General Purpose library for Freestanding C++ and POSIX systems
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#pragma once
#include <gp/algorithms/sort.hpp>
#include <gp/containers/array.hpp>
#include <gp/math/integral.hpp>
#include <gp/utils/iterator.hpp>
#include <gp/functional/optional.hpp>
// UNIMPLEMENTED: see filename
namespace gp {
namespace ordinators {
struct less {
template<typename T>
bool operator() (const T& lhs, const T& rhs){
return lhs < rhs;
}
};
}
/**
* @brief
*
* @tparam T The type to store, must be either final or primitive
* @tparam capacity The number of elements that can be stored in the structure
*/
template<typename T, size_t capacity, typename ordinator = gp::ordinators::less>
class flat_tree {
using node_t = gp::optional<T>;
gp::array<node_t, capacity> data_;
static void ordain(auto destination_space, auto value_workspace, index_to_1 idx) {
if(!value_workspace.size()) return;
size_t pivot;
if(value_workspace.size()%2) {
pivot = value_workspace.size()/2 + 1;
} else {
pivot = value_workspace.size()/2;
}
destination_space[idx] = gp::move(value_workspace[pivot]);
auto left = idx;
left.left();
ordain(destination_space, value_workspace.slice_start(pivot), left);
auto right = idx;
right.right();
ordain(destination_space, value_workspace.trim_start(pivot+1), left);
};
public:
using iterator = gp::flat_tree_iterator<flat_tree, T, 1>;
using riterator = gp::flat_tree_iterator<flat_tree, T, -1>;
friend iterator;
friend riterator;
flat_tree(auto data) {
gp_config::assertion(data.size() <= data_.size(), "Couldn't construct flat tree from C array");
for(auto v : data) {
insert(v);
}
}
bool insert(T& value) {
index_to_1 idx(0);
while(idx < data_.size() && data()[idx].has_value()) {
if(ordinator()(data()[idx].value(), value)) {
idx.left();
} else {
idx.right();
}
}
if (idx >= data_.size()) [[unlikely]] {
if(rebalance_with_value(value)) return true;
if constexpr (gp_config::has_exceptions) {
}
return false;
}
data()[idx] = value;
return true;
}
/**
* @brief Rebalance the tree
*
* @param value The value to try to push along with the rebalance
*
* @return true if the operation suceeded
* @return false if the operation failed
*/
bool rebalance_with_value(T& value) {
// TODO: Add constant memory shenanigans
/*
auto workspace = data_.as_buffer();
bool ok = false;
for(auto& elem : workspace) {
if(!elem.has_value()) {
ok = true;
break;
}
}
if(!ok) return false;
gp::sort(workspace.begin(), workspace.end(), [](const node_t& lhs, const node_t& rhs){ return lhs.has_value() > rhs.has_value(); });
size_t cnt = 0;
for(auto& elem : workspace) {
if(elem.has_value()) break;
++cnt;
}
--cnt;
workspace[cnt] = value;
auto value_workspace = workspace.trim_start(cnt);
gp::sort(value_workspace.begin(), value_workspace.end(), [](const node_t& lhs, const node_t& rhs){ return ordinator(lhs.value(), rhs.value()); });
auto destination_space = workspace.slice_start(value_workspace.size());
for(auto )
*/
auto oth = gp::move(data_);
auto workspace = oth.as_buffer();
bool ok = false;
for(auto& elem : workspace) {
if(!elem.has_value()) {
ok = true;
break;
}
}
if(!ok) return false;
gp::sort(workspace.begin(), workspace.end(), [](const node_t& lhs, const node_t& rhs){ return lhs.has_value() > rhs.has_value(); });
size_t cnt = 0;
for(auto& elem : workspace) {
if(elem.has_value()) break;
++cnt;
}
--cnt;
workspace[cnt] = value;
auto value_workspace = workspace.trim_start(cnt);
gp::sort(value_workspace.begin(), value_workspace.end(), [](const node_t& lhs, const node_t& rhs){ return ordinator()(lhs.value(), rhs.value()); });
auto destination_space = workspace.slice_start(value_workspace.size());
ordain(destination_space, value_workspace, 0);
return true;
}
iterator begin() {
return ++iterator{.tree = *this, .index = (size_t)-1};
}
iterator end() {
return iterator{.tree = *this, .index = (size_t)-1};
}
auto data() {
return data_.as_buffer();
}
};
}