perf: ⚡️ improve further genVarInt performance

streamich · Oct 5, 2020 · 34a4196 · 34a4196
1 parent fa3f4a4
commit 34a4196
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Showing 3 changed files with 9 additions and 9 deletions.
diff --git a/benchmarks/genVarInt.js b/benchmarks/genVarInt.js
@@ -6,10 +6,10 @@ const {genVarInt: v4} = require('../es6/util/genVarInt/v4');
 const {genVarInt: v5} = require('../es6/util/genVarInt/v5');
 const {parseVarInt} = require('../es6/util/parse');
 
-const max = 1e5;
+const max = 5e6;
 const suite = new Benchmark.Suite;
 const run = (genVarInt) => {
-  for (let i = 0; i < max; i++) {
+  for (let i = 0; i < max; i += 11) {
     if (i !== parseVarInt(genVarInt(i), 0)[0])
       throw Error('Invalid parsing');
   }

diff --git a/src/util/genVarInt/README.md b/src/util/genVarInt/README.md
@@ -1,9 +1,9 @@
 ```
 node benchmarks/genVarInt.js 
-genVarInt v1 x 50.24 ops/sec ±1.75% (65 runs sampled)
-genVarInt v2 x 111 ops/sec ±0.48% (81 runs sampled)
-genVarInt v3 x 123 ops/sec ±1.16% (79 runs sampled)
-genVarInt v4 x 124 ops/sec ±1.39% (79 runs sampled)
-genVarInt v5 x 171 ops/sec ±0.41% (87 runs sampled)
+genVarInt v1 x 10.74 ops/sec ±2.54% (31 runs sampled)
+genVarInt v2 x 23.68 ops/sec ±0.55% (43 runs sampled)
+genVarInt v3 x 27.15 ops/sec ±0.53% (49 runs sampled)
+genVarInt v4 x 27.11 ops/sec ±1.28% (49 runs sampled)
+genVarInt v5 x 38.55 ops/sec ±0.50% (67 runs sampled)
 Fastest is genVarInt v5
 ```
diff --git a/src/util/genVarInt/v5.ts b/src/util/genVarInt/v5.ts
@@ -18,7 +18,7 @@ export const genVarInt = (num: number): Buffer => {
   }
 
   const buf = Buffer.allocUnsafe(4);
-  buf.writeUInt16LE(((0b100000000000000 | (num & 0b011111110000000)) << 1) | (0b10000000 | (num & 0b01111111)), 0);
-  buf.writeUInt16LE((((num >> 21) & 0b01111111) << 8) | (0b10000000 | ((num >> 14) & 0b01111111)), 2);
+  buf.writeUInt32LE((((((num >> 21) & 0b01111111) << 8) | (0b10000000 | ((num >> 14) & 0b01111111))) << 16) |
+    ((0b100000000000000 | (num & 0b011111110000000)) << 1) | (0b10000000 | (num & 0b01111111)), 0);
   return buf;
 };