crypto: update randomUUIDv7() to construct UUID string directly from bytes

Author: nabeel378

lib/internal/crypto/random.js

@@ -14,6 +14,7 @@ const {
   DateNow,
   FunctionPrototypeBind,
   FunctionPrototypeCall,
+  MathFloor,
   MathMin,
   NumberIsNaN,
   NumberIsSafeInteger,
@@ -433,19 +434,38 @@ function randomUUIDv7() {
   randomFillSync(uuidV7Buffer);
 
   const now = DateNow();
-  uuidV7Buffer[0] = (now / 0x10000000000) & 0xff;
-  uuidV7Buffer[1] = (now / 0x100000000) & 0xff;
-  uuidV7Buffer[2] = (now / 0x1000000) & 0xff;
-  uuidV7Buffer[3] = (now / 0x10000) & 0xff;
-  uuidV7Buffer[4] = (now / 0x100) & 0xff;
+  uuidV7Buffer[0] = MathFloor(now / 0x10000000000) & 0xff;
+  uuidV7Buffer[1] = MathFloor(now / 0x100000000) & 0xff;
+  uuidV7Buffer[2] = MathFloor(now / 0x1000000) & 0xff;
+  uuidV7Buffer[3] = MathFloor(now / 0x10000) & 0xff;
+  uuidV7Buffer[4] = MathFloor(now / 0x100) & 0xff;
   uuidV7Buffer[5] = now & 0xff;
 
   uuidV7Buffer[6] = (uuidV7Buffer[6] & 0x0f) | 0x70;
 
   uuidV7Buffer[8] = (uuidV7Buffer[8] & 0x3f) | 0x80;
-  
-  const result = serializeUUID(uuidV7Buffer);
-  return result;
+
+  const kHexBytes = getHexBytes();
+  return kHexBytes[uuidV7Buffer[0]] +
+    kHexBytes[uuidV7Buffer[1]] +
+    kHexBytes[uuidV7Buffer[2]] +
+    kHexBytes[uuidV7Buffer[3]] +
+    '-' +
+    kHexBytes[uuidV7Buffer[4]] +
+    kHexBytes[uuidV7Buffer[5]] +
+    '-' +
+    kHexBytes[uuidV7Buffer[6]] +
+    kHexBytes[uuidV7Buffer[7]] +
+    '-' +
+    kHexBytes[uuidV7Buffer[8]] +
+    kHexBytes[uuidV7Buffer[9]] +
+    '-' +
+    kHexBytes[uuidV7Buffer[10]] +
+    kHexBytes[uuidV7Buffer[11]] +
+    kHexBytes[uuidV7Buffer[12]] +
+    kHexBytes[uuidV7Buffer[13]] +
+    kHexBytes[uuidV7Buffer[14]] +
+    kHexBytes[uuidV7Buffer[15]];
 }   
 
 function createRandomPrimeJob(type, size, options) {