Initial commit

helloalloc.cpp

@@ -0,0 +1,71 @@
+#include <set>
+#include "fmt/format.h"
+
+namespace sky {
+constexpr std::size_t address_size = 3;
+constexpr std::size_t payload_size = 15;
+using address_t = uint8_t[address_size];
+using payload_t = uint8_t[payload_size];
+
+auto mcp_u32_to_address(address_t& dest, std::uint32_t const& addr) -> void {
+    dest[0] = static_cast<std::uint8_t>((addr & 0x000000FF) >>  0);
+    dest[1] = static_cast<std::uint8_t>((addr & 0x0000FF00) >>  8);
+    dest[2] = static_cast<std::uint8_t>((addr & 0x00FF0000) >> 16);
+}
+}
+
+template <typename T, std::size_t N>
+class FixedSizeAllocator {
+public:
+    using value_type   = T;
+    using pointer_type = T*;
+    using size_type    = std::size_t;
+
+    FixedSizeAllocator() : m_used_size(0) {}
+
+    auto operator()(const T& lhs, const T& rhs) const -> bool {
+        return lhs < rhs;
+    }
+
+    auto allocate(size_type n) -> pointer_type {
+        if (m_used_size + n > N) throw std::bad_alloc();
+
+        T* result = std::reinterpret_pointer_cast<value_type>(&m_pool[m_used_size]);
+        m_used_size += n;
+        return result;
+    }
+
+    auto deallocate(pointer_type ptr, size_type n) -> void {
+        if (ptr != &m_pool[m_used_size - n])
+            throw std::logic_error("Deallocating out of order");
+        m_used_size -= n;
+    }
+
+private:
+    std::uint8_t m_pool[N]{};
+    std::size_t  m_used_size;
+};
+
+auto main() -> int {
+    std::set<std::uint32_t, FixedSizeAllocator<std::uint32_t , 1024>> hello{};
+
+    std::uint32_t addr1_u32 = 32;
+    std::uint32_t addr2_u32 = 64;
+    std::uint32_t addr3_u32 = 128;
+    std::uint32_t addr4_u32 = 256;
+
+    hello.insert(addr1_u32);
+    hello.insert(addr2_u32);
+    hello.insert(addr3_u32);
+    hello.insert(addr4_u32);
+    hello.insert(addr1_u32);
+    hello.insert(addr1_u32);
+
+    for (auto const& addr : hello) {
+        sky::address_t buffer;
+        sky::mcp_u32_to_address(buffer, addr);
+        fmt::print("{:#04x}:{:#04x}:{:#04x}\n", buffer[2], buffer[1], buffer[0]);
+    }
+
+    return 0;
+}