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Fix edge cases in fromOwnedSlice

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This commit is contained in:
Zander Khan 2021-01-16 18:06:44 +00:00
parent a162a21947
commit 4d09803414
2 changed files with 50 additions and 4 deletions
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31
lib/std/priority_dequeue.zig
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@ -349,19 +349,22 @@ pub fn PriorityDequeue(comptime T: type) type {
/// allocated with `allocator`. /// allocated with `allocator`.
/// De-initialize with `deinit`. /// De-initialize with `deinit`.
pub fn fromOwnedSlice(allocator: *Allocator, lessThanFn: fn (T, T) bool, items: []T) Self { pub fn fromOwnedSlice(allocator: *Allocator, lessThanFn: fn (T, T) bool, items: []T) Self {
var dequeue = Self{ var queue = Self{
.items = items, .items = items,
.len = items.len, .len = items.len,
.allocator = allocator, .allocator = allocator,
.lessThanFn = lessThanFn, .lessThanFn = lessThanFn,
}; };
const half = (dequeue.len >> 1) - 1;
if (queue.len <= 1) return queue;
const half = (queue.len >> 1) - 1;
var i: usize = 0; var i: usize = 0;
while (i <= half) : (i += 1) { while (i <= half) : (i += 1) {
const index = half - i; const index = half - i;
dequeue.siftDown(index); queue.siftDown(index);
} }
return dequeue; return queue;
} }
pub fn ensureCapacity(self: *Self, new_capacity: usize) !void { pub fn ensureCapacity(self: *Self, new_capacity: usize) !void {
@ -646,6 +649,26 @@ test "std.PriorityDequeue: addSlice max" {
} }
} }
test "std.PriorityDequeue: fromOwnedSlice trivial case 0" {
const items = [0]u32{};
const heap_items = try testing.allocator.dupe(u32, &items);
var heap = Heap.fromOwnedSlice(testing.allocator, lessThanComparison, heap_items[0..]);
defer heap.deinit();
expectEqual(@as(usize, 0), heap.len);
expect(heap.removeMinOrNull() == null);
}
test "std.PriorityDequeue: fromOwnedSlice trivial case 1" {
const items = [1]u32{1};
const heap_items = try testing.allocator.dupe(u32, &items);
var heap = Heap.fromOwnedSlice(testing.allocator, lessThanComparison, heap_items[0..]);
defer heap.deinit();
expectEqual(@as(usize, 1), heap.len);
expectEqual(items[0], heap.removeMin());
expect(heap.removeMinOrNull() == null);
}
test "std.PriorityDequeue: fromOwnedSlice" { test "std.PriorityDequeue: fromOwnedSlice" {
const items = [_]u32{ 15, 7, 21, 14, 13, 22, 12, 6, 7, 25, 5, 24, 11, 16, 15, 24, 2, 1 }; const items = [_]u32{ 15, 7, 21, 14, 13, 22, 12, 6, 7, 25, 5, 24, 11, 16, 15, 24, 2, 1 };
const heap_items = try testing.allocator.dupe(u32, items[0..]); const heap_items = try testing.allocator.dupe(u32, items[0..]);

23
lib/std/priority_queue.zig
View File

@ -166,6 +166,9 @@ pub fn PriorityQueue(comptime T: type) type {
.allocator = allocator, .allocator = allocator,
.compareFn = compareFn, .compareFn = compareFn,
}; };
if (queue.len <= 1) return queue;
const half = (queue.len >> 1) - 1; const half = (queue.len >> 1) - 1;
var i: usize = 0; var i: usize = 0;
while (i <= half) : (i += 1) { while (i <= half) : (i += 1) {
@ -352,6 +355,26 @@ test "std.PriorityQueue: addSlice" {
} }
} }
test "std.PriorityQueue: fromOwnedSlice trivial case 0" {
const items = [0]u32{};
const queue_items = try testing.allocator.dupe(u32, &items);
var queue = PQ.fromOwnedSlice(testing.allocator, lessThan, queue_items[0..]);
defer queue.deinit();
expectEqual(@as(usize, 0), queue.len);
expect(queue.removeOrNull() == null);
}
test "std.PriorityQueue: fromOwnedSlice trivial case 1" {
const items = [1]u32{1};
const queue_items = try testing.allocator.dupe(u32, &items);
var queue = PQ.fromOwnedSlice(testing.allocator, lessThan, queue_items[0..]);
defer queue.deinit();
expectEqual(@as(usize, 1), queue.len);
expectEqual(items[0], queue.remove());
expect(queue.removeOrNull() == null);
}
test "std.PriorityQueue: fromOwnedSlice" { test "std.PriorityQueue: fromOwnedSlice" {
const items = [_]u32{ 15, 7, 21, 14, 13, 22, 12, 6, 7, 25, 5, 24, 11, 16, 15, 24, 2, 1 }; const items = [_]u32{ 15, 7, 21, 14, 13, 22, 12, 6, 7, 25, 5, 24, 11, 16, 15, 24, 2, 1 };
const heap_items = try testing.allocator.dupe(u32, items[0..]); const heap_items = try testing.allocator.dupe(u32, items[0..]);