Make CSUUID able to use PCG32 in addition to ISAAC. It seems that ISAAC has a bug, and in some scenarios, simply instantiating it will cause really fun GC problems.

Author: wyhaines

Diff for: shard.yml

@@ -1,5 +1,5 @@
 name: csuuid
-version: 0.3.1
+version: 0.4.0
 
 authors:
   - Kirk Haines <[email protected]>

Diff for: spec/csuuid_spec.cr

@@ -129,4 +129,15 @@ describe CSUUID do
     (uuid2 >= uuid1).should be_true
     (uuid1 >= uuid1).should be_true
   end
+
+  it "can work with PCG32 as the generator" do
+    CSUUID.prng = Random::PCG32.new
+    uuid1 = CSUUID.unique
+    uuid2 = CSUUID.unique
+    CHECKUUID.match(uuid1.to_s).should_not be_nil
+    CHECKUUID.match(uuid2.to_s).should_not be_nil
+    uuid1.should_not eq uuid2
+    uuid2.should be > uuid1
+  end
+
 end

Diff for: spec/spec_helper.cr

@@ -2,3 +2,5 @@ require "spec"
 require "../src/csuuid"
 require "parse_date"
 require "benchmark"
+require "random/pcg32"
+require "random/secure"

Diff for: src/csuuid.cr

@@ -39,11 +39,12 @@ require "crystal/spin_lock"
 # +-------------+-----------------+------------+
 # ```
 #
+
 struct CSUUID
-  VERSION = "0.3.1"
+  VERSION = "0.4.0"
 
+  class_property prng : Random::ISAAC | Random::PCG32 = Random::ISAAC.new
   @@mutex = Crystal::SpinLock.new
-  @@prng = Random::ISAAC.new
   @@unique_identifier : Slice(UInt8) = Slice(UInt8).new(6, 0)
   @@unique_seconds_and_nanoseconds : Tuple(Int64, Int32) = {0_i64, 0_i32}
 
@@ -62,7 +63,7 @@ struct CSUUID
         increment_unique_identifier
       else
         @@unique_seconds_and_nanoseconds = {t.internal_seconds, t.internal_nanoseconds}
-        @@unique_identifier = @@prng.random_bytes(6)
+        @@unique_identifier = prng.random_bytes(6)
       end
 
       new(
@@ -107,7 +108,7 @@ struct CSUUID
   end
 
   def initialize(identifier : Slice(UInt8) | String | Nil = nil)
-    identifier ||= @@prng.random_bytes(6)
+    identifier ||= CSUUID.prng.random_bytes(6)
     t = Time.local
     initialize_impl(t.internal_seconds, t.internal_nanoseconds, identifier)
   end
@@ -128,7 +129,7 @@ struct CSUUID
       # Random::ISAAC.random_bytes doesn't appear to be threadsafe.
       # It sometimes dies ugly in multithreaded code, so we need a
       # lock in this one tiny little space to avoid that.
-      @bytes[10, 6].copy_from(id || @@prng.random_bytes(6))
+      @bytes[10, 6].copy_from(id || CSUUID.prng.random_bytes(6))
     end
   end