authorgravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2020-01-30 09:45:35-05:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2020-01-30 09:45:35-05:00
loge3a383a661aaf9b43016358e2951ff9d792f240e
treea0d4005ef78ac8531d95fb05b776348d2fc2c63b
parent0303e7bd8e4fb245b4dfae51c7c1e34a66e0855c
parentad15a73240324fce93a659fbee9dab7be24dfbb0
signaturebadge-question-mark Signed by PGP key 4AEE18F83AFDEB23

Merge pull request #4239 from shawnl/rb

rb: **breaking** change API to be thread-safe

1 files changed, 37 insertions(+), 14 deletions(-)

lib/std/rb.zig+37-14
......@@ -1,4 +1,4 @@
1const std = @import("std.zig");
1const std = @import("std");
22const assert = std.debug.assert;
33const testing = std.testing;
44const Order = std.math.Order;
......@@ -11,6 +11,7 @@ const Red = Color.Red;
1111const Black = Color.Black;
1212
1313const ReplaceError = error{NotEqual};
14const SortError = error{NotUnique}; // The new comparison function results in duplicates.
1415
1516/// Insert this into your struct that you want to add to a red-black tree.
1617/// Do not use a pointer. Turn the *rb.Node results of the functions in rb
......@@ -132,7 +133,21 @@ pub const Node = struct {
132133
133134pub const Tree = struct {
134135 root: ?*Node,
135 compareFn: fn (*Node, *Node) Order,
136 compareFn: fn (*Node, *Node, *Tree) Order,
137
138 /// Re-sorts a tree with a new compare function
139 pub fn sort(tree: *Tree, newCompareFn: fn (*Node, *Node, *Tree) Order) SortError!void {
140 var newTree = Tree.init(newCompareFn);
141 var node: *Node = undefined;
142 while (true) {
143 node = tree.first() orelse break;
144 tree.remove(node);
145 if (newTree.insert(node) != null) {
146 return error.NotUnique; // EEXISTS
147 }
148 }
149 tree.* = newTree;
150 }
136151
137152 /// If you have a need for a version that caches this, please file a bug.
138153 pub fn first(tree: *Tree) ?*Node {
......@@ -244,6 +259,7 @@ pub const Tree = struct {
244259 return doLookup(key, tree, &parent, &is_left);
245260 }
246261
262 /// If node is not part of tree, behavior is undefined.
247263 pub fn remove(tree: *Tree, nodeconst: *Node) void {
248264 var node = nodeconst;
249265 // as this has the same value as node, it is unsafe to access node after newnode
......@@ -389,7 +405,7 @@ pub const Tree = struct {
389405 var new = newconst;
390406
391407 // I assume this can get optimized out if the caller already knows.
392 if (tree.compareFn(old, new) != .eq) return ReplaceError.NotEqual;
408 if (tree.compareFn(old, new, tree) != .eq) return ReplaceError.NotEqual;
393409
394410 if (old.getParent()) |parent| {
395411 parent.setChild(new, parent.left == old);
......@@ -404,9 +420,11 @@ pub const Tree = struct {
404420 new.* = old.*;
405421 }
406422
407 pub fn init(tree: *Tree, f: fn (*Node, *Node) Order) void {
408 tree.root = null;
409 tree.compareFn = f;
423 pub fn init(f: fn (*Node, *Node, *Tree) Order) Tree {
424 return Tree{
425 .root = null,
426 .compareFn = f,
427 };
410428 }
411429};
412430
......@@ -469,7 +487,7 @@ fn doLookup(key: *Node, tree: *Tree, pparent: *?*Node, is_left: *bool) ?*Node {
469487 is_left.* = false;
470488
471489 while (maybe_node) |node| {
472 const res = tree.compareFn(node, key);
490 const res = tree.compareFn(node, key, tree);
473491 if (res == .eq) {
474492 return node;
475493 }
......@@ -498,7 +516,7 @@ fn testGetNumber(node: *Node) *testNumber {
498516 return @fieldParentPtr(testNumber, "node", node);
499517}
500518
501fn testCompare(l: *Node, r: *Node) Order {
519fn testCompare(l: *Node, r: *Node, contextIgnored: *Tree) Order {
502520 var left = testGetNumber(l);
503521 var right = testGetNumber(r);
504522
......@@ -512,13 +530,17 @@ fn testCompare(l: *Node, r: *Node) Order {
512530 unreachable;
513531}
514532
533fn testCompareReverse(l: *Node, r: *Node, contextIgnored: *Tree) Order {
534 return testCompare(r, l, contextIgnored);
535}
536
515537test "rb" {
516538 if (@import("builtin").arch == .aarch64) {
517539 // TODO https://github.com/ziglang/zig/issues/3288
518540 return error.SkipZigTest;
519541 }
520542
521 var tree: Tree = undefined;
543 var tree = Tree.init(testCompare);
522544 var ns: [10]testNumber = undefined;
523545 ns[0].value = 42;
524546 ns[1].value = 41;
......@@ -534,7 +556,6 @@ test "rb" {
534556 var dup: testNumber = undefined;
535557 dup.value = 32345;
536558
537 tree.init(testCompare);
538559 _ = tree.insert(&ns[1].node);
539560 _ = tree.insert(&ns[2].node);
540561 _ = tree.insert(&ns[3].node);
......@@ -557,8 +578,7 @@ test "rb" {
557578}
558579
559580test "inserting and looking up" {
560 var tree: Tree = undefined;
561 tree.init(testCompare);
581 var tree = Tree.init(testCompare);
562582 var number: testNumber = undefined;
563583 number.value = 1000;
564584 _ = tree.insert(&number.node);
......@@ -582,8 +602,7 @@ test "multiple inserts, followed by calling first and last" {
582602 // TODO https://github.com/ziglang/zig/issues/3288
583603 return error.SkipZigTest;
584604 }
585 var tree: Tree = undefined;
586 tree.init(testCompare);
605 var tree = Tree.init(testCompare);
587606 var zeroth: testNumber = undefined;
588607 zeroth.value = 0;
589608 var first: testNumber = undefined;
......@@ -601,4 +620,8 @@ test "multiple inserts, followed by calling first and last" {
601620 var lookupNode: testNumber = undefined;
602621 lookupNode.value = 3;
603622 assert(tree.lookup(&lookupNode.node) == &third.node);
623 tree.sort(testCompareReverse) catch unreachable;
624 assert(testGetNumber(tree.first().?).value == 3);
625 assert(testGetNumber(tree.last().?).value == 0);
626 assert(tree.lookup(&lookupNode.node) == &third.node);
604627}