std.rand: Refactor `Random` interface

These changes have been made to resolve issue #10037. The `Random`
interface was implemented in such a way that causes significant slowdown
when calling the `fill` function of the rng used.

The `Random` interface is no longer stored in a field of the rng, and is
instead returned by the child function `random()` of the rng. This
avoids the performance issues caused by the interface.

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/std/hash/benchmark.zig b/lib/std/hash/benchmark.zig
index 9e6ec5b6bc..42102d644e 100644
--- a/lib/std/hash/benchmark.zig
+++ b/lib/std/hash/benchmark.zig
@@ -11,6 +11,7 @@ const MiB = 1024 * KiB;
 const GiB = 1024 * MiB;
 
 var prng = std.rand.DefaultPrng.init(0);
+const random = prng.random();
 
 const Hash = struct {
     ty: type,
@@ -88,7 +89,7 @@ pub fn benchmarkHash(comptime H: anytype, bytes: usize) !Result {
     };
 
     var block: [block_size]u8 = undefined;
-    prng.random.bytes(block[0..]);
+    random.bytes(block[0..]);
 
     var offset: usize = 0;
     var timer = try Timer.start();
@@ -110,7 +111,7 @@ pub fn benchmarkHash(comptime H: anytype, bytes: usize) !Result {
 pub fn benchmarkHashSmallKeys(comptime H: anytype, key_size: usize, bytes: usize) !Result {
     const key_count = bytes / key_size;
     var block: [block_size]u8 = undefined;
-    prng.random.bytes(block[0..]);
+    random.bytes(block[0..]);
 
     var i: usize = 0;
     var timer = try Timer.start();