insert with lookup
3rd lvl is broken
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parent
29ebb53e8c
commit
94f42f24c5
120
src/main.zig
120
src/main.zig
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@ -22,16 +22,26 @@ const BTree = struct {
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self.dbg();
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if (self.root) |*root| {
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const result = try root.as_leaf().insert_value(value);
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if (result) |split| {
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// create new node which will replace self.
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const parent = try Node.create(self.ally);
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parent.leaf.level = split.left.level + 1;
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parent.leaf.push_value(split.middle);
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parent.insert_node(NodeOrLeaf.from_leaf(split.left));
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parent.insert_node(NodeOrLeaf.from_leaf(split.right));
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const search = root.find_key(value);
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self.root = .{ .internal = parent };
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switch (search) {
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.Leaf => |node| {
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std.debug.print("key already present: {}", .{node});
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return error.Occupied;
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},
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.Edge => |edge| {
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const result = try edge.leaf.insert_value(value);
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if (result) |split| {
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// create new node which will replace self.
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const parent = try Node.create(self.ally);
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parent.leaf.level = split.left.level + 1;
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parent.leaf.push_value(split.middle);
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parent.insert_node(NodeOrLeaf.from_leaf(split.left));
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parent.insert_node(NodeOrLeaf.from_leaf(split.right));
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self.root = .{ .internal = parent };
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}
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},
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}
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} else {
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var leaf: *Leaf = try self.ally.create(Leaf);
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@ -94,6 +104,32 @@ const BTree = struct {
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}
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}
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fn find_key(self: NodeOrLeaf, key: u32) Leaf.SearchResult {
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var leaf = self.as_leaf();
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while (true) {
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const search = leaf.find_key(key);
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switch (search) {
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.Leaf => {
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return search;
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},
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.Edge => |edge| {
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const node = NodeOrLeaf.from_leaf(edge.leaf);
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switch (node) {
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.internal => |internal| {
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if (internal.get_edges()[edge.idx]) |child| {
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leaf = child.as_leaf();
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continue;
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}
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},
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.leaf => {},
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}
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return search;
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},
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}
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}
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}
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fn dbg(self: NodeOrLeaf) void {
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switch (self) {
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.internal => |node| {
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@ -237,11 +273,12 @@ const BTree = struct {
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}
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const SplitResult = struct {
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// attached
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// attached, old node that may be modified
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left: *Leaf,
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// lose value, previously attacked, must be inserted
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// if we go all the way to the top, the root node must have some value and this is it
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middle: u32,
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// free floating leaf, must be attached
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// new, free floating leaf, must be attached
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right: *Leaf,
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};
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@ -254,36 +291,51 @@ const BTree = struct {
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}
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}
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std.debug.assert(idx > 0 and idx < CAPACITY - 1);
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std.debug.assert(self.len == CAPACITY);
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//std.debug.assert(idx > 0 and idx < CAPACITY - 1);
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var new = try Leaf.create(self.ally);
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new.level = self.level;
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var middle: u32 = undefined;
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new.len = B - 1;
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std.mem.copy(u32, &new.values, self.values[B..]);
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middle = self.values[B - 1];
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self.len = B - 1;
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// take from right half
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if (idx > B) {
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new.len = self.len - (idx + 1);
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std.mem.copy(u32, &new.values, self.values[(idx + 1)..self.len]);
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middle = self.values[idx];
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self.len = idx;
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self.push_value(value);
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} else {
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// take from left half
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new.len = self.len - (idx);
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std.mem.copy(u32, &new.values, self.values[idx..self.len]);
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if (idx >= B) {
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new.push_value(value);
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middle = self.values[idx - 1];
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self.len = idx - 1;
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} else {
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self.push_value(value);
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}
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return .{ .left = self, .middle = middle, .right = new };
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}
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const SearchResultTag = enum { Edge, Leaf };
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const SearchResult = union(SearchResultTag) {
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Edge: struct { leaf: *Leaf, idx: u16 },
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Leaf: struct { leaf: *Leaf, idx: u16 },
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};
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fn find_key(self: *Leaf, key: u32) SearchResult {
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std.debug.print("looking for {} in {any}\n", .{ key, self.get_values() });
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for (self.get_values(), 0..) |v, i| {
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if (key < v) {
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std.debug.print("decending left of {}\n", .{v});
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return .{ .Edge = .{ .leaf = self, .idx = @intCast(u16, i) } };
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} else if (key == v) {
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std.debug.print("located {} at {}\n", .{ key, v });
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return .{ .Leaf = .{ .leaf = self, .idx = @intCast(u16, i) } };
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}
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}
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std.debug.print("decending right of {}\n", .{self.get_values()[self.len - 1]});
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return .{ .Edge = .{ .leaf = self, .idx = self.len } };
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}
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// returns null on success, or a split result which could not be merged
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// up because we are at the root node
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fn insert_value(self: *Leaf, value: u32) !?SplitResult {
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@ -394,6 +446,16 @@ test "btree insert" {
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try tree.insert(9);
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try tree.insert(8);
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tree.dbg();
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try tree.insert(11);
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tree.dbg();
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try tree.insert(12);
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try tree.insert(16);
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tree.dbg();
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try tree.insert(1);
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try tree.insert(2);
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try tree.insert(0);
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try tree.insert(5);
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tree.dbg();
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}
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test "btree new" {
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