Make the normal mode keymap a compile time hash map

This hash map is now fully constexpr, and ends up stored in the read
only data segment instead of being recomputed at each startup.

1 files changed, 44 insertions, 0 deletions

diff --git a/src/meta.hh b/src/meta.hh
index 2126d4f4..aa84b8a4 100644
--- a/src/meta.hh
+++ b/src/meta.hh
@@ -37,6 +37,50 @@ constexpr Array<T, N> make_array(const T (&data)[N])
     return make_array(data, std::make_index_sequence<N>());
 }
 
+template<typename T, size_t capacity>
+struct ConstexprVector
+{
+    using iterator = T*;
+    using const_iterator = const T*;
+
+    constexpr ConstexprVector() : m_size{0} {}
+    constexpr ConstexprVector(std::initializer_list<T> items)
+        : m_size{items.size()}
+    {
+        T* ptr = m_data;
+        for (auto& item : items)
+            *ptr++ = std::move(item);
+    }
+
+    constexpr bool empty() const { return m_size == 0; }
+    constexpr size_t size() const { return m_size; }
+
+    constexpr void resize(size_t n, const T& val)
+    {
+        if (n >= capacity)
+            throw "capacity exceeded";
+        if (n > m_size)
+        {
+            for (int i = n; i < m_size; ++i)
+                m_data[i] = val;
+        }
+        m_size = n;
+        kak_assert(this->size() == m_size);
+    }
+
+    constexpr T& operator[](size_t i) { return m_data[i]; }
+    constexpr const T& operator[](size_t i) const { return m_data[i]; }
+
+    constexpr iterator begin() { return m_data; }
+    constexpr iterator end() { return m_data + m_size; }
+
+    constexpr const_iterator begin() const { return m_data; }
+    constexpr const_iterator end() const { return m_data + m_size; }
+
+    size_t m_size;
+    T m_data[capacity] = {};
+};
+
 }
 
 #endif // meta_hh_INCLUDED