ump->midi1 WIP

Author: paulhuggett

.gitignore

@@ -1,3 +1,31 @@
-/.idea/
-/cmake-build-debug/
+# Backup files
 *~
+
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app

CMakeLists.txt

@@ -26,16 +26,19 @@ set(INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/include")
 set(MIDI2_HEADERS
   "${INCLUDE_DIR}/midi2/bitfield.hpp"
   "${INCLUDE_DIR}/midi2/bytestream_to_ump.hpp"
+  "${INCLUDE_DIR}/midi2/cache.hpp"
   "${INCLUDE_DIR}/midi2/ci7text.hpp"
+  "${INCLUDE_DIR}/midi2/ci_create_message.hpp"
+  "${INCLUDE_DIR}/midi2/ci_dispatcher.hpp"
   "${INCLUDE_DIR}/midi2/ci_types.hpp"
   "${INCLUDE_DIR}/midi2/fifo.hpp"
+  "${INCLUDE_DIR}/midi2/iumap.hpp"
+  "${INCLUDE_DIR}/midi2/lru_list.hpp"
   "${INCLUDE_DIR}/midi2/mcoded7.hpp"
-  "${INCLUDE_DIR}/midi2/ci_create_message.hpp"
-  "${INCLUDE_DIR}/midi2/ci_dispatcher.hpp"
   "${INCLUDE_DIR}/midi2/ump_dispatcher.hpp"
-  "${INCLUDE_DIR}/midi2/ump_types.hpp"
   "${INCLUDE_DIR}/midi2/ump_to_bytestream.hpp"
   "${INCLUDE_DIR}/midi2/ump_to_midi1.hpp"
+  "${INCLUDE_DIR}/midi2/ump_types.hpp"
   "${INCLUDE_DIR}/midi2/utils.hpp"
 )
 

include/midi2/cache.hpp

@@ -0,0 +1,82 @@
+//
+//  cache.hpp
+//  hasht
+//
+//  Created by Paul Bowen-Huggett on 24/10/2024.
+//
+
+#ifndef CACHE_HPP
+#define CACHE_HPP
+
+#include <cassert>
+#include <cstddef>
+#include <ostream>
+#include <utility>
+
+#include "iumap.hpp"
+#include "lru_list.hpp"
+
+template <typename Key, typename Mapped, std::size_t Size> class cache {
+public:
+  using key_type = Key;
+  using mapped_type = Mapped;
+  using value_type = std::pair<key_type, mapped_type>;
+
+  mapped_type *find(key_type const &k);
+  bool set(key_type const &k, mapped_type const &v);
+
+  void dump(std::ostream &os) {
+    lru.dump(os);
+    h.dump(os);
+  }
+
+private:
+  using lru_container = lru_list<value_type, Size>;
+
+  lru_container lru;
+  iumap<Key const, typename decltype(lru)::node *, Size> h;
+};
+
+template <typename Key, typename Mapped, std::size_t Size>
+auto cache<Key, Mapped, Size>::find(key_type const &k) -> mapped_type * {
+  auto const pos = h.find(k);
+  if (pos == h.end()) {
+    return nullptr;
+  }
+  auto *const node = pos->second;
+  lru.touch(*node);
+  assert(lru.size() == h.size());
+  return &(static_cast<value_type &>(*node).second);
+}
+
+template <typename Key, typename Mapped, std::size_t Size>
+bool cache<Key, Mapped, Size>::set(key_type const &k, mapped_type const &v) {
+  auto pos = h.find(k);
+  if (pos == h.end()) {
+    auto const fn = [this](value_type &kvp) {
+      // delete the key being evicted from the LUR-list from the hash table so that
+      // they always match.
+      if (auto const evict_pos = this->h.find(kvp.first); evict_pos != this->h.end()) {
+        this->h.erase(evict_pos);
+      }
+    };
+    h.insert(std::make_pair(k, &lru.add(std::make_pair(k, v), fn)));
+    assert(lru.size() == h.size());
+    return false;
+  }
+
+  // The key _was_ found in the cache.
+  typename lru_container::node &lru_entry = *pos->second;
+  lru.touch(lru_entry);
+  auto &cached_value = static_cast<value_type &>(lru_entry).second;
+  if (cached_value == v) {
+    // The key was in the cache and the values are equal.
+    assert(lru.size() == h.size());
+    return true;
+  }
+  cached_value = v;
+  assert(lru.size() == h.size());
+  return false;
+}
+
+#endif  // CACHE_HPP