111 lines
2.7 KiB
Zig
111 lines
2.7 KiB
Zig
const std = @import("std");
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pub fn Dynamic(comptime Key: type, comptime Value: type, comptime key_context: KeyContext(Key)) type {
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return struct {
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load_maximum: f32,
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buckets_used: usize,
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buckets: []Bucket,
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///
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///
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///
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const Bucket = struct {
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maybe_entry: ?struct {
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key: Key,
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value: Value,
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},
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maybe_next_index: ?usize,
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};
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///
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///
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///
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const Self = @This();
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///
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///
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///
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pub fn delete(self: Self, key: Key) bool {
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_ = key;
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_ = self;
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}
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///
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///
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///
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pub fn insert(self: Self, key: Key, value: Value) InsertError!void {
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if ((@intToFloat(f32, self.buckets_used) / @intToFloat(
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f32, self.buckets.len)) >= self.load_maximum) try self.rehash();
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var hash = @mod(key_context.hash(key), self.buckets.len);
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while (true) {
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const bucket = &(self.buckets[hash]);
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const entry = &(bucket.maybe_entry orelse {
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bucket.maybe_entry = .{
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.key = key,
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.value = value
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};
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});
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if (key_context.equals(entry.key, key)) return error.KeyExists;
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hash = @mod(hashHash(hash), self.buckets.len);
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}
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}
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///
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/// Searches for a value indexed with `key` in `self`, returning it or `null` if no matching
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/// entry was found.
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///
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pub fn lookup(self: Self, key: Key) ?*Value {
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var bucket = &(self.buckets[@mod(key_context.hash(key), self.buckets.len)]);
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if (bucket.maybe_entry) |*entry|
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if (key_context.equals(entry.key, key)) return &entry.value;
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while (bucket.maybe_next_index) |index| {
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bucket = &(self.buckets[index]);
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if (bucket.maybe_entry) |*entry|
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if (key_context.equals(entry.key, key)) return &entry.value;
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}
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return null;
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}
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};
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}
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///
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///
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///
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pub const InsertError = std.mem.Allocator || error {
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KeyExists,
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};
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pub fn KeyContext(comptime Key: type) type {
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return struct {
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hash: fn (Key) usize,
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equals: fn (Key, Key) bool,
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};
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}
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fn equalsString(this_string: []const u8, that_string: []const u8) bool {
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return std.mem.eql(u8, this_string, that_string);
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}
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fn hashString(string: []const u8) usize {
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var hash = @as(usize, 5381);
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for (string) |byte| hash = ((hash << 5) + hash) + byte;
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return hash;
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}
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pub const string_context = KeyContext([]const u8){
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.hash = hashString,
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.equals = equalsString,
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};
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