Commit 22e1d92d3e
Changed files (1)
lib
lib/std/priority_dequeue.zig
@@ -8,27 +8,29 @@ const expectEqual = testing.expectEqual;
const expectError = testing.expectError;
/// Priority Dequeue for storing generic data. Initialize with `init`.
-/// Provide `compareFn` that returns `Order.lt` when its first
-/// argument should get min-popped before its second argument,
+/// Provide `compareFn` that returns `Order.lt` when its second
+/// argument should get min-popped before its third argument,
/// `Order.eq` if the arguments are of equal priority, or `Order.gt`
-/// if the second argument should be min-popped first.
+/// if the third argument should be min-popped second.
/// Popping the max element works in reverse. For example,
/// to make `popMin` return the smallest number, provide
-/// `fn lessThan(a: T, b: T) Order { return std.math.order(a, b); }`
-pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) type {
+/// `fn lessThan(context: void, a: T, b: T) Order { _ = context; return std.math.order(a, b); }`
+pub fn PriorityDequeue(comptime T: type, comptime Context: type, comptime compareFn: fn (context: Context, a: T, b: T) Order) type {
return struct {
const Self = @This();
items: []T,
len: usize,
allocator: Allocator,
+ context: Context,
/// Initialize and return a new priority dequeue.
- pub fn init(allocator: Allocator) Self {
+ pub fn init(allocator: Allocator, context: Context) Self {
return Self{
.items = &[_]T{},
.len = 0,
.allocator = allocator,
+ .context = context,
};
}
@@ -87,7 +89,7 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
const parent = self.items[parent_index];
const min_layer = self.nextIsMinLayer();
- const order = compareFn(child, parent);
+ const order = compareFn(self.context, child, parent);
if ((min_layer and order == .gt) or (!min_layer and order == .lt)) {
// We must swap the item with it's parent if it is on the "wrong" layer
self.items[parent_index] = child;
@@ -120,7 +122,7 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
const grandparent = self.items[grandparent_index];
// If the grandparent is already better or equal, we have gone as far as we need to
- if (compareFn(child, grandparent) != target_order) break;
+ if (compareFn(self.context, child, grandparent) != target_order) break;
// Otherwise swap the item with it's grandparent
self.items[grandparent_index] = child;
@@ -215,10 +217,10 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
// Find the best grandchild
const best_left = self.bestItemAtIndices(first_grandchild_index, index2, target_order);
const best_right = self.bestItemAtIndices(index3, last_grandchild_index, target_order);
- const best_grandchild = Self.bestItem(best_left, best_right, target_order);
+ const best_grandchild = self.bestItem(best_left, best_right, target_order);
// If the item is better than or equal to its best grandchild, we are done
- if (compareFn(best_grandchild.item, elem) != target_order) return;
+ if (compareFn(self.context, best_grandchild.item, elem) != target_order) return;
// Otherwise, swap them
self.items[best_grandchild.index] = elem;
@@ -235,7 +237,7 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
const best_descendent = self.bestDescendent(first_child_index, first_grandchild_index, target_order);
// If the item is better than or equal to its best descendant, we are done
- if (compareFn(best_descendent.item, elem) != target_order) return;
+ if (compareFn(self.context, best_descendent.item, elem) != target_order) return;
// Otherwise swap them
self.items[best_descendent.index] = elem;
@@ -259,7 +261,7 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
const parent_index = parentIndex(child_index);
const parent = self.items[parent_index];
- if (compareFn(parent, child) == target_order) {
+ if (compareFn(self.context, parent, child) == target_order) {
self.items[parent_index] = child;
self.items[child_index] = parent;
}
@@ -277,8 +279,8 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
};
}
- fn bestItem(item1: ItemAndIndex, item2: ItemAndIndex, target_order: Order) ItemAndIndex {
- if (compareFn(item1.item, item2.item) == target_order) {
+ fn bestItem(self: Self, item1: ItemAndIndex, item2: ItemAndIndex, target_order: Order) ItemAndIndex {
+ if (compareFn(self.context, item1.item, item2.item) == target_order) {
return item1;
} else {
return item2;
@@ -288,7 +290,7 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
fn bestItemAtIndices(self: Self, index1: usize, index2: usize, target_order: Order) ItemAndIndex {
var item1 = self.getItem(index1);
var item2 = self.getItem(index2);
- return Self.bestItem(item1, item2, target_order);
+ return self.bestItem(item1, item2, target_order);
}
fn bestDescendent(self: Self, first_child_index: usize, first_grandchild_index: usize, target_order: Order) ItemAndIndex {
@@ -336,11 +338,12 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
/// Dequeue takes ownership of the passed in slice. The slice must have been
/// allocated with `allocator`.
/// De-initialize with `deinit`.
- pub fn fromOwnedSlice(allocator: Allocator, items: []T) Self {
+ pub fn fromOwnedSlice(allocator: Allocator, items: []T, context: Context) Self {
var queue = Self{
.items = items,
.len = items.len,
.allocator = allocator,
+ .context = context,
};
if (queue.len <= 1) return queue;
@@ -394,7 +397,7 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
}
pub const Iterator = struct {
- queue: *PriorityDequeue(T, compareFn),
+ queue: *PriorityDequeue(T, Context, compareFn),
count: usize,
pub fn next(it: *Iterator) ?T {
@@ -453,14 +456,15 @@ pub fn PriorityDequeue(comptime T: type, comptime compareFn: fn (T, T) Order) ty
};
}
-fn lessThanComparison(a: u32, b: u32) Order {
+fn lessThanComparison(context: void, a: u32, b: u32) Order {
+ _ = context;
return std.math.order(a, b);
}
-const PDQ = PriorityDequeue(u32, lessThanComparison);
+const PDQ = PriorityDequeue(u32, void, lessThanComparison);
test "std.PriorityDequeue: add and remove min" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(54);
@@ -482,11 +486,12 @@ test "std.PriorityDequeue: add and remove min structs" {
const S = struct {
size: u32,
};
- var queue = PriorityDequeue(S, struct {
- fn order(a: S, b: S) Order {
+ var queue = PriorityDequeue(S, void, struct {
+ fn order(context: void, a: S, b: S) Order {
+ _ = context;
return std.math.order(a.size, b.size);
}
- }.order).init(testing.allocator);
+ }.order).init(testing.allocator, {});
defer queue.deinit();
try queue.add(.{ .size = 54 });
@@ -505,7 +510,7 @@ test "std.PriorityDequeue: add and remove min structs" {
}
test "std.PriorityDequeue: add and remove max" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(54);
@@ -524,7 +529,7 @@ test "std.PriorityDequeue: add and remove max" {
}
test "std.PriorityDequeue: add and remove same min" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(1);
@@ -543,7 +548,7 @@ test "std.PriorityDequeue: add and remove same min" {
}
test "std.PriorityDequeue: add and remove same max" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(1);
@@ -562,7 +567,7 @@ test "std.PriorityDequeue: add and remove same max" {
}
test "std.PriorityDequeue: removeOrNull empty" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try expect(queue.removeMinOrNull() == null);
@@ -570,7 +575,7 @@ test "std.PriorityDequeue: removeOrNull empty" {
}
test "std.PriorityDequeue: edge case 3 elements" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(9);
@@ -583,7 +588,7 @@ test "std.PriorityDequeue: edge case 3 elements" {
}
test "std.PriorityDequeue: edge case 3 elements max" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(9);
@@ -596,7 +601,7 @@ test "std.PriorityDequeue: edge case 3 elements max" {
}
test "std.PriorityDequeue: peekMin" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try expect(queue.peekMin() == null);
@@ -610,7 +615,7 @@ test "std.PriorityDequeue: peekMin" {
}
test "std.PriorityDequeue: peekMax" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try expect(queue.peekMin() == null);
@@ -624,7 +629,7 @@ test "std.PriorityDequeue: peekMax" {
}
test "std.PriorityDequeue: sift up with odd indices" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
const items = [_]u32{ 15, 7, 21, 14, 13, 22, 12, 6, 7, 25, 5, 24, 11, 16, 15, 24, 2, 1 };
for (items) |e| {
@@ -638,7 +643,7 @@ test "std.PriorityDequeue: sift up with odd indices" {
}
test "std.PriorityDequeue: sift up with odd indices" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
const items = [_]u32{ 15, 7, 21, 14, 13, 22, 12, 6, 7, 25, 5, 24, 11, 16, 15, 24, 2, 1 };
for (items) |e| {
@@ -652,7 +657,7 @@ test "std.PriorityDequeue: sift up with odd indices" {
}
test "std.PriorityDequeue: addSlice min" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
const items = [_]u32{ 15, 7, 21, 14, 13, 22, 12, 6, 7, 25, 5, 24, 11, 16, 15, 24, 2, 1 };
try queue.addSlice(items[0..]);
@@ -664,7 +669,7 @@ test "std.PriorityDequeue: addSlice min" {
}
test "std.PriorityDequeue: addSlice max" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
const items = [_]u32{ 15, 7, 21, 14, 13, 22, 12, 6, 7, 25, 5, 24, 11, 16, 15, 24, 2, 1 };
try queue.addSlice(items[0..]);
@@ -678,7 +683,7 @@ test "std.PriorityDequeue: addSlice max" {
test "std.PriorityDequeue: fromOwnedSlice trivial case 0" {
const items = [0]u32{};
const queue_items = try testing.allocator.dupe(u32, &items);
- var queue = PDQ.fromOwnedSlice(testing.allocator, queue_items[0..]);
+ var queue = PDQ.fromOwnedSlice(testing.allocator, queue_items[0..], {});
defer queue.deinit();
try expectEqual(@as(usize, 0), queue.len);
try expect(queue.removeMinOrNull() == null);
@@ -687,7 +692,7 @@ test "std.PriorityDequeue: fromOwnedSlice trivial case 0" {
test "std.PriorityDequeue: fromOwnedSlice trivial case 1" {
const items = [1]u32{1};
const queue_items = try testing.allocator.dupe(u32, &items);
- var queue = PDQ.fromOwnedSlice(testing.allocator, queue_items[0..]);
+ var queue = PDQ.fromOwnedSlice(testing.allocator, queue_items[0..], {});
defer queue.deinit();
try expectEqual(@as(usize, 1), queue.len);
@@ -698,7 +703,7 @@ test "std.PriorityDequeue: fromOwnedSlice trivial case 1" {
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 queue_items = try testing.allocator.dupe(u32, items[0..]);
- var queue = PDQ.fromOwnedSlice(testing.allocator, queue_items[0..]);
+ var queue = PDQ.fromOwnedSlice(testing.allocator, queue_items[0..], {});
defer queue.deinit();
const sorted_items = [_]u32{ 1, 2, 5, 6, 7, 7, 11, 12, 13, 14, 15, 15, 16, 21, 22, 24, 24, 25 };
@@ -708,7 +713,7 @@ test "std.PriorityDequeue: fromOwnedSlice" {
}
test "std.PriorityDequeue: update min queue" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(55);
@@ -723,7 +728,7 @@ test "std.PriorityDequeue: update min queue" {
}
test "std.PriorityDequeue: update same min queue" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(1);
@@ -739,7 +744,7 @@ test "std.PriorityDequeue: update same min queue" {
}
test "std.PriorityDequeue: update max queue" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(55);
@@ -755,7 +760,7 @@ test "std.PriorityDequeue: update max queue" {
}
test "std.PriorityDequeue: update same max queue" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(1);
@@ -771,7 +776,7 @@ test "std.PriorityDequeue: update same max queue" {
}
test "std.PriorityDequeue: iterator" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
var map = std.AutoHashMap(u32, void).init(testing.allocator);
defer {
queue.deinit();
@@ -793,7 +798,7 @@ test "std.PriorityDequeue: iterator" {
}
test "std.PriorityDequeue: remove at index" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.add(3);
@@ -816,7 +821,7 @@ test "std.PriorityDequeue: remove at index" {
}
test "std.PriorityDequeue: iterator while empty" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
var it = queue.iterator();
@@ -825,7 +830,7 @@ test "std.PriorityDequeue: iterator while empty" {
}
test "std.PriorityDequeue: shrinkAndFree" {
- var queue = PDQ.init(testing.allocator);
+ var queue = PDQ.init(testing.allocator, {});
defer queue.deinit();
try queue.ensureTotalCapacity(4);
@@ -864,7 +869,7 @@ fn fuzzTestMin(rng: std.rand.Random, comptime queue_size: usize) !void {
const allocator = testing.allocator;
const items = try generateRandomSlice(allocator, rng, queue_size);
- var queue = PDQ.fromOwnedSlice(allocator, items);
+ var queue = PDQ.fromOwnedSlice(allocator, items, {});
defer queue.deinit();
var last_removed: ?u32 = null;
@@ -893,7 +898,7 @@ fn fuzzTestMax(rng: std.rand.Random, queue_size: usize) !void {
const allocator = testing.allocator;
const items = try generateRandomSlice(allocator, rng, queue_size);
- var queue = PDQ.fromOwnedSlice(testing.allocator, items);
+ var queue = PDQ.fromOwnedSlice(testing.allocator, items, {});
defer queue.deinit();
var last_removed: ?u32 = null;
@@ -922,7 +927,7 @@ fn fuzzTestMinMax(rng: std.rand.Random, queue_size: usize) !void {
const allocator = testing.allocator;
const items = try generateRandomSlice(allocator, rng, queue_size);
- var queue = PDQ.fromOwnedSlice(allocator, items);
+ var queue = PDQ.fromOwnedSlice(allocator, items, {});
defer queue.deinit();
var last_min: ?u32 = null;
@@ -957,3 +962,31 @@ fn generateRandomSlice(allocator: std.mem.Allocator, rng: std.rand.Random, size:
return array.toOwnedSlice();
}
+
+fn contextLessThanComparison(context: []const u32, a: usize, b: usize) Order {
+ return std.math.order(context[a], context[b]);
+}
+
+const CPDQ = PriorityDequeue(usize, []const u32, contextLessThanComparison);
+
+test "std.PriorityDequeue: add and remove" {
+ const context = [_]u32{ 5, 3, 4, 2, 2, 8, 0 };
+
+ var queue = CPDQ.init(testing.allocator, context[0..]);
+ defer queue.deinit();
+
+ try queue.add(0);
+ try queue.add(1);
+ try queue.add(2);
+ try queue.add(3);
+ try queue.add(4);
+ try queue.add(5);
+ try queue.add(6);
+ try expectEqual(@as(usize, 6), queue.removeMin());
+ try expectEqual(@as(usize, 5), queue.removeMax());
+ try expectEqual(@as(usize, 3), queue.removeMin());
+ try expectEqual(@as(usize, 0), queue.removeMax());
+ try expectEqual(@as(usize, 4), queue.removeMin());
+ try expectEqual(@as(usize, 2), queue.removeMax());
+ try expectEqual(@as(usize, 1), queue.removeMin());
+}