mirrors/zig
1
0
Fork 0
mirror of https://codeberg.org/ziglang/zig.git synced 2025-12-06 13:54:21 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

std.enums: fix EnumIndexer branch quota

Browse source 
It's quite silly to have this override which nonetheless makes
assumptions about the input type. Encode the actual complexity of the
sort.

Also, simplify the sorting logic, and fix a bug (grab min and max
*after* the sort, not *before*!)
This commit is contained in:
mlugg 2025-07-31 10:10:40 +01:00 • committed by Matthew Lugg
parent 04d7b491b4
commit ac1e73e249
1 changed files with 36 additions and 22 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

58
lib/std/enums.zig
View file

@ -1317,9 +1317,9 @@ test "EnumSet non-exhaustive" {
} }
pub fn EnumIndexer(comptime E: type) type { pub fn EnumIndexer(comptime E: type) type {
// Assumes that the enum fields are sorted in ascending order (optimistic). // n log n for `std.mem.sortUnstable` call below.
// Unsorted enums may require the user to manually increase the quota. const fields_len = @typeInfo(E).@"enum".fields.len;
@setEvalBranchQuota(3 * @typeInfo(E).@"enum".fields.len + eval_branch_quota_cushion); @setEvalBranchQuota(3 * fields_len * std.math.log2(@max(fields_len, 1)) + eval_branch_quota_cushion);
if (!@typeInfo(E).@"enum".is_exhaustive) { if (!@typeInfo(E).@"enum".is_exhaustive) {
const BackingInt = @typeInfo(E).@"enum".tag_type; const BackingInt = @typeInfo(E).@"enum".tag_type;
@ -1354,10 +1354,6 @@ pub fn EnumIndexer(comptime E: type) type {
}; };
} }
const const_fields = @typeInfo(E).@"enum".fields;
var fields = const_fields[0..const_fields.len].*;
const fields_len = fields.len;
if (fields_len == 0) { if (fields_len == 0) {
return struct { return struct {
pub const Key = E; pub const Key = E;
@ -1373,22 +1369,17 @@ pub fn EnumIndexer(comptime E: type) type {
}; };
} }
var fields: [fields_len]EnumField = @typeInfo(E).@"enum".fields[0..].*;
std.mem.sortUnstable(EnumField, &fields, {}, struct {
fn lessThan(ctx: void, lhs: EnumField, rhs: EnumField) bool {
ctx;
return lhs.value < rhs.value;
}
}.lessThan);
const min = fields[0].value; const min = fields[0].value;
const max = fields[fields.len - 1].value; const max = fields[fields_len - 1].value;
const SortContext = struct {
fields: []EnumField,
pub fn lessThan(comptime ctx: @This(), comptime a: usize, comptime b: usize) bool {
return ctx.fields[a].value < ctx.fields[b].value;
}
pub fn swap(comptime ctx: @This(), comptime a: usize, comptime b: usize) void {
return std.mem.swap(EnumField, &ctx.fields[a], &ctx.fields[b]);
}
};
std.sort.insertionContext(0, fields_len, SortContext{ .fields = &fields });
if (max - min == fields.len - 1) { if (max - min == fields.len - 1) {
return struct { return struct {
pub const Key = E; pub const Key = E;
@ -1538,6 +1529,29 @@ test "EnumIndexer empty" {
try testing.expectEqual(0, Indexer.count); try testing.expectEqual(0, Indexer.count);
} }
test "EnumIndexer large dense unsorted" {
@setEvalBranchQuota(500_000); // many `comptimePrint`s
// Make an enum with 500 fields with values in *descending* order.
const E = @Type(.{ .@"enum" = .{
.tag_type = u32,
.fields = comptime fields: {
var fields: [500]EnumField = undefined;
for (&fields, 0..) |*f, i| f.* = .{
.name = std.fmt.comptimePrint("f{d}", .{i}),
.value = 500 - i,
};
break :fields &fields;
},
.decls = &.{},
.is_exhaustive = true,
} });
const Indexer = EnumIndexer(E);
try testing.expectEqual(E.f0, Indexer.keyForIndex(499));
try testing.expectEqual(E.f499, Indexer.keyForIndex(0));
try testing.expectEqual(499, Indexer.indexOf(.f0));
try testing.expectEqual(0, Indexer.indexOf(.f499));
}
test values { test values {
const E = enum { const E = enum {
X, X,