Squashed 'third_party/immer/' content from commit ad3e3556d

git-subtree-dir: third_party/immer
git-subtree-split: ad3e3556d38bb75966dd24c61a774970a7c7957e

1 files changed, 509 insertions, 0 deletions

diff --git a/immer/detail/rbts/rbtree.hpp b/immer/detail/rbts/rbtree.hpp
new file mode 100644
index 000000000000..b31f5e9b0788
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+++ b/immer/detail/rbts/rbtree.hpp
@@ -0,0 +1,509 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <immer/detail/rbts/node.hpp>
+#include <immer/detail/rbts/operations.hpp>
+#include <immer/detail/rbts/position.hpp>
+
+#include <immer/detail/type_traits.hpp>
+
+#include <cassert>
+#include <memory>
+#include <numeric>
+
+namespace immer {
+namespace detail {
+namespace rbts {
+
+template <typename T, typename MemoryPolicy, bits_t B, bits_t BL>
+struct rbtree
+{
+    using node_t  = node<T, MemoryPolicy, B, BL>;
+    using edit_t  = typename node_t::edit_t;
+    using owner_t = typename MemoryPolicy::transience_t::owner;
+
+    size_t size;
+    shift_t shift;
+    node_t* root;
+    node_t* tail;
+
+    static const rbtree& empty()
+    {
+        static const rbtree empty_{
+            0, BL, node_t::make_inner_n(0u), node_t::make_leaf_n(0u)};
+        return empty_;
+    }
+
+    template <typename U>
+    static auto from_initializer_list(std::initializer_list<U> values)
+    {
+        auto e      = owner_t{};
+        auto result = rbtree{empty()};
+        for (auto&& v : values)
+            result.push_back_mut(e, v);
+        return result;
+    }
+
+    template <typename Iter,
+              typename Sent,
+              std::enable_if_t<compatible_sentinel_v<Iter, Sent>, bool> = true>
+    static auto from_range(Iter first, Sent last)
+    {
+        auto e      = owner_t{};
+        auto result = rbtree{empty()};
+        for (; first != last; ++first)
+            result.push_back_mut(e, *first);
+        return result;
+    }
+
+    static auto from_fill(size_t n, T v)
+    {
+        auto e      = owner_t{};
+        auto result = rbtree{empty()};
+        while (n-- > 0)
+            result.push_back_mut(e, v);
+        return result;
+    }
+
+    rbtree(size_t sz, shift_t sh, node_t* r, node_t* t)
+        : size{sz}
+        , shift{sh}
+        , root{r}
+        , tail{t}
+    {
+        assert(check_tree());
+    }
+
+    rbtree(const rbtree& other)
+        : rbtree{other.size, other.shift, other.root, other.tail}
+    {
+        inc();
+    }
+
+    rbtree(rbtree&& other)
+        : rbtree{empty()}
+    {
+        swap(*this, other);
+    }
+
+    rbtree& operator=(const rbtree& other)
+    {
+        auto next = other;
+        swap(*this, next);
+        return *this;
+    }
+
+    rbtree& operator=(rbtree&& other)
+    {
+        swap(*this, other);
+        return *this;
+    }
+
+    friend void swap(rbtree& x, rbtree& y)
+    {
+        using std::swap;
+        swap(x.size, y.size);
+        swap(x.shift, y.shift);
+        swap(x.root, y.root);
+        swap(x.tail, y.tail);
+    }
+
+    ~rbtree() { dec(); }
+
+    void inc() const
+    {
+        root->inc();
+        tail->inc();
+    }
+
+    void dec() const { traverse(dec_visitor()); }
+
+    auto tail_size() const { return size ? ((size - 1) & mask<BL>) +1 : 0; }
+
+    auto tail_offset() const { return size ? (size - 1) & ~mask<BL> : 0; }
+
+    template <typename Visitor, typename... Args>
+    void traverse(Visitor v, Args&&... args) const
+    {
+        auto tail_off  = tail_offset();
+        auto tail_size = size - tail_off;
+
+        if (tail_off)
+            make_regular_sub_pos(root, shift, tail_off).visit(v, args...);
+        else
+            make_empty_regular_pos(root).visit(v, args...);
+
+        make_leaf_sub_pos(tail, tail_size).visit(v, args...);
+    }
+
+    template <typename Visitor, typename... Args>
+    void traverse(Visitor v, size_t first, size_t last, Args&&... args) const
+    {
+        auto tail_off  = tail_offset();
+        auto tail_size = size - tail_off;
+
+        if (first < tail_off)
+            make_regular_sub_pos(root, shift, tail_off)
+                .visit(v, first, last < tail_off ? last : tail_off, args...);
+        if (last > tail_off)
+            make_leaf_sub_pos(tail, tail_size)
+                .visit(v,
+                       first > tail_off ? first - tail_off : 0,
+                       last - tail_off,
+                       args...);
+    }
+
+    template <typename Visitor, typename... Args>
+    bool traverse_p(Visitor v, Args&&... args) const
+    {
+        auto tail_off  = tail_offset();
+        auto tail_size = size - tail_off;
+        return (tail_off ? make_regular_sub_pos(root, shift, tail_off)
+                               .visit(v, args...)
+                         : make_empty_regular_pos(root).visit(v, args...)) &&
+               make_leaf_sub_pos(tail, tail_size).visit(v, args...);
+    }
+
+    template <typename Visitor, typename... Args>
+    bool traverse_p(Visitor v, size_t first, size_t last, Args&&... args) const
+    {
+        auto tail_off  = tail_offset();
+        auto tail_size = size - tail_off;
+
+        return (first < tail_off ? make_regular_sub_pos(root, shift, tail_off)
+                                       .visit(v,
+                                              first,
+                                              last < tail_off ? last : tail_off,
+                                              args...)
+                                 : true) &&
+               (last > tail_off
+                    ? make_leaf_sub_pos(tail, tail_size)
+                          .visit(v,
+                                 first > tail_off ? first - tail_off : 0,
+                                 last - tail_off,
+                                 args...)
+                    : true);
+    }
+
+    template <typename Visitor>
+    decltype(auto) descend(Visitor v, size_t idx) const
+    {
+        auto tail_off = tail_offset();
+        return idx >= tail_off ? make_leaf_descent_pos(tail).visit(v, idx)
+                               : visit_regular_descent(root, shift, v, idx);
+    }
+
+    template <typename Fn>
+    void for_each_chunk(Fn&& fn) const
+    {
+        traverse(for_each_chunk_visitor{}, std::forward<Fn>(fn));
+    }
+
+    template <typename Fn>
+    void for_each_chunk(size_t first, size_t last, Fn&& fn) const
+    {
+        traverse(for_each_chunk_i_visitor{}, first, last, std::forward<Fn>(fn));
+    }
+
+    template <typename Fn>
+    bool for_each_chunk_p(Fn&& fn) const
+    {
+        return traverse_p(for_each_chunk_p_visitor{}, std::forward<Fn>(fn));
+    }
+
+    template <typename Fn>
+    bool for_each_chunk_p(size_t first, size_t last, Fn&& fn) const
+    {
+        return traverse_p(
+            for_each_chunk_p_i_visitor{}, first, last, std::forward<Fn>(fn));
+    }
+
+    bool equals(const rbtree& other) const
+    {
+        if (size != other.size)
+            return false;
+        if (size == 0)
+            return true;
+        return (size <= branches<BL> ||
+                make_regular_sub_pos(root, shift, tail_offset())
+                    .visit(equals_visitor{}, other.root)) &&
+               make_leaf_sub_pos(tail, tail_size())
+                   .visit(equals_visitor{}, other.tail);
+    }
+
+    void ensure_mutable_tail(edit_t e, count_t n)
+    {
+        if (!tail->can_mutate(e)) {
+            auto new_tail = node_t::copy_leaf_e(e, tail, n);
+            dec_leaf(tail, n);
+            tail = new_tail;
+        }
+    }
+
+    void push_back_mut(edit_t e, T value)
+    {
+        auto tail_off = tail_offset();
+        auto ts       = size - tail_off;
+        if (ts < branches<BL>) {
+            ensure_mutable_tail(e, ts);
+            new (&tail->leaf()[ts]) T{std::move(value)};
+        } else {
+            auto new_tail = node_t::make_leaf_e(e, std::move(value));
+            try {
+                if (tail_off == size_t{branches<B>} << shift) {
+                    auto new_root = node_t::make_inner_e(e);
+                    try {
+                        auto path = node_t::make_path_e(e, shift, tail);
+                        new_root->inner()[0] = root;
+                        new_root->inner()[1] = path;
+                        root                 = new_root;
+                        tail                 = new_tail;
+                        shift += B;
+                    } catch (...) {
+                        node_t::delete_inner_e(new_root);
+                        throw;
+                    }
+                } else if (tail_off) {
+                    auto new_root =
+                        make_regular_sub_pos(root, shift, tail_off)
+                            .visit(push_tail_mut_visitor<node_t>{}, e, tail);
+                    root = new_root;
+                    tail = new_tail;
+                } else {
+                    auto new_root = node_t::make_path_e(e, shift, tail);
+                    assert(tail_off == 0);
+                    dec_empty_regular(root);
+                    root = new_root;
+                    tail = new_tail;
+                }
+            } catch (...) {
+                node_t::delete_leaf(new_tail, 1);
+                throw;
+            }
+        }
+        ++size;
+    }
+
+    rbtree push_back(T value) const
+    {
+        auto tail_off = tail_offset();
+        auto ts       = size - tail_off;
+        if (ts < branches<BL>) {
+            auto new_tail =
+                node_t::copy_leaf_emplace(tail, ts, std::move(value));
+            return {size + 1, shift, root->inc(), new_tail};
+        } else {
+            auto new_tail = node_t::make_leaf_n(1, std::move(value));
+            try {
+                if (tail_off == size_t{branches<B>} << shift) {
+                    auto new_root = node_t::make_inner_n(2);
+                    try {
+                        auto path            = node_t::make_path(shift, tail);
+                        new_root->inner()[0] = root;
+                        new_root->inner()[1] = path;
+                        root->inc();
+                        tail->inc();
+                        return {size + 1, shift + B, new_root, new_tail};
+                    } catch (...) {
+                        node_t::delete_inner(new_root, 2);
+                        throw;
+                    }
+                } else if (tail_off) {
+                    auto new_root =
+                        make_regular_sub_pos(root, shift, tail_off)
+                            .visit(push_tail_visitor<node_t>{}, tail);
+                    tail->inc();
+                    return {size + 1, shift, new_root, new_tail};
+                } else {
+                    auto new_root = node_t::make_path(shift, tail);
+                    tail->inc();
+                    return {size + 1, shift, new_root, new_tail};
+                }
+            } catch (...) {
+                node_t::delete_leaf(new_tail, 1);
+                throw;
+            }
+        }
+    }
+
+    const T* array_for(size_t index) const
+    {
+        return descend(array_for_visitor<T>(), index);
+    }
+
+    T& get_mut(edit_t e, size_t idx)
+    {
+        auto tail_off = tail_offset();
+        if (idx >= tail_off) {
+            ensure_mutable_tail(e, size - tail_off);
+            return tail->leaf()[idx & mask<BL>];
+        } else {
+            return make_regular_sub_pos(root, shift, tail_off)
+                .visit(get_mut_visitor<node_t>{}, idx, e, &root);
+        }
+    }
+
+    const T& get(size_t index) const
+    {
+        return descend(get_visitor<T>(), index);
+    }
+
+    const T& get_check(size_t index) const
+    {
+        if (index >= size)
+            throw std::out_of_range{"index out of range"};
+        return descend(get_visitor<T>(), index);
+    }
+
+    const T& front() const { return get(0); }
+
+    const T& back() const { return tail->leaf()[(size - 1) & mask<BL>]; }
+
+    template <typename FnT>
+    void update_mut(edit_t e, size_t idx, FnT&& fn)
+    {
+        auto& elem = get_mut(e, idx);
+        elem       = std::forward<FnT>(fn)(std::move(elem));
+    }
+
+    template <typename FnT>
+    rbtree update(size_t idx, FnT&& fn) const
+    {
+        auto tail_off = tail_offset();
+        if (idx >= tail_off) {
+            auto tail_size = size - tail_off;
+            auto new_tail =
+                make_leaf_sub_pos(tail, tail_size)
+                    .visit(update_visitor<node_t>{}, idx - tail_off, fn);
+            return {size, shift, root->inc(), new_tail};
+        } else {
+            auto new_root = make_regular_sub_pos(root, shift, tail_off)
+                                .visit(update_visitor<node_t>{}, idx, fn);
+            return {size, shift, new_root, tail->inc()};
+        }
+    }
+
+    void assoc_mut(edit_t e, size_t idx, T value)
+    {
+        update_mut(e, idx, [&](auto&&) { return std::move(value); });
+    }
+
+    rbtree assoc(size_t idx, T value) const
+    {
+        return update(idx, [&](auto&&) { return std::move(value); });
+    }
+
+    rbtree take(size_t new_size) const
+    {
+        auto tail_off = tail_offset();
+        if (new_size == 0) {
+            return empty();
+        } else if (new_size >= size) {
+            return *this;
+        } else if (new_size > tail_off) {
+            auto new_tail = node_t::copy_leaf(tail, new_size - tail_off);
+            return {new_size, shift, root->inc(), new_tail};
+        } else {
+            using std::get;
+            auto l = new_size - 1;
+            auto v = slice_right_visitor<node_t>();
+            auto r = make_regular_sub_pos(root, shift, tail_off).visit(v, l);
+            auto new_shift = get<0>(r);
+            auto new_root  = get<1>(r);
+            auto new_tail  = get<3>(r);
+            if (new_root) {
+                IMMER_ASSERT_TAGGED(new_root->compute_shift() == get<0>(r));
+                assert(new_root->check(new_shift, new_size - get<2>(r)));
+                return {new_size, new_shift, new_root, new_tail};
+            } else {
+                return {new_size, BL, empty().root->inc(), new_tail};
+            }
+        }
+    }
+
+    void take_mut(edit_t e, size_t new_size)
+    {
+        auto tail_off = tail_offset();
+        if (new_size == 0) {
+            // todo: more efficient?
+            *this = empty();
+        } else if (new_size >= size) {
+            return;
+        } else if (new_size > tail_off) {
+            auto ts    = size - tail_off;
+            auto newts = new_size - tail_off;
+            if (tail->can_mutate(e)) {
+                destroy_n(tail->leaf() + newts, ts - newts);
+            } else {
+                auto new_tail = node_t::copy_leaf_e(e, tail, newts);
+                dec_leaf(tail, ts);
+                tail = new_tail;
+            }
+            size = new_size;
+            return;
+        } else {
+            using std::get;
+            auto l = new_size - 1;
+            auto v = slice_right_mut_visitor<node_t>();
+            auto r = make_regular_sub_pos(root, shift, tail_off).visit(v, l, e);
+            auto new_shift = get<0>(r);
+            auto new_root  = get<1>(r);
+            auto new_tail  = get<3>(r);
+            if (new_root) {
+                root  = new_root;
+                shift = new_shift;
+            } else {
+                root  = empty().root->inc();
+                shift = BL;
+            }
+            dec_leaf(tail, size - tail_off);
+            size = new_size;
+            tail = new_tail;
+            return;
+        }
+    }
+
+    bool check_tree() const
+    {
+#if IMMER_DEBUG_DEEP_CHECK
+        assert(shift >= BL);
+        assert(tail_offset() <= size);
+        assert(check_root());
+        assert(check_tail());
+#endif
+        return true;
+    }
+
+    bool check_tail() const
+    {
+#if IMMER_DEBUG_DEEP_CHECK
+        if (tail_size() > 0)
+            assert(tail->check(0, tail_size()));
+#endif
+        return true;
+    }
+
+    bool check_root() const
+    {
+#if IMMER_DEBUG_DEEP_CHECK
+        if (tail_offset() > 0)
+            assert(root->check(shift, tail_offset()));
+        else {
+            IMMER_ASSERT_TAGGED(root->kind() == node_t::kind_t::inner);
+            assert(shift == BL);
+        }
+#endif
+        return true;
+    }
+};
+
+} // namespace rbts
+} // namespace detail
+} // namespace immer