| author |  sentientwaffle <sentientwaffle@gmail.com> 2023-06-09 12:52:36-07:00 |
| committer |  Veikka Tuominen <git@vexu.eu> 2023-06-10 02:24:35+03:00 |
| log | f04e65bc09ab77eafc317b2d2981970509aae6af |
| tree | 707964d29fbc65bc693fe543a47c14f5231f4e52 |
| parent | 99fe2a23c0b45395be3c71192aeaeaea77e1fb0c |
std.hash_map: fetchRemove increment available
To avoid leaking slots, `fetchRemove` must increment `available` (when the "fetch" succeeds).
Without the `available += 1`, the added test `"std.hash_map repeat fetchRemove"` fails with
run test std-x86-linux-none-Debug: error: thread 432734 panic: integer overflow
.../zig/lib/std/hash_map.zig:1365:28: 0x6471d5 in getOrPutAssumeCapacityAdapted__anon_47495 (test)
self.available -= 1;
^
.../zig/lib/std/hash_map.zig:1308:62: 0x616950 in getOrPutAssumeCapacityContext (test)
const result = self.getOrPutAssumeCapacityAdapted(key, ctx);
^
Alternatively, `fetchRemove` could call `removeByIndex`, though that would entail calling `header()` twice instead of once.1 files changed, 25 insertions(+), 0 deletions(-)
lib- std
lib/std/hash_map.zig+25
| ... | ... | @@ -1113,6 +1113,7 @@ pub fn HashMapUnmanaged( |
| 1113 | 1113 | old_key.* = undefined; |
| 1114 | 1114 | old_val.* = undefined; |
| 1115 | 1115 | self.size -= 1; |
| 1116 | self.available += 1; | |
| 1116 | 1117 | return result; |
| 1117 | 1118 | } |
| 1118 | 1119 | |
| ... | ... | @@ -2193,3 +2194,27 @@ test "std.hash_map removeByPtr 0 sized key" { |
| 2193 | 2194 | |
| 2194 | 2195 | try testing.expect(map.count() == 0); |
| 2195 | 2196 | } |
| 2197 | ||
| 2198 | test "std.hash_map repeat fetchRemove" { | |
| 2199 | var map = AutoHashMapUnmanaged(u64, void){}; | |
| 2200 | defer map.deinit(testing.allocator); | |
| 2201 | ||
| 2202 | try map.ensureTotalCapacity(testing.allocator, 4); | |
| 2203 | ||
| 2204 | map.putAssumeCapacity(0, {}); | |
| 2205 | map.putAssumeCapacity(1, {}); | |
| 2206 | map.putAssumeCapacity(2, {}); | |
| 2207 | map.putAssumeCapacity(3, {}); | |
| 2208 | ||
| 2209 | // fetchRemove() should make slots available. | |
| 2210 | var i: usize = 0; | |
| 2211 | while (i < 10) : (i += 1) { | |
| 2212 | try testing.expect(map.fetchRemove(3) != null); | |
| 2213 | map.putAssumeCapacity(3, {}); | |
| 2214 | } | |
| 2215 | ||
| 2216 | try testing.expect(map.get(0) != null); | |
| 2217 | try testing.expect(map.get(1) != null); | |
| 2218 | try testing.expect(map.get(2) != null); | |
| 2219 | try testing.expect(map.get(3) != null); | |
| 2220 | } |