Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

src: refactor rotating functions to make them more readable. #16

Merged
merged 1 commit into from
Oct 20, 2024
Merged

src: refactor rotating functions to make them more readable. #16

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
105 changes: 56 additions & 49 deletions src/avl.zig
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -780,51 +780,68 @@ pub fn TreeWithOptions(comptime K: type, comptime V: type, comptime Cmp: fn (a:
}
}

fn treeRotated(self: *Self, parent: ?Location, oldRoot: Location, newRoot: Location) void {
if (parent) |p| {
reparent(p, childDir(p, oldRoot), newRoot);
} else {
self.setRoot(newRoot);
}
}

fn checkBalance(self: *Self, loc: ?Location, all_way_up: bool) void {
var mutLoc = loc;
while (mutLoc) |*l| {
while (mutLoc) |*mlPtr| {
const l = mlPtr.*;
const parent = l.parent();
switch (balance(l.*)) {
switch (balance(l)) {
-2 => {
switch (balance(l.*.child(.left).?)) {
-1, 0 => self.rr(l.*),
1 => self.lr(l.*),
else => unreachable,
}
const subRoot = blk: {
switch (balance(l.child(.left).?)) {
-1, 0 => {
break :blk rr(l);
},
1 => {
break :blk lr(l);
},
else => unreachable,
}
};
self.treeRotated(parent, l, subRoot);
},
2 => {
switch (balance(l.*.child(.right).?)) {
-1 => self.rl(l.*),
0, 1 => self.ll(l.*),
else => unreachable,
}
const subRoot = blk: {
switch (balance(l.child(.right).?)) {
-1 => {
break :blk rl(l);
},
0, 1 => {
break :blk ll(l);
},
else => unreachable,
}
};
self.treeRotated(parent, l, subRoot);
},
else => {
if (!recalcHeight(l.*) and !all_way_up) {
if (!recalcHeight(l) and !all_way_up) {
if (options.countChildren) {
updateCounts(l.*);
updateCounts(l);
}
return;
}
if (options.countChildren) {
recalcCounts(l.*);
recalcCounts(l);
}
},
}
mutLoc = parent;
}
}

fn rr(self: *Self, loc: Location) void {
fn rr(loc: Location) Location {
var l = loc;
var left = l.child(.left) orelse unreachable;
var left = l.child(.left).?;
const left_right = left.child(.right);
const parent = l.parent();
if (parent) |p| {
reparent(parent, childDir(p, l), left);
} else {
self.setRoot(left);
}

reparent(l, .left, left_right);
reparent(left, .right, l);
Expand All @@ -836,18 +853,14 @@ pub fn TreeWithOptions(comptime K: type, comptime V: type, comptime Cmp: fn (a:
recalcCounts(l);
recalcCounts(left);
}

return left;
}

fn lr(self: *Self, loc: Location) void {
fn lr(loc: Location) Location {
var l = loc;
var left = l.child(.left) orelse unreachable;
var left_right = left.child(.right) orelse unreachable;
const parent = l.parent();
if (parent) |p| {
reparent(parent, childDir(p, l), left_right);
} else {
self.setRoot(left_right);
}
var left = l.child(.left).?;
var left_right = left.child(.right).?;
const left_right_right = left_right.child(.right);
const left_right_left = left_right.child(.left);

Expand All @@ -866,18 +879,14 @@ pub fn TreeWithOptions(comptime K: type, comptime V: type, comptime Cmp: fn (a:
recalcCounts(left);
recalcCounts(left_right);
}

return left_right;
}

fn rl(self: *Self, loc: Location) void {
fn rl(loc: Location) Location {
var l = loc;
var right = l.child(.right) orelse unreachable;
var right_left = right.child(.left) orelse unreachable;
const parent = l.parent();
if (parent) |p| {
reparent(parent, childDir(p, l), right_left);
} else {
self.setRoot(right_left);
}
var right = l.child(.right).?;
var right_left = right.child(.left).?;

const right_left_left = right_left.child(.left);
const right_left_right = right_left.child(.right);
Expand All @@ -897,18 +906,14 @@ pub fn TreeWithOptions(comptime K: type, comptime V: type, comptime Cmp: fn (a:
recalcCounts(right);
recalcCounts(right_left);
}

return right_left;
}

fn ll(self: *Self, loc: Location) void {
fn ll(loc: Location) Location {
var l = loc;
var right = l.child(.right) orelse unreachable;
var right = l.child(.right).?;
const right_left = right.child(.left);
const parent = l.parent();
if (parent) |p| {
reparent(parent, childDir(p, l), right);
} else {
self.setRoot(right);
}

reparent(l, .right, right_left);
reparent(right, .left, l);
Expand All @@ -920,6 +925,8 @@ pub fn TreeWithOptions(comptime K: type, comptime V: type, comptime Cmp: fn (a:
recalcCounts(l);
recalcCounts(right);
}

return right;
}

fn locate(self: *Self, k: K) LocateResult {
Expand Down
Loading