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fix(hamt): shrink root pointer by 8 bytes

This commit is contained in:
Rekai Nyangadzayi Musuka 2024-09-14 18:52:01 -05:00
parent 052dd57cdd
commit 8e89cc5f4f
1 changed files with 6 additions and 7 deletions
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7
src/trie.zig
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@ -18,7 +18,7 @@ pub fn HashArrayMappedTrie(comptime K: type, comptime V: type, comptime Context:
const t: Log2Int(Digest) = @intCast(@typeInfo(Log2Int(Digest)).Int.bits); const t: Log2Int(Digest) = @intCast(@typeInfo(Log2Int(Digest)).Int.bits);
free_list: FreeList, free_list: FreeList,
root: []?*Node, root: *[table_size]?*Node,
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 };
@ -146,7 +146,7 @@ pub fn HashArrayMappedTrie(comptime K: type, comptime V: type, comptime Context:
pub fn init(allocator: Allocator) !Self { pub fn init(allocator: Allocator) !Self {
// TODO: Add ability to have a larger root node (for quicker lookup times) // TODO: Add ability to have a larger root node (for quicker lookup times)
const root = try allocator.alloc(?*Node, table_size); const root = try allocator.create([table_size]?*Node);
@memset(root, null); @memset(root, null);
return Self{ .root = root, .free_list = try FreeList.init(allocator) }; return Self{ .root = root, .free_list = try FreeList.init(allocator) };
@ -198,13 +198,12 @@ pub fn HashArrayMappedTrie(comptime K: type, comptime V: type, comptime Context:
switch (current.*) { switch (current.*) {
.table => |table| { .table => |table| {
const mask = @as(Digest, 1) << tableIdx(hash, hash_offset); const mask = @as(Digest, 1) << tableIdx(hash, hash_offset);
if (table.map & mask == 0) return null; // empty table
if (table.map & mask != 0) {
const idx = @popCount(table.map & (mask - 1)); const idx = @popCount(table.map & (mask - 1));
current = &table.base[idx]; current = &table.base[idx];
hash_offset += t; hash_offset += t;
} else return null; // hash table entry is empty
}, },
.kv => |pair| { .kv => |pair| {
if (!Context.eql(pair.key, key)) return null; if (!Context.eql(pair.key, key)) return null;