srctree

Travis Staloch parent ea9d817a 44db92d1
std.StaticStringMap: bump eval branch quota

closes #19803 by changing quota from (30 * N) to (10 * N * log2(N)) whereN = kvs_list.len

  • * adds reported adversarial test case
  • * update doc comment of getLongestPrefix()
inlinesplit
lib/std/static_string_map.zig added: 40, removed: 5, total 35
@@ -70,11 +70,15 @@ pub fn StaticStringMapWithEql(
/// (only keys) tuples if `V` is `void`.
pub inline fn initComptime(comptime kvs_list: anytype) Self {
comptime {
@setEvalBranchQuota(30 * kvs_list.len);
var self = Self{};
if (kvs_list.len == 0)
return self;
 
// Since the KVs are sorted, a linearly-growing bound will never
// be sufficient for extreme cases. So we grow proportional to
// N*log2(N).
@setEvalBranchQuota(10 * kvs_list.len * std.math.log2_int_ceil(usize, kvs_list.len));
 
var sorted_keys: [kvs_list.len][]const u8 = undefined;
var sorted_vals: [kvs_list.len]V = undefined;
 
@@ -212,8 +216,12 @@ pub fn StaticStringMapWithEql(
}
}
 
/// Returns the longest key, value pair where key is a prefix of `str`
/// Returns the key-value pair where key is the longest prefix of `str`
/// else null.
///
/// This is effectively an O(N) algorithm which loops from `max_len` to
/// `min_len` and calls `getIndex()` to check all keys with the given
/// len.
pub fn getLongestPrefix(self: Self, str: []const u8) ?KV {
if (self.kvs.len == 0)
return null;
@@ -497,6 +505,33 @@ test "getLongestPrefix2" {
try testing.expectEqual(null, map.getLongestPrefix("xxx"));
}
 
test "long kvs_list doesn't exceed @setEvalBranchQuota" {
_ = TestMapVoid.initComptime([1]TestKVVoid{.{"x"}} ** 1_000);
test "sorting kvs doesn't exceed eval branch quota" {
// from https://github.com/ziglang/zig/issues/19803
const TypeToByteSizeLUT = std.StaticStringMap(u32).initComptime(.{
.{ "bool", 0 },
.{ "c_int", 0 },
.{ "c_long", 0 },
.{ "c_longdouble", 0 },
.{ "t20", 0 },
.{ "t19", 0 },
.{ "t18", 0 },
.{ "t17", 0 },
.{ "t16", 0 },
.{ "t15", 0 },
.{ "t14", 0 },
.{ "t13", 0 },
.{ "t12", 0 },
.{ "t11", 0 },
.{ "t10", 0 },
.{ "t9", 0 },
.{ "t8", 0 },
.{ "t7", 0 },
.{ "t6", 0 },
.{ "t5", 0 },
.{ "t4", 0 },
.{ "t3", 0 },
.{ "t2", 0 },
.{ "t1", 1 },
});
try testing.expectEqual(1, TypeToByteSizeLUT.get("t1"));
}