zig

commit d0c8fd2ce90805a6097e7b9d7a563b27e23e824c (tree)
parent ad3828db45b7830d5953e7c728c227e78f574cf9
Author: GasInfinity <me@gasinfinity.dev>
Date:   Tue, 13 Jan 2026 22:16:51 +0100

feat(std.Random): add a linear congruent generator

Diffstat:
M
lib/std/Random.zig
 | 
1
+
A
lib/std/Random/lcg.zig
 | 
28
++++++++++++++++++++++++++++

2 files changed, 29 insertions(+), 0 deletions(-)
diff --git a/lib/std/Random.zig b/lib/std/Random.zig
@@ -26,6 +26,7 @@ pub const Sfc64 = @import("Random/Sfc64.zig");
 pub const RomuTrio = @import("Random/RomuTrio.zig");
 pub const SplitMix64 = @import("Random/SplitMix64.zig");
 pub const ziggurat = @import("Random/ziggurat.zig");
+pub const lcg = @import("Random/lcg.zig");
 
 /// Any comparison of this field may result in illegal behavior, since it may be set to
 /// `undefined` in cases where the random implementation does not have any associated
diff --git a/lib/std/Random/lcg.zig b/lib/std/Random/lcg.zig
@@ -0,0 +1,28 @@
+//! Linear congruential generator
+//!
+//! X(n+1) = (a * Xn + c) mod m
+//!
+//! PRNG
+
+const std = @import("std");
+
+/// Linear congruent generator where the modulo is `std.math.maxInt(T)`,
+/// wrapping over the integer.
+pub fn Wrapping(comptime T: type) type {
+    return struct {
+        xi: T,
+        a: T,
+        c: T,
+
+        pub fn init(xi: T, a: T, c: T) LcgSelf {
+            return .{ .xi = xi, .a = a, .c = c };
+        }
+
+        pub fn next(lcg: *LcgSelf) T {
+            lcg.xi = (lcg.a *% lcg.xi) +% lcg.c;
+            return lcg.xi;
+        }
+
+        const LcgSelf = @This();
+    };
+}