1 files changed, 166 insertions, 0 deletions
diff --git a/subprojects/boost-sqlite/include/boost/sqlite/detail/aggregate_function.hpp b/subprojects/boost-sqlite/include/boost/sqlite/detail/aggregate_function.hpp
new file mode 100644
index 0000000..de0c447
--- /dev/null
+++ b/subprojects/boost-sqlite/include/boost/sqlite/detail/aggregate_function.hpp
@@ -0,0 +1,166 @@
+// Copyright (c) 2023 Klemens D. Morgenstern
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#ifndef BOOST_SQLITE_DETAIL_AGGREGATE_FUNCTION_HPP
+#define BOOST_SQLITE_DETAIL_AGGREGATE_FUNCTION_HPP
+
+#include <boost/sqlite/detail/config.hpp>
+#include <boost/sqlite/detail/catch.hpp>
+#include <boost/sqlite/error.hpp>
+#include <boost/sqlite/cstring_ref.hpp>
+#include <boost/sqlite/memory.hpp>
+#include <boost/sqlite/result.hpp>
+#include <boost/sqlite/value.hpp>
+
+#include <boost/callable_traits/args.hpp>
+#include <boost/callable_traits/return_type.hpp>
+#include <boost/callable_traits/has_void_return.hpp>
+#include <boost/core/span.hpp>
+
+
+BOOST_SQLITE_BEGIN_NAMESPACE
+
+namespace detail
+{
+
+template<typename Func>
+struct aggregate_function_maker
+{
+  void * mem;
+
+  template<typename ... Args>
+  Func* operator()(Args && ... args)
+  {
+    return new (mem) Func(std::forward<Args>(args)...);
+  }
+};
+
+template<typename Func, typename Args>
+int create_aggregate_function(sqlite3 * db, cstring_ref name, Args && args, int flags,
+                              std::true_type /* void return */)
+{
+  using args_type    = callable_traits::args_t<decltype(&Func::step)>;
+  using span_type    = typename std::tuple_element<1U, args_type>::type;
+  using func_type    = typename std::decay<Func>::type;
+  using func_args_type    = typename std::decay<Args>::type;
+
+  return sqlite3_create_function_v2(
+      db, name.c_str(),
+      span_type::extent == boost::dynamic_extent ? -1 : static_cast<int>(span_type::extent),
+      SQLITE_UTF8 | flags,
+      new (memory_tag{}) func_args_type(std::forward<Args>(args)),
+      nullptr,
+      +[](sqlite3_context* ctx, int len, sqlite3_value** args)
+      {
+        auto aa =  reinterpret_cast<value*>(args);
+        auto fa = reinterpret_cast<func_args_type*>(sqlite3_user_data(ctx));
+        auto c = static_cast<func_type*>(sqlite3_aggregate_context(ctx, 0));
+
+        execute_context_function(
+            ctx,
+            [&]() -> result<void>
+            {
+              if (c == nullptr)
+              {
+                auto p = sqlite3_aggregate_context(ctx, sizeof(func_type));
+                if (!p)
+                  return error(SQLITE_NOMEM);
+                c = mp11::tuple_apply(aggregate_function_maker<func_type>{p}, *fa);
+              }
+              c->step(span_type{aa, static_cast<std::size_t>(len)});
+              return {};
+            });
+      },
+      [](sqlite3_context* ctx)
+      {
+        auto fa = reinterpret_cast<func_args_type*>(sqlite3_user_data(ctx));
+        auto c = static_cast<func_type*>(sqlite3_aggregate_context(ctx, 0));
+
+        execute_context_function(
+            ctx,
+            [&]() -> result<decltype(c->final())>
+            {
+              if (c == nullptr)
+              {
+                auto p = sqlite3_aggregate_context(ctx, sizeof(func_type));
+                if (!p)
+                  return error(SQLITE_NOMEM);
+                c = mp11::tuple_apply(aggregate_function_maker<func_type>{p}, *fa);
+              }
+              struct reaper {void operator()(func_type * c) { c->~func_type();}};
+              std::unique_ptr<func_type, reaper> cl{c};
+              return c->final();
+            });
+      },
+      [](void * ptr) noexcept { delete_(static_cast<func_type*>(ptr));}
+  );
+}
+
+
+template<typename Func, typename Args>
+int create_aggregate_function(sqlite3 * db, cstring_ref name, Args && args, int flags,
+                              std::false_type /* void return */)
+{
+  using args_type    = callable_traits::args_t<decltype(&Func::step)>;
+  using span_type    = typename std::tuple_element<1U, args_type>::type;
+  using func_type    = typename std::decay<Func>::type;
+  using func_args_type    = typename std::decay<Args>::type;
+
+  return sqlite3_create_function_v2(
+      db, name.c_str(),
+      span_type::extent == boost::dynamic_extent ? -1 : static_cast<int>(span_type::extent),
+      SQLITE_UTF8 | flags,
+      new (memory_tag{}) func_args_type(std::forward<Args>(args)),
+      nullptr,
+      +[](sqlite3_context* ctx, int len, sqlite3_value** args)
+      {
+        auto aa =  reinterpret_cast<value*>(args);
+        auto fa = reinterpret_cast<func_args_type*>(sqlite3_user_data(ctx));
+        auto c = static_cast<func_type*>(sqlite3_aggregate_context(ctx, 0));
+
+        execute_context_function(
+            ctx,
+            [&]() -> result<void>
+            {
+              if (c == nullptr)
+              {
+                auto p = sqlite3_aggregate_context(ctx, sizeof(func_type));
+                if (!p)
+                  return {system::in_place_error, error(SQLITE_NOMEM)};
+                c = mp11::tuple_apply(aggregate_function_maker<func_type>{p}, *fa);
+              }
+              return c->step(span_type{aa, static_cast<std::size_t>(len)});
+            });
+      },
+      [](sqlite3_context* ctx)
+      {
+        auto fa = reinterpret_cast<func_args_type*>(sqlite3_user_data(ctx));
+        auto c = static_cast<func_type*>(sqlite3_aggregate_context(ctx, 0));
+
+        execute_context_function(
+            ctx,
+            [&]() -> result<decltype(c->final())>
+            {
+              if (c == nullptr)
+              {
+                auto p = sqlite3_aggregate_context(ctx, sizeof(func_type));
+                if (!p)
+                  return {system::in_place_error, error(SQLITE_NOMEM)};
+                c = mp11::tuple_apply(aggregate_function_maker<func_type>{p}, *fa);
+              }
+              struct reaper {void operator()(func_type * c) { c->~func_type();}};
+              std::unique_ptr<func_type, reaper> cl{c};
+              return c->final();
+            });
+      },
+      [](void * ptr) noexcept { delete_(static_cast<func_type*>(ptr));}
+  );
+}
+
+}
+
+BOOST_SQLITE_END_NAMESPACE
+
+
+#endif //BOOST_SQLITE_DETAIL_AGGREGATE_FUNCTION_HPP