feat: add README.md

This commit is contained in:
Rekai Nyangadzayi Musuka 2023-04-18 00:35:31 -05:00
parent 49a5d1b72a
commit b353458d68
4 changed files with 71 additions and 9 deletions

46
README.md Normal file
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@ -0,0 +1,46 @@
# Hash Array Mapped Trie
A barebones implementation of [this paper](https://infoscience.epfl.ch/record/64398) by Phil Bagwell.
### Usage
As an example:
```zig
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`;

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@ -15,6 +15,9 @@ pub fn build(b: *std.Build) void {
// set a preferred release mode, allowing the user to decide how to optimize. // set a preferred release mode, allowing the user to decide how to optimize.
const optimize = b.standardOptimizeOption(.{}); const optimize = b.standardOptimizeOption(.{});
const module = b.addModule("hamt", .{ .source_file = .{ .path = "src/lib.zig" } });
_ = module;
const lib = b.addStaticLibrary(.{ const lib = b.addStaticLibrary(.{
.name = "hamt", .name = "hamt",
// In this case the main source file is merely a path, however, in more // In this case the main source file is merely a path, however, in more

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@ -1,5 +1,5 @@
.{ .{
.name = "SDL", .name = "hamt",
.version = "0.0.1", .version = "0.1.0",
.dependencies = .{}, .dependencies = .{},
} }

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@ -21,7 +21,7 @@ pub fn HashArrayMappedTrie(comptime K: type, comptime V: type, comptime Context:
const Node = union(enum) { kv: Pair, table: Table }; const Node = union(enum) { kv: Pair, table: Table };
const Table = struct { map: Digest = 0, base: [*]Node }; const Table = struct { map: Digest = 0, base: [*]Node };
const Pair = struct { key: K, value: V }; pub const Pair = struct { key: K, value: V };
pub fn init() Self { pub fn init() Self {
return Self{ .root = [_]?*Node{null} ** table_size }; return Self{ .root = [_]?*Node{null} ** table_size };
@ -291,23 +291,23 @@ const StringContext = struct {
} }
}; };
const TestHamt = HashArrayMappedTrie([]const u8, void, StringContext); const StringTrie = HashArrayMappedTrie([]const u8, void, StringContext);
test "trie init" { test "trie init" {
_ = TestHamt.init(); _ = StringTrie.init();
} }
test "init and deinit" { test "init and deinit" {
const allocator = std.testing.allocator; const allocator = std.testing.allocator;
var trie = TestHamt.init(); var trie = StringTrie.init();
defer trie.deinit(allocator); defer trie.deinit(allocator);
} }
test "trie insert" { test "trie insert" {
const allocator = std.testing.allocator; const allocator = std.testing.allocator;
var trie = TestHamt.init(); var trie = StringTrie.init();
defer trie.deinit(allocator); defer trie.deinit(allocator);
try trie.insert(allocator, "hello", {}); try trie.insert(allocator, "hello", {});
@ -315,10 +315,10 @@ test "trie insert" {
} }
test "trie search" { test "trie search" {
const Pair = TestHamt.Pair; const Pair = StringTrie.Pair;
const allocator = std.testing.allocator; const allocator = std.testing.allocator;
var trie = TestHamt.init(); var trie = StringTrie.init();
defer trie.deinit(allocator); defer trie.deinit(allocator);
try std.testing.expectEqual(@as(?Pair, null), trie.search("sdvx")); try std.testing.expectEqual(@as(?Pair, null), trie.search("sdvx"));
@ -331,3 +331,16 @@ test "trie search" {
try trie.insert(allocator, "", {}); try trie.insert(allocator, "", {});
try std.testing.expectEqual(@as(?Pair, .{ .key = "", .value = {} }), trie.search("")); try std.testing.expectEqual(@as(?Pair, .{ .key = "", .value = {} }), trie.search(""));
} }
test "README.md example" {
const Pair = StringTrie.Pair;
const allocator = std.testing.allocator;
var trie = StringTrie.init();
defer trie.deinit(allocator);
try trie.insert(allocator, "hello", {});
try std.testing.expectEqual(@as(?Pair, .{ .key = "hello", .value = {} }), trie.search("hello"));
try std.testing.expectEqual(@as(?Pair, null), trie.search("world"));
}