dolphin/Source/Core/Common/Assembler/CaseInsensitiveDict.h
2024-10-09 17:26:10 -07:00

127 lines
3 KiB
C++

// Copyright 2023 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <array>
#include <optional>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
#include <vector>
namespace Common::GekkoAssembler::detail
{
// Hacky implementation of a case insensitive alphanumeric trie supporting extended entries
// Standing in for std::map to support case-insensitive lookups while allowing string_views in
// lookups
template <typename V, char... ExtraMatches>
class CaseInsensitiveDict
{
public:
CaseInsensitiveDict(const std::initializer_list<std::pair<std::string_view, V>>& il)
{
for (auto&& [k, v] : il)
{
Add(k, v);
}
}
template <typename T>
V const* Find(const T& key) const
{
auto&& [last_e, it] = TryFind(key);
if (it == key.cend() && last_e->_val)
{
return &*last_e->_val;
}
return nullptr;
}
static constexpr size_t NUM_CONNS = 36 + sizeof...(ExtraMatches);
static constexpr uint32_t INVALID_CONN = static_cast<uint32_t>(-1);
private:
struct TrieEntry
{
std::array<uint32_t, 36 + sizeof...(ExtraMatches)> _conns;
std::optional<V> _val;
TrieEntry() { _conns.fill(INVALID_CONN); }
};
constexpr size_t IndexOf(char c) const
{
size_t idx;
if (std::isalpha(c))
{
idx = std::tolower(c) - 'a';
}
else if (std::isdigit(c))
{
idx = c - '0' + 26;
}
else
{
idx = 36;
// Expands to an equivalent for loop over ExtraMatches
if constexpr (sizeof...(ExtraMatches) > 0)
{
(void)((c != ExtraMatches ? ++idx, true : false) && ...);
}
}
return idx;
}
template <typename T>
auto TryFind(const T& key) const -> std::pair<TrieEntry const*, decltype(key.cbegin())>
{
std::pair<TrieEntry const*, decltype(key.cbegin())> ret(&m_root_entry, key.cbegin());
const auto k_end = key.cend();
for (; ret.second != k_end; ret.second++)
{
const size_t idx = IndexOf(*ret.second);
if (idx >= NUM_CONNS || ret.first->_conns[idx] == INVALID_CONN)
{
break;
}
ret.first = &m_entry_pool[ret.first->_conns[idx]];
}
return ret;
}
template <typename T>
auto TryFind(const T& key) -> std::pair<TrieEntry*, decltype(key.cbegin())>
{
auto&& [e_const, it] =
const_cast<CaseInsensitiveDict<V, ExtraMatches...> const*>(this)->TryFind(key);
return {const_cast<TrieEntry*>(e_const), it};
}
void Add(std::string_view key, const V& val)
{
auto&& [last_e, it] = TryFind(key);
if (it != key.cend())
{
for (; it != key.cend(); it++)
{
const size_t idx = IndexOf(*it);
if (idx >= NUM_CONNS)
{
break;
}
last_e->_conns[idx] = static_cast<uint32_t>(m_entry_pool.size());
last_e = &m_entry_pool.emplace_back();
}
}
last_e->_val = val;
}
TrieEntry m_root_entry;
std::vector<TrieEntry> m_entry_pool;
};
} // namespace Common::GekkoAssembler::detail