hamt/README.md

Hash Array Mapped Trie

A barebones implementation of this paper by Phil Bagwell.

Usage

As an example:

const std = @import("std");
const expectEqual = std.testing.expectEqual;
const HashArrayMappedTrie = @import("hamt").HashArrayMappedTrie ;

const StringTrie = HashArrayMappedTrie([]const u8, void, StringContext);

const StringContext = struct {
	// Note: This definition is *required*
	// TODO: I could just grab the @typeInfo(HashFn).Fn.return_type right? 
	pub const Digest = u64;

	pub inline fn hash(key: []const u8) Digest {
	  return std.hash.Wyhash.hash(0, key);
  }

  pub inline fn eql(left: []const u8, right: []const u8) bool {
    return std.mem.eql(u8, left, right);
  }
};

test {
  const Pair = StringTrie.Pair;
  const allocator = std.testing.allocator;

  var trie = StringTrie.init();
  defer trie.deinit(allocator);

  try trie.insert(allocator, "hello", {});

  try expectEqual(@as(?Pair, .{ .key = "hello", .value = {} }), trie.search("hello"));
  try expectEqual(@as(?Pair, null), trie.search("world"));
}

Building

Build in release mode with zig build -Doptimzie=ReleaseSafe;