char = str[i];
-            res += BigInt(byChar[char]) * bigMax ** BigInt(length - i - 1);
+            res = res * bigMax + BigInt(byChar[char]);
         }
         return res;
     }
 
     var res = 0;
     for (i = 0; i < length; i++) {
         char = str[i];
-        res += byChar[char] * Math.pow(max, (length - i - 1));
+        res = res * max + byChar[char];
     }
     return res;
 };

package.json

@@ -23,7 +23,7 @@
   },
   "scripts": {
     "test": "node --test test/*.js",
-    "benchmark": "node benchmark/benchmarks.js; echo; node benchmark/benchmarks_legacy.js"
+    "benchmark": "node benchmark/benchmarks.js"
   },
   "devDependencies": {}
 }