feat: add build command for benchmark tests

build.zig

@@ -15,8 +15,7 @@ pub fn build(b: *std.Build) void {
     // set a preferred release mode, allowing the user to decide how to optimize.
     const optimize = b.standardOptimizeOption(.{});
 
-    const module = b.addModule("hamt", .{ .source_file = .{ .path = "src/lib.zig" } });
-    _ = module;
+    const hamt_module = b.addModule("hamt", .{ .source_file = .{ .path = "src/lib.zig" } });
 
     const lib = b.addStaticLibrary(.{
         .name = "hamt",
@@ -32,6 +31,19 @@ pub fn build(b: *std.Build) void {
     // running `zig build`).
     b.installArtifact(lib);
 
+    // Benchmark
+    const bench = b.addExecutable(.{
+        .name = "hamt-benchmark",
+        .root_source_file = .{ .path = "src/bench.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+    bench.addModule("hamt", hamt_module);
+
+    const bench_cmd = b.addRunArtifact(bench);
+    const bench_step = b.step("bench", "Run benchmark");
+    bench_step.dependOn(&bench_cmd.step);
+
     // Creates a step for unit testing. This only builds the test executable
     // but does not run it.
     const main_tests = b.addTest(.{

src/bench.zig

@@ -0,0 +1,41 @@
+const std = @import("std");
+const HashArrayMappedTrie = @import("hamt").HashArrayMappedTrie;
+
+const StringContext = struct {
+    pub const Digest = u64;
+
+    pub fn hash(input: []const u8) Digest {
+        return std.hash.Wyhash.hash(0, input);
+    }
+
+    pub fn eql(left: []const u8, right: []const u8) bool {
+        return std.mem.eql(u8, left, right);
+    }
+};
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer std.debug.assert(!gpa.deinit());
+
+    const allocator = gpa.allocator();
+
+    const keys = try allocator.alloc([32]u8, 10);
+    defer allocator.free(keys);
+
+    var rand = std.rand.DefaultPrng.init(0);
+    for (keys) |*key| rand.fill(key);
+
+    var trie = HashArrayMappedTrie([]const u8, void, StringContext).init();
+    defer trie.deinit(allocator);
+
+    for (keys) |*key| {
+        try trie.insert(allocator, key, {});
+    }
+
+    var timer = try std.time.Timer.start();
+    for (keys) |*key| {
+        _ = trie.search(key);
+    }
+
+    std.debug.print("{}ns\n", .{timer.read()});
+}