optimize encodeInt64 (2 times faster)

Author: gfx

src/utils/int.ts

@@ -11,17 +11,11 @@ export function encodeUint64(value: number, view: DataView, offset: number): voi
 export function encodeInt64(value: number, view: DataView, offset: number): void {
   if (value < 0) {
     const absMinusOne = -value - 1;
-    const high = absMinusOne / 0x100000000;
-    const low = absMinusOne & 0xffffffff;
+    const high = absMinusOne / 0x1_0000_0000;
+    const low = absMinusOne & 0xffff_ffff;
 
-    view.setUint8(offset, (((high >> 24) & 0xff) ^ 0xff) | 0x80);
-    view.setUint8(offset + 1, ((high >> 16) & 0xff) ^ 0xff);
-    view.setUint8(offset + 2, ((high >> 8) & 0xff) ^ 0xff);
-    view.setUint8(offset + 3, (high & 0xff) ^ 0xff);
-    view.setUint8(offset + 4, ((low >> 24) & 0xff) ^ 0xff);
-    view.setUint8(offset + 5, ((low >> 16) & 0xff) ^ 0xff);
-    view.setUint8(offset + 6, ((low >> 8) & 0xff) ^ 0xff);
-    view.setUint8(offset + 7, (low & 0xff) ^ 0xff);
+    view.setUint32(offset, (high ^ 0xffff_ffff) | 0x8000_0000);
+    view.setUint32(offset + 4, low ^ 0xffff_ffff);
   } else {
     encodeUint64(value, view, offset);
   }