Proof of concept

packages/myid/src/uuid.zig

@@ -0,0 +1,41 @@
+const std = @import("std");
+
+var lock: std.Thread.Mutex = .{};
+var last_timestamp: std.atomic.Value(u64) = .{ .raw = 0 };
+var counter: std.atomic.Value(u32) = .{ .raw = 0 };
+
+fn getCount(timestamp: u64) u32 {
+    lock.lock();
+    defer lock.unlock();
+
+    if (last_timestamp.swap(timestamp, .monotonic) != timestamp) {
+        counter.store(0, .monotonic);
+    }
+
+    return counter.fetchAdd(1, .monotonic) % 4096;
+}
+
+pub fn uuid_v7() [16]u8 {
+    const timestamp: u64 = @intCast(@max(0, std.time.milliTimestamp()));
+    const count = getCount(timestamp);
+    const random = blk: {
+        var bytes: [8]u8 = undefined;
+        std.crypto.random.bytes(&bytes);
+        break :blk bytes;
+    };
+
+    var res: [16]u8 = undefined;
+
+    res[0] = @truncate(timestamp >> 40);
+    res[1] = @truncate(timestamp >> 32);
+    res[2] = @truncate(timestamp >> 24);
+    res[3] = @truncate(timestamp >> 16);
+    res[4] = @truncate(timestamp >> 8);
+    res[5] = @truncate(timestamp);
+    res[6] = (@as(u8, 7) << 4) | @as(u8, @truncate((count >> 8) & 0x0F));
+    res[7] = @truncate(count);
+    res[8] = 0x80 | (random[0] & 0x3F);
+    @memcpy(res[9..16], random[1..8]);
+
+    return res;
+}