comphash is a very lightweight Zig package offering a zero-cost compile-time hash map for immutable, O(1) string-keyed lookups without any runtime allocations.
Perfect for command‑line flag tables, protocol constant look‑ups, compile‑time DSLs, and any situation where the set of keys is known ahead of time.
| Category | Details |
|---|---|
| Lookup | O(1) expected access. |
| Hash Algorithms | Use any fn([]const u8) u64 — the default is xxHash64 from zighash. |
| Probing | Prober enum: Linear, DoubleHash, Bidirectional, Triangular. |
| Iterators | Type‑driven keys(), values(), items()—all lazy and allocation‑free. |
| No Deps | Pure Zig, no libc, no external libs. |
| Allocation | No runtime allocations or pointer chasing. |
| Comprehensive Tests | Built‑in std.testing ensures correctness across probing strategies. |
zig fetch --save git+https://github.com/galactixx/comphash#v0.1.0This adds a
comphashentry under.dependenciesin yourbuild.zig.zon.
Then in your build.zig:
const comphash_mod = b.dependency("comphash", .{
.target = target,
.optimize = optimize,
}).module("comphash");
// add to library
lib_mod.addImport("comphash", comphash_mod);
// add to executable
exe.root_module.addImport("comphash", comphash_mod);This lets you const ch = @import("comphash"); in your Zig code.
const std = @import("std");
const ch = @import("comphash");
const FruitMap = ch.ComptimeHashMap(u32, null, null, null);
pub fn main() !void {
const kv = &.{ .{ "apple", 10 }, .{ "banana", 20 }, .{ "cherry", 30 } };
const map = FruitMap.init(kv);
std.debug.print("apple → {}\n", .{map.get("apple") orelse 0});
std.debug.print("Length: {}\n", .{map.length()});
}pub fn ComptimeHashMap(
comptime V: type, // value type
comptime hasher: ?fn([]const u8) u64, // optional hash func
comptime prober: ?Prober, // optional probe strategy
comptime eql: ?fn([]const u8,[]const u8)bool // optional equality
) typeCalling this generic returns a new struct type with the following notable members:
| Method | Description |
|---|---|
init(kvs) |
Build the table at comptime. Accepts []const struct { []const u8, V }. |
get(key) |
Returns ?V. |
contains(key) |
Boolean containment check. |
length() / isEmpty() |
Item count helpers. |
keys() / values() / items() |
Lazy iterators. |
capacity() |
Underlying table size (power‑of‑two). |
Enum controlling collision resolution:
Linear–base + iDoubleHash–base + i * (h(key) | 1)Bidirectional– Alternates ±offsetsTriangular–base + i * (i + 1) / 2
Select with the third parameter to ComptimeHashMap.
This project is licensed under the MIT License. See the LICENSE file for details.
Feel free to open an issue or a pull request. Discussion and feedback are welcome!