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std.ArrayHashMap: introduce setKey

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Only available in the "unmanaged" variant since the other one is
deprecated.
This commit is contained in:
Andrew Kelley 2025-02-11 11:31:51 -08:00
parent b2b830e0e9
commit c2a3d8cbb9
1 changed files with 43 additions and 10 deletions
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39
lib/std/array_hash_map.zig
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@ -1335,8 +1335,26 @@ pub fn ArrayHashMapUnmanaged(
hash.* = h;
}
}
// Rebuild the index.
if (self.entries.capacity > linear_scan_max) {
try rebuildIndex(self, gpa, ctx);
}
/// Modify an entry's key without reordering any entries.
pub fn setKey(self: *Self, gpa: Allocator, index: usize, new_key: K) Oom!void {
if (@sizeOf(ByIndexContext) != 0)
@compileError("Cannot infer context " ++ @typeName(Context) ++ ", call setKeyContext instead.");
return setKeyContext(self, gpa, index, new_key, undefined);
}
pub fn setKeyContext(self: *Self, gpa: Allocator, index: usize, new_key: K, ctx: Context) Oom!void {
const key_ptr = &self.entries.items(.key)[index];
key_ptr.* = new_key;
if (store_hash) self.entries.items(.hash)[index].* = checkedHash(ctx, key_ptr.*);
try rebuildIndex(self, gpa, undefined);
}
fn rebuildIndex(self: *Self, gpa: Allocator, ctx: Context) Oom!void {
if (self.entries.capacity <= linear_scan_max) return;
// We're going to rebuild the index header and replace the existing one (if any). The
// indexes should sized such that they will be at most 60% full.
const bit_index = try IndexHeader.findBitIndex(self.entries.capacity);
@ -1345,7 +1363,6 @@ pub fn ArrayHashMapUnmanaged(
self.insertAllEntriesIntoNewHeader(if (store_hash) {} else ctx, new_header);
self.index_header = new_header;
}
}
/// Sorts the entries and then rebuilds the index.
/// `sort_ctx` must have this method:
@ -2530,6 +2547,22 @@ test "0 sized key and 0 sized value" {
try testing.expectEqual(map.get(0), null);
}
test "setKey" {
const gpa = std.testing.allocator;
var map: AutoArrayHashMapUnmanaged(i32, i32) = .empty;
defer map.deinit(gpa);
try map.put(gpa, 12, 34);
try map.put(gpa, 56, 78);
try map.setKey(gpa, 0, 42);
try testing.expectEqual(2, map.count());
try testing.expectEqual(false, map.contains(12));
try testing.expectEqual(34, map.get(42));
try testing.expectEqual(78, map.get(56));
}
pub fn getHashPtrAddrFn(comptime K: type, comptime Context: type) (fn (Context, K) u32) {
return struct {
fn hash(ctx: Context, key: K) u32 {