Merge pull request #3 from karwa/perf

Perf tweaks

Author: karwa

Sources/UniqueID/Time.swift

@@ -29,11 +29,13 @@ internal func _get_system_timestamp() -> UInt64 {
   if #available(macOS 10.12, *) {
     var time = timespec()
     clock_gettime(CLOCK_REALTIME, &time)
-    timestamp = (UInt64(time.tv_sec) &* 10_000_000) &+ (UInt64(time.tv_nsec) / 100)
+    timestamp =
+      (UInt64(bitPattern: Int64(time.tv_sec)) &* 10_000_000) &+ (UInt64(bitPattern: Int64(time.tv_nsec)) / 100)
   } else {
     var time = timeval()
     gettimeofday(&time, nil)
-    timestamp = (UInt64(time.tv_sec) &* 10_000_000) &+ (UInt64(time.tv_usec) &* 10)
+    timestamp =
+      (UInt64(bitPattern: Int64(time.tv_sec)) &* 10_000_000) &+ (UInt64(bitPattern: Int64(time.tv_usec)) &* 10)
   }
   return timestamp & 0x0FFF_FFFF_FFFF_FFFF
 }

Sources/UniqueID/UniqueID+v4.swift

@@ -73,15 +73,23 @@ extension UniqueID {
   ///
   @inlinable
   public static func random<RNG>(using rng: inout RNG) -> UniqueID where RNG: RandomNumberGenerator {
-    var randomBytes: (UInt64, UInt64) = (rng.next(), rng.next())
-    return withUnsafeMutableBytes(of: &randomBytes) { bytes in
-      // octet 6 = time_hi_and_version (high octet).
-      // high 4 bits = version number.
-      bytes[6] = (bytes[6] & 0xF) | 0x40
-      // octet 8 = clock_seq_high_and_reserved.
-      // high 2 bits = variant (10 = standard).
-      bytes[8] = (bytes[8] & 0x3F) | 0x80
-      return UniqueID(bytes: bytes.load(as: UniqueID.Bytes.self))
+    var bytes = UniqueID.null.bytes
+    withUnsafeMutableBytes(of: &bytes) { dest in
+      var random = rng.next()
+      Swift.withUnsafePointer(to: &random) {
+        dest.baseAddress!.copyMemory(from: UnsafeRawPointer($0), byteCount: 8)
+      }
+      random = rng.next()
+      Swift.withUnsafePointer(to: &random) {
+        dest.baseAddress!.advanced(by: 8).copyMemory(from: UnsafeRawPointer($0), byteCount: 8)
+      }
     }
+    // octet 6 = time_hi_and_version (high octet).
+    // high 4 bits = version number.
+    bytes.6 = (bytes.6 & 0xF) | 0x40
+    // octet 8 = clock_seq_high_and_reserved.
+    // high 2 bits = variant (10 = standard).
+    bytes.8 = (bytes.8 & 0x3F) | 0x80
+    return UniqueID(bytes: bytes)
   }
 }

Sources/UniqueID/UniqueID+v6.swift

@@ -71,9 +71,6 @@ internal var _uuidv6GeneratorState = UUIDv6GeneratorState()
     guard pthread_mutexattr_init(&attrs) == 0 else { fatalError("Failed to create pthread_mutexattr_t") }
     // Use adaptive spinning before calling in to the kernel (GNU extension).
     let _ = pthread_mutexattr_settype(&attrs, CInt(PTHREAD_MUTEX_ADAPTIVE_NP))
-    // Bump lock-holder's priority if waited on by higher-priority threads.
-    // Prevents priority inversion.
-    let _ = pthread_mutexattr_setprotocol(&attrs, CInt(PTHREAD_PRIO_INHERIT))
     guard pthread_mutex_init(mutex, &attrs) == 0 else { fatalError("Failed to create pthread_mutex_t") }
     pthread_mutexattr_destroy(&attrs)